On the Design of a Substrate Integrated Waveguide Butler Matrix for K-Band Applications

Abstract

This paper presents a Butler matrix design and construction in the K band using -3 dB and 0 dB hybrid couplers designed in Substrate Integrated Waveguide (SIW) technology that covers the 18 - 22 GHz bandwidth with excellent performance in terms of phase error and amplitude imbalance. The measured results, supported by simulations, show an input coincidence better than 20 dB, transmission and coupling losses of around 8 dB, and isolation better than 15 dB.