Compensation of Time-Division Multiplexing Distortion in Switched Antenna Arrays With a Single RF Front-End and Digitizer

Switched antenna arrays in which a single RF front-end and a single digitizer are used to perform digital array processing are considered in this communication. These arrays offer more simplicity and versatility than time-modulated arrays, and have the advantage of significantly simplifying the design and implementation of smart and MIMO antennas, while minimizing their size, weight, power consumption and cost. They also lend themselves well to an implementation in which a single off-the-shelf software defined radio is used. Unlike previous work where bandwidth was sacrificed to avoid distortion caused by interference between the multiplexed time channels, this work introduces a digital compensation technique that maximizes the system bandwidth and yields performance approaching that of conventional antenna arrays. The technique is demonstrated in various applications, including direction of arrival estimation and beamforming, and can be employed in arrays of other sensor types.

I. Introduction

Smart antenna systems offer a variety of interesting applications for civilian and military organizations, including direction of arrival (DOA) estimation, multiple-input-multiple-output (MIMO) operation, digital beamforming and interference suppression [1]. However, these conventional array systems typically require a separate RF front-end and digitizer for each of the array antenna elements, thereby increasing the size, weight, power consumption and cost of the systems, in addition to complicating their design and implementation. To alleviate these problems, it is desirable to implement smart antennas with a single RF front-end and a single digitizer using microwave switches to rapidly rotate between the elements of the arrays.