Dipole Antennas: Dual Band 2.4GHz & 5GHz
Dipole Antennas: Dual band in 2.4GHz-5GHz bands
Dipole dual-band antennas for Wi-Fi are omnidirectional antennas that radiate RF (radio frequency) signals in both the 2.4GHz and 5GHz frequencies. The dual-band WiFi dipole antenna radiates and receives signals in a 360-degree angle around it. The antenna is designed to be mounted directly onto the RP-SMA female or SMA female connector of a client or radio device. The right angle versions are designed to be adjusted by up to 90 degrees or less.
Since they are vertically polarized, dual-band antennas for Wi-Fi find usage in many communication and machine to machine applications that include mesh networking, remote monitoring, and telemetry applications. Most SMA and RP-SMA connectors are gold plated for low loss and hence they provide superior performance for longer.
Similar to most dipole antennas dual-band antennas for Wi-Fi have Reverse Polarity SMA for RP-SMA. As such, the gender determination is counterintuitive with the gender referring not to the threads but rather to the pins. The SMA male and the RP-SMA have threads on the inside while the SMA male is designed with a pin in the threaded chamber and RP-SMA male comes with a socket in the chamber.
The high gain of the dual-band antennas and the omnidirectional coverage for Wi-Fi makes them suitable for a variety of applications such as large indoor spaces, warehouses, building, and marine installations. Other uses of the dual-band antennas include:
- 802.11ac Wi-Fi Routers and Access points
- 802.11b/g/n applications
- WLAN and WiFi systems
- Bluetooth, LoRa, ZigBee
- 4.9 GHz Public safety bands
- Wireless Video systems
- Mobile and multipoint applications
- Public wireless hotspots
Dual-Band WiFi Antennas: 2.4 GHz and 5.8 GHz Bands
Dual-band antennas provide the functionality of two separate antennas in one unit.
A dual-band antenna is an antenna that can send and receive radio frequency signals at two distinct frequencies. Depending on their configuration, these antennas are capable of using either of the two frequencies individually or at the same time. The 2.4 GHz and 5 GHz frequency bands are commonly paired for dual-band antennas, due to their widespread use for WiFi networking. They have proven an advantageous antenna for WiFi because the 802.11 protocol for the functioning of WiFi specifies the use of both the 2.4 and 5 GHz bands, as well as multi-antenna networking which can be supported by our broad range of dual-band antennas.
Our selection of high-quality dual-band antennas is compliant with conflict minerals legislation including the EU’s Conflict Minerals Regulation and The Dodd-Frank Act. They also comply with the standards outlined in the Restriction of Hazardous Substances (RoHS) directive and equivalent legislation around the world.
Dual-band antennas are made by combining multiple antenna elements.
These antennas are usually built by taking at least two monopole or dipole elements. Internal dual-band inverted F antennas are a printed, PCB version. As the frequency bands used for WiFi are above 1 GHz the antenna sizes are generally smaller than their sub-Gigahertz counterparts.
Each integrated antenna element resonates at a fundamental frequency that is one of the two target frequencies. The individual antenna elements vary in length according to the wavelength of the different frequencies, ensuring a true distinction in their sensitivity to each frequency. The copper wire used within these antennas can also vary in thickness to alter the bandwidth of the antenna. The elements may also have separate feed structures, stacking separate antennas one on top of the other, each with a separate feedline.
For reliable performance, a dual-band antenna is built to deliver optimal resonance and phasing in each of the respective bands of operation. These antennas should not be designed to be centered between the two bands. A well-designed dual-band antenna will be properly impedance matched (50 Ohm standard), with an optimal Voltage Standing Wave Ratio for both bands. Dual-band antenna impedance matching involves analyzing the antenna’s frequency response at each of the frequencies on a Smith Chart with comparison to the related VSWR. The aim is to ensure optimal (not always exact) matching for both the low-band frequency and the high-band frequency.
Dual-band antennas operate at key frequencies for WiFi.
These antennas are designed to deliver superb performance at the key portions of the radio frequency spectrum used by the most common versions of WiFi described below. WiFi uses unlicensed frequency bands, originally used for Industrial, Scientific, and Medical (ISM) applications, but which are now largely used for various forms of wireless networking and are free to use.
The 2.4 GHz frequency band
The 2.4 GHz band spans 2400 MHz to 2485 MHz and is the lower of the two bands served by these dual-band antennas. Within the frequency band, there are up to fourteen overlapping 20 MHz sub-bands known as channels, that can be used for data transfer. Eleven channels, numbered 1 to 11 are available in the US, with channels numbered up to 14 in Europe, Africa, and Asia.
