Date of Award

5-31-2019

Document Type

Dissertation

Publisher

Santa Clara : Santa Clara University, 2019

Degree Name

Doctor of Philosophy (PhD)

Department

Electrical and Computer Engineering

First Advisor

Ramesh Abhari

Abstract

A millimeter-wave 2-D beam switching microstrip patch antenna array excited by a 4x4 substrate integrated waveguide (SIW) Modified Butler Matrix is designed and experimentally evaluated in this thesis. A novel architecture is introduced for the Butler Matrix feed network to give designers a choice for phase shifter location to pursue a smaller circuit area. In addition, it enables the designer to control the BM phased outputs for achieving a set of desired 2-D beam directions, e.g., ϕ0=45°, 135°, 225°, and 315° at θ0=45°, with a passive beam switching network for a given array geometry. Full-wave simulation results show when the so designed 4x4 Butler Matrix feeds a 2x2 planar patch antenna array, 4-quadrant beam switching is achieved.

To meet the goal of providing a low cost small footprint solution, the presented Modified Butler Matrix features straight SIW phase shifter using periodic apertures. The Modified Butler Matrix is fabricated on a single layer Rogers RO4350B substrate, achieving a circuit area of 222.5 mm2, which is a 54% improvement over previously published 60 GHz results. The fully-integrated antenna array system is created by development of a new SIW to planar patch antenna transition structure which maintains a total antenna frontend area of 333 mm2, just 42% of the area of the next closest SIW 2-D beam switching publication at 60 GHz.

For verification of beam switching via over the air (OTA) measurements at 60 GHz, a benchtop anechoic chamber with proper transmitter and receiver antenna positioners is designed and fabricated using in-house maker laboratory resources. 2-D beam steering is proved in the intended 4 quadrants of radiation space at ϕ0=50°, 140°, 220°, and 300° and θ0=30±5° demonstrating meeting the design specifications with a very good margin. As well, for each switched beam the gain of antenna array was measured to be between 4.8 to 6 dBi at 60 GHz which is within 1dB deviation from the simulated results.

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