A Broadband High-Efficiency Dipole Array Based on Frequency Selective Surface and Integrated Feeding Structure
Hong Tang, Bowen Zheng, Sensong An, Hang Li, Mohammad Haerinia, Clayton Fowler, Hualiang Zhang
Abstract
In this paper, an ultra-wideband tightly couple antenna array based on a low-loss phase-modulated frequency selective surface and a microstrip-based feeding structure is reported. The proposed antenna array, which employs tightly coupled bow-tie elements, features a very low profile (1.08 λhigh). Specifically, a microstrip-to-parallel strip transition serves as an impedance transformer and a wideband balun to enable the array element to be excited with a 50 Ω unbalanced feeding scheme. Additionally, one shorting sheet is employed to expand the bandwidth by shifting the common-mode to a higher frequency band. The presented design achieves a bandwidth of 13.66:1 (0.52 GHz. 7.10 GHz) with VSWR < 2.49 and simulated radiation efficiency greater than 96% across the whole band. To validate the design concepts, an 8 × 8 array prototype is fabricated and characterized experimentally. The measured results match well with the numerical analysis.