Performance of a Spiral Antenna System for Wideband Sensing and Direction Finding

A design of a wideband two-arm spiral antenna system is presented. By squinting the elements off boresight, spectrum sensing and direction finding over a wide range of angles and frequencies can be achieved. With a 10 turn spiral element fed by stripline balun and squint angle of 30°, a minimum gain of -6 dBic, maximum axial ratio of 5 dB and minimum DFF slope of 0.1 dB/o is seen over the field of view of ± 60°.