Square-shaped Resonator Research Articles

High-performance plasmonic graphene-based multiplexer/demultiplexer

This paper proposes the use of two innovative single-mode plasmonic resonator-based filters to design a two-channel multiplexer/demultiplexer that demonstrates high transmission efficiencies and small sizes below 0.042 μm2. The proposed filters utilize slits in the center of rectangular and square-shaped resonators which results in a single-mode filtering effect. The study employs numerical and theoretical analyses, specifically the finite difference time domain method and coupled-mode theory, to evaluate the designed structures. The simulation results indicate that the rectangular-based demultiplexer has a cross-talk of −34 dB, a maximum transmission efficiency of 0.93, and an amplitude modulation of 0.44 dB, while the square-shaped resonator-based demultiplexer has a maximum transmission efficiency of 0.83, an amplitude modulation of 0.1 dB, and a cross-talk of −39.5 dB. These findings suggest that the proposed structures hold potential for application in optical communication systems.

An Ultrathin Compact Polarization-Sensitive Triple-band Microwave Metamaterial Absorber

In this study, an ultra-compact metamaterial absorber (MMA) has been proposed for microwave applications comprising two modified square-shaped resonators printed on a dielectric substrate and terminated by a metallic plane. The proposed MMA exhibits perfect absorption at 3.36 GHz, 3.95 GHz and 10.48 GHz, covering S- and X-band applications. The absorber is ultra-compact (0.112 λ) in size and ultra-thin (0.018 λ) in thickness at the lowest resonating frequency. The normalized impedance, constitutive electromagnetic parameters, electric field and surface current distribution have been studied to understand the physical mechanism of the triple-band absorption. Furthermore, the absorber is analyzed with different polarization and incident angles for transverse electric waves. The proposed MMA has been experimentally demonstrated to verify the results obtained from simulations. Moreover, the effect of over-layer thickness is investigated to examine the sensing application of the absorber.

Planar antenna beam deflection using low‐loss metamaterial for future 5G applications

A method to tilt the beam of a planar antenna in the E-plane is demonstrated by implementing a metamaterial (MM) structure onto the antenna substrate at the fifth-generation (5G) band of 3.5 GHz. The beam tilting is achieved due to the phase change that occurs when the electromagnetic (EM) wave traverses through two media with different refractive indices. A new adjacent square-shaped resonator (ASSR) structure is proposed to achieve the beam tilting in a dipole antenna. This structure provides a very low loss of −0.2 dB at 3.17 GHz. The simulation and measurement results illustrate that the radiation beam of the dipole antenna is tilted by +25° and −24° depending on the position of the ASSR array onto the dipole antenna substrate. In addition, no degradation in the gain is observed as in the conventional beam-tilting methods; in fact, gain enhancement values of 3 dB (positive deflection) and 2.7 dB (negative deflection) are obtained compared with that of a dipole antenna with no ASSR array. The reflection coefficient of the dipole antenna with ASSR array has a good agreement with that of the dipole antenna with no ASSR array. The measured results agree well with the simulated ones.

V‐band dual‐polarised dielectric resonator antenna with bondwire feeding structures

In this Letter, a V-band chip-level dual-polarised dielectric resonator antenna implemented by using bondwires and silicon-based integrated passive device technology is proposed. The square-shaped resonator is fed by two bondwire coupling structures which excite two degenerate modes orthogonal to each other. The resonance of bondwire itself is also found to enhance the antenna bandwidth to cover the 60 GHz band. Reasonable agreement between the simulation and the measurement is obtained. The measured antenna bandwidth is from 52.8 to 65 GHz. The measured isolation is better than 20 dB at frequencies of interest. The measured antenna gain is 4.5 dBi at 60 GHz. The proposed design can provide further applications for circularly polarised systems.

Investigation of Unequal Planar Wireless Electricity Device for Efficient Wireless Power Transfer

This article focuses on the design and investigation of a pair of unequally sized wireless electricity (Witricity) devices that are equipped with integrated planar coil strips. The proposed pair of devices consists of two different square-shaped resonator sizes of 120 mm × 120 mm and 80 mm × 80 mm, acting as a transmitter and receiver, respectively. The devices are designed, simulated and optimized using the CST Microwave Studio software prior to being fabricated and verified using a vector network analyzer (VNA). The surface current results of the coupled devices indicate a good current density at 10 mm to 30 mm distance range. This good current density demonstrates that the coupled devices' surface has more electric current per unit area, which leads to a good performance up to 30 mm range. Hence, the results also reveal good coupling efficiency between the coupled devices, which is approximately 54.5 % at up to a 30 mm distance, with both devices axially aligned. In addition, a coupling efficiency of 50 % is achieved when a maximum lateral misalignment (LM) of 10 mm, and a varied angular misalignment (AM) from 0° to 40° are implemented to the proposed device.

Ultra-wideband reflective polarization converter based on anisotropic metasurface**Project supported by the National Natural Science Foundation of China (Grant Nos. 61471387, 61271250, and 61571460).

In this paper, we propose an ultra-wideband reflective linear cross-polarization converter based on anisotropic metasurface. Its unit cell is composed of a square-shaped resonator with intersectant diagonal and metallic ground sheet separated by dielectric substrate. Simulated results show that the converter can generate resonances at four frequencies under normal incident electromagnetic (EM) wave, leading to the bandwidth expansion of cross-polarization reflection. For verification, the designed polarization converter is fabricated and measured. The measured and simulated results agree well with each other, showing that the fabricated converter can convert x- or y-polarized incident wave into its cross polarized wave in a frequency range from 7.57 GHz to 20.46 GHz with a relative bandwidth of 91.2%, and the polarization conversion efficiency is greater than 90%. The proposed polarization converter has a simple geometry but an ultra wideband compared with the published designs, and hence possesses potential applications in novel polarization-control devices.

Asymmetric transmission of linearly polarized electromagnetic waves using chiral metamaterials with constant chirality over a certain frequency band

In this study, a dynamic chiral metamaterial (MTM) structure leading to an asymmetric electromagnetic (EM) wave transmission for linear polarization is presented. The structure is composed of square-shaped resonator with gaps on both sides of a dielectric substrate with a certain degree of rotation. The dynamic structure is adjustable via various parameters to fit any desired frequency ranges. Theoretical and experimental analysis of the proposed structure are conducted and given in detail. The suggested model can provide constant chirality over a certain frequency band and thus, it can be used to design myriad novel devices such as EM transmission and antireflection filters, and polarization rotators for desired frequency regimes.

Asymmetric transmission of linearly polarized light through dynamic chiral metamaterials in a frequency regime of gigahertz–terahertz

In a lossy media, anisotropic chiral metamaterial (MTM) structures with normal incidence asymmetric transmission of linearly polarized electromagnetic (EM) waves are investigated and analyzed in both microwave and terahertz frequency regimes. The proposed lossy structures are used to perform dynamic polarization rota- tion and consist of square-shaped resonators with gaps on both sides of dielectric substrates with a certain degree of rotation. Asymmetric transmission of a linearly polarized EM wave through the chiral MTMs is realized by experimental and numerical studies. The dynamic structures are adjustable via various parameters to be tuned for any desired frequency regimes. From the obtained results, the suggested structure can be used to design new polarization control devices for desired frequency regimes. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. (DOI: 10.1117/1.OE.53.7.075109)