Antenna Cable Adapters are specialized radio frequency connector components that facilitate compatibility between different sizes, classes, genders, and polarity of RF connectors. They are passive components that facilitate the transmission of megahertz to gigahertz frequency RF signals via connected cables. The use of coaxial connector adapters is widespread including radio devices and components like antennas, GPS receivers, surge protectors, and test and measurement devices.

This expansive range of RF adapters are designed and precision manufactured to provide the required transition in connector class or gender without creating discontinuities or steps in impedance that would compromise the performance of the radio frequency circuit they are connected to.

Each end of the coaxial cable connector adapter can mate with its complementary connector meaning that an in-line connection can be made between antenna cables, antennas, or other components that are terminated with RF connectors that normally would be unable to be directly mated.

Adapters are diverse and have a broad range of combinations. Types of connections that can be created with these adapters span:

  • Screw-coupling

  • Snap-on coupling

  • Bayonet-coupling

There are three main types of antenna cable adapter:

  1. In series RF-adapters can connect with RF connectors of the same type or series at both ends. For example, N-Type connector adapters carry N-Type connectors at both ends. In series connectors usually provide conversion based on gender (e.g. male-female, female-female, male-male). They may also be described as gender-changing adapters.

  2. Between series adapters can create a connection between two radio frequency connectors of different types or classes, for example, an RP-SMA to N adapter or a BNC to N adapter. The electrical connections between the different interfaces on the adapter are carefully machined to keep signal loss to a minimum as the adapter structurally transitions between its two connector types.

  3. Pigtail adapters connect a micro-miniature or miniature RF connector to a connector of a larger class via a short length of low-loss coaxial cable. They are typically used with U.FL or MMCX connectors and facilitate a connection between a PCB mounted connector and a standard sized connector which may not be able to fit in a densely packed environment. They also spare a micro-miniature connector class from being repeatedly re-mated as the larger and more robust connector can be used.

Adapters can also have straight or angled configurations as well as a bulkhead feature for panel mounting or silicone gaskets for robust ingress protection.

The quality of antenna cable adapters affects the performance of the radio frequency circuit they are in

These in-line RF adapters are precision-manufactured to keep non-linearities to a minimum. Mismatching in a line introduced by a poorly machined or matched adapter will generate discontinuities. These are step changes in impedance along the line and can be caused by changes in adapter diameter, insulator diameter, changes in interface dimension, or defects and gaps in the adapter. This means that when a signal travels down the line through the adapter, reflected traveling waves propagate that contribute to signal loss in the forward direction. Careful machining also prevents Passive Intermodulation (PIM), where two or more fundamental frequencies are present in the RF circuit.

RoHS compliant RF connector adapters

Our range of antenna cable adapters is manufactured to the highest standards with quality materials of good provenance. We ensure that all of the RF connector adapters supplied and distributed by our company comply with the Restriction of Hazardous Substances (RoHS) directive. This EU directive and its domestic equivalents, set limits on the inclusion of hazardous substances such as lead, cadmium, and mercury in electrical and electronic equipment (EEE).

The RF connector adapters also comply with Federal and international legislation regarding conflict minerals, in particular, The Conflict Minerals Regulation and Section 1502 of the Dodd-Frank Act. These laws prohibit the use of the key metals Tantalum, Tungsten, Tin, and Gold that are sourced from areas of conflict or forced labor, being used in the electronics sector.

Quality antenna cable adapters cover all the major RF connector classes

Our range of coaxial adapters covers all the main 50 and 75 Ohm applications with either in-series or between series RF interfaces. Here are the most commonly used interfaces for antenna cable adapters:

[A] SMA adapters

SMA adapters feature an SMA connector as one or both of the connector interfaces on the adapter.

About the SMA connector

The SMA connector is a Sub-Miniature type A coaxial connector. This semi-precision connector was designed in the 1960s and has since become which is widely used in telecommunications and electronics. Its compact design makes it suitable for use in small spaces and its screw coupling mating mechanism forms a secure connection that is resistant to vibrations and jolts. SMA connectors are hard-wearing and rated for at least 500 mating cycles.

Key physical features of the SMA connector

The SMA connector consists of male and female connectors that carry 36 threads per inch, threading. Both connectors are made of either stainless steel, nickel, or gold-plated brass.

  • The diameter of the male SMA connector is 11 millimeters (0.433 inches) is a barrel-shaped connector with internalized threads. The male connector also has an external hex nut for tightening the connector when it is mated. The mating interface of the male SMA connector carries a brass center pin surrounded by a Teflon dielectric.

  • The female SMA connector is slightly small with a diameter of 9.5 millimeters (0/374 inches). The mating interface consists of a beryllium copper receptacle surrounded by a Teflon insulator.

Electrical specifications of the SMA connector

This is a 50-Ohm connector that supports microwave frequencies up to a maximum frequency of 18 GHz.Its Voltage Standing Wave Ratio is between 1.05 and 1.2.

The SMA connector has exemplary power handling and has a voltage rating of 500 volts. The maximum radio frequency leakage of the standard connector is -90 dB/min at 2-3 GHz, but this may vary with adapters.

Applications of SMA adapters

The applications of SMA adapters are determined largely by the applications for the SMA connector. Though initially developed for the defense, aerospace, radio astronomy, and Testing and Measurement sectors, in contemporary times the SMA connector has become much more prevalent in use in cellular telecommunications, radio navigation (including GPS), and wireless networking, being used often for sub-6 GHz frequencies.

Available SMA adapter configurations include

  • SMA female to SMA male adapter - This and other gender combinations allow the correct mating between SMA antennas, cables, and radio equipment.

