Novel Multiplexer Topologies Based on All-Resonator Structures

This paper presents two novel multiplexer topologies based on all-resonator structures. Such all-resonator structures remove the need for conventional transmission-line-based splitting networks. The first topology is a diplexer with transmission zeros in the guard band, shared by both channels. These transmission zeros are generated by introducing a cross coupling in a quadruplet in resonators common to both channels. A twelfth-order diplexer with a pair of transmission zeros is presented here as an example. The second topology is a multiplexer with a bifurcate structure that limits the connections to any resonator to three or less, regardless of the number of output channels. A sixteenth-order four-channel multiplexer is presented as an example. Both topologies have been demonstrated at X-band using waveguide technology. Good agreements between measurements and simulations have been achieved.