Presentation

This glossary defines common terms used in antenna cables, coaxial cable assemblies, RF connectors, and adapters. These terms are commonly encountered when selecting antenna extension cables, pigtails, adapters, and antenna cable assemblies for wireless systems.

Data Alliance manufactures and supplies high-quality antenna cable assemblies used in IoT, cellular (4G/5G), WiFi, GPS, LoRa, and industrial wireless systems. These cable assemblies typically use low-loss double-shielded coaxial cables and precision RF connectors such as SMA, RP-SMA, N-type, TNC, MMCX, and U.FL.

This glossary helps explain the components, connector types, cable characteristics, and electrical concepts used when selecting antenna cables and RF adapters.

Definitions of Components and Terms

A

Adapter. An RF adapter is a short connector device used to join two RF connectors of different types or genders without using a cable. Adapters are commonly used to convert between connector standards such as SMA to N-type or RP-SMA to SMA.

Adapter Cable is a coaxial cable assembly with different connector types on each end. Adapter cables are used to connect devices that use incompatible connectors.

Examples include:

• SMA male to RP-SMA female
• U.FL to SMA
• MMCX to SMA

Adapter cables are commonly used when connecting embedded wireless modules to external antennas.

Adapter Polarity refers to the orientation of the center conductor in RF adapters and connectors.

Most RF connectors follow the standard convention:

• Male connector → center pin
• Female connector → center socket

However, reverse polarity connectors such as RP-SMA intentionally reverse this configuration. When selecting adapters, both connector type and polarity must match to ensure proper mating.

American Wire Gauge (AWG) is a wire gauging system used in electronics that works on a logarithmic scale. As the AWG number increases the actual cable cross-sectional diameter decreases. It may also be known as Brown & Sharpe Wire Gauge (B&S).

Antenna adapters are specially designed connectors that screw connect to a particular class of connector at one end and facilitate compatibility with a different class of connector at its opposite end. An example is an RP-TNC to n-type connector. A high-quality antenna adapter will maintain the electrical profile of the two connector classes with discontinuities kept to a minimum to prevent signal reflections and losses.

Antenna adapter cable is a length of coax capped with connectors that facilitate compatibility between an antenna and a downstream connection that would be otherwise incompatible. The cable may be a pigtail, as discussed further down. Examples include:

• SMA male to RP SMA female
• U.FL to SMA
• RP SMA female to RP TNC female
• FAKRA antenna adapters for car radio

Attenuation is the reduction of signal strength as radio frequency energy travels along a coaxial cable. It is measured in decibels (dB) per unit length (for example dB per meter or dB per 100 feet). Lower attenuation cables are preferred in antenna systems because they preserve more of the transmitted or received signal.

B

BNC (Bayonet Neill–Concelman) connectors are bayonet-style RF connectors that lock with a quarter-turn mechanism. They are commonly used for test equipment, video signals, and some RF applications. BNC connectors are available in 50-ohm and 75-ohm versions and are typically used for frequencies up to approximately 2 GHz, depending on connector quality.

Brass is a copper-zinc alloy which is of particular importance as a base material for radio frequency connectors. It is easily machined and is effective in containing radio frequency energy and preventing cross-talk between electronic components. It is often plated with gold, silver, nickel, or proprietary alloys.

Bulkhead Connector is an RF connector designed to mount through a panel or enclosure wall. Bulkhead connectors allow antenna cables to pass through equipment housings while maintaining a secure mechanical mounting and electrical connection.

Bulkhead connectors typically include:

• a threaded body
• a mounting nut
• a sealing washer

They are commonly used in antenna enclosures, radio equipment panels, and outdoor antenna installations.

C

Cable Assembly is a pre-manufactured coaxial cable with connectors installed on both ends. Cable assemblies are used to connect antennas, radios, and RF equipment without requiring field installation of connectors.

Cable Bend Radius

The bend radius of a coaxial cable is the minimum radius the cable can be bent without damaging its internal structure.

Exceeding the recommended bend radius can:

• deform the dielectric
• damage the shielding
• increase signal loss.

