Historically, the term “zoom antenna” has been erroneously applied to reflector antennas that are used to broaden the beam through a defocusing effect; there are a number of these types of antennas described in available literature and existing patents. However, a true zoom antenna incorporates lenses and produces a collimated beam of electromagnetic (EM) energy with a planar wavefront and with continuously variable diameter. This type of antenna provides beam control in terms of spot size and power density on target. A true high power microwave (HPM) zoom antenna greatly extends the range of an HPM source and is useful for such applications as target acquisition and tracking, communications, and electronic attack. Until now, true zoom antenna capability for high power microwave applications did not exist.
Air Force researchers have designed and built a high power microwave zoom antenna comprising a moderate gain feed horn antenna and two parallel plate waveguide antennas. The antenna radiates a collimated beam of linearly polarized electromagnetic waves with continuously variable diameter and an achievable zoom ratio of 10:1. This zoom antenna works with any HPM source with as much as 10% bandwidth that can produce a TE10 mode into a waveguide output. Carbon fiber reinforced polymer composites have sufficient conductivity to replace metal for the lens elements and would provide a stronger, lighter-weight alternative to metal. Such compounds should be considered for lower frequency applications to minimize overall system weight.
- True zoom capability in the transverse electromagnetic mode
- Excellent power handling capability: ranging from tens of megawatts (MW) at 10GHz to several gigawatts (GW) at 1GHz
- Parallel plate waveguide lenses have relatively high tolerance to warping and twisting and are sufficiently lightweight to employ in a field system
- Continuously variable diameter pencil beam output and approximately 10% bandwidth
- US patent 9,583,840 available for license
- Potential for collaboration with Air Force researchers