A higher-order mode air-patch antenna with a T-shape feed

In this paper, an air-patch antenna operating at quasi-TM21 mode with a wide impedance bandwidth characteristic is proposed. The proposed antenna has a simple configuration, which mainly composed of a radiating patch and a T-probe. After the analysis of cavity model, the electromagnetic coupling point on the rectangular patch is chosen, which inspires a higher-order mode (quasi-TM
21
mode). Different from the other feed ways, the T-shape feed can supply a wider impedance bandwidth. The proposed antenna achieves a matching bandwidth of 54.9% (
$\text{VSWR} < 1.5$
) ranging from 1.61 to 2.83 GHz. A prototype has been fabricated and then measured, and the measurement results are in good agreement with the simulated ones.