Design of a Novel Superwideband Dual Port Antenna with Second-Order Hilbert Branches and a Modified T-Decoupling Structure

Abstract

A novel super wideband (SWB) dual port antenna with second-order Hilbert branches and a modified T-decoupling structure is proposed. The overall size of the antenna is only 32 mm × 26 mm × 1 mm. The SWB antenna front comprises a “house” shaped radiating patch and a trapezoidal-shaped microstrip line. Two SWB antenna units are placed symmetrically on FR4 dielectric substrate to form the SWB-MIMO (multiple-in multiple-out) antenna. Two second-order Hilbert branches expand the wideband of the SWB-MIMO antenna. The antenna decoupling is mainly achieved by loading a fence-like “T” decoupling structure on the ground plane. The antenna is also miniaturized and isolated by adjusting the distance between the radiating patches of the units. The simulations and measurements show that the SWB-MIMO antenna operates in the frequency band of 1.98-30.8 GHz (175.84% relative bandwidth). The bandwidth dimensional ratio (BDR) (BDR is a measure of the compactness of the antenna, the higher the BDR, the better the compactness of the antenna, and the wider the working bandwidth of the antenna.) is 14653.33. The overall isolation is below −16.4 dB, and the important part (8.5–24.1 GHz) is below −20 dB. The envelope correlation coefficient (ECC) is less than 0.03, and the radiation characteristics are excellent.