Squint Video SAR by Exploiting Frequency Dispersion of Wideband Phased Array.

The frequency dispersion of wideband phased array will lead to the variation of beam point angle with the frequency of transmit signal. In this letter, such phenomenon will be exploited for squint video SAR. Firstly, the frequency dispersion will make the centroid Doppler frequency independent from the range frequency. The spectrum support region will be rectangular in such case. Therefore, the different frequency components of the transmit signal will illuminate the same ground target in different slow time duration. A SAR video can be obtained through splitting the range frequency spectrum instead of the Doppler spectrum. Then, the azimuth resolution can be maintained. Meanwhile, the large bandwidth being employed can not only maintain the range resolution after splitting but also can enlarge the time duration of squint SAR video. Numerical simulations verify the effectiveness of the proposed method.