Handed Transmission Research Articles

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.

Small Antenna Based on MEMS and Metamaterial Properties for Reconfigurable Applications

This paper presents the design of a novel, small coplanar antenna using microelectromechanical systems (MEMS) and metamaterial (MTM) properties. The antenna is designed using coplanar waveguide (CPW) technology, presenting lower dielectric losses and higher signal integrity. The design method for this MEMS-MTM antenna, herein presented, is based on a composite right/left hand (CRLH) transmission Line (TL) using a mixed approach; considering the circuit model and full-wave simulations. The fabrication process is based on high-resistivity silicon wafers. The radiator has dimensions of0.017 λg×0.033 λgand a thickness of0.0116 λg, whereas the complete circuit, of 5 mm × 11 mm, is equivalent to0.14 λg×0.31 λg. The antenna is designed using MEMS parallel-plate capacitors as the radiator, which also allows for the reconfiguration of the central frequency by electrostatically varying the capacitance. The results presented here correspond to a central frequency of 8.4 GHz. Due to its small size, this antenna has a wide variety of applications in wireless circuits for different fields.

A WIDEBAND QUADRATURE POWER DIVIDER/COMBINER AND ITS APPLICATION TO AN IMPROVED BALANCED AMPLIFIER

In this paper, a novel broadband quadrature power divider and its robust design method are presented. The QPD consists of a two-section power divider in combination with a 90-degree difierential phase shifter. The two-section power divider is calculated to provide equal power split, high output port isolation, and good return loss at all three ports. The difierential phase shifter consists of a composed right/left handed transmission line and pure-right handed transmission line named CRLHu-TL and PRHd-TL, respectively. The CRLHu-TL is divided into two parts; one of them consists of a pure-left handed section whose parasitic pad efiects are represented by means of a pure right handed section named PRHp. On the other hand, the PRHd- TL is composed by a microstrip transmission line of characteristic impedance 50› and electrical length 50 - and two sections equivalents to PRHp. The proposed circuit is applied to develop a broadband balanced amplifler with measured fractional bandwidth (FBW) of 124.4% at the center frequency of 2GHz.

An improved full scanning antenna using left-handed materials

An improved version of full scanning antenna using left-handed metamaterial is reported in this article. The antenna profile is designed based on microstrip technology using balanced composite right left handed transmission lines (CRLH TL) approach. Conventional LC network representation of the CRLH TL uses cascaded combination of interdigital capacitor (IDC) in series and vias to the ground plane at the stub ends in shunt, whereas in this article, the design of full scanning antenna using wire-bonded IDC is reported and its performance is compared with conventional IDC based full scanning antenna. Dispersion diagram of the balanced CRLH TL based dominant mode leaky wave antenna shows the capability of backfire (−90° < θ < 0°) to broadside (θ = 0°) and to endfire (0° < θ < 90°) scanning. Radiation patterns confirm the full scanability of the antenna and it also shows the designed structure has reduced sidelobes in the endfire radiations. Simulated and measured return loss characteristics of the reported antenna structure show an increase in the antenna's operational bandwidth. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:261–265, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27333

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.

Bloch impedance analysis for a left handed transmission line

In this study, the dispersion relation and the frequency dependence of Bloch impedance in a left handed transmission line (LH-TL) is carried out using the F-matrix formulation and Bloch-Floquet theorem. The artificial LH-TL formed by periodic lumped elements is described and the F-matrix, dispersion relation and the Bloch impedance are formulated according to this description. Numerical results for lossless and lossy LH-TL are presented and discussed.

