Hybrid Dual Band High Gain Antenna

This paper presents a hybrid high gain multi-resonance antenna. A rectangular split ring planar metamaterial antenna and rectangular slotted planar antenna are hybridized to achieve multi- resonance and high gain. This work is based on a rectangular slotted antenna of three iterations. The single structure provides both the metamaterial and normal patch antenna performance. The hybrid structure provides a bandwidth of 210 MHz with metamaterial characteristics at 17.28 GHz and bandwidth of 430 MHz as slotted antenna at 21.90 GHz frequency. Antenna gain of 7dBi is achieved with overall dimensions of 40 mm×12 mm×0.787 mm. The simulated results are in good agreement with the experimental findings. Index Terms- Hybrid antenna, metamaterial antenna, iteration, dual band Metamaterials are the artificially engineered structures or materials which shows electromagnetic properties beyond the materials existing in nature. Metamaterial exhibits negative magnetic permeability ( μ ) and/or negative dielectric permittivity (e ) below plasma frequency whereas the materials existing in nature possesses positive permeability and almost positive permittivity (1)-(3). Veselago, in 1968 reported an astonishing phenomenon in electromagnetic theory by assuming materials with negative magnetic permeability and permittivity. Further, the research on this phenomenon was preceded by Pendry, Smith and Ziolkowski to study characteristics and applications of metamaterials. The novel characteristics of metamaterials lead to design new devices and applications like planar antennas, frequency selective surfaces, filters, resonators and optical devices. Metamaterial structure consists of split ring resonators to produce negative permeability and thin wire elements generate negative permeability (2)-(4). R.W. Ziolkowski et al. reported that the radiation power of small antennas increases due to the metamaterial characteristics (5). In microstrip patch antennas, different techniques like insertion of air in the substrates, making the slots, shorting the patch by inserting pin and loading the patch are used to achieve application specific resonant frequency, bandwidth, and radiation patterns (6). These techniques have certain limitations which restricts the performance of microstrip antennas. The metamaterial planar antennas are superior to microstrip antennas, further their functioning capabilities can be enhanced by blending these techniques to boost their performance and make them more versatile. In this paper a novel hybridized structure of a new slotted type rectangular microstrip antenna and rectangular split ring (RSR) planar metamaterial antenna is presented. In military and satellite communication services slotted antennas are commonly used due to their compact size, multi-band, high gain and bandwidth performance. But these antennas need improvement in bandwidth and gain. The important advantages of metamaterial antennas are high gain, high bandwidth and higher efficiency in smaller size (2)-(5). The performance of slotted antennas can be enhanced by hybridizing with metamaterial planar antennas which integrates the features of both antennas. This paper is organized in four folds as section II discusses geometrical details of antenna structures. In section III results and discussions are presented and paper is concluded in section IV.