A beam steering single-arm rectangular spiral antenna with large azimuth space coverage

A novel beam steering single-arm rectangular spiral antenna operating at 3.3 GHz is analyzed using Ansys HFSS. There are 5 switches mounted on the spiral arm. If PIN diodes are used as switches, only one bias signal is required for actuation. Based on different operation of the switches, two cases with maximum beam directions spaced around 1500 in φ-plane are achieved. Both cases have maximum right hand circular polarization (RHCP) gain of approximately 5 dBi and meanwhile cross polarization is suppressed to a very low level. The variation with frequency of the maximum gain, maximum beam direction, and axial ratio is inspected. The proposed design has a 100-MHz bandwidth with good matching, stable maximum beam direction, maximum gain, and circular polarization purity for both cases.