Broadband Contiguous Multiplexer Design Using Wideband Pseudo-Highpass Channel Filters

A broadband contiguous multiplexer is introduced using octave-bandwidth pseudo-highpass filters. The proposed design minimizes the number of capacitors in the highpass channel filters, which minimizes total radiation loss from the capacitors. It enables single-layer fabrication such as microstrip line which facilitates size reduction using high dielectric constant substrate. A DC-18 GHz triplexer is fabricated on a microstrip substrate and measured to demonstrate multiplexer performance using the proposed pseudo-highpass filters, which has three channels at DC-6 GHz, 6-12 GHz, and 12-18 GHz bandwidth with the passband losses of less than 2dB.