Wideband microstrip antenna loaded by elliptical rings

Abstract

The paper presents elliptical ring-loaded microstrip antennas for wideband applications. The parasitic stack elliptical rings bring in new resonances to enhance antenna bandwidth while maintaining the characteristics of compact size, low profile, and reasonable good polarization of microstrip antenna. By utilizing one or two elliptical rings upon a reference microstrip antenna (RMA) as parasitic, more resonances appeared as the rings operated as half-wavelength resonators. Thus, two and three resonances are observed for the one ring-loaded microstrip antenna (ORLMA) and dual ring-loaded microstrip antenna (DRLMA), respectively. The antennas maintain compact size and low-profile characteristics, and the volumes of RMA, ORLMA, and DRLMA compared to their corresponding low edge free space wavelength are 0.345 λ × 0.285 λ × 0.020 λ, 0.330 λ × 0.273 λ × 0.038 λ, and 0.392 λ × 0.287 λ × 0.037 λ, respectively, while their measured bandwidth increased from 2.8 to 6.3 and 7.0%. Reasonable good polarization and radiation patterns are also obtained for the antennas.

Keywords:

• bandwidth enhancement
• parasitic
• elliptical ring
• microstrip antenna

Disclosure statement

No potential conflict of interest was reported by the authors.