A Detached Zero Index Metamaterial Lens for Antenna Gain Enhancement

Abstract

Abstract-In this paper, a detached zero index metamaterial lens (ZIML) consisting of metal strips and modified split ring resonators (MSRRs) is proposed for antenna gain enhancement. The effective permittivity and permeability of the detached ZIML are designed to synchronously approach zero, which leads the ZIML to having an effective wave impedance matching with air and near-zero index simultaneously. As a result, neither does the detached ZIML need to be embedded in horns aperture nor depends on auxiliary reflectors in enhancing antenna gain, which is quite different from conventional ZIMLs. Moreover, the distance between antenna and the detached ZIML slightly affect the gain enhancement, which further confirms that the ZIML can be detached from antennas. Simulated results show that the effective refractive index of the detached ZIML is near zero in a broad frequency range where the effective relative wave impedance is close to 1. The detached ZIML is fabricated and tested by placing it in front of an H-plane horn antenna. One finds that evident gain enhancement is obtained from 8.9 GHz to 10.8 GHz and the greatest gain enhancement reaches up to 4.02 dB. In addition, the detached ZIML can also work well at other frequencies by adjusting its geometric parameters to scale, which is demonstrated by designing and simulating two detached ZIMLs with center frequencies of 2.4 GHz and 5.8 GHz, respectively.

A Miniaturized Lotus Shaped Microstrip Antenna Loaded With Ebg Structures for High Gain-Bandwidth Product Applications

“…These drawbacks take effects severely when the ZRI inclusions are embedded in the substrate of the microstrip antenna [19]. Nevertheless, the design complexity of the ZRI inclusions may be limited to the current production technology and fabrication cost [20,21].…”

Terahertz Sensing Application by Using Fractal Geometries of Split-Ring Resonators

“…Since numerical and experimental studies of the first splitring-resonator-based MTM structure in the microwave region [1][2][3][4], this kind of structure has been used in many applications such as sensing [1,3,5], absorber [6][7][8], superlensing [9][10][11], and so on. With respect to sensing, MTMs have been proven to be good candidates in the THz regime for highly sensitive chemical or biological detection since the unit cell dimensions are typically sub-wavelength and frequency response can be tuned according to their shape and geometrical dimensions [12][13][14].…”

Plane Wave Beam Produced by an Exclusive Medium

“…Same performance of transforming a cylindrical wave into a plane wave can also be realized by zero-index medium, which is widely studied in recent years [14][15][16][17][18][19][20][21][24][25][26]. People may mix up the two media sometimes.…”