Metamaterial Transmission Lines Research Articles

Particle creation in left-handed metamaterial transmission lines

Transmission lines (TLs) are excellent examples of quantum simulators of quantum fields. By appropriately driving-specific circuit elements, these devices can reproduce relativistic and quantum phenomena such as particle creation due to the nonadiabatic stimulation of the quantum vacuum. We investigate particle creation in left-handed TLs induced by the modulation of the Josephson energy in superconducting quantum interference devices. Our results show that, as a consequence of the peculiar dispersion relations present in these systems, particle production occurs with much more favorable conditions with respect to the usual right-handed TLs. Published by the American Physical Society 2024

Design and performance evaluation of a compact radiation absorber for 5G applications

Introduction: The emergence of electromagnetic wave pollution as a new form of pollution in human society is attributed to the advancements in communication technology and the electronic information business. In addition to harming priceless electronic equipment, these electromagnetic radiation and interference issues brought on by electrical and electronic devices have a major negative influence on human productivity and wellbeing. The secret to getting rid of electromagnetic radiation interference (EMI) and improving performance is electromagnetic shielding technology. Metamaterial absorber is a type of metamaterial that absorb EMI radiation. The benefits of metamaterial absorbers include their lightweight, simple construction, and excellent absorptivity.Methods: This paper proposes a novel metamaterial absorber for EMI radiation absorption. It consists of dielectric layers, metamaterial shielding layer and transmission line. The reflection of radiation is reduced by miniaturization of metamaterials.Results and Discussion: Simulation results show that the proposed design has better performance as compared to existing methods. The operating frequency range is from 23.1 to 28.3 GHz. The values of S21 with and without shielding are −5 dB and −0.05 dB, and the shielding effectiveness is 10.10 dB and a maximum of 12.63 dB.

Inverse design of ultrawideband one-dimensional metamaterial photonic filters using Riccati equation constrained gradient descent.

One-dimensional photonic wave devices exhibit a pivotal role in wave engineering. Despite their relative simplicity, designing 1D wave devices that implement complex functionalities over a broad frequency range is challenging and requires careful sculpting and multiple optimizations. This paper theoretically and experimentally demonstrates a new inverse design paradigm to achieve a desired broadband frequency response efficiently. Specifically, we calculate the required dielectric profile along the device using constrained gradient descent optimization to minimize the L 2 norm between the desired and actual responses. In each optimization step, we avoid the need to solve the complete set of Maxwell equations by using Riccati's equation or its discrete ancestor as the optimization constraint for calculating the local reflection coefficient. Using this approach, we design several unorthodox filters, such as dual-band narrowband bandpass filters located within a wideband bandstop and ultrawideband first and second-order differentiators. The technique produces excellent results for ultrawideband frequency ranges, with very low computational complexity and, remarkably, with a single trivial guess for the optimization starting point. We experimentally implemented the two differentiator designs in radio frequencies using electronic circuit elements that comprise a metamaterial transmission line structure.

Entangling Interactions Between Artificial Atoms Mediated by a Multimode Left-Handed Superconducting Ring Resonator

Superconducting metamaterial transmission lines implemented with lumped circuit elements can exhibit left-handed dispersion, where the group and phase velocity have opposite sign, in a frequency range relevant for superconducting artificial atoms. Forming such a metamaterial transmission line into a ring and coupling it to qubits at different points around the ring results in a multimode bus resonator with a compact footprint. Using flux-tunable qubits, we characterize and theoretically model the variation in the coupling strength between the two qubits and each of the ring-resonator modes. Although the qubits have negligible direct coupling between them, their interactions with the multimode ring resonator result in both a transverse exchange coupling and a higher-order ZZ interaction between the qubits. As we vary the detuning between the qubits and their frequency relative to the ring-resonator modes, we observe significant variations in both of these interqubit interactions, including zero crossings and changes of sign. The ability to modulate interaction terms such as the ZZ scale between zero and large values for small changes in qubit frequency provides a promising pathway for implementing entangling gates in a system capable of hosting many qubits. Published by the American Physical Society 2024

Impact of viscothermal loss on modulation instability and rogue waves in left-handed nonlinear diffractive acoustic transmission line metamaterials

In this study, the transmission line approach is used to describe the studied acoustic metamaterial model. Through Kirchoff’s pressure and volume-velocity laws and using multiple scales method, nonlinear coupled Schrödinger equations are obtained. Then, the amplitude disturbance method is applied to these equations to obtain and plot the modulational instability gain curves. Analytically, the impact of viscothermal loss on the modulational instability gain is studied. The similarity technique is used to derive integrable Manakov’s equations. First and second-order rational rogue wavelike solutions of coupled nonlinear Schrödinger are deduced. The results indicate that the modulational instability gain and Rogue wave intensities depend on the viscothermal parameter. This parameter can be considered in the design of nonlinear acoustic metamaterials to minimize the damage caused by the dynamics of freak waves.

