Wideband and Flexible Beamforming of Frequency Diverse Array Based on Microwave Photonic Dual-Carrier Signal Generation

In contrast to conventional phased array technology, frequency diverse array (FDA) presents a promising technology for addressing applications sensitive to distance. In order to generate FDA signals with a large bandwidth, as well as to solve the problem of beam decoupling in distance and angle, a novel microwave photonic (MWP) method designed for the generation of dual-carrier FDA signals is first proposed and experimentally verified. The innovative approach utilizes an integrated modulator to successfully produce 16-channel dual-carrier FDA signals, with a power flatness below 1.75 dB and a spurious signal suppression ratio of 35.17 dB. The resultant beampattern deviates from the conventional “S”-shaped pattern, adopting an “X”-shaped configuration instead. It is also demonstrated that increasing the number of array elements can significantly improve the resolution of the beampattern. Dual-carrier FDA signals with different frequency offsets and operating in distinct frequency bands (Ku and Ka bands) are successfully generated and experimentally validated. Furthermore, the capacity of generating 8–12-GHz wideband dual-carrier FDA signals is confirmed. The method further substantiates its versatility by successfully generating dual-carrier FDA signals with nonfixed frequency offsets, such as those based on square, reciprocal, and logarithmic functions. Challenges and prospects of the proposed scheme are also detailed discussed. By harnessing the inherent benefits of MWPs, the proposed method fulfills the demands of high bandwidth and anti-electromagnetic interference, which provide a promising method for future FDA applications.