Multi-mode resonator-fed dual polarized antenna array with enhanced bandwidth and selectivity

A novel design concept of multi-mode filtering antenna, which is realized by integrating a multi-mode resonator and an antenna, has been applied to the design of dual-polarized antenna arrays for achieving a compact size and high performance in terms of broad bandwidth, high frequency selectivity and out-of-band rejection. To verify the concept, a 2×2 array at C-band is designed and fabricated. The stub-loaded resonator (SLR) is employed as the feed of the antenna. The resonant characteristics of SLR and patch as well as the coupling between them are presented. The method of designing the integrated resonator-patch module is explained. This integrated design not only removes the need for separated filters and traditional 50 Ω interfaces, but also improves the frequency response of the module. A comparison with the traditional patch array has been made, showing that the proposed design has a more compact size, wider bandwidth, better frequency selectivity and out-of-band rejection. Such low-profile light weigh broadband dual polarized arrays are useful for space-borne synthetic aperture radar (SAR) and wireless communication applications. The simulated and measured results agree well, demonstrating a good performance in terms of impedance bandwidth, frequency selectivity, isolation, radiation pattern and antenna gain