Dual-Band Dual-Polarized Antenna Elements And Arrays

To meet the urgent requirements of national economy and military applications formicrowave image synthentic aperture radar (SAR) and wireless communications, thisdissertation makes a deeper study on several antenna elements and arrays including thedual-band dual-polarized (DBDP) microstrip antennas and dielectric resonator antennas(DRAS) for SAR systems. Several novel designs are proposed and and validated byexperiment or simulation. The major work is outlined as follows:Firstly，a wideband L/S DBDP microstrip antenna array is designed with3×8element dual-polarized microstrip array in S-band. During element antenna design, aperturbation technique is used to optimize the two orthogonal ports isolation level. For thisarray, its measured impedance bandwidth is larger than15%with isolation between twoorthogonal ports higher than47dB. The antenna achieve±30°phase scanningperformance of one dimension for both orthogonal ports with cross-polarization levellower than-30dB. A wide beam dual-polarized slot antenna is introduced.Secondly, a high-isolation dual-polarization dielectric resonator antenna and a2×2element dielectric resonator antenna array are developed. By using the multi-stubsmicrostrip feed, the level of port isolation is improved, while the “pair-wise anti-phase”feed technology is used in array for the better cross-polarization level of the dual polarizedarray. The measured isolation between two ports is higher than45dB, and the measuredcross polarization level in the main lobe of DRA array is less than-21dB. Furthermore, ahigh isolation low cross-polarization DP DRA has been design. The measured isolationbetween two ports is higher than46.8dB, standing in the advanced level among thepublished papers.Finally, a novel design of share-aperture S/X DBDP DRA array is proposed, whichcombines S-band microstrip dipoles and X-band DRA in an interleaved manner to achievefrequency ratio of1:3in a shared-aperture configuration. Besides the stub microstripfeedline, H-shaped and U-shaped slots are used for high isolation and low polarizationduring the X-band dual-polarized DRA element design. The simulated impedancebandwidth is over16%. One scheme is discussed to suppress the diffraction for an edge in a perfectly conduction sufface.