Smaller diameter cables generally allow tighter bend radii than larger low-loss cables such as LMR-400.

Capacitance is the ability of a system to store electrical charge. In coaxial cables, capacitance is determined by the spacing between the center conductor and the outer conductor and the dielectric material between them. Capacitance affects signal propagation characteristics and impedance.

Center Conductor is the internal metal wire of a coaxial cable that carries the RF signal. It is typically made of copper or copper-clad steel.

Coaxial antenna cable assemblies are pre-assembled antenna cables with the required connectors attached at each end. Purchasing high-quality pre-assembled antenna cables can save the expense and time of self-assembly of coax cable and connectors by soldering or crimping.

Coaxial cable, also known as coax cable is a type of transmission line used to carry radio frequency signals between antennas, radios, and wireless equipment. The cable is designed to maintain a controlled impedance and prevent signal leakage.

A typical coaxial cable consists of four layers:

1. Center conductor – carries the RF signal
2. Dielectric insulator – maintains spacing and impedance
3. Shielding layer – braided copper and/or foil shielding to block interference
4. Outer jacket – protective layer against environmental damage

Coaxial radio frequency connectors  are electrical connectors that are specifically designed to attach to coaxial cable and maintain its structural, electrical, and functional continuity. This is essential to minimize not only signal loss but impedance mismatch and the creation of reflections at the junction between the cable and  connector. Connectors are designed to form a secure mated union of complementary male and female components that may be threaded, bayonet, or press-down. A variety of types and classes of radio frequency connectors used with antenna cables are precision engineered and able to facilitate transmission at up to microwave frequencies.

Connection cables is a general term for a coaxial cable assembly used to connect RF devices such as antennas, radios, and amplifiers. Connector types and genders vary depending on the application.

Connector Gender. RF connectors are identified by both connector type and gender.

Typical rules:

• Male connector – contains a center pin
• Female connector – contains a center socket (receptacle)

However, reverse polarity connectors reverse the center pin arrangement while maintaining the same external threading.

Understanding connector gender prevents incorrect cable selection.

Connector Mating Cycle refers to the number of times a connector can be connected and disconnected while maintaining reliable electrical performance.

Typical mating cycle ratings:

• SMA connectors: ~500 cycles
• U.FL connectors: ~30 cycles
• MMCX connectors: ~500 cycles

Micro connectors such as U.FL are not designed for frequent reconnection.

Connector Series refers to a family of RF connectors with a standardized mechanical design and electrical characteristics.

Common RF connector series include:

• SMA
• RP-SMA
• N-Type
• TNC
• BNC
• MMCX
• U.FL

Connector series determine compatibility between connectors.

Copper is used for the central conducting wire or strands in most coaxial cables, as well as the braided shield layer. It is a particularly effective conductor of electrical current and heat and is fairly resistant to corrosion. It is easy to machine and can also be used to plate coax and connector elements.

Coupling Nut is the rotating threaded component used to tighten certain RF connectors such as SMA, TNC, and N connectors. It secures the connection while maintaining proper RF contact.

Crimping is an attachment method for joining a radio frequency connector to coaxial cable to form a cable assembly. Crimping produces a solder-free electrical connection and can be used to attach the connector pin and shank using a specially calibrated crimping tool. Key advantages of crimping over soldering of antenna cable connectors include improved mechanical strength, a gas and moisture-tight union, and convenience.

D

Dielectrics are electrical insulators that surround both the conducting wire in a coaxial cable and the inner conductor of a coaxial connector. The electrical current is unable to flow freely through this insulating layer, which carries high resistance, preventing signal loss. Dielectric diameter and completeness of  enclosure will affect impedance, capacitance, and the shielding efficacy of the outer conductor. Plastics such as PTFE or PE are used as dielectrics.

Double Shielded Coaxial Cable includes both a foil shield and braided copper shield. This design improves protection against electromagnetic interference (EMI) and reduces signal leakage.

Double shielding is common in low-loss antenna cables used for cellular and WiFi systems.

E

EMI (Electromagnetic Interference) refers to unwanted electromagnetic signals that interfere with radio communication. Proper shielding in coaxial cables helps prevent EMI from affecting RF signal transmission.

