A T-Shaped Strips Loaded Wideband Filtering Patch Antenna With High Selectivity

A novel wideband filtering patch antenna loaded with T-shaped strips is proposed in this letter. The antenna consists of a radiating patch with a pair of symmetrical T-shaped strips and a parasitic branch located at the bottom of the dielectric substrate. Introducing a pair of T-shaped strips on both sides of the square patch excites a low-frequency resonant mode and generates a radiating null at the edge of the lower band. Then, a rectangular branch is introduced underneath the substrate as a quarter-wavelength open-circuit strip, and a high-frequency resonant mode and upper-band radiation null are created. In addition, the introduction of the two structures above excites double resonant modes, which will efficiently improve the bandwidth of the antenna. The prototype has been fabricated and measured. The measurement results of the proposed wideband filtering antenna show that the −10 dB impedance bandwidth is 16.1% (from 2.29 to 2.69 GHz), with a peak gain of 9.6 dBi. Two radiation nulls besides the passband are located at 2.23 and 2.81 GHz, separately. What's more, the antenna is simple in structure and easy to manufacture.