Development of Dual-Band Antenna Using Embedded Filters Technique for Medical Applications

Abstract

Antennas are considered as one of the most important elements of Ultra Wide-Band (UWB) systems. It greatly determines the system specifications in terms of bandwidth and interference removal with narrowband systems located in the same frequency range. This paper presents an analytical and design study of a UWB antenna that can be used for medical applications operating in two separate frequency ranges [3.25-4.75] GHz and [6.6-10.25] GHz. The embedded filters technology is used to make the antenna dual-band, and to obtain good frequency specifications without affecting the radiation of the antenna. Thus we can obtain the filtering and radiation specifications within the same structure. We relied on the modeling and simulation process on CST Microwave Studio. To verify the simulation results, we fabricated the proposed antenna using an Arlon substrate with dielectric constant 3.25  , loss factor 0.0032 , and thickness 0.8 mm . The experimental results showed agreement with the simulation results, and we got two working bands, the first [3.1-4.76] GHz and the second [6.64-10.21] GHz. We were able to obtain a wide rejection range of 2.26 GHz with a very high Voltage Standing Wave Ratio (VSWR) up to 43 and thus a large isolation between the upper and lower bands of the antenna. The gain of the antenna ranges between 3.4-4.5 dBi, and the radiation efficiency is in range [80-95]%. The specifications we have obtained are suitable and conform to the requirements of medical applications specified in the IEEE 802.15.6 standard.