A 28-GHz Vivaldi Array Antenna With Power Divider Structure for Achieving Wide Band and Gain Enhancement

Abstract

This article presents a planar Vivaldi array antenna based on a power divider structure. A half-loop defected ground structure (DGS) is performed to decrease the mutual coupling between antennas in the bottom layer of the substrate. The proposed Vivaldi antenna has a 1×8 power divided microstrip line structure and performs well in antenna gain and beam directivity. To validate the design, the proposed high-gain planar Vivaldi array antenna was manufactured, and the measured results were very similar to the simulated one. The size of the proposed antenna is 67×44 mm2, the application band is 25–27.3 GHz, and the measured peak gain is 12.6 dBi. The antenna is simulated with an electromagnetic power density (PD) of 28.5 W/m2 at 1 cm2 and 7.27 W/m2 at 4 cm2, which are in compliance with the FCC regulations. Therefore, this antenna is suitable for wearable devices and is applied to n257, n258, and n261.