Cavity-Backed Dual-Sinuous Antenna Modeling

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.

Thin-wire radiating structures with double symmetry

The problems of electrodynamic analysis of thin-wire radiating structures with double symmetry are considered. New generalized integral representations of the electromagnetic field are obtained for the case of structures with single and double symmetries. Based on the obtained expressions, mathematical models of two - and four-way elliptical spiral antennas are constructed. It is shown that taking into account double symmetry in solving the internal electrodynamic problem leads to a set of independent Fredholm integral equations of the first kind written with respect to the distributions of normal current waves, which significantly simplifies the solution of the internal electrodynamic problem. Comparisons of current distributions along conductors, their input resistance dependences on the radius of the structure, and normalized radiation patterns for two- and four-way spiral emitters are presented.