Right-left Handed Transmission Line Research Articles

Simulation-Driven Triple-Tuned Array for 1H, 31P and 23Na Using Composite Right- and Left-Handed Transmission Line for Rat Brain at 9.4T MRI

The use of ultrahigh-field-strength magnetic resonance imaging (MRI), such as 9.4T, is able to acquire multi-nuclear imaging with better image quality than lower field strengths. In particular the acquisition of sodium ( <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">23</sup> Na) or phosphorus ( <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">31</sup> P) images could benefit with higher signal-to-noise ratio (SNR). The design of radiofrequency RF coils is required to achieve a uniform field and to operate at the corresponding frequency. The general method to make multiple frequency coils has the drawback of using multilayers or reducing the size of the coils, which impose restriction on the utilization of space. For the conventional multiple frequency array, the design for the coil size imposes a challenge for the optimization of SNR and field intensity. In addition, the use of multiple coils increases the coupling between each coil. To circumvent these problems, we propose the use of composite right-left handed (CRLH) transmission lines (TL), which are able to resonate to multiple frequencies. This work demonstrates a design of an array of four channels, in which each channel consists of a single CRLH element capable to resonate at three frequencies corresponding to <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> H at 400 MHz, <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">31</sup> P at 162 MHz, and <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">23</sup> Na at 105 MHz. The design was demonstrated with electromagnetic (EM) simulations and applied for rat brain for use in a 9.4T MRI system.

비아를 이용한 CRLH 전송선로 안테나 소형화

In this study, miniaturization of composite right-left handed (CRLH) transmission line (TL) antennas using via structure is proposed. The proposed CRLH TL antenna replaces the planar interdigital capacitor structure of the conventional CRLH TL antenna using vias in the printed circuit board multilayer structure. Via structure derives series capacitance values by replacing the finger-shaped patterned parts that comprise the conventional interdigital capacitor. The proposed model reduces the increased length of 8.34 mm to 2.66 mm for every one-cell increase based on an operating frequency of 2.9 GHz. Unlike the three-cell conventional model that utilizes 5.17 dBi at a size of 47.79 mm, the proposed four-cell model utilizes 5.35 dBi at a size of 33.41 mm.

A Novel Design Approach for Compact Wearable Antennas Based on Metasurfaces.

This paper presents a novel approach to design compact wearable antennas based on metasurfaces. The behavior of compact metasurfaces is modeled with a composite right-left handed transmission line (CRLH TL). By controlling the dispersion curve, the resonant modes of the compact metasurface can be tuned efficiently. A printed coplanar waveguide (CPW) monopole antenna is used as the feed structure to excite the compact metasurface, which will result in a low profile antenna with low backward radiation. Following this approach, two compact antennas are designed for wearable applications. The first antenna is designed to operate at its first negative mode (-1 mode), which can realize miniaturization, but maintain the broadside radiation as for a normal microstrip antenna. The proposed prototype resonates around 2.65GHz, with a matching bandwidth of 300 MHz. The total dimensions of the antenna are 39.4×33.4 mm2 (0.1 λ02), and its maximum gain is 2.99 dBi. The second antenna targets dual-band operation at 2.45 and 3.65 GHz. A pair of symmetric modes (±1 modes) are used to generate similar radiation patterns in these two bands. The size of the antenna is 55.79×52.25 mm2 (0.2 λ02), and the maximum gains are 4.25 and 7.35 dBi in the two bands, respectively. Furthermore, the performance of the antennas is analyzed on the human body. The results show that the proposed antennas are promising candidates for Wireless Body Area Networks (WBAN).

Left-handedness in the balanced/unbalanced resonance conditions of a quantized composite right-left handed transmission line

Left-handedness signifies negative permittivity (e r ) and permeability (μ r ) in the same frequency band. The e r and μ r are evaluated in a quantized composite right-left handed transmission line (CRLH-TL), and the frequency band for left-handedness is also valuated in the balanced resonance (L r C l = L l C r ) and unbalanced resonance (L l C r ≠ L r C l ) cases in the displaced squeezed Fock state. The results show that the balanced resonance plays an important role in bandwidth and achieving for left-handedness. This displays some quantum mechanical behaviors and proposes a new potential approach to wider frequency band left-handedness for the quantized CRLH-TL.

