An optimized lossy back cavity loaded four arm sinuous antenna

Sinuous antennas have wideband characteristics (constant beam width and low axial ratio over a broad range of frequencies), and thus they are suitable for communicating (transmitting and receiving) over bands of frequencies (multiple channels) in airborne and communication systems. In the presence of the back cavity, the performance of the sinuous antenna is affected. This paper presents an optimized loaded lossy back cavity that does not degrade the performance of the antenna. The simulated performance of a four arm sinuous antenna with unloaded back cavity is compared with the antenna loaded with the optimized back cavity.