Design And Implementation Of Frequency-controlled Array Based On Chirp Continuous Wave

FDA is a new concept of antenna array,which increases the frequency offset degree of freedom between array elements.FDA has many new characteristics that are not found in traditional antennas,so FDA is one of the hot topics in current academic research.Recently,there are a lot of research achievements on FDA,but most of them focus on simulation research,and there are few public reports on the hardware implementation of FDA.In order to solve this problem,this paper makes a deep research on FDA based on LFMCW system.Not only uniform FDA is developed,but also a new kind of FDA with non-uniform frequency offset is put forward,and experimental verification is also carried out.The specific work is as follows:(1)A four-element uniform frequency offset FDA based on LFMCW is realized,and the frequency bandwidth is 6-10 GHz,time delay between two adjacent array elements is 0.58 ns,the distance between two adjacent array elements is 25 mm.This kind of FDA is range-angle-time dependent,the beam pattern on the range-angle is of “S” shape,and has periodicity in the distance dimension.By adjusting the slope of LFMCW,frequency offset between two adjacent array elements is changed.LFMCW are transmitted to each array element through a four-channel beam former,and provide different frequencies to each element.The signals on each array element are combined into a single signal through a power combiner,the amplitude modulation of FDA in the time dimension can be detected on the oscilloscope through RF coaxial detector.(2)An eight-element non-uniform frequency offset FDA based on LFMCW is realized,and the frequency bandwidth is 9-11 GHz,the distance between two adjacent array elements is25 mm.Different from the “S” shape beam pattern of uniform frequency offset FDA,the non-uniform frequency offset FDA can concentrate energy to the expected target position,the maximum of the beam pattern only exists at the desired target,the side-lobe distribution is sparse and the amplitude does not exceed 50% of the peak value.The signals on each array element are combined into a single signal through a power synthesizer,the amplitude modulation of FDA in the time dimension can be detected on the oscilloscope through RF coaxial detector.