  • Right angle SMA male to SMA female adapter - The right-angle geometry is space-saving in a range of applications. The attached cable also projects straight down and is less likely to become damaged.

  • SMA female to SMA female bulkhead adapter - This bulkhead connector is used with an L antenna mount to connect an SMA connector antenna and antenna cable.

  • SMA male to RP-SMA male adapter - As the RP-SMA connector is widely used in wireless networking, this adapter supports the connection of SMA antennas and cable to routers and other equipment.

  • SMA female to TNC male adapter - This adapter supports an electrically competent connection to a larger caliber connector.

  • SMA male to FME male adapter -This adapter provides a useful step-down in size (without compromising the robust threaded connection) to the smaller, threaded FME connector that is often used in vehicles and boats.

  • SMA male to Type N male adapter - The N connector can be used for mounting or connecting in-line components like surge protection devices.

  • SMA female to U.FL adapter - this connection is used to facilitate the connection of an SMA antenna to a PCB. It is not designed for repeated mating cycles.

  • SMA female to BNC female adapter - This adapter can make key connections in testing and measurement equipment and panel mounted connector arrangements.

[B] RP SMA adapters

Reverse Polarity or RP SMA adapters carry an RP-SMA connector as one or both of the connector interfaces of the adapter.

About the RP-SMA connector

The RP-SMA connector is a variant of the standard SMA connector. It was developed in the late 1990s as part of a strategy to prevent consumers from connecting powerful industry antennas to consumer wireless networking gear.

Key physical features of the SMA connector

The RP-SMA connector has a deliberate reversal of the inner mating interface of the male and female connectors. In an RP SMA connector, the male connector has a receptacle and the female connector carries a pin. This arrangement makes RP-SMA connectors electrically incompatible with SMA connectors as they cannot properly mate.

Like the SMA connector, the RP-SMA connector forms a mechanically strong, low signal loss connection by screw-coupling. It is physically identical to the standard SMA connector except for the switched gender of the mating interface.

Electrical specifications of the RP-SMA connector

The RP-SMA connector is a 50-Ohm connector that is widely used for sub-gigahertz and gigahertz frequencies up to 18 GHz. Like the SMA connector its Voltage Standing Wave Ratio is between 1.05 and 1.2, its voltage rating is 500 volts, and its maximum radio frequency leakage is -90 dB/min at 2-3 GHz, but this may vary with adapters.

Applications of RP-SMA adapters

RP-SMA connectors were developed for consumer wireless networking products and they have remained the predominant type of RF connector used in equipment like WiFi routers, access points, and 2.4 and 5 GHz antennas. The SMA and RP-SMA connectors are very easily confused and can only be truly identified by examination of the mating interface. An RP-SMA to SMA adapter can be used to make a competent connection between these two common connector types.

Available RP-SMA adapter configurations include:

  • SMA male to RP-SMA female adapter - This is a popular adapter for correcting matching errors between RP-SMA and SMA antennas and antennas cables.

  • Right angle RP-SMA male to RP-SMA female adapter - This is a compact and space-saving design that does not stress cables. There is also an articulating RP-SMA male to RP-SMA male/female right angle connector that is ideal to use for positioning RP-SMA antennas on a router.

  • RP-SMA female to RP-SMA female bulkhead adapter - This bulkhead connector can be used for mounting RP-SMA antenna and cable securely. The O-rubber or silicone O-ring waterproofs the connections.

  • RP-SMA female to MMCX male adapter - This pigtail adapter provides a reliable step-down in size between the RP-SMA connector and the microminiature MMCX. This adapter can be used to connect an RP-SMA antenna to a PCB.

[C] TNC adapters

Threaded Neil Concelman (TNC) adapters carry a TNC connector as one or both of the connector interfaces of the adapter.

About the TNC connector

The Threaded Neil Concelman connector is a threaded version of the Bayonet Neil Concelman (BNC) connector discussed below. The screw-coupling mating mechanism of this miniature RF connector enhances its performance at microwave frequencies. The mated connection is low-noise, and stable making it ideal for environments where there may be shocks or vibration.

Key physical features of the TNC connector

The connector body is typically made from brass and phosphor bronze and both genders of connector carry 7/16 - 28 UNEF threading.

  • The male TNC connector is larger, with a diameter of 15 millimeters (0.59 inches). It internalized threading and carries a phosphor bronze center pin surrounded by a Teflon insulator.

  • The smaller female TNC connector has a diameter of 9.6 millimeters (0.378 inches). The female connector has a center receptacle, also surrounded by Teflon.

Electrical specifications of the TNC connector

The TNC connector is available with characteristic impedances of 50 and 75 Ohms, so it is important to establish that the impedance of any TNC adapter is used to prevent mismatching. The TNC connector can support gigahertz range frequencies up to 11GHz. Its VSWR is 1.3 and the working voltage is 500 volts. At 2 -3 GHz, the maximum radio frequency leakage is -60 dB/min.

Applications of TNC adapters

TNC adapters are utilized in a range of wireless and telecommunications applications where a robust, stable connection is critical to performance. Because of their ruggedness, and excellent power handling they are also used in industrial, defense, aviation and space market settings.

Available TNC adapter configurations include:

  • TNC male to RP-TNC female adapter - The RP-TNC connector described below is a key miniature connector type used in wireless networking applications. It is structurally similar to the TNC connector but unable to mate with a TNC connector without an adapter.

  • TNC female to SMA female adapter - This is a useful adapter for making connections in cellular networking applications where the SMA connector is widely used.

