Research And Design Of Broadband Reflectarray Antennas

With the development of society and science and technology, there is a growingdemand for social life; meanwhile, there is a serious need for antennas with the features ofhigh gain and low cost by modern communication system. As a combination of theadvantages of parabolic reflectors and phased arrays, a microstrip reflectarray antenna hasthe advantages of small size, low mass, easy deploying, low cost, and easy fabricationwhich makes it widely used in the fields of space exploration, satellite communication,radar system and so on.However, one distinct disadvantage associated with the reflectarray antenna is itsinherent characteristic of narrow bandwidth. To overcome this problem, this thesis is aimedat developing a novel broadband reflectarray antenna and exploring the possibilities inengineering applications. Firstly, after completely studying and summarizing the previouscontributions in microstrip reflectarray, especially paying much attention to variousmethods of increasing the bandwidth of reflectarray elements, the author of this thesispropose three novel wideband element structures. Then, a vivaldi antenna being used as thefeed to decrease the effect of blockage, broadband reflectarrays are designed and realizedusing the proposed broadband elements, which also validates the broadband property of theelements. At last, some research on dual-beam reflectarray antennas and beam-scanningreflectarray antennas is done.