Wider frequency domain for negative refraction index in a quantized composite right–left handed transmission line**Project supported by the National Natural Science Foundation of China (Grant Nos. 61205205 and 6156508508), the General Program of Yunnan Provincial Applied Basic Research Project, China (Grant No. 2016FB009), and the Foundation for Personnel Training Projects of Yunnan Province, China (Grant No. KKSY201207068).

The refraction index of the quantized lossy composite right-left handed transmission line (CRLH-TL) is deduced in the thermal coherence state. The results show that the negative refraction index (herein the left-handedness) can be implemented by the electric circuit dissipative factors(i.e., the resistances R and conductances G) in a higher frequency band (1.446 GHz≤ ω ≤ 15 GHz), and flexibly adjusted by the left-handed circuit components (Cl, Ll) and the right-handed circuit components (Cr, Lr) at a lower frequency (ω = 0.995 GHz). The flexible adjustment for left-handedness in a wider bandwidth will be significant for the microscale circuit design of the CRLH-TL and may make the theoretical preparation for its compact applications.

The thermal effect on the left-handedness of the mesoscopic composite right-Left handed transmission line

Starting from the quantum fluctuation of current in the mesoscopic composite right-left handed transmission line (CRLH-TL) in the thermal Fock state, we investigate the left-handedness dependent of the frequencies, intensity and quantum fluctuations of the current field in the CRLH-TL under different thermal environment. The results show that the intensity and quantum fluctuations of current field in lower frequency bands affect the left-handedness distinctly under different thermal environment. The thermal effect on the left-handedness in the mesoscopic CRLH-TL deserves further experimental investigation in its miniaturization application.

基于复合左右手传输线的移相器设计

本文利用复合左右手传输线特殊的非线性相位响应特性，提出一种宽带移相器的设计方法。宽带移相器的使用可以控制天线波束在宽带内实现较固定的倾角。该方法由主副两个通路组成四端口的差分移相，其中主通路由复合左右手传输线组成，副通路由传统的右手传输线构成。两通路在很宽的带宽内相位变化一致，能够实现宽带移相。通过HFSS软件仿真设计出90˚移相器，在8~15.9 GHz (66.4%)带宽内相位不平衡度为±3˚，带内回波损耗 < −12 dB，最大插入损耗为0.3 dB。该结构设计简单，加工方便。 A design of broadband phase-shifter is presented by utilizing the unique nonlinear phase response of the composite right-left handed transmission line. The use of wideband phase-shifter can control antenna beam to achieve a fixed angle in broadband. The four-port differential phase- shifter consists of two paths, one path using composite right-left handed transmission line while the other using conventional right hand transmission line. A stable phase difference can be obtained over a wide bandwidth, so that broadband phase shift can be achieved. Simulated results show that the 90˚, phase-shift with phase imbalance of ±3 can be achieved over a broad bandwidth from 8 GHz to15.9 GHz (66.4%), with the return losses more than 12 dB and the insertion losses less than 0.3 dB. Moreover, the proposed structure is easy to design and convenient to fabricate.

Using of Scattering Bond Graph Methodology for a Physical Characteristics Analysis of “D-CRLH” Transmission Line

In this paper, we propose to analyze the physical characteristics of a planar dual-composite right-left handed transmission line by a common application of Bond Graph approach and Scattering formalism (Methodology S.BG). The technique, we propose consists, on the one hand, of modeling of a dual composite right-left metamaterial transmission line (D-CRLH-TL) by Bond Graph approach, and, it consists of extracting the equivalent circuit of this studied structure. On the other hand, it consists to exploiting the scattering parameters (Scattering matrix) of the DCRLH-TL using the methodology which we previously developed since 2009. Finally, the validation of the proposed and used technique is carried out by comparisons between the simulations results with ADS and Maple (or MatLab).