  • TNC male to N male adapter - This pigtail adapter is ideal for making connections with the N connector that is used in outdoor installations.

  • TNC male to RP-SMA female adapter - The RP-SMA is the predominant connector in consumer wireless applications and so this adapter can be used to make connections with this common connector type.

[D] RP-TNC adapters

Reverse Polarity Threaded Neil Concelman (TNC) adapters make in-series or between series RF connections that include an RP TNC connector.

About the RP-TNC connector

This is a Reverse Polarity (RP) version of the TNC connector that was developed in the late 1990s as a new connector class for use with consumer wireless networking gear. The RP-TNC is structural and electrically identical to the standard TNC connector but reverses the mating interfaces of the male and female TNC connector.

Key physical features of the TNC connector

The reversal of the inner mating interfaces in the RP-TNC connector means:

  • The male RP-TNC connector carries a receptacle rather than the pin in the standard version of the connector.

  • The female RP-TNC connector carries the center pin rather than a receptacle in the standard TNC connector.

Electrical specifications of the RP-TNC connector

The electrical specifications of the 50-Ohm RP-TNC connector are identical to the standard version, making this connector suitable for sub-gigahertz and gigahertz frequencies.

Applications of RP-TNC adapters

RP-TNC adapters are used for wireless networking equipment, similarly to the RP-SMA connector. They can be used to make connections of the same or different class on routers, wireless access points, and antennas.

Available RP-TNC adapter configurations include:

  • RP-TNC male to RP-SMA male adapter - This between series adapter can be used for making a variety of connections in wireless networking.

  • RP-TNC female to SMA female adapter - This useful adapter can be used in telecommunications applications where the SMA connector is widely used.

  • RP-TNC male to N male adapter - The N-Type connector is a large connector that is suited to mount outdoor, weatherproof antennas. This adapter makes RP-TNC connections with this rugged connector type.

[E] BNC adapters

Bayonet Neill Concelman (BNC) adapters are used for making in-series or between series connections that include a BNC connector.

About the BNC connector

The Bayonet Neil Concelman connector is a distinctive RF connector that has a unique bayonet-coupling mechanism. It was developed in the late 1940s from an existing design by Paul Neill and Carl Concelman and contemporary versions deliver consistent performance at microwave frequencies.

Key physical features of the BNC connector

The BNC connector is made from nickel plated brass. The male connector body houses grooves that are designed to twist and snap onto the two lugs of the female connector body. Within the male BNC connector is a gold-plated brass inner conductor pin surrounded by PTFE. The female BNC connector has a gold-plated phosphor bronze receptacle as its mating interface. A silicone rubber gasket waterproofs the mated connection.

Electrical specifications of the BNC connector

The BNC connector is available in both 50 and 75 Ohm versions, meaning that the characteristic impedance of the adapter should be checked before mating to prevent a mismatch. The 50-Ohm connector has a maximum frequency of 4 GHz with a VSWR of 1.3. Its working voltage is 500 volts.

Applications of BNC adapters

The 50-Ohm BNC adapter may be used in radio, testing, and measurement, telecom, and networking applications. A 50-Ohm BNC adapter can be used in analog video applications but not digital video.

Available BNC adapter configurations include:

  • BNC male to RP-SMA male adapter - This between series adapter can be used for making a variety of connections in wireless networking.

  • BNC female to SMA female adapter - This useful adapter can be used in telecommunications applications where the SMA connector is widely used.

[F] N Connector adapters

N connector, N-type, or Type N adapters carry an N connector as one or both of the connector interfaces of the adapter.

About the N connector

This medium-sized, threaded radio frequency connector was designed in the 1940s by Paul Neill of Bell Labs, NY. The N connector was one of the first connectors capable of supporting microwave frequencies and the contemporary version is widely used in the multi-gigahertz range.

The N connector is waterproof and rugged making it suitable for outdoor antenna and networking installations.

Key physical features of the N connector

This cylindrical medium-sized connector has a diameter of 20.3 millimeters (0.827 inches) for the male connector and 15.7 millimeters (0.627 inches) for the female. It has 5/8-24 UNEF pitch threading for secure screw-coupling.

  • The male N connector has a silver or nickel-plated brass body and a gold-plated brass center pin. Its threading is internalized and the body of the connector may carry a hex nut to aid tightening to the correct torque.

  • The female Type N connector (jack) has externalized threads and carries a beryllium copper receptacle.

  • N connectors do not have an insulator but carry a gasket to form an air and watertight seal.

Electrical specifications of the N connector

The N connector has a characteristic impedance of either 50 Ohm or 75 Ohm. It can support frequencies up to a maximum of 11 GHz. It has excellent power handling with a peak voltage rating of 1500 volts. The VSWR of the N connector is 1.35 and the maximum radio frequency leakage at 3 GHz is -90dB per min.

Applications of N connector adapters

The robustness of this connector makes it an advantageous choice for industrial and defense installations where conditions may be harsh. N connectors are used for Satcom and radar, instrumentation and outdoor antenna, and base station installations for wireless and cellular networking. Its exemplary power handling makes the N connector a connector of choice for lightning arrestors and surges protectors. N connector adapters will be used to form competent in-series and between series connections in these settings.

Available N connector adapter configurations include:

  • N female to N female bulkhead adapter - This in-series adapter is advantageous for the safe and secure mounting of N connector antennas. The bulkhead connector can be secured to the mount and the N connector antenna secured to one end and the N connector antenna cable to the other end. The rubber gaskets aid in waterproofing the connection.

