01/08/2018: This antenna covers a frequency range of 4.4 - 5.9 GHz, with 3.75 dBic of peak gain. The antenna features an Ultra-Flex sealed spring base and a black chrome Type-N(m) non-rotating RF connector.
Bifilar antennas have several benefits owing to the helical design of the antenna elements:
• Circular polarization
o Ideal for communication between aircraft and ground stations, as the aircraft can turn and bank without creating a polarization mismatch between the ground station and aircraft. This can occur with two linearly polarized antennas if they are rotated and their polarizations are no longer in the same plane. Circularly polarized antennas can also communicate with linear polarized antennas, with a polarization mismatch loss of -3 dB.
o Circular polarization is less susceptible to disruption by atmospheric layers or inclement weather conditions.
• Continuous overhead coverage, no “keyhole” null – unlike dipole antennas which have an elevation radiation pattern that resembles a donut with a hole in the middle (directly above the antenna), bifilar antennas offer complete overhead coverage without a keyhole null. This makes them useful for close-in communication with vehicles such as airplanes, helicopters, and UAVs.
Also available in RHCP version.
19/07/2018: Technology is an ever-changing field. For this reason, Alaris Antennas is constantly improving existing technologies as well as coming up with new ideas which complement and/or provide better performance than the older methods.
One of our patented technologies is our Hybrid Loop/Adcock Technology, which provides improved Radio Direction Finding performance.
The technology was developed as a result of the constant efforts to reduce the size of antennas while sacrificing little or no performance, often driven by the particular requirements for tactical applications. This technology provides the desirable qualities of Adcock arrays at high frequencies whilst substantially improving the low frequency sensitivity of electrically small Adcock arrays.
This method overcomes to a large extent the shortcomings that loops have when used in a DF array as the approach significantly reduces the sensitivity of the loop to undesirable cross-polarised signals which allows the loop to be used in a wider range of applications to perform DF. The new topology also overcomes the pattern breakup observed in normal loop topologies when the antenna starts becoming large. This allows the new loop design to be used over a much wider frequency range and to start approaching conventional Adcock Array performance at higher frequencies.
The loop antenna technology is able to suppress cross-polarized gain typical of traditional loops and when used in an Adcock array provides enhanced sensitivity when the array size is electrically small.