Extension Cable. An antenna extension cable is a coaxial cable assembly with connectors of the same type on both ends but opposite genders. This allows the cable to extend the distance between a wireless device and its antenna.

Extension cables are commonly used when an antenna must be mounted away from the device to improve signal reception, such as mounting antennas on rooftops, vehicles, or outdoor enclosures.

To minimize signal loss, extension cables should be kept as short as practical and use low-loss coaxial cable when longer runs are required.

F

FAKRA Connectors. FAKRA connectors are automotive RF connectors commonly used for GPS antennas, satellite radio, vehicle telematics, and automotive LTE antennas. They feature a plastic keyed housing that prevents incorrect mating and typically use 50-Ohm impedance coaxial cable.

Female Connector contains a center socket (receptacle) designed to accept the center pin of a male connector.

Example: SMA Female Connector

Flexible coaxial cable is often used for creating high-speed wireless links as it can be installed in confined spaces. Its flexibility is due to a finely stranded copper inner conductor which is surrounded by a flexible polymer insulator, tinned copper braided shield (with 90% coverage), and outer plastic jacket. A second aluminum foil outer jacket can be added for extra insulation. These coax cables are relatively thin and have diameters ranging from 0.109 inches / 2.79 millimeters (RG174) to 0.405 inches / 10.28mm (RG 8). Flexible coax can be prone to kinking of both the shield and inner conductor if the bend radius is exceeded. To improve resilience, a solid wire core and insulating PTFE foam may be used. Flexible coax usually has an impedance of 50 Ohms. Examples include:

• RG 58
• RG 59
• RG 141
• RG 142
• RG 174
• RG 178

Fluoroethylenepropylene (FEP) is a plastic that is used to manufacture the outer jacket of coaxial cable. It is usually extruded and has high thermal stability and weather resistance.

Formable coaxial cable is similar to semi-rigid cable in terms of performance and is engineered to be able to be reformed multiple times by hand without damaging the coax. Most types used tinned copper braid as the outer shield. Their flexibility makes routing and layouts easy, without the need for tools.

H

Hardline coaxial cable is a heavy-duty form of coaxial cable used for long term installation. It uses solid metal shielding (often rigid copper or aluminum), a foam dielectric, and is capable of withstanding high voltages and harsh environments. It is thick, with an average diameter of 1.75 inches. Hardline coaxial cable may be manufactured in 50-Ohm or 75-Ohm impedance versions. Hardline coax is highly durable but prone to kinking so needs to be carefully handled when installed. This type of coax is often used as antenna cabling by Ham radio enthusiasts but requires specialist hardline connectors and stripping and assembly with professional tools.

I

Impedance is a measure of resistance to the flow of electrical current within the coaxial cable, connectors, and antennas and is measured in Ohms. The dielectric constant of the coax insulating layer is a key determinant of coax impedance as well as the radio of both the inner and outer conductors.

Impedance matching refers to designing RF systems so that the impedance of the transmission line (coaxial cable), connectors, and antenna are equal.

Most RF antenna systems use 50-ohm impedance.

Proper impedance matching minimizes signal reflections and maximizes power transfer between components.

Poor impedance matching results in:

• signal loss
• reflections
• reduced antenna efficiency.

Insertion Loss describes the amount of signal power lost when a component such as a cable, connector, or adapter is inserted into a transmission line.

Insertion loss is measured in decibels (dB).

High-quality antenna cables and connectors are designed to minimize insertion loss.

J

Jacket layers of coaxial cable are essential for protecting the outer and inner conducting layers from environmental exposure, which can cause corrosion and other forms of damage. The outer jacket is typically made from plastics such as polyethylene and PFA which can contribute to the flexibility of the cable as well as its thermal stability and resistance to corrosive substances and solvents.

Jack connector is the stationary portion of an RF connector pair, typically mounted on equipment or panels. A jack usually contains a female interface that receives a plug connector, although some connectors such as U.FL use different gender conventions.