A Planar Compact Absorber for Microwave Sensing Based on Transmission-Line Metamaterials

A Planar Compact Absorber for Microwave Sensing Based on Transmission-Line Metamaterials

On the Performance of Metamaterial based Printed Circuit Antenna for Blood Glucose Level Sensing Applications: A Case Study

Due to the urgent need to develop technologies for continuous glucose monitoring in diabetes individuals, poten tial research has been applied by invoking the microwave tech niques. Therefore, this work presents a novel technique based on a single port microwave circuit, antenna structure, based on Metamaterial (MTM) transmission line defected patch for sensing the blood glucose level in noninvasive process. For that, the proposed antenna is invoked to measure the blood glu cose through the field leakages penetrated to the human blood through the skin. The proposed sensor is constructed from a closed loop connected to an interdigital capacitor to magnify the electric field fringing at the patch center. The proposed an tenna sensor is found to operate excellently at the first mode, 0.6GHz, with S11 impedance matching less than -10dB. The proposed sensor performance is tested experimentally with 15 cases, different patients, through measuring the change in the S11 spectra after direct touching to the sensor a finger print of a patient. The proposed sensor is found to be effectively very efficient detector for blood glucose variation with a low manu facturing cost when printed on an FR-4 substrate. The experi mental measurements are analyzed mathematically to obtain the calibration equation of the sensor from the curve fitting. Finally, the theoretical and the experimental results are found to be agreed very well with a percentage of error less than 10%.

Composite Right/Left-Handed Transmission Line Metamaterial-Inspired Small Antenna Design: Topologies, reconfigurability, and applications

With the development of modern wireless communication systems, the demand for high-performance, multifunctional, low-cost, and compact antennas has been increasing substantially. The greatest challenge when designing this type of antennas is the tradeoff between complexity and performance. More design freedom is therefore highly desired. As an important subtype of metamaterials, composite right/left-handed transmission line (CRLH-TL) metamaterials have paved the way to achieve this compromise. In this review article, first, the possible CRLH-TL topologies that can be used in antenna design are discussed, involving structures based on not only Cartesian but also polar coordinates and 2D CRLH-TLs. The reconfigurability of the CRLH-TLs in terms of operating mechanisms, reconfigurability methods, and control techniques is then reviewed. By applying these structures to electrically small antenna design, considerable extra design freedom can be obtained. In the literature, a whole range of novel antennas with remarkable performances have been reported, holding great potential for various applications, such as wireless body area networks (WBANs), multiple-input, multiple-output (MIMO), radio-frequency identification devices (RFIDs), wireless power harvesting, and so on. All of these applications are briefly discussed.

Multibeam antennas with customized elevation angles based on near-field magnetic field coupling of metamaterials

In this paper, we propose the design of multibeam antennas with customized elevation angles based on near-field magnetic field coupling of metamaterials. The antenna consists of a monopole feed and four identical metamaterial transmission-line (MTL) structures surrounding the feed. The MTL structure is composed of two pairs of broadside-coupled omega rings (BCORs) that are connected by two straight strip-lines. Under such a framework, magnetic fields within the near-field zone of the monopole feed can be coupled efficiently by the inner BCOR, converted to travelling waves along the double strip-lines, guided toward the outer end of the MTL structure, and radiated by the outer BCOR like a loop antenna. Due to travelling wave nature of the MTL structure, there is phase lag along the MTL structure and the radiation main lobes are tilted towards the outward direction. By arranging several MTL structures around the feed monopole, multi-beam directional radiation can be realized. More interestingly, by adjusting structural parameters and pitch angles of the MTL structures, elevation angle of the radiation main lobes can be customized. To validate the design, we simulated, fabricated and measured four prototypes with pitch angles 0°, 15°, 30° and 45°. Both the simulated and measured results verify the design and show that multiple-beam radiation with customized elevation angle can be obtained. This work provides an alternative method of designing multi-beam antennas and may find applications in communication, surveillance, etc.

Analytical and numerical modeling of reconfigurable reflecting metasurfaces with capacitive memory

In this article, we develop analytical–numerical models for reconfigurable reflecting metasurfaces (MSs) formed by chessboard-patterned arrays of metallic patches. These patch arrays are loaded with varactor diodes in order to enable surface impedance and reflection phase control. Two types of analytical models are considered. The first model based on the effective medium approach is used to predict the MS reflectivity. The second model is the Bloch wave dispersion model for the same structure understood as a two-dimensional transmission line metamaterial. The latter model is used to study ways to suppress parasitic resonances in finite-size beamforming MSs. We validate the developed analytical models with full-wave numerical simulations. Finally, we propose a design of the MS control network with capacitive memory that allows for independent programming of individual unit cells of the beamforming MS.

