Study on optical compensation method for beam squint problem of broadband phased array antenna

Phased array radar has important applications in military and civil fields. In order to improve the performance of radar systems, there is a growing demand for increased the signal bandwidth. However, with the larger bandwidth, the traditional phased array system based on microwave phase shifter will have obvious beam squint phenomenon when realizing beam pointing adjustment. Hence, the microwave photonic broadband phased array with the core of light-controlled microwave technology has become a much-appreciated realization of broadband phased array. For the beam squint phenomenon caused by broadband signals, this paper proposes a scheme of using the true time delay introduced by a continuously tunable Mach-Zehnder interferometer for compensation in optical domain. Four different bandwidth with different center frequencies were designed and validated to achieve a squint free beamforming within the scanning angles of ±30°.