Improving Bandwidth of the Phased Array Antennas Based on Sub-array True Time Delayers

The beam pointing of phased array antennas that adopt phased shifter irrelevant to frequency is changed with frequency.The true time delayer(TTD) for wideband phased arrays is an important method to improve the beam-pointing accuracy.In this paper,the excursion of beam pointing versus frequency is analyzed while the planar phased array scanning.It is shown by analysis and simulation that the beam-pointing is just changed in elevation and changed invariably in azimuth plane.The beam-controlling techniques which subarray division is adopted,the TTD is used in sub-arrays and phased shifter is used in elements,are discussed in detail.The results shown that the bandwidth of phased array antennas can be expanded effectively.