Tanuj K. Garg ¹, S. C. Gupta ², S. S. Pattnaik ³

Affiliations
1 Department of Electronics & Communication Engineering, Gurukul Kangri University, Haridwar, IN
2 Department of Electronics & Communication Engineering, DIT, Dehradun, IN
3 Department of ETV, NITTTR, Sector-26, Chandigarh, IN

Abstract

In this paper, we present a metamaterial loaded frequency tunable electrically small planar patch antenna. Metamaterial structure has square shaped split ring resonator (SRR) with micro-splits. Frequency tunability is achieved by using RF MEMS switches. By making RF MEMS switches ON/OFF, the reactance of SRR structure changes and thus frequency of antenna is controlled. The patch antenna resonates at 27 GHz. But when the patch antenna is loaded with SRR structure, the loaded antenna is tuned to 9.02GHz, 9.08 GHz and 9.16 GHz by making RF MEMS switches ON/OFF. The resonant frequency of loaded antenna increases because as additional micro-splits are incorporated, series capacitances are introduced in SRR which decreases the overall capacitance of SRR. In all cases the loaded antenna satisfies the condition, Chu limit ka < 1, for an antenna to be electrically small. Also there is no requirement of additional matching networks.

Keywords

Chu Limit, Electrically Small Antenna, RF MEMS Switch, Micro-splits, Single Negative Material (SNG) Split Ring Resonator (SRR), Negative Mu Material (MNG).

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Danvir Mandal ¹, S. S. Pattnaik ²

Affiliations
1 I. K. Gujral Punjab Technical University, Kapurthala – 144603, Punjab, IN
2 NITTTR, Chandigarh – 160 019, IN

Abstract

Wearable antennas are prone to bending and crumpling. This work presents the analysis of input impedance of a wearable patch antenna with milli bends using Finite Difference Time Domain (FDTD) method. FDTD method using stair case scheme is used to model milli bends at different places along the length of a wearable patch antenna and the effect of milli bends on input impedance of the wearable patch antenna is presented developing a FDTD code for it. It is shown that presence of milli bends in a wearable patch antenna significantly changed the input impedance of the antenna under consideration. It is observed that milli bends closer to the feeding strip line provided better input impedance matching. Results concluded that change in input impedance leads to change in resonant frequency and reflection coefficient of the antenna. General Terms: RF and microwave communication, Antenna design and analysis.

Keywords

Wearable antennas are prone to bending and crumpling. This work presents the analysis of input impedance of a wearable patch antenna with milli bends using Finite Difference Time Domain (FDTD) method. FDTD method using stair case scheme is used to model milli bends at different places along the length of a wearable patch antenna and the effect of milli bends on input impedance of the wearable patch antenna is presented developing a FDTD code for it. It is shown that presence of milli bends in a wearable patch antenna significantly changed the input impedance of the antenna under consideration. It is observed that milli bends closer to the feeding strip line provided better input impedance matching. Results concluded that change in input impedance leads to change in resonant frequency and reflection coefficient of the antenna. General Terms: RF

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