  • N male to RP SMA female adapter - This N connector adapter configuration introduces the benefits of the larger and more rugged N connector to wireless networking installations where the RP-SMA connector is common.

[G] U.FL adapters

The U.FL connector is one of the smallest and lowest profile radio frequency connectors. U.FL adapters allow larger connectors to make connections via a U.FL connector, usually to a PCB.

About the U.FL connector

The U.FL connector is an Ultra Miniature Coax Connector first designed in the 1990s and manufactured by the Japanese company Hirose. IPEX and other manufacturers also produce near-identical compatible connectors. It is one of the world's smallest radio frequency connectors and can reliably support multi-gigahertz frequencies despite its small size.

Key physical features of the N connector

U.FL connector is incredibly compact with a nominal mated height as low as 1.9 millimeters (0.07 inches) and a small mounting area of 7.7 square millimeters. It consists of a plug that is pushed onto a PCB mounted receptacle. Correct mating produces a tactile click sensation. The U.FL connector is not designed for repeated connection/disconnection and is rated for only 30 mating cycles. The connector is made from phosphor bronze with a liquid crystal polymer (LCP) insulator. The male connector is surface mounted and carries a center pin. The female receptacle is attached to the coax and presses onto the male connector.

Electrical specifications of the U.FL connector

This is a 50-Ohm connector that can support frequencies up to 6 GHz with a VSWR of 1.3 to 1.5.

Applications of U.FL adapters

U.FL adapters are a key solution for supporting the connection of external antennas to PCB radio circuits. More powerful SMA or RP-SMA connector antennas can be securely mated via the small footprint of the U.FL antenna. U.FL pigtails are particularly useful for making connections in a RF development kit.

Available N connector adapter configurations include:

  • U.FL male to RP SMA male adapter - Pigtail adapters can be used to add external WiFi antennas to routers and laptops. The cable length can vary to allow the SMA connector to be positioned at a distance from the PCB where the U.FL connector is attached.

  • U. FL to SMA adapter - This adapter is frequently used with Vector Network Analyzers (VNAs) that come with SMA ports.

[H] MCX adapters

Between series Micro CoaXial (MCX) connector adapters provide an appreciable step down in size from the subminiature connectors and a convenient snap-on connection.

About the MCX connector

This miniature connector is used in compact settings. It is lightweight and approximately 30% smaller than the SMB connector despite having the same interface dimensions.

Key physical features of the MCX connector

The connector is made from machined brass and beryllium copper. The snap-on mating mechanism is robust and repeatable for up to 500 mating cycles. It is achieved by beryllium copper spring fingers. The male connector carries a center pin of gold-plated brass and the female connector has a gold-plated beryllium copper receptacle. The overall diameter of the connector is 3.6 millimeters (0.14 inches).

Electrical specifications of the MCX connector

This is a 50-Ohm connector that can support frequencies up to 6 GHz with a VSWR of 1.35.

Applications of MCX adapters

The size, functionality, and convenience of the MCX connector mean that it has a wide range of applications. MCX adapters are used to make connections in GPS, wireless, and cellular networking applications.

Available MCX connector adapter configurations include:

  • MCX to SMA male adapter - This adapter can be used to make advantageous connections in cellular networking.

  • MCX to RP-SMA adapter - This between series adapter combination can be used in wireless networking.

  • MCX to FME adapter - The FME connector is used in networking solutions for vehicles and watercraft where compact, well-insulated connectors are required due to limited space and routing requirements.

Frequently asked questions

What is a T-splitter / Y adapter?

This is a passive radio frequency device that receives an input signal from an antenna and delivers two output signals via cables attached to the outlet connectors. When an input signal enters the T-splitter the output signal power is halved at each of the two outputs. T-splitters can be selected according to the RF connector they carry.

In conclusion

Radio frequency adapters are a key solution for facilitating competent connections between differing connectors in a variety of RF devices and equipment. High-quality adapters for the leading classes of RF connectors, cables, and antennas mean that the performance of radio equipment is not compromised by mismatching and discontinuities.

Learn more

SMA antennas

RP-SMA antennas 

N connector antennas

BNC cables 

Antenna wall mounts

U.FL antenna

Connectors and Adapters Insertion Loss

Loss of signal power caused by the connection between an RF device and an RF cable across a connector is called insertion loss. It is calculated and expressed in decibels (dB). 

Insertion loss is attributed to three main causes:

  • Dielectric loss- power loss in the dielectric material. 
  • Copper loss- heat dissipated at the conductor’s surface (skin effect), relative to main conductor and metal plating used.
  • Reflected loss- reflected energy lost in the direction of transmission.

Different connectors have different insertion loss rating, depending on the dielectric material used, the level of shielding and frequency used. For example, a BNC connector is rated at a 0.2dB maximum loss at 3GHz, an SMA and RP-SMA connector has a 0.06dB loss at 6GHz, N-type connectors are rated at 0.15 dB at 10 GHz.

Insertion loss rating for most connectors is usually given at a single optimum frequency due to the complexity of precision testing for such low values at different frequencies. 

Using connector adapters to interface antenna cables and devices using incompatible connectors increases the insertion loss due to the extra connections. Most connector adapters have an insertion loss of 0.1dB at the optimum frequency. Adding an adapter to a connection line also adds to the sum of insertion loss.

Differences in the choice of metal housing for connectors and adapter (stainless steel or brass) only affects the durability of the connector. Choice of plating metal; gold, silver, and nickel determines the conductive and durability characteristic of the contacts. Collectively these characteristics may affect insertion loss but not in a significant way.

