Radiation Pattern Decoupled Patch Antennas Based on TM₀₁ and TM₁₁ Modes

In this letter, 1 × 2 L-probe fed patch antennas are decoupled with undistorted radiation patterns, based on the TM₀₁ and TM₁₁ modes of the patch. Metallic vias are employed to increase the resonant frequency of the TM₀₁ mode, whereas slots can be cut on the patch to decrease the frequency of the TM₁₁ mode. When the E-fields of these two modes are with appropriate amplitude ratio and phase difference, the E-fields inside the excited patch will be superposed whereas those inside the coupled patch will be canceled to a relatively low level. Further fine tuning the vias and slots can merge the resonant frequencies together and restore the maximum radiation along the boresight direction. To verify the effectiveness of the design idea, a prototype with zero edge-to-edge spacing is designed for 2.4-GHz WLAN applications. Good agreement can be observed between the measured and simulated results. The measured overlapping 10 dB impedance bandwidth is 5.7%, over which the isolation is larger than 20 dB. It should be highlighted that undistorted radiation patterns can be obtained with this approach. © 2023 IEEE.