Broadband and Low-profile Microstrip Antennas with Periodical Structures

In this paper, we have presented two designs of broadband and low-profile microstrip antenna with periodical structures. Broadband performance is mainly achieved by two design principles: Firstly, different periodical radiating patches (strip-slotted or grid-slotted) are applied in proposed antennas to excite TM 10 mode and antiphase TM 20 mode simultaneously; furthermore, antennas are fed by coupling aperture with Y-shaped feeding line, which are utilized to couple two resonant modes together and improve matching performances. Through numerical results, relative bandwidths of two proposed antennas are both higher than 39% with very low profiles of 0.06 lambda(0) . Single polarization and dual polarization can be realized by two proposed antennas, respectively. The design concepts offer possibilities for antennas to be integrated in broadband MIMO communication systems.