A Novel Aperture-Loaded Decoupling Concept for Patch Antenna Arrays

In this article, a novel decoupling approach is proposed for large-scale patch antenna arrays. With the additional coupling path from the feeding line of an element to its adjacent element through a small aperture, the mutual coupling between the two elements can be well canceled. Completely different from the traditional transmission-line-based decoupling methods, the proposed approach does not employ direct transmission/coupling bridges between the feeding lines of the elements. Besides, there is no additional impedance matching network, resulting in a simple design procedure. For verification purposes, a decoupled dual-polarized 1 x 8 linear antenna array is developed and tested. Results denote that both the E- and the H-plane coupling are suppressed to less than -30 dB at the center frequency of 4.9 GHz. To further improve the decoupling bandwidth, a magnitude-compensation technique using a dual-aperture configuration is developed. A design example of a 4 x 4 single-polarized patch antenna array integrated with the decoupling method is measured. The results depict that the array is well-decoupled within the band from 4.7 to 5.04 GHz, with an isolation level of over 24.7 dB. The proposed decoupling approach features simple implementation and low profile, with almost no influence on element radiation performance, and can be utilized for 2-D large-scale arrays.