Multibeam Amplitude Comparison Problems for MIMO Radar's Angle Measurement

Amplitude comparison angle measurement is a practical technology for its simple structure and low complexity. MIMO radar can view a broad angular sector and form multiple simultaneous joint-beams. It is very suitable to implement multi- beam amplitude comparison angle measurement in MIMO radar. As the accuracy of angle measurement depends directly on the half-power beamwidth of the antenna pattern, we make detailed analysis on the joint-beam properties for MIMO radar, and derive the mathematical expressions of the half-power beamwidth and peak sidelobe level. We also provide an effective method for allocating the multibeam directions in this paper.

I. Introduction

MIM Oradar [1]–[4] has become a hot topic in recent years. As waveforms transmitted by different channels are orthogonal, the radiated energy will cover a broad angular sector [2]. Based on the orthogonally coded waveforms and the knowledge of array elements positions, MIMO radar can form receive beam and virtual transmit beam jointly at the receiver. Compared with the conventional phased array radar, MIMO radar enjoys both narrower beamwidth and lower sidelobes of the joint-beam [3]. In section II, we discuss the joint beamforming process in MIMO radar.