LAUSR

Incontrast to the steady angle-dependent transmit beampattern of the conventional phased array, the counterpart of a frequency diverse array (FDA) is basically time variant and range–angle coupled, which limits its potential application in many scenarios. In this article, we consider the beamforming in joint transmit and receive domains to handle the time-variant problem and propose a novel range–angle transceiver beamforming approach based on the semicircular-FDA scheme. In particular, the transceiver scheme of semicircular-FDA is first established.In the sequel, the periodicities of its transceiver beampattern in range and angle dimensions are briefly analyzed. Based on this analysis, a semicircular-FDA applied with nonlinearly increasing frequency offset (NIFO), termed as NIFO semicircular-FDA, is proposed to achieve the beampattern with a single mainlobe peak in range–angle space. Then, an optimization problem is constructed based on an advanced bat algorithm to further reduce the sidelobe level (SLL) of the NIFO semicircular-FDA. Numerical results show that focused time-invariant beampattern with low SLL in both range and angle dimensions can be achieved with the proposed approach.