Composite Right/Left-Handed Transmission Line With Wire Bonded Interdigital Capacitor

An enhanced composite right/left-handed (CRLH) transmission line (TL) is presented in this letter. This TL, designed in microstrip technology, is implemented by means of a new improved interdigital capacitor (IDC), the so-called wire bonded IDC (WBIDC). The use of the WBIDC broadens the frequency band where the CRLH TL can be considered as a TL. A conventional 70-Omega CRLH TL (using IDCs) has been compared, by full-wave simulation and measurements, with its enhanced counterpart (using WBIDCs). In addition, this enhanced CRLH TL has been used to design a CRLH diplexer which presents several advantages over standard CRLH coupled lines (using IDCs). The diplexer response has been verified by means of a full-wave electromagnetic solver     

Novel Compact Dual-Band Rat-Race Coupler Combining Fractal Geometry and CRLH TLs

A super compact fractal-shaped composite right/left handed (CRLH) rat-race coupler (RRC) is proposed for the first time by skillfully combining two circuit schematics of the RRC operating at two arbitrary frequencies. For dual-band (DB) purpose, novel circuit schematics of RRC are deducted, and close-form formula and design procedures are derived in detail. The CRLH transmission line (TL) consists of lumped elements for the left handed part and Koch-shaped microstrip lines (MLs) for the right handed part. Since conventional RRC exhibits two types of unique branches, the DB design often suffers a tedious process. By employing the CRLH TL, the realization of a DB RRC becomes much easier. Moreover, constructing the microstrip lines as Koch curves enables the compactness of the circuit. For verification, a coupler operating at 0.75 and 1.8? GHz is fabricated and measured. Consistent results between simulation and measurement have confirmed the design and shown that the RRC with an area of 10.2% of its conventional counterpart owns excellent in-band performances.     

Small-size CPW silicon resonating antenna based on transmission-line meta-material approach

A small-size zeroth-order resonating antenna based on a composite right/left-handed transmission line (CRLH TL) fabricated on high resistivity silicon substrate using coplanar waveguides (CPW) is proposed. The CRLH TL consists of a series of CPW interdigital capacitors and parallel short-ended CPWs. The predicted and experimental results for return loss, gain and radiation pattern are in very good agreement.     

一种 CRLH 传输线结构的电调移相器设计

基于左右手复合传输线（CRLHTL,Composite Right／Left-Handed Transmission Line）提出了一种加载变容管结构的电调移相器,该移相器由两个电调复合传输线单元级联构成,每个复合传输线单元含3个变容二极管用以实现其相位传播常数以及等效特性阻抗的大范围调配。为方便工程使用,整个移相器6个变容二极管采用单一偏置电压控制,仿真以及最终测试结果均显示,在其工作的S频段内实现了可调相移量大于180°,相对带宽大于10％且回波损耗优于10dB的良好性能。     

CRLH-TL引领未来多频带小型化低损耗传输新变革

文章从左右手复合传输线(CRLH-TL)的机理出发,以传输特性为依据,阐述了其与传统平面传输线的相位响应区别,揭示了构成的左手传输线(LH-TL)的正向非线性及右手传输线(RH-TL)的负向线性传输特性导致的任意两个频率下四分之波长独特的响应及任意一个频率下的零度响应特征。根据这一原理,论证了不同于传统CRLH-TL而体现高选择性的T形双频带传输线和高设计灵活性的多频带传输网络的优越特性。上述不同结构的传输线分别应用于双频带威尔金森功分器和三频带的吉赛尔功分器两种无源器件的设计,证实了CRLH-TL具有实现多频带、小型化、低损耗传输的优异特性,为CRLH-TL引领未来小型化低损耗传输新变革提供了强有力的理论及实验依据。     

基于分形复合左右手传输线的小型化微带双工器设计

基于分形几何与复合左右手传输线的混合技术方法,提出了一种新型小型化微带双工器并对其进行了研究.该双工器将工作于一对不同频率的两个三端口网络进行合成,由构成其左手部分的集总元件和右手部分的Sierpinski分形微带线组成.双工器的小型化得益于Sierpinski分形曲线的空间填充特性.而双工器的双频特性是由于复合左右手...     