L

LMR Coaxial Cable. LMR® is a family of low-loss coaxial cables designed for RF communication systems. These cables use a foam dielectric, foil shield, and braided shield to reduce signal attenuation. LMR cables are widely used for cellular, WiFi, and IoT antenna installations where longer cable runs are required.

Common types include:

• LMR 100
• LMR 195
• LMR 200
• LMR-240
• LMR 400

Lower attenuation improves signal performance over longer distances.

Low-Loss Coaxial Cable is designed to minimize signal attenuation over distance. These cables typically use improved dielectric materials, foil shielding, and high-coverage braided shields.

Examples include:

• LMR-100
• LMR-195
• LMR-240
• LMR-400

Low-loss cables are recommended for long antenna cable runs or high-frequency wireless systems.

‘Low loss’ LMR cable is a coaxial cable type that has lower rates of signal loss compared to coaxial cabling of equivalent diameter. An example is low loss LMR 100 coax which has the same diameter as RG 174 and is commonly sought as a replacement. They typically have a solid inner conductor, high resistance dielectric, wire braid, and foil shielding within their outer jacket which all contribute to their superior performance.

Lossy transmission line is a cable or transmission medium that dissipates a portion of the signal energy as heat. Signal loss can occur due to conductor resistance, dielectric loss, and imperfect shielding.

M

Male Connector. A male RF connector contains a center pin that inserts into the socket of a female connector.

Example: N-Type Male Connector

MCX or Micro-coax connectors are connectors designed to connect to micro coaxial cable. They are snap-on connectors that are structurally comparable to SMB connectors but around a third smaller.

MHF Connector Series. MHF connectors are the smallest type of RF micro-connectors for coaxial antenna cables. MHF-series connectors offer a controlled 50 impedance connection and stable frequency of 0 to 6 GHz. These connectors are made of copper alloy, and gold plated which enhances their performance. Just like MMCX connector, MHF connector allows 360-degree mounting of the cable which makes it highly flexible to use. MHF can be terminated with a 1.13 mm and 1.32 mm coaxial cable.

MHF4 Connectors. MHF4 connectors are ultra-miniature RF connectors used inside compact wireless devices such as cellular modules, LTE routers, and laptop wireless cards. They are similar to U.FL connectors but significantly smaller and are designed for micro-coax cables.

Micro coaxial cable also is known as mini-coax because of its small outer diameter. This lightweight miniature coaxial antenna cable has  50 Ohm impedance with low capacitance and signal loss and is usually used within devices that require high-frequency connectivity, especially where there are hinges or articulating parts. It is of particular benefit in applications where space is limited. Micro-coax retains the standard coaxial cable structure and may have a stranded center conductor and single or double shielded outer layer depending on the type. They are classified according to their outer diameter in millimeters:

• 1.13mm - 1.32mm
• 1.37mm

MMCX connectors are miniature micro coax connectors that mate using a lock-snap mechanism and are capable of rotation at their connection. They have 50 Ohm impedance and can support frequencies up to 6 GHz. They are commonly used with internalized antennas or to facilitate the connection of an external antenna to a device.

N

N Type connectors are standard-sized threaded, weatherproof connectors that are typically paired with semi-rigid coax for antenna cables. They have impedances of either 50 or 75 Ohms and can support frequency transmissions of up to 18 GHz.

Nickel is a metal that is widely used in the manufacture of antenna cable connectors, due to its malleability and resistance to oxidation. It can be combined with other metals as an alloy or used in plating.

O

Operating frequency range describes the range of radio frequencies over which a cable, connector, or RF component maintains acceptable electrical performance such as impedance matching, shielding effectiveness, and attenuation.

Outer Conductor of a coaxial cable forms the shielding layer that surrounds the dielectric. It protects the signal from interference and acts as the ground return path.

P

Panel Mount Connector is installed through a panel, enclosure, or chassis wall. These connectors allow external antenna cables to connect to internal circuitry.

Patch cable is also known as accessory cable  is a length of coax that is used to 'patch in' radio frequency components and route signals. It is fitted with the appropriate connectors at both ends, performing similarly to a pigtail. They may also have superior shielding or low attenuation making them a suitable swap-in for a more inferior grade of coax.

