Compact Metamaterials Induced Circuits and Functional Devices

Abstract

In recent years, we have witnessed a rapid expansion of using metamaterials to manipulate light or electromagnetic (EM) wave in a subwavelength scale. Specially, metamaterials have a strict limitation on element dimension from effective medium theory with respect to photonic crystals and other planar structures such as frequency selective surface (FSS). In this chapter, we review our effort in exploring physics and working mechanisms for element miniaturization along with the resulting effects on element EM response. Based on these results, we afford some guidelines on how to design and employ these compact meta-atoms in engineering functional devices with high performances. We found that some specific types of planar fractal or meandered structures are particularly suitable to achieve element miniaturization. In what follows, we review our effort in Section 1 to explore novel theory and hybrid method in designing broadband and dual band planar devices. By using single or double such compact composite right-/left-handed (CRLH) atom, we show that many microwave/RF circuits, i.e., balun, rat-race coupler, power divider and diplexer, can be further reduced while without inducing much transmission loss from two perspectives of lumped and distributed CRLH TLs. In Section 2, we show that a more compact LH atom can be engineered by combining a fractal ring and a meandered thin line. Numerical and experimental results demonstrate that a subwavelength focusing is achieved in terms of smooth outgoing field and higher imaging resolution. Section 3 is devoted to a clocking device from the new concept of superscatterer illusions. To realize the required material parameters, we propose a new mechanism by combining both electric and magnetic particles in a composite meta-atom. Such deep subwavelength particles enable exact manipulation of material parameters and thus facilitate desirable illusion performances of a proof-of-concept sample constructed by 6408 gradually varying meta-atoms. Finally, we summarize our results in the last section.

Enhanced gain and broadband of endfire antenna by using I-shaped resonator structures

“…Both unloaded and ISR-loaded antennas are fabricated for verification. The measurements show that the ISR-loaded antenna presents gain of about 7 dB-10 dB in the whole working band (3)(4)(5)(6)(7)(8)(9)(10)(11), which is about 2 dB-3.5 dB more than the unloaded one. According to its advantages, the proposed antenna is a good candidate for ultra-wideband wireless communications, phase antenna array systems, and power combines.…”

“…In recent years, many metamaterials, which exhibit unique properties, have been widely used for microwave component and antenna applications . Among them, low/zero‐index (LIM/ZIM) materials have features of controlling the direction of emission .…”

“…In recent years, many metamaterials, which exhibit unique properties, have been widely used for microwave component and antenna applications. [5][6][7][8][9] Among them, low/zero-index (LIM/ZIM) materials have features of controlling the direction of emission. 7,8 In Zhou et al, 9 with ZIM structure as the superstrate of a microstrip patch antenna, 1 dB-2 dB gain improvement is obtained.…”