CRLH-TL을 이용한 2.45GHz 무선랜용 ZOR 안테나 설계

본 논문은 CRLH-TL(composite right left handed transmission line) 메타물질을 이용하여 2.45GHz 무선랜용 ZOR(zeroth order resonance) 안테나를 설계하는 것이다. 일반적으로 안테나는 파장에 대비한 선로의 길이에 따라 공진주파수가 결정되지만 ZOR 안테나는 파장의 길이와 상관없이 안테나의 공진주파수를 결정한다. 그러므로 소형화 할 수 있는 장점이 있으며 방사패턴 또한 등방성의 방사패턴을 가지는 장점이 있다. ZOR 안테나를 설계하기 위해 먼저 단위 셀 길이를 <TEX>${\lambda}/4$</TEX>의 길이보다 작도록 조정하여 균질한 매질 특성을 가질 수 있도록 하였다. 제안된 안테나는 공진 주파수의 감소와 대역폭의 증가를 위하여 CPW 급전을 사용하였고, 기존의 mush-room 형태의 CRLH-TL 보다 높은 인덕턴스와 낮은 캐패시턴스를 얻기 위하여 방사패치와 접지면 사이에 단락 스터브가 사용 되었다. ZOR(zeroth order resonance) antenna for 2.45GHz WLAN(wireless local area network) is designed by use of CRLH-TL(composite right left handed transmission line) meta-material. The electrical length of conventional antennas is determined generally according to the resonant frequency, whereas that of ZOR antenna can be determined without reference to the resonant frequency. Therefore ZOR antenna has advantage in miniaturization of antenna in comparison with conventional antennas. In order to design such ZOR antenna, first unit cell with electrical length shorter than a quarter wavelength at 2.45GHz is designed to the some characteristics of homogeneous medium. In order to decrease resonant frequency and enhance frequency bandwidth, the proposed antenna is fed by CPW(co-planar waveguide) and short stub between radiation patch and ground plane is used for obtaining both higher inductance and smaller capacitance than previous mush-room type of CRLH-TL.

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 %.

Design and analysis of a novel tunable Ferrite based left handed strip line

This paper proposes, for the first time, a tunable left handed transmission line consisting of a strip line sandwiched between a ferrite superstrate and a dielectric substrate containing a metallic wire array. The left-handed behavior is realized by combining the negative permittivity of the wire array with the negative permeability of the longitudinally magnetized ferrite substrate despite them being spatially separated. Theoretical and numerical results demonstrate the tunability of the left-handed frequency band by changing the DC bias magnetic field applied to the ferrite. Compared to other tunable lefthanded structures, the fabrication requirements on this structure are not critical, which enhances its potential applicability.

Dual-shunt branch circuit and harmonic suppressed device application

A new type of planar left handed transmission line (LH TL) circuit was investigated theoretically and experimentally. It consists of a capacitive gap and Koch-shaped extended complementary single split ring resonator pair (K-ECSSRRP) etched on the host conductor line and ground plane, respectively. Distinguished from any previous counterparts possessing only one shunt branch, the current K-ECSSRRP features dual-shunt branches in the capacitive–inductive equivalent circuit. As a consequence, an additional attenuation pole is introduced above the upper edge passband of the LH TL, which is a very desirable characteristic. For verification and illustration of potential applications, a compact diplexer is designed and fabricated with an enhanced harmonic suppression. The dual-shunt branch circuit is of reference value and suggests a variety of device implementations where miniaturization and harmonic suppression are major concerns.

Ring-Resonator-Inspired Power Recycling Scheme for Gain-Enhanced Distributed Amplifier-Based CRLH-Transmission Line Leaky Wave Antennas

We propose a novel power recycling scheme for distributed amplifiers (DAs) integrated with composite-right/left handed transmission line leaky wave antennas (LWAs). This new type of power recycling scheme is essentially inspired by a ring-resonator. By forming a closed-loop on the drain side LWA of the DA, we create the ring-resonator that is actively coupled by the DA from the gate line and hence can obtain a substantial gain enhancement compared to the one directly terminated without the loop. Such enhancement fluctuates with respect to the frequency. At the resonant frequencies of the closed-loop ring-resonator, the enhancement reaches a maximum. The phenomenon will be explained and derived theoretically in detail, and then validated through the real implementation.

The role of adaptations in two-strain competition for sylvatic Trypanosoma cruzi transmission

This study presents a continuous-time model for the sylvatic transmission dynamics of two strains of Trypanosoma cruzi enzootic in North America, in order to study the role that adaptations of each strain to distinct modes of transmission (classical stercorarian transmission on the one hand, and vertical and oral transmission on the other) may play in the competition between the two strains. A deterministic model incorporating contact process saturation predicts competitive exclusion, and reproductive numbers for the infection provide a framework for evaluating the competition in terms of adaptive trade-off between distinct transmission modes. Results highlight the importance of oral transmission in mediating the competition between horizontal (stercorarian) and vertical transmission; its presence as a competing contact process advantages vertical transmission even without adaptation to oral transmission, but such adaptation appears necessary to explain the persistence of (vertically-adapted) T. cruzi IV in raccoons and woodrats in the southeastern United States.

