A power divider based on a new kind of composite right/left-handed transmission line (CRLH TL) unit

A new power divider, composed of a novel composite right/left-handed (CRLH) transmission line (TL) unit, is proposed. The properties of the power divider based on four CRLH TL unit cells are investigated theoretically. By adjusting the parameters of the capacitors and the inductors, the power divider shows perfectly symmetric power division at 5.13 GHz, return loss up to ?24 dB, with the transmitted power being close to ?3.1 dB. The phenomena are demonstrated by simulation results. Being compact in size and low-cost, the proposed power divider is very suitable for microwave and millimeter wave integrated circuits.

Novel resonator based on composite right/left-handed transmission lines

A new approach was introduced to analyze composite right/left-handed transmission lines （CRLH TLs）. The Bloch impedance and the dispersion relations are directly obtained from the S parameters of the unit cells. The LH and RH frequency bands are then identified by the real parts of the Bloch impedance and the phase delay of the unit cells. The new approach has some advantages over the LC parameters extraction method introduced by Caloz et a1.（2004）. Based on the new approach, a novel resonator is designed using CRLH TLs. The simulation and experimental results accorded well with the theoretical analysis. The novel resonator may have potential applications in filters with high harmonic suppression and compact structures,

Science Letters:Dual structure of composite right/left-handed transmission line

A dual structure of composite right/left handed (CRLH) transmission line (TL) is analyzed in which an inductance LR is in parallel with a capacitance CL and a shunt capacitance CR is in series with an inductance LL. Both the distributed and lumped cases are considered. The dispersion diagram and transmission properties of the dual CRLH TL are given and compared with those of a standard CRLH TL. Contrary to the frequency response of a standard CRLH TL, a dual CRLH TL has a left-handed (negative phase shift) band at higher frequencies and a right-handed (positive phase shift) band at lower frequencies. A novel dual-band balun is presented as an application.

Design of Miniaturized Band-Pass Filter with Composite Right/Left-Handed Transmission Line

In this paper, a new miniaturized wide-pass-band filter at U band based on composite right/left- handed transmission line (CRLH TL) is implemented. The CRLH TL contributed to a broadband filter is a balanced structure with a small size of only 1.428 mm*0.5530 mm. The frequency characteristics are simulated and the results show that the 3 dB band width of the proposed filter is about 13.5 GHz from 45.8 GHz to 59.3 GHz. The insertion loss is quite flat through the pass-band and the return loss is relatively low.

Wider frequency domain for negative refraction index in a quantized composite right–left handed transmission line

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.

A monolithic distributed phase shifter based on right-handed nonlinear transmission lines at 30 GHz

The epitaxial material, device structure, and corresponding equivalent large signal circuit model of GaAs planar Schottky varactor diode are successfully developed to design and fabricate a monolithic phase shifter, which is based on right-handed nonlinear transmission lines and consists of a coplanar waveguide transmission line and periodically distributed GaAs planar Schottky varactor diode. The distributed-Schottky transmission-line-type phase shifter at a bias voltage greater than 1.5 V presents a continuous 0°–360° differential phase shift over a frequency range from 0 to 33 GHz. It is demonstrated that the minimum insertion loss is about 0.5 dB and that the return loss is less than-10 dB over the frequency band of 0–33 GHz at a reverse bias voltage less than 4.5 V. These excellent characteristics, such as broad differential phase shift, low insertion loss, and return loss, indicate that the proposed phase shifter can entirely be integrated into a phased array radar circuit.

Broadband microwave frequency doubler based on left-handed nonlinear transmission lines

A bandwidth microwave second harmonic generator is successfully designed using composite right/left-handed non- linear transmission lines （CRLH NLTLs） in a GaAs monolithic microwave integrated circuit （MMIC） technology. The structure parameters of CRLH NLTLs, e.g. host transmission line, rectangular spiral inductor, and nonlinear capacitor, have a great impact on the second harmonic performance enhancement in terms of second harmonic frequency, output power, and conversion efficiency. It has been experimentally demonstrated that the second harmonic frequency is deter- mined by the anomalous dispersion of CRLH NLTLs and can be significantly improved by effectively adjusting these structure parameters. A good agreement between the measured and simulated second harmonic performances of Ka-band CRLH NLTLs frequency multipliers is successfully achieved, which further validates the design approach of frequency multipliers on CRLH NLTLs and indicates the potentials of CRLH NLTLs in terms of the generation of microwave and millimeter-wave signal source.