Rogue Waves Induced by Modulational Instability in Acoustic Transmission Line Metamaterials

Rogue Waves Induced by Modulational Instability in Acoustic Transmission Line Metamaterials

Metamaterial Impedance Matching Network for Ambient RF-Energy Harvesting Operating at 2.4 GHz and 5 GHz

This paper points out the viability of the utilization of metamaterial transmission lines as a multifrequency impedance matching network, improving RF-Energy Harvesting systems operating around 2.4 GHz and 5 GHz. Metamaterial transmission lines introduce additional degrees of freedom in the transmission line design, providing the possibility to match the impedance in multiple bands. The impedance matching structure has been designed and optimized using ADS simulator to match the input impedance of a four-diode-bridge rectifier connected to an energy management system. The proposed Metamaterial Impedance Matching Network (MIMN) has been fabricated using standard PCB technologies and tested in a full operative ambient RF-Energy Harvesting System obtaining a DC output voltage of 1.8 V in a 6.8 mF supercapacitor.

Bandwidth and gain enhancement of composite right left handed metamaterial transmission line planar antenna employing a non foster impedance matching circuit board

The paper demonstrates an effective technique to significantly enhance the bandwidth and radiation gain of an otherwise narrowband composite right/left-handed transmission-line (CRLH-TL) antenna using a non-Foster impedance matching circuit (NF-IMC) without affecting the antenna’s stability. This is achieved by using the negative reactance of the NF-IMC to counteract the input capacitance of the antenna. Series capacitance of the CRLH-TL unit-cell is created by etching a dielectric spiral slot inside a rectangular microstrip patch that is grounded through a spiraled microstrip inductance. The overall size of the antenna, including the NF-IMC at its lowest operating frequency is 0.335λ0 × 0.137λ0 × 0.003λ0, where λ0 is the free-space wavelength at 1.4 GHz. The performance of the antenna was verified through actual measurements. The stable bandwidth of the antenna for |S11|≤ − 18 dB is greater than 1 GHz (1.4–2.45 GHz), which is significantly wider than the CRLH-TL antenna without the proposed impedance matching circuit. In addition, with the proposed technique the measured radiation gain and efficiency of the antenna are increased on average by 3.2 dBi and 31.5% over the operating frequency band.

Metamaterial‐based, miniaturised circularly polarised antennas for RFID application

Miniaturised circularly polarised (CP) antennas based on dispersion-engineered metamaterial transmission lines (TLs) are proposed and developed for RFID applications. It is first studied and developed based on the equivalent circuit and dispersion curves of composite right/left-handed TL (CRLH-TL), which is featured by a novel/low-cost double-layered 3D structure, including metallic screws, one ground layer and metal-insulator-metal (MIM) capacitor loaded on the top layer. CP radiation is achieved by two crossed CRLH-TLs with a microstrip-slot coupling excitation. One CP antenna and one polarisation reconfigurable antenna, which utilise CRLH-TLs are then implemented, respectively. Compared with the conventional right-handed (RH) TL-based antennas (positive resonance-based antennas), miniaturisation is achieved by pushing down the dispersion curve to a lower frequency using larger LH capacitance or/and inductance. Negative-order resonances could be successfully excited by cascading π-type unit-cells. It shows similar radiation characteristics and additional size reduction as the positive resonance-based antennas. This antenna shows an electrical size of 0.24 λ0 × 0.24 λ0 × 0.03 λ0, a −10 dB bandwidth of 4.8%, and a peak gain of 4.2 dBic. It demonstrates advantages in terms of flexible size reduction, low cost, easy manufacturing, and good radiation performance, which are very suitable for 902–928 MHz UHF band RFID application.

ENGTL based antenna for Wi-Fi and 5G

This article reported patch antenna functioning at Wi- Fi and 5G bands. Wi-Fi band (2.4 GHz) is obtained by loading Epsilon Negative Transmission Line (ENGTL) metamaterials into the patch radiating at 5G band (3.5 GHz). To acquire Circular Polarization (CP) at 5G band, conventional square patch is embedded with poly fractals. The experimental and simulated data are in close proximity. The obtained impedance bandwidth is 4.01% at Wi-Fi and is 10.68% at 5G band. CP bandwidth is 2.43% at 5G. This mix of ENGTL as well as fractals provides good compactness appropriate for portable gadgets

2-D Circuit-Based Bianisotropic Omega Media

In one dimension, a circuit network representation has been established for bianisotropic materials with an omega response (omega media). However, 2-D circuit-based or transmission-line metamaterials have been restricted to those with only magnetic and electric responses. This article proposes a 2-D circuit-based metamaterial that is equivalent to an omega medium. A lumped element unit cell composed of asymmetric $\pi $ -networks is proposed and validated using a circuit simulator. Circuit analysis of the metamaterial is performed using transmission (ABCD) matrices. A medium equivalency is then established in the homogeneous limit. The application of a 2-D omega medium as an impedance matching layer with phase and power flow control is explored, and a design procedure is developed. The impedance matching layer is then implemented using the proposed lumped element unit cell, and its performance is confirmed using Keysight’s Advanced Design System (ADS).

