Wideband substrate integrated waveguide power splitter with high isolation

Design and realisation of a novel substrate integrated waveguide (SIW) power splitter with high isolation is presented. The configuration of the proposed splitter is similar to a conventional four-port waveguide magic Tee whose E-plane arm is matched. To implement the matched E-plane arm in the SIW technology, a slot on the upper conductor of the SIW along with a number of terminating resistors is used. The designed SIW splitter is then fabricated and measured on the coaxial ports of three coaxial-to-SIW transitions. Measured results on the coaxial ports indicate that the fabricated power splitter features more than 10 dB of input and output return loss across a 42% bandwidth from 9.6 to 14.8 GHz. The isolation between output ports is better than 10 dB within a wider frequency range from 8.7 to 15.5 GHz.