Micromachined millimeter-wave Butler matrix with a patch antenna array

Abstract

This paper presents a micromachined patch antenna array with an integrated 2×2 Butler matrix (BM) beamformer. It was designed at 63 GHz and simulated using CST Microwave Studio 3D simulator. The BM is made using a low loss air filled rectangular coaxial line. The structure is constructed by bonding five layers of gold coated photoresist SU-8, each 200 microns thick. The experimental result shows a good matching achieved with return loss of −13 dB and inter-port isolation of about −22 dB at 63 GHz.