Pigtail Adapter is a short coaxial cable assembly used to connect small RF connectors to larger external connectors.

Pigtails are commonly used to connect internal wireless modules to external antennas.

Example:

U.FL to SMA pigtail cable.

Pigtails are typically 4–12 inches long to minimize signal loss.

Pigtail cables are short lengths of coaxial cable capped with radiofrequency connectors of the same or differing types. Pigtail wire connections are useful to extend a connection to where it can be more easily accessed, for example connecting an external antenna to a PCB. Pigtails can also perform the job of an antenna adapter allowing connectors of differing sizes or caliber to be used.

Pins are the male inner contact of a radio frequency connector which is designed to insert into the receptacle of the corresponding female connector.

Plug connectors is the movable connector typically attached to the end of a cable. It mates with a jack connector to complete the RF connection.

Polyethylene (PE) is a low-density polyolefins plastic that is widely used in antenna cable manufacturing for insulators and outer jackets. It is an efficient electrical insulator and has superb water-resistance. A disadvantage is its relatively low melting temperature.

Polytetrafluoroethylene (PTFE) is a commonly used plastic that has good chemical resistance and thermal stability. It is used for the dielectric layer of many forms of coax.

R

Receptacle is the portion of the mating interface of a female connector that receives the male pin when a mechanically and electrically functional connection occurs.

Return loss measures how much RF signal power is reflected back toward the source due to impedance mismatch in a transmission line.

It is expressed in decibels (dB).

Higher return loss values indicate better performance because less signal is reflected.

Return loss is closely related to VSWR and is commonly used to evaluate antenna and cable performance.

RF (Radio Frequency) refers to electromagnetic signals used for wireless communication. RF signals typically range from a few kilohertz to many gigahertz.

Antenna cables are designed specifically to transmit RF signals efficiently.

RF Connector is a specialized electrical connector used to join coaxial cables while maintaining controlled impedance and shielding.

Examples include:

SMA
 N-type
 TNC
 BNC
 MMCX
 U.FL

RP-SMA Connectors (Reverse Polarity SMA). RP-SMA connectors are a variation of SMA connectors where the gender of the center conductor is reversed. This connector type is commonly used on WiFi routers and wireless networking equipment. For example, an RP-SMA male connector has a center socket rather than a pin.

RP-SMA Gender (Reverse Polarity SMA) is one of the most common causes of connector confusion. RP-SMA connectors reverse the gender of the center conductor compared to standard SMA connectors.

Typical configuration:

• RP-SMA Male
  External threads with a center socket
• RP-SMA Female
  Internal threads with a center pin

Although the threading resembles standard SMA connectors, the reversed center conductor prevents accidental mating with standard SMA connectors. RP-SMA connectors are commonly used on WiFi routers, antennas, and wireless networking equipment.

RP-TNC Connectors (Reverse Polarity TNC) are a variant of the TNC connector with deliberate reversal of the gender of the inner conductor. The male RP-TNC carries a receptacle and the female RP-TNC connector carries a pin.

RG (Radio Guide) refers to a historical military designation system for coaxial cables originally defined in U.S. military specifications. Although the formal specification is obsolete, many cable types such as RG-58, RG-174, and RG-213 remain widely used and identified by their RG numbers.

S

Semi-rigid coaxial cable is a type of 50 Ohm impedance coaxial cable which is favored for its flexibility and wide frequency range, including microwave performance. Semi-rigid coaxial cable is a high-performance coaxial cable with a solid copper outer conductor and a solid dielectric surrounding the center conductor. It provides excellent shielding and stable electrical characteristics and is commonly used in microwave and laboratory RF applications. The cable is bendable but retains its shape after forming. Outer diameters range from 0.047 inches (1.19 millimeters) to 0.250 inches (6.35 millimeters). This type of coax is described as semi-rigid because it is malleable and will retain its shape once conformed. Examples include:

• RG 401
• RG 405

Shielding of coaxial cables refers to layers of braided tinned copper, copper tubing, or aluminum foil that are used to protect the insulated inner conductor from electromagnetic interference. Shielding helps maintain the electrical and magnetic fields between the two conductors. It is reliant on the conducting wire being fully enclosed by a dielectric.