 

Adapters for Antenna Cables

Antenna Cable Adapters are specialized radio frequency connector components that facilitate compatibility between different sizes, classes, genders, and polarity of RF connectors. They are passive components that facilitate the transmission of megahertz to gigahertz frequency RF signals via connected cables. The use of coaxial connector adapters is widespread including radio devices and components like antennas, GPS receivers, surge protectors, and test and measurement devices.

This expansive range of RF adapters are designed and precision manufactured to provide the required transition in connector class or gender without creating discontinuities or steps in impedance that would compromise the performance of the radio frequency circuit they are connected to.

Each end of the coaxial cable connector adapter can mate with its complementary connector meaning that an in-line connection can be made between antenna cables, antennas, or other components that are terminated with RF connectors that normally would be unable to be directly mated.

Adapters are diverse and have a broad range of combinations. Types of connections that can be created with these adapters span:

  • Screw-coupling

  • Snap-on coupling

  • Bayonet-coupling

There are three main types of antenna cable adapter:

  1. In series RF-adapters can connect with RF connectors of the same type or series at both ends. For example, N-Type connector adapters carry N-Type connectors at both ends. In series connectors usually provide conversion based on gender (e.g. male-female, female-female, male-male). They may also be described as gender-changing adapters.

  2. Between series adapters can create a connection between two radio frequency connectors of different types or classes, for example, an RP-SMA to N adapter or a BNC to N adapter. The electrical connections between the different interfaces on the adapter are carefully machined to keep signal loss to a minimum as the adapter structurally transitions between its two connector types.

  3. Pigtail adapters connect a micro-miniature or miniature RF connector to a connector of a larger class via a short length of low-loss coaxial cable. They are typically used with U.FL or MMCX connectors and facilitate a connection between a PCB mounted connector and a standard sized connector which may not be able to fit in a densely packed environment. They also spare a micro-miniature connector class from being repeatedly re-mated as the larger and more robust connector can be used.

Adapters can also have straight or angled configurations as well as a bulkhead feature for panel mounting or silicone gaskets for robust ingress protection.

The quality of antenna cable adapters affects the performance of the radio frequency circuit they are in

These in-line RF adapters are precision-manufactured to keep non-linearities to a minimum. Mismatching in a line introduced by a poorly machined or matched adapter will generate discontinuities. These are step changes in impedance along the line and can be caused by changes in adapter diameter, insulator diameter, changes in interface dimension, or defects and gaps in the adapter. This means that when a signal travels down the line through the adapter, reflected traveling waves propagate that contribute to signal loss in the forward direction. Careful machining also prevents Passive Intermodulation (PIM), where two or more fundamental frequencies are present in the RF circuit.

RoHS compliant RF connector adapters

Our range of antenna cable adapters is manufactured to the highest standards with quality materials of good provenance. We ensure that all of the RF connector adapters supplied and distributed by our company comply with the Restriction of Hazardous Substances (RoHS) directive. This EU directive and its domestic equivalents, set limits on the inclusion of hazardous substances such as lead, cadmium, and mercury in electrical and electronic equipment (EEE).

The RF connector adapters also comply with Federal and international legislation regarding conflict minerals, in particular, The Conflict Minerals Regulation and Section 1502 of the Dodd-Frank Act. These laws prohibit the use of the key metals Tantalum, Tungsten, Tin, and Gold that are sourced from areas of conflict or forced labor, being used in the electronics sector.

Quality antenna cable adapters cover all the major RF connector classes

Our range of coaxial adapters covers all the main 50 and 75 Ohm applications with either in-series or between series RF interfaces. Here are the most commonly used interfaces for antenna cable adapters:

[A] SMA adapters

SMA adapters feature an SMA connector as one or both of the connector interfaces on the adapter.

About the SMA connector

The SMA connector is a Sub-Miniature type A coaxial connector. This semi-precision connector was designed in the 1960s and has since become which is widely used in telecommunications and electronics. Its compact design makes it suitable for use in small spaces and its screw coupling mating mechanism forms a secure connection that is resistant to vibrations and jolts. SMA connectors are hard-wearing and rated for at least 500 mating cycles.

Key physical features of the SMA connector

The SMA connector consists of male and female connectors that carry 36 threads per inch, threading. Both connectors are made of either stainless steel, nickel, or gold-plated brass.

  • The diameter of the male SMA connector is 11 millimeters (0.433 inches) is a barrel-shaped connector with internalized threads. The male connector also has an external hex nut for tightening the connector when it is mated. The mating interface of the male SMA connector carries a brass center pin surrounded by a Teflon dielectric.

  • The female SMA connector is slightly small with a diameter of 9.5 millimeters (0/374 inches). The mating interface consists of a beryllium copper receptacle surrounded by a Teflon insulator.

Electrical specifications of the SMA connector

This is a 50-Ohm connector that supports microwave frequencies up to a maximum frequency of 18 GHz.Its Voltage Standing Wave Ratio is between 1.05 and 1.2.

The SMA connector has exemplary power handling and has a voltage rating of 500 volts. The maximum radio frequency leakage of the standard connector is -90 dB/min at 2-3 GHz, but this may vary with adapters.

Applications of SMA adapters

The applications of SMA adapters are determined largely by the applications for the SMA connector. Though initially developed for the defense, aerospace, radio astronomy, and Testing and Measurement sectors, in contemporary times the SMA connector has become much more prevalent in use in cellular telecommunications, radio navigation (including GPS), and wireless networking, being used often for sub-6 GHz frequencies.

