Cavity-Backed Dual-Sinuous Antenna Modeling

Abstract

Recently, for Radio Frequency (RF) signal identification on air vehicles, it has become critical to not only be able to detect the direction and angle of arrival of signals, but to also properly identify the polarization of such signals. For decades, cavity-backed dual-spiral antennas were heavily used for this purpose. However, that required the placement of both right-hand and left-hand elements to perform this function. Due to limited space and other issues, an alternative type of broadband antenna had to be identified. The Cavity-Backed Dual-Sinuous (CBDS) antenna makes an excellent replacement for this function. With its elements rotated 45° about its center, each element exhibits slant linear performance. Such an antenna, paired with proper connections and detection hardware, allows the detector to determine the polarization of arriving RF signals. A CBDS antenna was developed in the WIPL-D CEM code. Its RHCP and LHCP performance was studied over a broad range of frequencies. Results did prove that CBDS antennas have excellent broadband performance and polarization extraction.