A tri-state SPDT switch using shunt open-end stub resonator for X-band applications

Abstract

This paper presents a tri-state single-pole double-throw (SPDT) switch for X-band applications. The proposed tri-state SPDT switch uses three PIN diodes to switch among three states; two 1:1 modes and one 1:2 mode. In the 1:1 mode, the input power is only delivered to one of the output ports, but in the 1:2 mode, the input power is distributed evenly to the output ports. The proposed concept provides excellent impedance matching in all three states. Proof of concept is experimentally verified using an X-band prototype. The insertion loss is around 2.0dB with better than 18-dB isolation in the case of two 1:1 modes. For 1:2 mode, the insertion loss is around 1.9dB, around 2dB deviates from the ideal 3-dB power splitting.