Wideband Self-Decoupled Closely Placed Dielectric Patch Antenna Array Without Additional Structures

A novel wideband self-decoupling method for a closely spaced dielectric patch (DP) antenna (DPA) array is proposed in this paper. Based on the miraculous characteristics of the employed resonator modes, the HEM $_{11\delta }$ and TE12 modes can be excited and decoupled simultaneously. For the fundamental HEM $_{11\delta }$ mode, the attenuation constant outside the DP is crucial to address the high mutual isolation issue. Furthermore, the E-field and H-field of the higher TE12 mode are both null at two marginal regions, which are attractive features for decoupling design. Therefore, with the appropriate dielectric constant of DP, the attenuation constant of fundamental HEM $_{11\delta }$ mode not only can be controlled but also the weak field region of higher TE12 mode can be constrained better. Thus, the two modes can be decoupled at the same time without adding extra components. To validate the proposed decoupling method, a two-element DPA array is developed and demonstrated. Then, a four-element DPA array is fabricated and measured with 21.5 dB isolation in a bandwidth of 10.5%. The DPA array supports up to ±46° beam scanning in the E-plane.