Available SMA adapter configurations include

  • SMA female to SMA male adapter - This and other gender combinations allow the correct mating between SMA antennas, cables, and radio equipment.

  • Right angle SMA male to SMA female adapter - The right-angle geometry is space-saving in a range of applications. The attached cable also projects straight down and is less likely to become damaged.

  • SMA female to SMA female bulkhead adapter - This bulkhead connector is used with an L antenna mount to connect an SMA connector antenna and antenna cable.

  • SMA male to RP-SMA male adapter - As the RP-SMA connector is widely used in wireless networking, this adapter supports the connection of SMA antennas and cable to routers and other equipment.

  • SMA female to TNC male adapter - This adapter supports an electrically competent connection to a larger caliber connector.

  • SMA male to FME male adapter -This adapter provides a useful step-down in size (without compromising the robust threaded connection) to the smaller, threaded FME connector that is often used in vehicles and boats.

  • SMA male to Type N male adapter - The N connector can be used for mounting or connecting in-line components like surge protection devices.

  • SMA female to U.FL adapter - this connection is used to facilitate the connection of an SMA antenna to a PCB. It is not designed for repeated mating cycles.

  • SMA female to BNC female adapter - This adapter can make key connections in testing and measurement equipment and panel mounted connector arrangements.

[B] RP SMA adapters

Reverse Polarity or RP SMA adapters carry an RP-SMA connector as one or both of the connector interfaces of the adapter.

About the RP-SMA connector

The RP-SMA connector is a variant of the standard SMA connector. It was developed in the late 1990s as part of a strategy to prevent consumers from connecting powerful industry antennas to consumer wireless networking gear.

Key physical features of the SMA connector

The RP-SMA connector has a deliberate reversal of the inner mating interface of the male and female connectors. In an RP SMA connector, the male connector has a receptacle and the female connector carries a pin. This arrangement makes RP-SMA connectors electrically incompatible with SMA connectors as they cannot properly mate.

Like the SMA connector, the RP-SMA connector forms a mechanically strong, low signal loss connection by screw-coupling. It is physically identical to the standard SMA connector except for the switched gender of the mating interface.

Electrical specifications of the RP-SMA connector

The RP-SMA connector is a 50-Ohm connector that is widely used for sub-gigahertz and gigahertz frequencies up to 18 GHz. Like the SMA connector its Voltage Standing Wave Ratio is between 1.05 and 1.2, its voltage rating is 500 volts, and its maximum radio frequency leakage is -90 dB/min at 2-3 GHz, but this may vary with adapters.

Applications of RP-SMA adapters

RP-SMA connectors were developed for consumer wireless networking products and they have remained the predominant type of RF connector used in equipment like WiFi routers, access points, and 2.4 and 5 GHz antennas. The SMA and RP-SMA connectors are very easily confused and can only be truly identified by examination of the mating interface. An RP-SMA to SMA adapter can be used to make a competent connection between these two common connector types.

Available RP-SMA adapter configurations include:

  • SMA male to RP-SMA female adapter - This is a popular adapter for correcting matching errors between RP-SMA and SMA antennas and antennas cables.

  • Right angle RP-SMA male to RP-SMA female adapter - This is a compact and space-saving design that does not stress cables. There is also an articulating RP-SMA male to RP-SMA male/female right angle connector that is ideal to use for positioning RP-SMA antennas on a router.

  • RP-SMA female to RP-SMA female bulkhead adapter - This bulkhead connector can be used for mounting RP-SMA antenna and cable securely. The O-rubber or silicone O-ring waterproofs the connections.

  • RP-SMA female to MMCX male adapter - This pigtail adapter provides a reliable step-down in size between the RP-SMA connector and the microminiature MMCX. This adapter can be used to connect an RP-SMA antenna to a PCB.

[C] TNC adapters

Threaded Neil Concelman (TNC) adapters carry a TNC connector as one or both of the connector interfaces of the adapter.

About the TNC connector

The Threaded Neil Concelman connector is a threaded version of the Bayonet Neil Concelman (BNC) connector discussed below. The screw-coupling mating mechanism of this miniature RF connector enhances its performance at microwave frequencies. The mated connection is low-noise, and stable making it ideal for environments where there may be shocks or vibration.

Key physical features of the TNC connector

The connector body is typically made from brass and phosphor bronze and both genders of connector carry 7/16 - 28 UNEF threading.

  • The male TNC connector is larger, with a diameter of 15 millimeters (0.59 inches). It internalized threading and carries a phosphor bronze center pin surrounded by a Teflon insulator.

  • The smaller female TNC connector has a diameter of 9.6 millimeters (0.378 inches). The female connector has a center receptacle, also surrounded by Teflon.

Electrical specifications of the TNC connector

The TNC connector is available with characteristic impedances of 50 and 75 Ohms, so it is important to establish that the impedance of any TNC adapter is used to prevent mismatching. The TNC connector can support gigahertz range frequencies up to 11GHz. Its VSWR is 1.3 and the working voltage is 500 volts. At 2 -3 GHz, the maximum radio frequency leakage is -60 dB/min.

Applications of TNC adapters

TNC adapters are utilized in a range of wireless and telecommunications applications where a robust, stable connection is critical to performance. Because of their ruggedness, and excellent power handling they are also used in industrial, defense, aviation and space market settings.

Available TNC adapter configurations include:

  • TNC male to RP-TNC female adapter - The RP-TNC connector described below is a key miniature connector type used in wireless networking applications. It is structurally similar to the TNC connector but unable to mate with a TNC connector without an adapter.

  • TNC female to SMA female adapter - This is a useful adapter for making connections in cellular networking applications where the SMA connector is widely used.

