Design of a Linearly Dual-Polarized and Dual-Wideband Multi-Ring Microstrip Antenna Fed by Two L-Probes for a Small Ground Plane

Abstract

This paper presents design of a linearly dual-polarized and dual-wideband multi-ring microstrip antenna (MR-MSA) fed by two L-probes for a small ground plane. The proposed antenna is composed of two circular ring patches with a different size printed on the top and middle layers and two L-shaped probes for feeding arranged orthogonally in the bottom layer with a large thickness of the triple-layered dielectric substrate for linearly dual-polarized and dual-wideband operation. Furthermore, in order to obtain stable gain characteristics for a large ground plane, the MR-MSA is surrounded by the cavity structure. In this paper, the dual-band and wideband MR-MSA fed by two L-probes for a small ground plane is considered by using numerical simulation with ANSYS HFSS. The design frequencies of the MR-MSA are around 4.5 GHz and 5.5 GHz. The simulated results reveal that the cavity provides stable gain characteristics for a side of the ground plane and the substrate more than 0.85 wavelengths at the center frequency of the lower band. It is also confirmed that better performance is obtained by the MR-MSA without the cavity for a smaller size of the ground plane and the substrate.