Shield Coverage refers to the percentage of the cable circumference covered by the braided shield.

Higher shield coverage improves:

• EMI protection
• signal containment
• overall cable performance

Typical braid coverage ranges from 60% to 95%.

Shielding Effectiveness refers to how well a coaxial cable prevents external electromagnetic interference from entering the cable and prevents internal signals from leaking out.

Signal Loss refers to the reduction of RF signal power as it travels through a cable, connector, or adapter. Signal loss increases with:

• cable length
• higher frequencies
• smaller diameter cables

Low-loss cables help maintain stronger signal performance.

Skin effect is the tendency of alternating current at high frequencies to concentrate near the surface of a conductor. As frequency increases, current flows in a thinner outer layer of the conductor, effectively increasing resistance and contributing to signal attenuation.

SMA Connectors (SubMiniature version A). SMA connectors are precision threaded RF connectors widely used in antenna cables for WiFi, cellular, GPS, and IoT applications. SMA connectors provide a reliable 50-Ohm impedance connection and support frequencies up to approximately 18 GHz. SMA male connectors contain a center pin and internal threads, while SMA female connectors contain a center socket and external threads.

Soldering is a method used to create a secure attachment between a connector and a length of antenna cabling. Soldering involves the use of a soldering iron to heat a filler metal known as solder, which is used to join metal components like the center pin and shank of the connector to the coax. Properly executed soldering produces a long-lasting and reliable physical and electrical connection between the connector and the coaxial cable.

Specialty cables are neither extension cables nor connection cables and should have complete descriptions of the type and gender of each plug/jack. Specialty coaxial cables differ from standard cable because of their proprietary design, superior engineering, and performance, or the ability to withstand extreme conditions. They are usually selected for the most demanding applications and have greater capability than their generic counterparts. Examples include:

• High voltage coaxial cable
• Low loss LMR coaxial cable
• Spiral flex coaxial cable

Stranded Conductor. A stranded center conductor consists of multiple small wires twisted together. Stranded conductors improve cable flexibility and resistance to repeated bending.

T

TNC connectors also known as Threaded Neill–Concelman connectors  are standard sized 50 Ohm coaxial connectors used for frequencies up to 11 GHz. It forms a screw-down connection with the male inner pin inserting into a female receptacle to conduct the radio frequency signal.

Transmission lines are radio frequency circuits capable of carrying alternative current from a source into a load. The coaxial cable acts as a transmission line by conducting signals to and from antenna and receiver components in radio devices.

U

U.FL connectors are miniature coaxial connectors that form a snap-on, 50 Ohm impedance connection. They are often PCB mounted and are not intended for repeated mating cycles. Male connectors carry a pin and female connectors a corresponding receptacle. They are often attached to a pigtail cable length of 1.32mm coax.

V

Velocity of propagation (Vp) is a measure of the speed of signal propagation along the coaxial cable as a proportion of the speed of light.

VSWR (Voltage Standing Wave Ratio)  also known as return loss measures the efficiency of transmission of radio frequency power through a cable or line from source to load. It is presented as a calculated ratio of the maximum (Vmax) and minimum (Vmin) voltages along the transmission line caused by reflections. In a perfect radio frequency setup, 100% of the energy would be transmitted into the load, but impedance mismatch in the cable assembly will increase the ratio.

W

Wireless Module is a small electronic component used in embedded systems to provide wireless communication such as WiFi, cellular LTE, or Bluetooth. These modules often use micro coax connectors such as U.FL or MHF4 to attach external antennas.

Selecting the Right Antenna Cable

When choosing an antenna cable assembly, several factors should be considered:

• Connector type and gender
• Cable length
• Cable attenuation (signal loss)
• Cable flexibility
• Operating frequency range
• Environmental conditions (indoor/outdoor use)

Selecting a high-quality low-loss antenna cable helps maintain signal strength and improve wireless system performance.