Low cost phased array antennas using analog and digital phase shifters technologies

In this paper we present two new low cost implementations of the Coplanar Waveguide Continuous Transverse Stub (CPW-CTS) antenna array technology in phased array systems with beam steering capabilities. The first is based on using a hybrid smart antenna technique and digital beamforming, while the other is derived from an integrated implementation of the CPW- CTS and Ferroelectric material technologies. The digital beamforming mechanism relies on the use of directional antennas elements in the array and the employment of a smart switch that connects a sub-array containing elements with highest receive signal strength to the receiver and the beamforming algorithm, thus reducing the hardware cost, improving computational efficiency and accuracy, and reducing latency. Simulation and experimental results are presented showing the trade-offs involved and clearly demonstrating the feasibility and accuracy of this approach. The analog beam steering approach, on the other hand, is based on an integrated multi-dielectric layers coplanar waveguide phase shifters and CPW-CTS array antenna design. Simulation results show that such an approach could provide analog beam steering of the order of 20° while maintaining acceptable levels of biasing voltages for the Ferroelectric material layer. These as well as other simulation results illustrating the complementary nature of these two approaches as well as the various trade-offs involved will be presented.

INTRODUCTION

Phased array antennas have and will continue to be a critically important component in the development of future wireless systems with applications in communications, radar, and Satellite technologies. In spite of the significant advances in the design of modern phased array antennas systems, there continue to be significant and growing need for developing high performance systems that are also low cost and with beam steering capabilities. In this paper we describe two complementary designs that focus on achieving this goal. The first is based on digital beamforming and utilizes the recently developed Hybrid Smart Antenna technique developed by our group while the other utilizes an analog phase-shifting approach using Ferroelectric material technology. In both cases the Coplanar Waveguide Continuous Transverse Stub (CPW-CTS) antenna array system is used in the design and simulation results.