A COMPACT ZEROTH ORDER RESONATING ANTENNA USING COMPLEMENTARY SPLIT RING RESONATOR WITH MUSHROOM TYPE OF STRUCTURE

A compact zeroth order resonance (ZOR) antenna based on composite right left handed Transmission Line (CRLH TL) with complementary split ring resonators (CSRR) is presented in this paper. In the proposed antenna, CRLH TL is realized by the conventional mushroom type (CMT) of structure. The unit cell of proposed antenna comprises the CMT structure and CSRR where the CSRR is etched on the patch of the mushroom. Presence of CSRR introduces the lumped components in the shunt arm of the unit cell which results in the reduction of the shunt resonance frequency. The presented antenna consists of 4 unit cells and is excited by the quarter wavelength TL. The simulation and experimental results are in close agreement. The proposed structure has nearly 8.32% footprint area of the conventional half wavelength antenna.

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.

메타물질 전송선로를 이용한 이중대역 평형증폭기

This paper describes a design of dual band balanced amplifier using a lefted handed meta-material transmission line structure for high frequency application. Meta-material transmission lines have been known to have dual band frequency responses. A dual band branch line hybrid coupler is designed using the meta-material transmission lines, and measured at first. Two identical dual band amplifiers are also designed, built and tested using the same meta-material transmission structure. The proposed dual band balanced amplifier is composed of those dual band branch line hybrid coupler and amplifiers. In order to suggest an design example, a prototype of dual band balanced amplifier is built and measured at the dual frequencies, 1800㎒(f₁) and 2300㎒(f₂). The simulation and measurement show that the fabricated balanced amplifier operates well at the desired dual frequencies bands with the gain of 11.12㏈ and 17.67㏈ at f₁ and f₂, respectively, with a good agreement with the simulation results.

Progress and Advances in Serial Powering of Silicon Modules for the ATLAS Tracker Upgrade

It is expected that at SLHC the number of detector channels in the ATLAS Semiconductor Tracker will increase by a factor 10, to cope with the increased luminosity. Currently every detector module has its own power cable, known as independent powering (IP). In the upgrade, this arrangement will no longer be tenable, due to cable volume and power losses. The serial powering alternative scheme, in which supermodules, with many readout hybrids, are connected in a serially powered chain, has been proposed and actively pursued over the last few years by the ATLAS Tracker Upgrade Community. This scheme presents some benefits, including simplicity, lower mass and reduced power losses. On the other hand, grounding, shielding and data transmission schemes are modified with respect to the conventional arrangement. Custom components specifically for serial powering have been produced, including the ABCN-25 readout ASICs and the SPI serial powering regulation ASIC, both in 250 nm CMOS, a dedicated programmable current source and power protection elements. In this paper the latest measurements from testing of the new custom electronics are presented and future plans are outlined.

Miniaturized Metamaterial Narrow Bandpass Filters Using CRLH Transmission Line CL-Loaded Approach

In this paper metmaterial narrow band bandpass filter is designed and tested. The filter designed has the following properties, resonant frequency at 900MHz for mobile communications, bandwidth equal to 80MHz, insertion loss lower than -1.3dB, with in-band return loss lower than -16dB, and a wide stopband. The total filter size is about 2cm×2.4cm which is very compact compared to other metamaterial and conventional microstrip filters. This metmaterial narrow bandpass filter is designed based on composite right left handed (CRLH) Transmission line CL-loaded approach. The design steps, simulated and experimental results of the designed filter are presented

EFFECTS OF PUBLIC HEALTH INTERVENTIONS IN REDUCING TRANSMISSION OF HAND, FOOT, AND MOUTH DISEASE

We evaluated the effect of public health interventions including territory-wide school closure and hygiene campaigns during 2003 and 2009 in reducing hand, foot, and mouth disease (HFMD). We compared the observed and projected HFMD consultation rates among sentinel general practitioners using a decomposition regression model. Public health measures were effective in reducing HFMD by 57.2% (95% CI: 53.0%-60.7%) and 26.7% (95% CI: 19.5%-32.7%) in 2003 and 2009, respectively.

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.

Hand hygiene and transmission of Pseudomonas aeruginosa on hands in a hospital environment

Colonisation and infection with Pseudomonas aeruginosa from the water supply constitutes a risk in neonatal hospital units. This short research note demonstrates that the use of correct hand hygiene minimises the risk of contamination of hands with P. aeruginosa even when heavily contaminated wash water is used.