Theory and Design of Intrinsically Switched Multiplexers With Optimum Phase Linearity

This paper presents the theory, design, and implementation of a new class of component called an intrinsically switched multiplexer, which is comprised of a number of contiguous bandpass filter channels that can be independently switched on and off with very low architecture-related insertion loss and flat group delay across adjacent switched-on channels. Coupled-resonator filter topologies are identified that allow for optimum performance of contiguous bandpass channel filters through the crossover frequencies, and a new intrinsically switched coupling section that provides for low on-state insertion loss and high broadband off-state isolation is presented. In addition, it is shown that the channel filters can be combined in a scalable fashion with the use of lossy manifolds. A three-channel eight-state intrinsically switched multiplexer microstrip prototype was designed, built, and tested and gives 6.7 dB of passband insertion loss and 0.15-ns p-p group delay ripple over 72% of the passband.