Miniaturized fractal-shaped branch-line coupler for dual-band applications based on composite right/left handed transmission lines

In this paper,novel dual-band (DB) branch-line couplers (BLCs) employing a composite right/left handed transmission line (CRLH TL) and fractal geometry are presented for the first time.The CRLH TL,with specified characteristic impedance and phase shift,consists of lumped elements for the left handed (LH) part and fractal-shaped microstrip lines (MLs) for the right handed (RH) part,which can be designed separately.Two designed BLCs are involved in size reduction,one using a 3/2 fractal curve of first iteration,the other constructed based on a hybrid shape of fractal and meandered lines.A miniaturized principle for CRLH TL realization is derived and an exact design method for fractal implementation is developed.For verification,an example coupler was fabricated and measured.Consistent numerical and experimental results confirmed the design concept,showing that the BLCs obtain DB behavior centered at 0.9 GHz and 1.8 GHz respectively with good in-band performance,except for slightly larger coupled insertion loss for the hybrid-shaped BLC case.In addition,the proposed fractal-and hybrid-shaped BLCs obtained a 49.7% and 64.1% size reduction respectively relative to their conventional counterparts working in the lower band.The most important contributions of this article are the demonstration of compatibility between the fractal and CRLH TL techniques and the provision of an alternative approach and a new concept for designing devices.

Harmonic suppressed bandpass filter using composite right/left handed transmission line

A wideband composite right/left handed transmission line (CRLH TL) in conjunction with its corresponding equivalent circuit model is studied based on a cascaded complementary single split ring resonator (CCSSRR).The characterization is performed by theory analysis,circuit simulation,and full-wave electromagnetic (EM) simulation.The negative refractive index (NRI) and backward wave propagation performance of the CRLH TL are demonstrated.For application,a bandpass filter (BPF) with enhanced out-of-band selectivity and harmonic suppression operating at the wireless local area network (WLAN) band is designed,fabricated,and measured by combining the CRLH TL with a complementary electric inductive-capacitive resonator (CELC).Three CELC cells with wideband stopband performance in the conductor strip and ground plane,respectively,are utilized in terms of single negative permeability.The design concept has been verified by the measurement data.

Nonlinear properties of the lattice network-based nonlinear CRLH transmission lines

The nonlinear properties of lattice network-based（LNB） composite right-/left-handed transmission lines（CRLH TLs）with nonlinear capacitors are experimentally investigated.Harmonic generation,subharmonic generation,and parametric excitation are clearly observed in an unbalanced LNB CRLH TL separately.While the balanced design of the novel nonlinear TL shows that the subharmonic generation and parametric processes can be suppressed,and almost the same power level of the higher harmonics can be achieved over a wide bandwidth range,which are difficult to find in conventional CRLH TLs.

Peregrine Soliton and Akhmediev Breathers in a Chameleon Electrical Transmission Line

We analyze the particular behavior exhibited by a chaotic waves field containing Peregrine soliton and Akhmediev breathers. This behavior can be assimilated to a tree with “roots of propagation” which propagate randomly. Besides, this strange phenomenon can be called “tree structures”. So, we present the collapse of dark and bright solitons in order to build up the above mentioned chaotic waves field. The investigation is done in a particular nonlinear transmission line called chameleon nonlinear transmission line. Thus, we show that this line acts as a bandpass filter at low frequencies and the impact of distance, frequency and dimensionless capacitor are also presented. In addition, the chameleon’s behavior is due to the fact that without modifying the appearance structure, it can present alternatively purely right- or left-handed transmission line. This line is different to the composite one.

基于单个CSRR CRLH结构的双频带通滤波器

提出了一种基于单个互补开口谐振环(CSRR)的复合左右手(CRLH)结构双频带通滤波器,利用CSRR CRLH结构谐振特性,并通过延长、弯曲开路枝节线,引入新的传输零点同时缩小滤波器的尺寸,实现了滤波器双通带、高选择性和小型化.加工并测试了基于CSRR CRLH结构的双频带通滤波器的原型(尺寸为3 cm×3 cm),结果显示第一通带和第二通带的中心频率和插入损耗分别为1.9 GHz/1.7 dB和2.9 GHz/2.8 dB,在DC-1.05 GHz、2.20-2.50 GHz和3.45-4.00 GHz阻带范围内的带外抑制优于20 dB,实现了双频带通特性.

