Wideband Spectrum Sensing and Direction Finding Antenna Subsystem

This paper presents the design and performance of a wideband amplitude-only direction finding (DF) antenna subsystem. The realized configuration is composed of four two-arm spiral antennas squinted symmetrically off boresight by ±35° to allow a DF capability within a wide field of view (FOV) over 1.58.75GHz frequency range in two orthogonal planes. The four spirals are resistively-terminated and backed by LS2O absorber to maintain good unidirectional operation. All measured spirals have gains of >2dBic, axial ratios <; 3dB over wide FOV, and high quality patterns. The system performance is also estimated and low RMS errors are demonstrated for different incident polarizations.