A Microwave Single-Pole Double-Throw T/R Switch Integrating Bandpass Response

This paper proposes a microwave single-pole double-throw (SPDT) T/R switch integrating bandpass response. The series-parallel configuration of p-i-n diodes embedded into the impedance matching circuit is proposed to combine two quasi-elliptic response bandpass filters to constitute the proposed SPDT T/R switch. To validate our design approach, a proposed SPDT T/R switch integrating bandpass response is designed and fabricated with a central frequency of 1.25 GHz and a 3 dB fractional bandwidth of 16%. Low insertion loss in the on state and good isolation in the off state are achieved. The switch size including bias circuits but excluding feeding lines is 0.4472 lambda(g) X 0.134 lambda(g).