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30 mm×15 mm×1.35 mm。测试结果表明,滤波器的中心频率及插入损耗分别为6.6 GHz和0.65 dB,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。

小型化5位数控延迟线的设计

设计了一种新颖的小型化5位数控延迟线.其中,小时延单元采用传统的右手传输线实现,而大的时延单元采用左手传输线来实现.该方法能够克服传统右手传输线实现大的时延单元时存在的体积和插入损耗大的缺点.该延迟线工作在9 GHz^10 GHz频段上,延迟时间调节范围可达100 ps^3 100 ps,时间步长间隔100 ps.整个延迟线尺寸仅10 mm×20 mm×0.5 mm,插入损耗小于6.2 dB.

复合左右手传输线构成的异向介质及其应用

首先从理论上证明了利用微带结构实现的复合左右手传输线具有异向介质特性,然后利用复合左右手传输线构造了具有宽带特性的异向介质.同时,介绍了近几年来我们在分析、设计和研制由该种异向介质构成的微波无源器件方面的研究成果.研究表明:由于复合左右手传输线的异向介质特性,使得这些新颖的无源器件无论在插损、尺寸以及性能上都优于由传统传输线构成的同类器件的特性.

基于微带传输线的由特异材料构成的一维光子晶体

通过左右手复合传输线(CRLH TLs)实现了一维的特异材料(Metamaterials),基于Metamaterials单元构成了光子晶体,并分析、测试了其传输特性.实验结果表明,由特异材料构成的一维光子晶体具有Bragg带隙和等效的单负带隙.当晶格尺度同比例改变时,等效的单负带隙基本上不发生移动,并且带边分别由零平均介电常数—ε=0和零平均磁导率—μ=0决定.零平均折射率(zero-—n)带隙和零有效相位(zero-Φeff)带隙可以理解为一种等效的单负带隙.对由Metamaterials构成的一维光子晶体传输特性的研究,有助于Metamaterials在射频/微波电路和仪器中的应用.

左手材料在天线中的应用研究进展

从理论上解释了左手材料用于天线设计时实现天线高指向性、高效率、小型化以及大扫描范围的原因,重点介绍了基于金属谐振结构和复合左/右手传输线(CRLH TL)结构的左手材料用于天线设计时的研究进展,指出金属谐振结构在提高天线方向性、增大天线增益、减小天线体积等方面具有很大优势,CRLH TL结构在提高天线带宽、增加天线频带、增大漏波天线扫描范围等方面具有潜在的应用价值。

左手微带传输线在毫米波天线阵中的应用

提出了一种新的左手微带传输线结构.基于这种结构,构建了左-右手混合式天线阵微带馈线,通过控制该馈线中左、右手传输线的长度,可以在特定长度传输线上获得零相位延迟.将此种传输线作为馈线应用到串联馈电的毫米波微带天线阵中.结果表明,利用此种传输线馈电和传统右手传输线馈电相比,可以避免由传统右手馈线在天线激励点之间引入的相位差,从而克服了固有的天线波束偏移.

一种开口环缺陷地面结构复合左右手传输线

提出了一种开口谐振环缺陷地面结构复合左右手传输线,采用曲线拟合技术提取出单元等效电路值,推导出该单元模型的传输零点位置、色散特性、折射率特性以及级联传输特性.理论和实验结果均表明,该结构呈现出复合左右手特性.这种新型复合左右手传输线具有带外传输零点,结构简单紧凑且不引入对地过孔,适合在微波集成电路中推广应用.

基于左右手传输线的贴片八木天线

运用左右手传输线的后向波理论,提出了一种新型的小型化微带贴片八木天线。该天线的有源振子部分采用左右手传输线结构;同时,为了进一步减小其物理尺寸,反射器和引向器分别采用了弯折线和微带线加载电容的结构来实现。实验结果表明,此天线的电性能优于传统八木天线,且尺寸只有传统天线的1/3。经测试,这种天线在性能上不亚于传统的八木天线。