Experimental investigations of an omni-directional dielectric resonator antenna for UWB systems

Abstract

Abstract —In this paper, a new dielectric resonator antenna (DRA) is presented and investigated for ultra wideband (UWB) applications. The UWB antenna has a U-shape and excited by a microstip fed monopole. The proposed antenna was simulated and designed using two electromagnetic simulators. To validate our design, a prototype antenna was fabricated and measured. From the measurements, the U-shaped DRA has a 117.6 % impedance bandwidth (from 2.94 GHz to 11.34 GHz, for return loss below -10 dB, largely covering the UWB spectrum band). Moreover, the proposed antenna provides an omni-directional radiation pattern. With these features, the present antenna can be used in ultra-wideband wireless systems. Index Terms — Dielectric Resonator Antennas, Measurements, Radition Pattern, UWB applications. I. Introduction The dielectric resonator antennas (DRAs) have become attractive to antenna engineers due to its several features, such as its small size, light weight, low loss, high radiation efficiency, and ease of excitation. The need of the high-data rate, in the communication devices, has forced the researchers to enhance the antenna bandwidth. In the literature, several studies have been reported to achieve wide-bandwidth enhancement of DRAs suitable for wideband applications, like using stacked segment W dielectric resonators DRs [1], stacked-embedded DRs [2], hybrid DRA [3], and special geometries of DR, such as conical [4], tetrahedral [5], elliptical [6], stair [7], H-shaped [8] and L-shaped [9]. In the last decade, the Federal Communications Commission (FCC) allowed the use of the frequency band from 3.1 to 10.6 GHz for UWB devices for commercial applications. Many investigations have been reported to design adequate antennas for UWB spectrum. The proposed antennas are mainly based on planar monopoles with different shapes such as rectangular, circular, elliptical, and trapezoidal forms [10-13] and on slot antennas, using a tuning stub with rectangular shape [14], circular shape [15], and fork-like shape [16]. Recently, some research papers have proposed the dielectric resonator antennas to be one of the attractive candidate antennas for UWB applications, such as a half cylindrical dielectric resonator antenna [18], an A-shaped resonator [19], an inserted DRA excited by CPW [20], and a conical-shape DR with monopole antenna [21], due to their advantages compared with metallic antennas. In this work, we propose a new U-shaped dielectric resonator antenna, with low profile, fed by a microtrip line, covering the UWB spectrum and having an omni-directional radiation pattern. The electromagnetic analysis was carried out using both CST microwave studio and HFSS software. Furthermore to validate the proposed concept, an experimental antenna prototype was fabricated and measured. Section II describes the proposed antenna where the simulated and measured results are presented and discussed in Section III. Finally, a conclusion is drawn in Section IV.