  • TNC male to N male adapter - This pigtail adapter is ideal for making connections with the N connector that is used in outdoor installations.

  • TNC male to RP-SMA female adapter - The RP-SMA is the predominant connector in consumer wireless applications and so this adapter can be used to make connections with this common connector type.

[D] RP-TNC adapters

Reverse Polarity Threaded Neil Concelman (TNC) adapters make in-series or between series RF connections that include an RP TNC connector.

About the RP-TNC connector

This is a Reverse Polarity (RP) version of the TNC connector that was developed in the late 1990s as a new connector class for use with consumer wireless networking gear. The RP-TNC is structural and electrically identical to the standard TNC connector but reverses the mating interfaces of the male and female TNC connector.

Key physical features of the TNC connector

The reversal of the inner mating interfaces in the RP-TNC connector means:

  • The male RP-TNC connector carries a receptacle rather than the pin in the standard version of the connector.

  • The female RP-TNC connector carries the center pin rather than a receptacle in the standard TNC connector.

Electrical specifications of the RP-TNC connector

The electrical specifications of the 50-Ohm RP-TNC connector are identical to the standard version, making this connector suitable for sub-gigahertz and gigahertz frequencies.

Applications of RP-TNC adapters

RP-TNC adapters are used for wireless networking equipment, similarly to the RP-SMA connector. They can be used to make connections of the same or different class on routers, wireless access points, and antennas.

Available RP-TNC adapter configurations include:

  • RP-TNC male to RP-SMA male adapter - This between series adapter can be used for making a variety of connections in wireless networking.

  • RP-TNC female to SMA female adapter - This useful adapter can be used in telecommunications applications where the SMA connector is widely used.

  • RP-TNC male to N male adapter - The N-Type connector is a large connector that is suited to mount outdoor, weatherproof antennas. This adapter makes RP-TNC connections with this rugged connector type.

[E] BNC adapters

Bayonet Neill Concelman (BNC) adapters are used for making in-series or between series connections that include a BNC connector.

About the BNC connector

The Bayonet Neil Concelman connector is a distinctive RF connector that has a unique bayonet-coupling mechanism. It was developed in the late 1940s from an existing design by Paul Neill and Carl Concelman and contemporary versions deliver consistent performance at microwave frequencies.

Key physical features of the BNC connector

The BNC connector is made from nickel plated brass. The male connector body houses grooves that are designed to twist and snap onto the two lugs of the female connector body. Within the male BNC connector is a gold-plated brass inner conductor pin surrounded by PTFE. The female BNC connector has a gold-plated phosphor bronze receptacle as its mating interface. A silicone rubber gasket waterproofs the mated connection.

Electrical specifications of the BNC connector

The BNC connector is available in both 50 and 75 Ohm versions, meaning that the characteristic impedance of the adapter should be checked before mating to prevent a mismatch. The 50-Ohm connector has a maximum frequency of 4 GHz with a VSWR of 1.3. Its working voltage is 500 volts.

Applications of BNC adapters

The 50-Ohm BNC adapter may be used in radio, testing, and measurement, telecom, and networking applications. A 50-Ohm BNC adapter can be used in analog video applications but not digital video.

Available BNC adapter configurations include:

  • BNC male to RP-SMA male adapter - This between series adapter can be used for making a variety of connections in wireless networking.

  • BNC female to SMA female adapter - This useful adapter can be used in telecommunications applications where the SMA connector is widely used.

[F] N Connector adapters

N connector, N-type, or Type N adapters carry an N connector as one or both of the connector interfaces of the adapter.

About the N connector

This medium-sized, threaded radio frequency connector was designed in the 1940s by Paul Neill of Bell Labs, NY. The N connector was one of the first connectors capable of supporting microwave frequencies and the contemporary version is widely used in the multi-gigahertz range.

The N connector is waterproof and rugged making it suitable for outdoor antenna and networking installations.

Key physical features of the N connector

This cylindrical medium-sized connector has a diameter of 20.3 millimeters (0.827 inches) for the male connector and 15.7 millimeters (0.627 inches) for the female. It has 5/8-24 UNEF pitch threading for secure screw-coupling.

  • The male N connector has a silver or nickel-plated brass body and a gold-plated brass center pin. Its threading is internalized and the body of the connector may carry a hex nut to aid tightening to the correct torque.

  • The female Type N connector (jack) has externalized threads and carries a beryllium copper receptacle.

  • N connectors do not have an insulator but carry a gasket to form an air and watertight seal.

Electrical specifications of the N connector

The N connector has a characteristic impedance of either 50 Ohm or 75 Ohm. It can support frequencies up to a maximum of 11 GHz. It has excellent power handling with a peak voltage rating of 1500 volts. The VSWR of the N connector is 1.35 and the maximum radio frequency leakage at 3 GHz is -90dB per min.

Applications of N connector adapters

The robustness of this connector makes it an advantageous choice for industrial and defense installations where conditions may be harsh. N connectors are used for Satcom and radar, instrumentation and outdoor antenna, and base station installations for wireless and cellular networking. Its exemplary power handling makes the N connector a connector of choice for lightning arrestors and surges protectors. N connector adapters will be used to form competent in-series and between series connections in these settings.

Available N connector adapter configurations include:

  • N female to N female bulkhead adapter - This in-series adapter is advantageous for the safe and secure mounting of N connector antennas. The bulkhead connector can be secured to the mount and the N connector antenna secured to one end and the N connector antenna cable to the other end. The rubber gaskets aid in waterproofing the connection.

