Design and Analysis of Absorptive Filter Integrated SPDT Switch using Coupled Line L-shape and Transmission Line Stub Resonators

This paper presents the design and analysis of absorptive filter integrated Single Pole Double Throw (SPDT) switch using coupled line L-shape and transmission line stub resonators. The design was based on coupled line L-shape resonators that can provide an absorptive feature. PIN diodes were used as switching elements to reconfigure between band-stop and band-pass responses on the coupled line L-shape resonators. Then, transmission line stub resonators were used to produce additional isolation improvement. The proposed design was demonstrated for 2.45 GHz applications such as Bluetooth and ZigBee. Therefore, the key advantages of the proposed design are high isolation and good return loss at both ON- and OFF-state during transmit and receive operations. As a result, the simulation and measurement showed the followings: higher than 10 dB of return loss and greater than 50 dB of isolation at the operating frequency of 2.45 GHz.