LFM Pulse Compression of Wideband Passive Phased Array Based on True Time Delay

Phase scanning is realized for narrow band phased array by the phase shift method that compensates wave path difference of signified directions. The resolution of the wideband phased array is higher than the narrow phased array. But the frequency band of the wideband phased array is wider. Traditional method can\´t compensate the wave path difference completely, which causes the beam broadening and the antenna gain decreasing. The phenomenon of """"aperture transition"""" will occur in the case of large scan angle for wideband phased array, which causes the range resolution decreases. A method based on true time delay that compensates the wave path differences of all frequency components within the signal bandwidth is presented in this paper. The wideband linear frequency modulated signal is illustrated to realize true time delay of phased array and demonstrate the effectiveness of the proposed method by computer simulation. The result of computer simulation demonstrates that the wideband passive phased array based on true time delay has the same antenna gain and azimuth resolution with the narrow band phased array and improves the range resolution.