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 split-ring 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 0.048λo (where λ
₀
is the free-space wavelength at the central frequency) is maintained in the proposed antenna.