Linear polarisation switchable ring-slot array antenna using single-pole double-throw switch circuit

Abstract

A linear polarisation switchable ring-slot array antenna is presented. The antenna is comprised of a four-element ring-slot array and a single-pole double-throw (SPDT) switch circuit. The linear polarisation switchable function is achieved using the SPDT switch circuit. Two Schottky barrier diodes are mounted on a slot ring of the SPDT switch circuit. Since the orthogonal linear polarisation switching depends on the diode ON/OFF conditions, the polarisation angle is easily controlled by the polarity of the bias voltage. The excellent design flexibility of double-sided microwave integrated circuit technology is effectively employed in forming this type of antenna. Experimental results show that the proposed antenna has good polarisation characteristics for the two orthogonal linear polarisations. The radiation performances of the two orthogonal polarisations are almost identical. Consequently, a linear polarisation switchable ring-slot array antenna is successfully verified.