UWB Miniature Antenna Based on the CRLH-TL with Increase Gain for Electromagnetic Requirements

In this paper, a novel ultra-wideband (UWB) miniature antenna based on the composite right-left handed transmission line (CRLH-TL) structure with enhancement gain is proposed and investigated. With CRLH metamaterial (MTM) technology embedded, the proposed UWB and miniature antenna is presented with best in bandwidth, size, efficiency and radiation patterns. To realize characteristics of the antenna, the printed -shaped gaps into the rectangular radiation patches are used. This antenna is constructed of the two unit cells, also presented antenna is designed from 2.25 GHz to 4.7 GHz which corresponding to 70.5% bandwidth. The overall size of the presented antenna is 10.8mm×6.9mm×0.8mm or 0.09λ0× 0.05λ0 × 0.006λ0 at the operating frequency f = 2.5 GHz (where λ0 is free space wavelength). The radiation peak gain and the maximum efficiency which occurs at 4.6 GHz, are 3.96dBi and 63.6%, respectively.

십자 개구 결합 급전을 이용한 -1 모드 원형 편파 안테나

Abstract In this paper, a compact circularly polarized metamaterial patch antenna using cross aperture-coupled feed is proposed. The CP antenna utilizes the 1 mode that is induced by the composit right-left handed(CRLH) transmission line. Since the 1 mode has the same properties with the TM 010 mode of the conventional patch antenna, the circular polarization(CP) can be realized [1] . If two orthogonal modes are excited with 90° phase difference, the CP property can be obtained. In order to obtain two orthogonal modes and 90° phase difference, 4 mushroom structures having the shape of square are employed. The width and length of the cross aperture are optimized through the design algorithm. The fabricated antenna is based on RT/duroid5880 substrate and the total area of the 4 mushroom is 0.25   × 0.25   . The center frequency of the LHCP(Left-Handed Circular Polarization) antenna is measured as 1.622 GHz and circular polarization bandwidth(3 dB) is measured as 3 MHz. The center frequency of the RHCP(Right-Handed Circular Polari-zation) antenna is measured as 1.609 GHz and circular polarization bandwidth (3 dB) is measured as 3 MHz, respectively. The measured radiation efficiency of LHCP antenna is 61.1 % and the measured radiation efficiency of RHCP antenna is 54.5 %.Key words: Metametrial, Composit Right-Left Handed(CRLH), 1 Mode, Cross Aperture, Circular Polarization(CP) mZ2013nopjq(rstOSnq)3u v +wxuy39 z{A|Gx}(No. NRF-2013R1A2A2A05005640)~ €gn j‚ƒ„ nS(Department of Electronic Information and Communication Engineering, Hongik University) Manuscript received October 28, 2013 ; Revised February 3, 2014 ; Accepted February 10, 2014. (ID No. 20131028-103)Corresponding Author: Jeong-Hae Lee (e-mail : jeonglee@hongik.ac.kr)

On the Study of Compact and Multi-Band CRLH Meta-Material Antenna for Wireless Applications

This paper presents a design of a small size composite right-left handed metamaterial multi-band antenna for wireless applications. The proposed antenna consists of two left handed cells. The proposed antenna operates at different frequency bands. The proposed antenna has compact size (its size is only 38 X 22 mm2). The design represents size reduction of approximately 65 % compared to conventional patch antennas operating at the same frequencies. The size reduction and low frequency ratios have been achieved due to the nonlinearity behavior of the left-handed region of composite right-left handed transmission line.

Time Reversal Applied to the Time Domain Response of a CRLH Transmission Line

In this letter, the concept of electromagnetic time reversal is applied to compensate for the non-linear phase response of a dispersive transmission line. To achieve a significant phase distortion on a short transmission line, a special type of transmission lines is chosen as an experimental platform. This special type is the so called composite right-left handed (CRLH) transmission line. The time domain response of the CRLH transmission line is calculated from a wideband frequency domain measurement.

