Switchable Multi‐Band Filtering Attenuator

This letter presents a design method for a switchable multi‐band filtering attenuator. First, a multi‐band filtering function is designed using the generalized Chebyshev function as the prototype. By incorporating a genetic algorithm and a minimum optimization algorithm, the filter can flexibly specify the number of passbands, center frequency, bandwidth, order, and return loss (RL) for each band. To enable independent amplitude control for each passband, the resonators corresponding to each band are decoupled. The amplitude attenuation is achieved by adjusting the quality factor (Q‐factor) of each resonator. To validate the theoretical approach, a switchable dual‐band filtering attenuator (SDBFA) is designed, with the first passband ranging from 435 to 455 MHz and the second from 860 to 920 MHz. Measurement results show that the amplitude of each passband can be independently controlled, and both passbands can be individually switched on or off.