Hybrid microstrip/SIW power divider with improved output isolation

An eight-way hybrid microstrip/substrate integrated waveguide (SIW) power divider with good output isolation performance is proposed in this paper. The circuit consists of microstrip/SIW transitions and a cross-shaped SIW cavity. The good isolation characteristics is obtained by adding the resistors between the microstrip lines and the isolation resistors on the radial slotlines. The equivalent circuit is given in this paper to analyse the proposed power divider. A prototype was fabricated and measured. The measurement results show that the insertion loss (IL) is about 1.5 dB from 9.1 GHz to 10.15 GHz, and the input return loss (RL) is higher than 20 dB. The isolation of adjacent ports on the same side, adjacent ports on the different side, and opposite ports are higher than 17.5, 19, and 15 dB, respectively. The error between measurement and simulation is acceptable.