Filtering T-Type Switch With Flexible Signal Routing Reconfigurability for Crossover-/Adjacent-Channel Applications

In this letter, a filtering T-type switch is proposed for the first time, which exhibits signal routing reconfigurability for crossover-channel (State 1) and adjacent-channel (State 2 or 3) applications. The circuit consists of four T-shaped feeding lines, eight short-ended half-wavelength resonators, and a ring resonator. The p-i-n diodes are loaded to the resonators for switching ON and OFF the signal channels. When the diode is turned off, the channel is switched ON and intrinsic filtering responses are integrated by the coupled resonators. When the diode is turned on, the input admittance of the resonator is tuned to infinite for switching OFF the channel. In addition, the second harmonic is suppressed by the feeding structure. For verification, the circuit is implemented. The measured results exhibit good bandpass responses with high out-of-band suppression and high isolation in each state.