60 GHz substrate integrated waveguide crossover structure

A four-port substrates integrated waveguide coupler in the form of a crossover structure is proposed and developed for signal distribution and routing applications. This coupler is composed of four-arms waveguide section connected by a central junction. It is well known that the standard crossover is generally composed of two 3 dB couplers whose loss and size are usually large. In this work, an extremely compact and low-loss 0 dB coupler (cross-over) is realised at 60 GHz with the proposed coupler configuration. Measured results on the basis of the realized prototypes agree well with theoretical predictions and simulated results. This coupler is demonstrated to have a 5% relative bandwidth with less than 0.2-dB coupling loss.