Bandwidth enhancement of capacitive fed monopole antenna using parasitic patches

Abstract

This paper proposed a compact planar monopole antenna operating at 5 GHz (5.180–5.825 GHz) industrial, scientific and medical (ISM) radio band. The antenna constructed with 20 mm × 12 mm radiating element and 25 mm square of the ground plane in FR4 substrate provided −10 dB bandwidth of 1 GHz (5.4–6.4 GHz). To improve the bandwidth, parasitic elements are added with the monopole antenna. A capacitive feed is also incorporated in the design. It observed that the proposed antenna with parasitic elements provides a larger impedance bandwidth of about 3 GHz (5.1–8.1 GHz), which is three-fold improvements over the one without parasitic patches. The prototype of the antenna that operates at 5.8 GHz frequency range is fabricated and characterized using a near-field measurement system. A good agreement is found between the simulation and measured results.