Design of a Dynamic Phase Shifter for Smart Antenna Applications in Mobile Communications

Abstract

This dissertation presents a research performed in the area of smart antenna transceivers in mobile communications. A circuit is developed to serve as a phase shifter for use in smart antenna arrays for beam control in Base Station Transceivers. The circuit is designed based on the reflection theory to implement a phase shift. The circuit has a good matching characteristics, low attenuation, and accurate phase shift. The design is tested by high frequency simulation software. Finally, to evaluate its overall performance, the return loss, insertion loss, and phase angle are studied. Fundamental theory for multiple antenna systems, phase shifters’topologies and fabrication methods are presented. Theory and some of the earlier research results are discussed. The control of phase is enabled by controlling the capacitance of the varactor optimized using field effect transistors. The circuit comprises a 3-dB directional coupler, inductors as resonating loads, junction field effect transistors (J-FETs) and single pole multiple terminals switching elements. The design steps of the circuit are described, and measurement results from are summarized and discussed thoroughly.