A Low-Profile Dual-Polarized Patch Antenna with Bandwidth Enhanced by Stacked Parasitic Elements

In this paper, a low-profile dual-linear polarized patch antenna composed of two stacked substrates, one air gap layer, and one grounded substrate is proposed. There is a feeding patch element with two excited probes placed on the top side of the grounded substrate, and one parasitic patch element and a 2.2 parasitic array patch elements printed on the lower and upper stacked substrate, respectively. The T- and rectangular slots and T-stubs are employed on/near the orthogonal axis of the patches for the impedance matching and two orthogonal polarizations improvement. Furthermore, four stacked complementary splitring resonators (CSRRs) are loaded in the two stacked substrates mainly to adjust the impedance matching and port isolation with an induced dual-polarized resonance. Thanks to the stacked patches and CSRRs, an enhanced impedance bandwidth from 1.2% to 7.4% was achieved by the introduced three additional dual-polarized resonances. Simulated results show the antenna has a impedance bandwidth across 2.362-2.544 GHz (fractional bandwidth 7.4%), a maximum realized gain of 10 dBi, and port isolation better than 22 dB over the operational bandwidth. In addition, a low profile of 0.048 lambda(0) (where lambda(0) is the free-space wavelength at the central frequency) is maintained in the proposed antenna.