It is in widespread mainstream use for wireless networking and alongside WiFi can be used to support Bluetooth and ZigBee as well as connectivity for domestic appliances like cordless phones. It is highly utilized for wireless communication because of the range and penetration it can achieve. Compared to the 5 GHz frequency band, 2.4 GHz transmissions lose less energy as they propagate and with less energy being absorbed as signals pass through materials like wood, insulation, and plaster. This makes 2.4 GHz networking able to provide multi-room coverage in indoor environments. In many ways, this frequency band has found itself a victim of its success, due to the high volume of wireless traffic using this band's finite amount of bandwidth. The main effect of this is interference, with reduced speed and impaired performance of networks. Dual-band networking solutions are a key strategy for addressing the problem of interference at 2.4 GHz.
The 5 GHz frequency band
The 5 GHz ISM band has much more bandwidth, spanning 5.15 GHz to 5.35 GHz and 5.725 GHz to 5.825 GHz. The 5GHz frequency band is divided into 4 large sub-bands:
- A upper (indoor) spans 5.150 GHz to 5.250 GHz
- A lower (indoor) spans 5.250 GHz to 5.350 GHz
- B (indoor or outdoor) spans 5470 GHz to 5725 GHz
- C (outdoor) spans 5735 GHz to 5850 GHz
Within these large portions of the spectrum are 26 channels that can be used for high speed and throughput networking with 19 of the channels being non-overlapping and channel widths of up to 160 MHz being possible. 5 GHz radio frequency signals have a much shorter wavelength (6 centimeters at 5 GHz versus just over 12 centimeters at 2.4 GHz).
It is the availability of bandwidth that makes the 5 GHz frequency band advantageous. As a far less congested frequency, users benefit from connectivity with interference from other commercial and consumer applications.
The high-energy signals propagate predominantly by direct line of sight as they are easily reflected, refracted, or absorbed. This limits the coverage that can be achieved by 5 GHz WiFi predominantly to the indoor environment, though it is capable of high speed, high throughput data transmission. If 5 GHz WiFi is used outdoors a raised limit on radiated power for outdoor transmission at 5 GHz helps to boost coverage for point-to-point links where line of sight is good.
Dual-band antennas are available in a range of models that suit a wide range of applications
This means that it has never been easier to find an antenna with the physical properties and electrical performance for your specific wireless networking setup. Dual-band WiFi antennas can be broadly grouped into omnidirectional directional dual-band antennas and directional dual-band antennas. Selection from these two classes of antenna will determine network structure. Dual-band omnidirectional antennas are the ideal choice for delivering all-round coverage in an area and are often used for point to multipoint or star networks. Directional antennas can focus their radio frequency energy in a specific direction and achieve higher gain. This makes them advantageous for wireless links or bridges.
Your antenna selection also needs to be suited to the environment where it will be mounted. Outdoor dual-band antennas, in particular, need a rugged weatherproof radome which will protect the sensitive electronics within from the ingress of dust, dirt, and moisture that can corrode the antenna. Indoor dual-band antennas are often ceiling or wall-mounted, or attached to a wireless access point and so can be smaller and less tough.
Here are some key types of dual-band wifi antennas:
[A] Dual-band dipole antennas are the most common type of dual-band antenna and are used to provide omnidirectional coverage. Dual-band antennas are usually made up of two or more dipole elements, which have a simple structure consisting of paired conductive arms and a centered feedline between them. The dipole arm lengths may be symmetric or unequal. Asymmetric dipole antennas separate the frequencies for dual-band operation by having distinct resonant nodes.
[B] Articulating dual-band antennas are often attached to routers or access points. They are ideal for indoor settings as they can be angled to get the required coverage. The articulation is a mechanical feature that uses a knuckle that can move the antenna into an angled position. This is a potential point of vulnerability to environmental exposure as the cables from the antenna run through the knuckle to the attached connector. The additional moving parts can make the antenna weaker also. Some of these articulating antennas are also capable of rotating due to an outer shell that can rotate independently of the radio frequency connector. Care may need to be taken in connecting this type of antenna to devices.
[C] i-Bar dual-band antennas are flexible, adhesive, and extremely low-profile antennas that deliver excellent performance despite their simplicity. These omnidirectional ultra-wideband antennas can be conveniently mounted on plastic or glass (not metal), making them ideal for vehicle interiors.
