Design of Wideband Filtering Patch Antenna Array With High Aperture Efficiency and Good Filtering Performance

In this work, a novel design concept of microstrip filtering array antennas is proposed and verified. In this concept, the radiation and filtering performance of the array will be first established by the filtering antenna element, and then optimized by the array topology and feeding structure with intrinsic filtering and resonant performance. This method achieves high-performance microstrip filtering array antennas without requiring additional filtering circuits, offering advantages over the existing design methods. To validate this concept, a microstrip filtering array was designed and fabricated. The filtering antenna element incorporated shorted pins, slots, and metal strips on the rectangular patch, resulting in satisfactory filtering and wideband radiation performance. Subsequently, the proposed filtering antenna elements were mirror-symmetrically placed to create a 1 x 2 array that exhibited superior filtering and radiation performance to the filtering element due to its unique array topology and feeding structure. Finally, a larger 2 x 2 filtering array was designed using a simple two-way power dividing network, which exhibited impressive results, such as an impedance bandwidth of 27.4%, high aperture efficiency (AE), and good filtering performance. Compared with the existing microstrip filtering array antennas, the proposed design provides a wide bandwidth, stable AE, and good filtering performance.