A Compact and Broadband Elliptical Antenna With Metallic Walls for Low Cross‐Polarization

ABSTRACT A multilayer compact and broadband elliptical microstrip antenna (MSA) is designed with low cross‐polarization using shorting posts and metallic walls. Two dumbbell‐shaped patches are stacked on top of a metallic elliptical fed patch. These patches are printed on an air‐suspended FR‐4 substrate in the area utilized by the elliptical patch. The dumbbell‐shaped patches are directly coupled with the elliptical patch by embedding shorting pins between them at symmetrical positions which improve the bandwidth (BW) and cross polarization (X‐pol). The antenna geometry is further enclosed in metallic walls to improve gain and to reduce X‐pol and front‐to‐back ratio (FBR). A systematic study of the antenna design is presented. The designed multilayer elliptical MSA is a low‐cost antenna with size 0.85 λ × 0.58 λ × 0.15 λ and provides 43.8% BW (1.619–2.526 GHz) with peak gain of 9 dBi and FBR of more than 16 dB over BW. The antenna X‐pol is below −20 dB from 1.7 to 2.52 GHz. The designed antenna can be used for IoT‐based smart devices and 5G cellular services in sub‐6 GHz frequency band.