  • N male to RP SMA female adapter - This N connector adapter configuration introduces the benefits of the larger and more rugged N connector to wireless networking installations where the RP-SMA connector is common.

[G] U.FL adapters

The U.FL connector is one of the smallest and lowest profile radio frequency connectors. U.FL adapters allow larger connectors to make connections via a U.FL connector, usually to a PCB.

About the U.FL connector

The U.FL connector is an Ultra Miniature Coax Connector first designed in the 1990s and manufactured by the Japanese company Hirose. IPEX and other manufacturers also produce near-identical compatible connectors. It is one of the world's smallest radio frequency connectors and can reliably support multi-gigahertz frequencies despite its small size.

Key physical features of the N connector

U.FL connector is incredibly compact with a nominal mated height as low as 1.9 millimeters (0.07 inches) and a small mounting area of 7.7 square millimeters. It consists of a plug that is pushed onto a PCB mounted receptacle. Correct mating produces a tactile click sensation. The U.FL connector is not designed for repeated connection/disconnection and is rated for only 30 mating cycles. The connector is made from phosphor bronze with a liquid crystal polymer (LCP) insulator. The male connector is surface mounted and carries a center pin. The female receptacle is attached to the coax and presses onto the male connector.

Electrical specifications of the U.FL connector

This is a 50-Ohm connector that can support frequencies up to 6 GHz with a VSWR of 1.3 to 1.5.

Applications of U.FL adapters

U.FL adapters are a key solution for supporting the connection of external antennas to PCB radio circuits. More powerful SMA or RP-SMA connector antennas can be securely mated via the small footprint of the U.FL antenna. U.FL pigtails are particularly useful for making connections in a RF development kit.

Available N connector adapter configurations include:

  • U.FL male to RP SMA male adapter - Pigtail adapters can be used to add external WiFi antennas to routers and laptops. The cable length can vary to allow the SMA connector to be positioned at a distance from the PCB where the U.FL connector is attached.

  • U. FL to SMA adapter - This adapter is frequently used with Vector Network Analyzers (VNAs) that come with SMA ports.

[H] MCX adapters

Between series Micro CoaXial (MCX) connector adapters provide an appreciable step down in size from the subminiature connectors and a convenient snap-on connection.

About the MCX connector

This miniature connector is used in compact settings. It is lightweight and approximately 30% smaller than the SMB connector despite having the same interface dimensions.

Key physical features of the MCX connector

The connector is made from machined brass and beryllium copper. The snap-on mating mechanism is robust and repeatable for up to 500 mating cycles. It is achieved by beryllium copper spring fingers. The male connector carries a center pin of gold-plated brass and the female connector has a gold-plated beryllium copper receptacle. The overall diameter of the connector is 3.6 millimeters (0.14 inches).

Electrical specifications of the MCX connector

This is a 50-Ohm connector that can support frequencies up to 6 GHz with a VSWR of 1.35.

Applications of MCX adapters

The size, functionality, and convenience of the MCX connector mean that it has a wide range of applications. MCX adapters are used to make connections in GPS, wireless, and cellular networking applications.

Available MCX connector adapter configurations include:

  • MCX to SMA male adapter - This adapter can be used to make advantageous connections in cellular networking.

  • MCX to RP-SMA adapter - This between series adapter combination can be used in wireless networking.

  • MCX to FME adapter - The FME connector is used in networking solutions for vehicles and watercraft where compact, well-insulated connectors are required due to limited space and routing requirements.

Frequently asked questions

What is a T-splitter / Y adapter?

This is a passive radio frequency device that receives an input signal from an antenna and delivers two output signals via cables attached to the outlet connectors. When an input signal enters the T-splitter the output signal power is halved at each of the two outputs. T-splitters can be selected according to the RF connector they carry.

In conclusion

Radio frequency adapters are a key solution for facilitating competent connections between differing connectors in a variety of RF devices and equipment. High-quality adapters for the leading classes of RF connectors, cables, and antennas mean that the performance of radio equipment is not compromised by mismatching and discontinuities.

Learn more

SMA antennas

RP-SMA antennas 

N connector antennas

BNC cables 

Antenna wall mounts

U.FL antenna

Connectors and Adapters Insertion Loss

Loss of signal power caused by the connection between an RF device and an RF cable across a connector is called insertion loss. It is calculated and expressed in decibels (dB). 

Insertion loss is attributed to three main causes:

  • Dielectric loss- power loss in the dielectric material. 
  • Copper loss- heat dissipated at the conductor’s surface (skin effect), relative to main conductor and metal plating used.
  • Reflected loss- reflected energy lost in the direction of transmission.

Different connectors have different insertion loss rating, depending on the dielectric material used, the level of shielding and frequency used. For example, a BNC connector is rated at a 0.2dB maximum loss at 3GHz, an SMA and RP-SMA connector has a 0.06dB loss at 6GHz, N-type connectors are rated at 0.15 dB at 10 GHz.

Insertion loss rating for most connectors is usually given at a single optimum frequency due to the complexity of precision testing for such low values at different frequencies. 

Using connector adapters to interface antenna cables and devices using incompatible connectors increases the insertion loss due to the extra connections. Most connector adapters have an insertion loss of 0.1dB at the optimum frequency. Adding an adapter to a connection line also adds to the sum of insertion loss.

Differences in the choice of metal housing for connectors and adapter (stainless steel or brass) only affects the durability of the connector. Choice of plating metal; gold, silver, and nickel determines the conductive and durability characteristic of the contacts. Collectively these characteristics may affect insertion loss but not in a significant way.