Compact substrate integrated waveguide six‐port directional coupler for X‐band applications

A substrate integrated waveguide six-port directional coupler is designed and characterized. The circuit exploits a very compact size and good reflection and transmission characteristics, as it exhibits both return loss and isolation higher than 15 dB over a 13% bandwidth. The device is made by connecting all ports to a single junction which mixes all signals. Some prototypes have been built and experimental results show a very good agreement with simulations. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2589–2592, 2015