Low Cost, Low RCS Antenna for Radio Frequency Anechoic Chambers

The objective of this effort is a preliminary design of a low RCS, low cost, controllable antenna system for use in RF anechoic chambers. The antenna technology proposed has been proven to work for Low Observable (LO) aircraft applications. The proposed utilization for chamber operation will involve design simplification and low cost construction. Beam width and beam direction are readily controlled since the antenna is an array. Costs can be controlled by using routine printed circuit etching technology to produce repeatable, accurate feed network on a single layer. Beam control can be achieved by an inexpensive switch network on each array column or row by a space feed. The low RCS aspects of the antenna design are achieved by carefully controlling array element input impedance for a wide range of scan angles by using compensating dielectric layers. Potential feed network returns are controlled by including integral hybrids in the etched as part of the feed network. both structural and antenna mode scattering are controlled by this array configuration. Array edges must be carefully blended into the surrounding chamber absorber. This concept has been proven to exhibit low RCS and dependable antenna performance over a 4:1 bandwidth.