Research On Microstrip Reflectarray Antennas

Microstrip reflectarray antenna is an antenna array which combines advantages of reflectorantennas and microstrip array antennas. It is made up of an array of microstrip radiating elements thatprovide a pre-adjusted phasing to form a focused beam in an assigned direction when it is illuminatedby a feed. Microstrip reflectarray antenna is extensively applied in high performance radar, remotecommunication, aerospace measurement and control, and deep-space exploration due to its attractivefeatures: low profile, light weight, and low cost, etc.A broadband microstrip reflectarray antenna and a reactive-loaded microstrip reflectarrayantenna are researched in this thesis. The research work is presented as follows:1. Parameters of a novel circular-single ring-combination element are optimized in HFSS, and abroadband microstrip reflectarray element is designed. A broadband microstrip reflectarray antenna isthen obtained by utilizing the circular-single ring-combination element as its phase shifting radiatingelement.2. Phase shifting curves of a single-resonance element, a double-resonance element and atriple-resonance element and the bandwidth of the reflectarrays are analyzed. The simulation resultshows that the phase shifting range will be larger as number of the resonance elements increases, butit might lead to a lower gain and a narrower bandwidth.3. A fast computing method based on scattering parameter matrix technology for reactive-loadedreflectarray antennas is deduced. A10GHz reactive-loaded microstrip reflectarray is designed byusing the fast computing method. The result shows that the calculated radiation patterns match theradiation patterns simulated in CST well.