[D] Dual-band puck antennas are low profile cylindrical antennas named because of their similarity to a hockey puck. Within this type of omnidirectional antenna are elements that have a sensitivity to the 2.4 and 5 GHz frequencies. They offer versatile mounting options and can be ceiling-mounted, through-hole mounted, or screw-mounted on an L-bracket for secure wall mounting.
[E] Dual-band collinear antennas are powerful Omni antennas that are made up of an array of vertically stacked dipole elements housed within a cylindrical fiberglass radome. The arrangement of the antenna elements makes each element perform like an extension of the element beneath it leading to a summing effect of their radiating power. They are weatherproof and designed to be mounted at height outdoors to provide coverage over a large area.
[F] Panel dual-band WiFi antennas deliver targeted connectivity because they are directional antennas. Their flat profile and directivity are advantageous in applications which require a reliable point to point connectivity, especially if the 5 GHz function is used for high data throughput. They can be wall-mounted or mounted on a stand.
Radio frequency connectors for dual-band antennas
Dual-band antennas carry a range of commonly encountered radio frequency connectors which maintain a competent mechanical and electrical connection to cabling and wireless equipment. Your selection of antenna may be, in part, determined by the connector it carries. All dual-band antenna connectors are 50 Ohm connectors with suitably matched electrical specifications to ensure optimal performance of the network.
- RP-SMA connectors are commonly used for consumer WiFi network equipment, including antennas. They are a variant of the SMA connector. The RP-SMA connector mates by screw-coupling and is rated for over 500 mating cycles.
- SMA connectors may also be found on wireless networking equipment and antennas. It has a near-identical external physical appearance to the RP-SMA connector but the inner mating interface of the reversed polarity variant is switched. This makes RP-SMA and SMA connectors incompatible.
- N-type connectors or N connectors are a medium-sized rugged class of threaded connector that is useful in outdoor antenna installations, especially where the antenna is mounted via an N female bulkhead.
- U.FL connectors are micro-miniature radio connectors that facilitate the connection of a dual-band antenna to a complementary male jack that is mounted on a PCB. They connect by pressing the female plug down onto the jack with a tactile clicking sensation. This connector can only tolerate a limited number of mating cycles.
Key advantages of using dual-band antennas for wireless networking
Single-band antennas have a design that is focused on functionality for only one band but dual-frequency antennas have greater utility in settings where space and outlet availability is limited. Here are some other benefits of installing dual-band antennas as part of your WiFi network.
- Only a single dual-band antenna is needed to access both frequencies
Combining two frequencies means your time, space, and cost requirements for mounting WiFi antennas are greatly reduced. Dual-band WiFi networking is becoming more widespread due to the increased use of the 5 GHz frequency band, so it is prudent to include 5 GHz capability as part of your network deployment even if it is not immediately used. Internal dual-band inverted F antennas within devices like phones often not only support 2.4 GHz and 5 GHz WiFi but also Bluetooth, saving space in an understandably compact environment.
- The use of an external dual-band antenna improves the stability of your wireless connections.
Installing dual-band antennas on your router or access points means that you have two frequencies available for data transfer. If one frequency is experiencing delays or interference the router is equipped to switch to the alternate frequency (or where there are available channels), meaning that there is little to no downtime in connectivity.
- Minimize interference in your WiFi network by using a dual-band antenna
If you are looking for solutions for improving the quality of your WiFi network’s performance, the use of non-overlapping WiFi channels is a demonstrable method of reducing the potential for interference that can reduce speeds. At 2.4 GHz there are only 3 non-overlapping channels available, but by being able to use the 5 GHz band WiFi networks have a further 19 non-overlapping channels to use.
- A dual-band antenna enables you to increase your network capacity
Accessing the 5 GHz frequency band more than doubles the bandwidth available for WiFi. For enterprise-level networking, dual-frequency WiFi can support high-throughput data transfer via wireless links at 5GHz while the 2.4 GHz frequency band can be used for routine wireless connectivity and internet access.
- Dual-band WiFi antennas deliver the best of both frequencies
Adding 5GHz connectivity means that your WiFi network can use the versions of WiFi that use this frequency for higher speeds and performance, while still harnessing the coverage (with penetration through walls) that is delivered by the 2.4 GHz frequency band. Dual-band WiFi routers can automatically switch between frequency bands and channels to continually provide optimal performance. The antennas that are supplied with dual-band routers typically have an antenna gain of less than 5 dBi. Purchasing an external dual-band antenna with higher gain (between 5 and 9 dBi) is a cost-effective method of improving signal quality and coverage at both frequencies.
