Design Of Low RCS And Wideband Microstrip Reflectarray Antennas

With the rapid development of modern radar and satellite communications, thehigh-gain antennas are playing a more and more important role. Traditionally,high-gain applications have relied upon parabolic reflectors or arrays. The microstripreflectarray combine certain advantages of parabolic reflectors and arrays, such aslight-weight, easy fabrication, low profile, low cost and so on. It attracts manyattentions in the past decades.In this paper, first of all, the review about the functional principle and basicconfigurations of the microstrip reflectarray is presented, including its advantage,disadvantages and development in the last decades.Furthermore, based on the discussion of the basic knowledge about RCS, sometechniques for the RCS reduction are stated, and a novel RCS reduction technique formicrostrip reflectarray antenna, employing the appropriate FSS as ground, is proposed.Then, a37-element FSS-backed microstrip reflectarray is fabricated and tested,compared with its conventional counterpart backed by solid ground. Appreciably goodRCS reduction has been achieved ‘out-of-band’, and ‘in-band’ performance keepsunchanged as well. A good agreement is achieved between simulated and measuredantenna characteristics.Finally, in order to break the limitation of the narrow bandwidth characteristic, anovel high-gain wideband microstrip reflectarray is proposed. The wideband isachieved by adjusting the structure of elements and the characteristic of substrates. Thefeature of the cell element is investigated along with the design of the feed and array. A52-element array prototype based on the proposed element has been fabricated andmeasured. The validity of this method is confirmed by computer simulation andmeasured results.