A four-input microwave antenna for line-of-sight video data link applications

A four-input L-band data link antenna has been demonstrated which can support simultaneous transmission of four channels of high resolution video. The design consists of four slots that are stacked on a cylindrical mast. Each slot is fed by four probes, with outputs combined and switched to form a variety of azimuth beam states. The antenna was designed using a body revolution method-of-moments code and excellent agreement with measured results was obtained for input impedance, radiation pattern shape, gain, and interelement isolation. Compared to the alternative approach of using a four-channel multiplexer with a single port antenna, an increase of up to 7 dB of link margin is obtained with the four-input antenna approach. The azimuth radiation pattern is switch selectable between omnidirectional coverage with 0 dBiL gain and directional coverage with as much as +5 dBiL gain. Potential benefits from the controllable pattern include enhanced link margin and non-line-of-sight performance through improved EIRP, and better vehicle survivability through LPI/LPD (low probability of interception/detection).<>