Low-Cost Approach Based on an Eigenfrequency Method to Obtain the Dispersion Diagram in CRLH Structures

A novel method to obtain the dispersion diagram of a composite right/left-handed (CRLH) unit-cell is presented. This method is based on CRLH transmission-line (TL) theory and on the structure eigenfrequencies. First, it is shown that computing the dispersion diagram of an M unit cell CRLH TL only needs three eigenfrequencies. Then, it is shown that this method drastically reduces the total computation time to obtain the CRLH unit cell dispersion diagram (from several hours to a few minutes). A four cell resonator has been designed and built to show the accuracy of the proposed method. Good agreement between the measured prototype and resonant frequencies provided by the dispersion diagram obtained with the eigenfrequency method has been achieved     

Enhanced CRLH Transmission Line Performances Using a Lattice Network Unit Cell

A novel topology for the composite right/left-handed transmission line (CRLH TL) is presented. This type of CRLH TLs has the advantage of exhibiting an all-pass behavior and a frequency-independent characteristic impedance, in the so-called balanced case. Moreover, it presents a larger group velocity than its conventional counterpart, thereby allowing for wider bandwidth operation. This letter investigates the fundamental properties of this structure, and demonstrates them by full-wave simulation and measurement results on a practical implementation in parallel stripline technology.      

Wide-band balun using composite right/left-handed transmission line

A wide-band balun is developed using a composite right/left-handed (CRLH) transmission line (TL) at 2 GHz. It is composed of a Wilkinson power divider and two phase-adjusting transmission lines, namely the CRLH TL and the conventional TL. The input reflection coefficient is better than -10 dB from 1 to 4 GHz. Over the frequency range of 1.24-3.58 GHz, an amplitude imbalance of less than 0.7 dB and a phase error of less than plusmn10deg have been experimentally demonstrated.     

CPW‐Fed Arbitrary Frequency‐Switchable Antenna Using CRLH Transmission Line

A novel frequency‐switchable antenna that uses PIN diodes and a composite right‐ and left‐handed transmission line (CRLH TL) is proposed. The CRLH TL provides multi‐order resonance, including a zeroth‐order resonance (ZOR), and its shunt stub determines the ZOR frequency. Thus, the resonant frequency is arbitrarily chosen by lumped chip inductors on the shunt stub. Two prototypes are designed using different chip inductors while maintaining the antenna geometries. Antenna #1 can switch the resonant frequency from 1.8 GHz to 2.3 GHz. Antenna #2 can switch its resonance from 0.9 GHz to 2.3 GHz.     

一种基于CSRR＿CRLH TL的带通滤波器设计

提出一种基于探针加载的互补开口谐振环(CSRR)的复合左右手传输线(CRLH TL)结构。利用CSRR+CRLH结构的谐振特性,并通过延长CRLH耦合缝隙的长度以及增加CSRR中短路探针的数量,在引入传输零点的同时缩小了滤波器的尺寸。经过仿真优化,实现了滤波器宽频带、高选择性和小型化设计。加工了基于该结构的带通滤波器样机,样机整体尺寸为30mm×15mm×1.35mm。测试结果表明,滤波器的中心频率及插入损耗分别为6.6GHz和0.65dB,3 dB带宽为9.3 GHz,在无线通信、导航等微波系统中具有良好的应用前景。     

CRLH metamaterial leaky-wave and resonant antennas

Composite right-/left-handed (CRLH) transmission-line (TL) metamnaterials, with their rich dispersion and fundamental right- /left-hand duality, represent a paradigm shift in electromagnetics engineering and, in particular, for antennas. This paper presents an overview of the most practical leaky-wave and resonant CRLH antennas, which all exhibit functionalities or/and performance superior to prior state of the art. The leaky-wave antennas provide full-space dynamic scanning capability, with fan beams, conical beams in uni-planar configurations, pencil beams without any complex feeding network, and actively shaped beams based on the concept of aperture digitization. The resonant antennas offer alternative properties and a solution to beam-squinting when no scanning is required, including multi-band (dual/tri-band) operation, zeroth-order high efficiency, high directivity, and planar electric and magnetic monopole radiators.     

基于左右手复合传输线的威尔金森功分器

基于左右手复合传输线(CRLH TL),提出了一种新型并行馈电的Wilkinson功率分配器.采用奇偶模分析方法证明了在Wilkinson功分器中用左右手复合传输线替代传统传输线的可行性,有效减小了功分器的尺寸.同时利用左右手复合传输线较平滑的相频特性,拓宽了新型左右手复合传输线功分器带宽.实测结果表明:和传统Wilkinson功分器相比,左右手复合传榆线功分器带宽能大幅度提高带宽,减小器件面积.另外与串行馈电CRLH功分器相比,由于左右手复合传输线Wilkinson功分器结构对称,各输出端口具有很好的相位一致性,隔离电阻的存在,使其各端口间也拥有较好的隔离度.     

Characteristics of the composite right/left-handed transmission lines

The composite right/left-handed (CRLH) transmission line (TL) is presented as a general TL possessing both left-handed (LH) and right-handed (RH) natures. The dispersion diagram of the two-dimensional (2-D) CRLH-TL is obtained analytically based on the Bloch-Floquet theory, and the unique phenomenon of infinite guided-wavelength propagation, with nonzero group velocity at a nonzero frequency, is explained. It is shown analytically that when the CRLH TL is "balanced", two eigenfrequencies at the /spl Gamma/ point (/spl beta/=0) of the Brillouin zone (BZ) degenerate at /spl omega//sub /spl Gamma// and a seamless transition from the LH to the RH modes without a bandgap can be achieved. In addition, these phenomena are demonstrated experimentally in the case of a CRLH microstrip line.     

