Split ring loaded broadband monopole with SAR reduction

Abstract

This article describes the design of a circular monopole antenna loaded with a partial split ring and a pair of symmetrical stubs. It operates for UMTS 2.1 GHz, ISM 2.45 GHz, and WiMAX 3.5 GHz applications covering a broad bandwidth of 2100 MHz (FBW = 71.18%). The stubs and the split ring, effectively perturbs the surface current path, which leads to bandwidth enhancement. The split ring not only accounts for a newer operating band, but also tend to reduce the specific absorption rate (SAR) by 12%. Analysis of the split ring is discussed, in brief, to understand SAR reduction. The antenna is compact with an overall dimension of 30 × 30 × 0.8 mm3. The proposed prototype is fabricated and the results are measured. Simulated and measured results are found to be in good agreement with each other. Consistent radiation patterns are observed at all the operating frequencies and a peak gain of 4.2 dB is inferred at 3.5 GHz. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:158–162, 2016