Resonant Manifold Multiplexers

This article presents a new compact multiplexer structure and its design approach, based on a novel resonant manifold. Different from typical transmission-line-based manifold multiplexers, the proposed manifold junction is formed of coupled resonators, so that the manifold also contributes to the filtering poles and selectivity in the passbands. The all-resonator configuration achieves a more compact footprint than the conventional manifold. This multiport filtering network can be represented by a single coupling matrix which can be obtained by using a robust optimization-based method. Tailored channel frequency allocation schemes are presented for the proposed multiplexers with a different number of channels. To validate the proposed concept, a triplexer and a five-channel multiplexer, both at X-band, are designed and tested using rectangular waveguide technology. Good agreements have been achieved between the measurement and simulations. Comparisons have been made with conventional multiplexers.