一种新型复合左右手结构四频微带天线

在传统互补开环谐振(CSSRR)结构上添加T型枝节,形成一种新型复合左右手传输线(CRLH TL)。采用理论分析、电磁仿真和电路仿真研究其电磁特性,给出了单元结构的等效电路,计算了色散曲线,证明该结构是一种具有双频特性的CRLH结构。利用该结构设计、制作并测试了一种C波段四频微带天线,测试结果表明该天线具有较宽的阻抗带宽和很好的辐射特性。     

复合左右手微带有源漏波阵列天线

本文通过分析左右手传输线的后向波理论,提出了一种基于复合左右手传输线的有源漏波阵列天线。该天线的有源辐射单元部分采用左右手传输线结构,通过添加有源放大器和移相器,在传输方向上可以实现前后向波束大范围扫描,在组阵方向实现波束相扫,整个阵列实现两维电扫功能。仿真与实验结果吻合良好,表明该设计方法的正确性和可行性。     

Arbitrary dual-band components using composite right/left-handed transmission lines

Arbitrary dual-band microstrip components using composite right/left-handed (CRLH) transmission lines (TLs) are presented. Theory, synthesis procedure, and implementation of the dual-band quarter-wave (/spl lambda//4) CRLH TL are presented. Arbitrary dual-band operation is achieved by the frequency offset and the phase slope of the CRLH TL. The frequency ratio of the two operating frequencies can be a noninteger. The dual-band /spl lambda//4 open/short-circuit stub, dual-band branch-line coupler (BLC), and dual-band rat-race coupler (RRC) are also demonstrated. The performances of these dual-band components are demonstrated by both simulated and measured results. Insertion loss is larger than 23 dB for the shunt /spl lambda//4 CRLH TL open-circuit stub and less than 0.25 dB for the shunt /spl lambda//4 CRLH TL short-circuit stub at each passband. The dual-band BLC exhibits S/sub 21/ and S/sub 31/ larger than -4.034 dB, return losses larger than 17 dB, isolations larger than 13 dB, phase differences 90/spl deg//spl plusmn/1.5/spl deg/, and gain imbalance less than 0.5 dB at each passband. The dual-band RRC exhibits S/sub 21/ and S/sub 31/ larger than -4.126 dB, return losses larger than 12 dB, isolations larger than 30 dB, phase difference 180/spl deg//spl plusmn/4/spl deg/, and gain imbalance less than 0.2 dB at each passband.     

左手加载共面波导激励槽环天线

基于复合右左手传输线的非线性相移特性,提出了一种左手加载的共面波导激励槽环天线。该天线由四个简化的复合左右手传输线结构单元构成,通过调整单元的并联电感值,可以改变天线的谐振频率和输入阻抗,利用仿真方法分析了天线的性能。结果表明,相比于传统天线,新天线尺寸减小了30.25%,总辐射效率达到98.34%,同时交叉极化比提高了2.9 dB。     

Composite right/left handed transmission line phase shifter using ferroelectric varactors

A composite right/left handed (CRLH) transmission line (TL) phase shifter, using ferroelectric (Ba/sub 0.25/Sr/sub 0.75/TiO/sub 3/) varactors as tunable element, is presented for the first time. It is theoretically and experimentally demonstrated how the unique features of CRLH TLs, enables a differential phase shift with flat frequency dependence around the center frequency. The experimental prototype is a coplanar design integrated on a high resistive Si substrate. It includes four CRLH T-unit cells and has a physical length of 3850/spl mu/m. The ferroelectric varactors are realized in parallel plate version. Under 15-V dc bias applied over each varactor, the differential phase shift is flat around 17GHz and has an absolute value of 50/spl deg/.     

Fully Printed Dual‐Band Power Divider Miniaturized by CRLH Phase‐Shift Lines

In this letter, a compact and fully printed composite right‐ and left‐handed (CRLH) dual‐band power divider is proposed. The branches of the conventional Wilkinson power divider are replaced by subwavelength CRLH phase‐shift lines having +90° for one frequency and ?90° for another frequency for dual‐band and miniaturization performance. Equations are derived for the even‐ and odd‐mode analysis combined with the dual‐band CRLH circuit. A PCS and a WLAN band are chosen as the test case and the circuit approach agrees with the CAD simulation and the measurement. Additionally, the CRLH property is shown with the dispersion diagram and the eightfold size reduction is noted.