A Hairpin Line Diplexer for Direct Sequence Ultra-Wideband Wireless Communications

A high performance hairpin line diplexer for the direct sequence ultra-wideband communication is designed and implemented. This microstrip diplexer is mainly composed of two hairpin line wideband bandpass filters and a tapped open stub. The design concept is proposed in detail and has been verified by the experimental results of the fabricated diplexer, including the two isolated wideband bandwidths of 3.1-5.0 GHz and 6.02-10 GHz, low insertion loss and high isolation. Experimental results also show a good agreement with the simulated results.