Design of a Dual-Polarized Omnidirectional Dielectric Resonator Antenna for Capsule Endoscopy System

Abstract

In this paper, a new dual-polarized (DP) omnidirectional hemisphere dielectric resonator antenna (DRA) for wireless capsule endoscope system (WCE) is proposed. The antenna was excited in its omnidirectional TM018 and TE018 modes to radiate DP wave by a feeding probe and arc microstrip line, respectively. Omnidirectional DP wave can be obtained when the TM018 and TE018 mode are equal in amplitude and phase. The TM018 mode that is equivalent to electric dipole can be obtained by probe feeding. The TE018 mode is excited by four arc microstrip lines feeding. They provide a pair of equivalent magnetic dipoles that are orthogonal to TM018 mode. The DP omnidirectional DRA be fabricated without the need of feed network than circularly polarized. The WCE and the human body equivalent tissue model are adopted in simulation. Water is equivalent to gastric juice during measurement. Communication links between the proposed capsule antenna and the external receiving antenna are measured to demonstrate the advantages the DP brings when capsule antenna is placed in different orientations. The capsule endoscope system with different antennas is placed in water to measure receiving power. The measurement shows that the fabricated antenna exhibits a wide impedance bandwidth for S11 <; -10 dB (2.4-2.48 GHz). The radiation efficiency of the antenna is between 15-18%, and the peak gain is between -13.5 and -15dBi.