CRLH 전송 선로 구조를 이용한 -1 모드 원형 편파 패치 안테나

본 논문에서는 composit right-left handed(CRLH) 전송 선로에서 발생하는 -1 모드를 이용하여 단일 급전을 갖는 소형 원형 편파 메타 물질 안테나를 제안한다. -1 모드는 일반적인 패치 안테나의 기본 모드인 +1 모드와 같은 성질을 가지고 있기 때문에, 원형 편파의 동작 원리를 동일하게 적용할 수 있다. 따라서 서로 수직하는 편파와 <TEX>$90^{\circ}$</TEX>의 위상차를 갖는 두 개의 -1 모드들을 이용하여 원형 편파 특성을 갖는 메타 물질 안테나의 설계가 가능하다. 두 개의 -1 모드를 얻기 위해서 삼각형의 형태를 갖는 4개의 버섯 구조를 이용하였고, 모드 간에 <TEX>$90^{\circ}$</TEX>의 위상차를 인가하기 위해서 삽입된 inter-digital gap의 크기를 최적화 하였다. 추가적으로 임피던스 매칭을 위해 coupled-fed 급전 구조를 사용하였다. 제안된 안테나의 4개로 배열된 버섯 구조의 면적은 <TEX>$0.161{\lambda}_0{\times}0.161{\lambda}_0$</TEX>이며, RT/duroid5880 기판에 설계되었다. 제작된 안테나의 중심 주파수는 2.845 GHz로 측정되었고, 2.830 GHz부터 2.850 GHz까지 동작하는 것을 확인하였다. 또한, 2.842 GHz부터 2.847 GHz까지 원형 편파의 특성이 확인되었고, 방사 효율은 46 %로 측정되었다. In this paper, a compact circularly polarized metamaterial patch antenna using the -1 mode that is induced by the composit right-left handed(CRLH) transmission line is proposed. Basically, since the -1 mode is the same properties with the +1 mode of the conventional patch antenna, the circular polarization(CP) is realized. If two orthogonal -1 modes are excited with <TEX>$90^{\circ}$</TEX> phase difference, the CP property can be obtained. In order to obtain two orthogonal modes and <TEX>$90^{\circ}$</TEX> phase difference, 4 mushroom structures having the shape of triangle are employed and the inter-digital gaps are optimized, respectively. The fabricated antenna is based on RT/duroid5880 substrate and the total area of the 4 mushrooms is <TEX>$0.161{\lambda}_0{\times}0.161{\lambda}_0$</TEX>. It is confirmed that the center frequency of the proposed antenna is measured as 2.845 GHz and it operates from 2.830 GHz to 2.850 GHz. In addition, the antenna maintains the CP property from 2.842 GHz to 2.847 GHz at the peak gain and the measured radiation efficiency is 46 %.

An Omnidirectional Small Loop Antenna Based on First-Negative-Order Resonance

A compact first-negative-order resonance-based small loop antenna is proposed which consists of two unit cells of composite right-left hand transmission line (CRLH TL). By folding one of the unit cells to the bottom layer, higher radiation efficiency and omnidirectional radiation property can be achieved. A prototype antenna is fabricated and measured. The size of the proposed antenna is only 10.45 mm × 7 mm (or 0.062λ0 × 0.042λ0) at 1.78 GHz. The measured antenna bandwidth is 6.4 MHz and gain is 0.53 dBi.

Second harmonic generation with zero phase velocity waves

We design a dual-band nonlinear composite right-left handed transmission line with phase-matching achieved between the fundamental frequency and second harmonic when both interacting waves have zero phase velocity. Additionally, we show that such a transmission line supports a new regime where the generation of backward second harmonic waves is achieved from a backward fundamental frequency wave.

Modelling and analysis of radiation effects for one-dimensional metamaterial-based transmission lines

Radiation effects due to the inclusion of a series capacitor and a shunt inductor in a unit cell for the right/left-handed transmission line (RLH-TL) are analysed and modelled using transmission line theory. The radiation rate per unit cell is derived and used as a key parameter for analysing and synthesising one-dimensional (1-D) metamaterial-based transmission lines (MTM-TL or RLH-TL). Various methods of extracting parameters related with radiation (or loss in general) from electromagnetic (EM) simulations (or measurements) are also provided. The S-parameters for 1-D periodic structures with a different number of unit cells are compared and analysed in various aspects based on EM and circuit simulations considering radiation effects, leading to close agreement. Some of the meta-structures are fabricated and measured for comparison with circuit/EM-simulated data. The presented modelling and analysis of 1-D MTM-TL considering radiation effects has drastically narrowed the gap between the characteristics based on circuit simulations (usually assumed lossless) and those based on EM simulations and measurements.

