A Shared-Aperture Slot/DR Antenna with Large Frequency Ratio and Reconfigurable Bidirectional/Endfire/Broadside Pattern

In this article, a shared-aperture antenna with a large frequency ratio is presented. It consists of a low-frequency (LF) slot antenna and a high-frequency (HF) dielectric resonator (DR) two-element array. The slot is etched in the ground, which acts as a radiator in the microwave band, and as part of the feeding structure for the millimeter-wave band (MMW). While achieving LF bidirectional radiation, reconfigurable HF endfire and broadside radiation can be implemented through a Wilkinson power divider controlled by PIN diodes. The radiation performance exhibited a $\mathbf{- 1 0 - \mathrm {dB}}$ impedance bandwidth of 5.5-7.0 GHz and $28.8-31.6 \mathrm{GHz}$, covering the main frequency bands of 5G communication.