Ultra-Wideband Metamaterial-Loaded Microstrip Array Antennas using Fibonacci & Fractal Geometric Patterns, Design and Modelling

In this study; theory, design and modeling of a new topology of ultra-wideband (UWB) metamaterial (MTM) loaded microstrip array antenna using Fibonacci & fractal geometric patterns are analyzed. This antenna is made basically from many monopole elements which are loaded by complementary metamaterial transmission line (CMTL) unit cells. The distributed CMTL element, contains a Koch-shaped expanded complementary single split ring resonator (CSRR) pair. At first step, the UWB microstrip array antenna designed with two CMTL-loaded monopole element. So, using an iterative method based on the Fibonacci and fractal geometry patterns, the array antenna is expanded. As the order of iteration increases, the impedance bandwidth of the proposed array antennas improve more, and the radar cross section (RCS) decreases. the impedance bandwidth of the proposed third-order Fibonacci and fractal CMTL-loaded array antennas are 250 MHz and 539 MHz more than the two-element CMTL-loaded array antenna, respectively. Finally, this paper presents an improved method to extract the parameters of an equivalent circuit model of the proposed MTM-loaded array antenna. Verification of the equivalent model have been validated utilizing ADS software. The obtained model, in addition to numerically efficient in comparison with the full wave analysis utilizing the moment method, gives a good physical insight to the mutual coupling mechanism of the array antenna.

Dual Q/V-Band SiGe BiCMOS Low Noise Amplifiers Using Q-Enhanced Metamaterial Transmission Lines

This brief presents two dual-band low noise amplifiers (LNAs) in Q/V-band fabricated in 0.18-μm SiGe BiCMOS technology. The developed LNAs function over the dual (44/60 GHz)-band with an integrated filtering function and achieve peak power gain of 19.1 dB with minimal gain imbalance of less than 0.2 dB between the two bands. The achieved 3-dB bandwidths are more than 6 GHz for each band of the two LNAs with the lowest measured noise figure of 5.6 dB in the targeted frequency bands. The synthesized Q-enhanced metamaterial transmission line structures proposed in this brief contribute a dual-band operation at 44/60 GHz with a rejection of more than 30 dB between the two bands. The Colpitts style negative generation circuit is utilized in conjunction with composite right/left-handed metamaterial transmission line and its dual structure, which is unprecedented, to realize multi-band millimeter-wave integrated circuits.

Transmission Line Metamaterial-Inspired Circularly Polarized RFID Antenna

A novel wideband (11.1% −10 dB bandwidth) and low-profile (0.03 λ 0 height) metamaterial transmission line (TL)-inspired circularly polarized (CP) antenna for radio-frequency identification (RFID) application is proposed. A capacitor-loaded TL (CL-TL) is realized by inserting multiple series metal–insulator–metal (MIM) capacitors into the TL. The MIM capacitor works as a series left-handed (LH) capacitor as well as a radiator. First, the CL-TL is studied and analyzed through circuit model and dispersion curves. Then, a linearly polarized (LP) antenna and a CP antenna based on the CL-TLs are implemented. Compared with the conventional right-handed (RH) TL-based antennas, here the size reduction is achieved by pushing down the dispersion curve to lower frequency using multistage structures and larger LH capacitance. The measured −10 dB impedance bandwidth, 3 dB axial-ratio (AR) bandwidth, and radiation efficiency for this CP antenna is 859–959 MHz (11.1%), 902–923 MHz (2.3%) and 83.9%, respectively. It features a compact size, low cost, wide bandwidth, and good radiation performance, which could be conveniently used for RFID reader.

Compact Metamaterial-based Coil Element for Combined 1H/23Na MRI at 7T

High static magnetic flux densities in the field of magnetic resonance imaging (MRI) allow X-nuclei-based imaging and spectroscopy as well as the utilization of electromagnetic metamaterials. A compact dual-tuned coil element based on a metamaterial transmission line which achieves a quarter-wave resonance at the two distinct operating frequencies of the hydrogen and sodium nuclei is presented. In addition, first combined 1 H/23Na MRI measurement results from a structured phantom are shown and discussed.