MODELING AND MEASUREMENT OF A ZEROTH-ORDER RESONATOR AND A COMPOSITE RIGHT-LEFT-HANDED TRANSMISSION LINE IN COPLANAR TECHNOLOGY

This paper presents a coplanar composite right-left handed zeroth-order resonator (CRLH CPW ZOR) and a coplanar composite right-left handed transmission line (CRLH CPW TL). These devices are realized using an elementary cell designed in a coplanar waveguide conflguration on alumina substrate. Additional lumped elements are carried out with an interdigital series capacitor and a short-circuited stub inductor as a shunt. The CRLH CPW ZOR is fabricated and analyzed using equivalent circuit modeling and three dimensional flnite element method. The proposed devices are fabricated and measured. The resonator has a measured insertion loss of 2.7dB and a return loss better than 13dB. The length of the proposed device is only 5.2mm; this very small size compared with a traditional half wave resonator, shows the interest of this kind of approach.

Metamaterial 발룬으로 급전된 Capacitively Loaded 루프 안테나

This paper presents a balun consisting of a T-junction, a Right/Left Handed Transmission line(RLH-TL), and a conventional Right Handed(RH) line. It is assumed that the RLH-TL consists of N unit-cells. We provide closed-form solutions and design a very compact wideband(80 %) balun using CPW lines based on the obtained solutions. Then, we propose a capacitively loaded loop antenna designed for a uniform current distribution. The antenna resistance of the proposed antenna at resonance is about 204 ohms. The length of the unit cell is about (total length: ). The magnetic field generated from the proposed antenna is stronger than that of the conventional one by as much as 20 dB. We used a coplanar strip line(CPS) to combine the loop antenna and balun. The proposed antenna may be used as a near field UHF RFID reader antenna.

회로 파라미터 추출을 통한 1-D RLH-TL의 방사 효과 분석

일반적으로 손실이 없는 우형 전송선 모델에 직렬 커패시터와 병렬 인덕터를 삽입하여 만든 우좌형 전송 선로에 손실을 고려한 등가 회로를 제안한다. 제안된 식을 이용하면 원하는 주파수에서의 위상 조절이 가능하며, 단위 셀을 점차 늘려갈수록 발생하는 방사율에 대한 조정 역시 용이하게 된다. 단위 셀의 구조의 증가는 안테나의 배열과 같으며, 이러한 배열 구조에서는 균등한 방사가 요구된다. 따라서 방사율의 조정을 위한 식은 일반적인 마이크로스트립 기판에 제작된 평면 안테나에 비해 소형화된 안테나를 구성하는데 적용될 수 있다. 그리고 회로 시뮬레이션과 EM 시뮬레이션 사이에서 발생하는 방사율에 대한 편차는 수정된 식을 적용하면 부합된 결과를 얻을 수 있으므로 간단한 방사 구조의 설계시 간편하게 이용할 수 있을 것으로 기대된다. The equivalent circuit for the RLH-TL is proposed considering radiation effects due to the inclusion of a series capacitor and shunt inductor in a unit cell for the right/left-handed transmission line(RLH-TL). The design equations to realize a specific phase shift at a given frequency is also provided. The S-parameters for unit cells with N=1, 3, 5, and 10 are analyzed in various aspects based on the EM and circuit simulations especially for the purpose of controlling radiation along RLH-TL's. A modification formula for the radiation rate per unit cell is also proposed for good agreement between the EM and circuit simulation results.

Zeroth Order Resonance Loop Antenna

A new type of low-profile omnidirectional antenna is proposed in this paper. The proposed antenna has the conceptual configuration of the horizontal magnetic loop current on perfect electric conductor plane, which has been realized by the zeroth-order resonator (ZOR) antenna using mushroom structure. The mushroom structure as a transmission line has negative, zero, and positive propagation constant depending on its operation frequency since mushroom structure is artificial composite right-left handed transmission line. Zeroth-order resonance, of which frequency is independent of physical length, is naturally presented. In particular, mushroom ZOR antenna generates a uniform vertical electric field against ground plane, so that it omnidirectionally radiates in a horizontal plane. Operation frequency, absolute gain, and gain variations for omnidirectional radiation of the designed prototype are 7.9 GHz, 2.6dBi, less than 1.5 dBi, respectively