A dual-band antenna can be used to support all the leading versions of WiFi
There are 6 versions of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 protocol that specifies WiFi networking. Of these, three versions use dual-frequency networking and can use a dual-band WiFi antenna:
- WiFi 2 which is 802.11a
- WiFi 4 which is 802.11n
- WiFi 5 which is 802.11ac
802.11a WiFi networking with dual-band antennas
This version of WiFi was the first to utilize the 5 GHz frequency band and can be used simultaneously, but not interchangeably with a 2.4 GHz WiFi network. It was developed to deliver 5 GHz WiFi networking and can achieve speeds of up to 54 Mbps. With this type of WiFi, the transmitted data is encoded onto the carrier signal using Orthogonal Frequency-Division Multiplexing (OFDM). This wideband form of modulation divides the transmitted data into smaller units that are spread across many orthogonally-aligned sub-channels. OFDM is resistant to interference, multipath effects, and fading and uses the spectrum portion allocated efficiently to improve the performance of WiFi.
802.11n WiFi networking features multiple dual-frequency WiFi antennas
WiFi 4 can support wireless networking at both 2.4 GHz and 5 GHz. It uses spatial diversity, which is the use of multiple antennas in a Multiple Input Multiple Output (MIMO) arrangement, to create multiple spatial streams for high-throughput data transfer. With 4 spatial streams, speeds of up to 600 Mbps can be achieved using this version which also uses OFDM. Also, WiFi 4 is backward compatible with 802.11b, 802.11g, and 802.11a, meaning that you can use legacy technology with this version and dual-band antennas to access both frequencies.
A dual-band antenna can be used with the latest available version of WiFi
802.11ac also known as WiFi 5 is the latest and fastest version of WiFi that is commercially available. Using MIMO networking technology, WiFi 5 has increased the capacity, throughput, and speeds that can be achieved with WiFi to up to 1 Gbit/sec. By using wideband networking with amalgamated channels of up to 160 MHz in width, up to 8 devices can exchange data simultaneously at this speed. Up to 8 dual-band antennas will be required for the specified performance at 5 GHz to be achieved.
Frequently asked questions
What are the benefits of a dual-band router?
Dual-band routers can use both the 2.4 GHz and 5 GHz frequency bands for data transfer. They can be used with dual-band antennas for outstanding performance at both frequencies with minimal setup. Simply attach the external dual-band WiFi antenna of choice via the radio frequency connector on the router. These routers are newer and more expensive in comparison to single-band routers that transmit and receive signals at a single frequency only. Key benefits of these routers include:
- Backward compatibility with earlier versions of WiFi that use either frequency.
- Faster speeds
- Less vulnerability to interference as the less congested 5 GHz band is used.
- A massive increase in bandwidth (up to 5334 Mbps) that is available for WiFi networking.
What is simultaneous dual-band?
Simultaneous dual-band describes the type of performance of a dual-band WiFi router that is capable of using both the 2.4 GHz and 5 GHz frequency bands simultaneously. By using both frequency bands at the same time, the available bandwidth is more than doubled and the 5 GHz portion can be dedicated for streaming or gaming. If multiple devices use the network a simultaneous dual-band router can also run the frequency bands as two separate networks to prevent overcrowding.
What is selectable dual-band?
Selectable dual-band uses only one frequency band at a time, providing either a 5 GHz or 2.4 GHz single-band service to serve all networked devices.
What are the Quality of Service controls on a dual-band router?
Many contemporary routers carry integrated Quality of Service (QoS) settings that monitor network traffic and routinely prioritizes devices for greater bandwidth consumption. This is done to optimize user experience across all networked devices. It leads to more efficient use of the available bandwidth, with lower latency, jitter, and loss of data packets. However, errors in the functioning of QoS can lead to misidentification and poor prioritization of devices with slow speeds. If problems are encountered with QoS, it can be disabled.
Can I use an external dual-band antenna with a USB WiFi adapter?
An indoor or outdoor external dual-band antenna can be connected directly to a dual-band USB WiFi adapter that has a removable antenna. Simply connect the antenna to the USB adapters port or connect an outdoor dual-band antenna via a length of suitable coaxial cable with in-line surge protection.
External dual-band antennas deliver excellent connectivity and can be installed with routers and access points to deliver optimal WiFi coverage and speeds at 2.4 GHz and 5 GHz in indoor or outdoor environments. They are a prudent investment for both selectable and simultaneous dual-band WiFi networking and be attached via the main classes of coaxial connectors to antenna cables or devices.
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