左手传输线研究

本文从工程设计的角度出发,在已经提出的几种左手传输线的基础上,对左手传输线进行了进一步的仿真研究,获得了有利于设计的一些规律.在此基础上,提出了一种变长交指电容的优化方法,将此方法应用到左手传输线的设计中,可以大大减少设计的优化工作量,并且从仿真结果的比较中可以看到该方法能够显著改善左手传输线的通带宽度.     

基于复合左右手传输线小型化功分器的设计

传统的一分多路功分器的隔离网络占用的尺寸较大.根据复合左右手传输线的双曲-线性色散关系可以设计出零相移复合左右手传输线,利用这种传输线来改进传统功分器的隔离网络,可以有效减小整个功分器的尺寸.采用零相移复合左右手传输线来改进三等分功分器的隔离网络,整个功分器的面积比传统的减小了70%,实验结果证明了设计方法的正确性.     

The DIGILATOR, a New Broadband Microwave Frequency Translator

Frequency translation of an RF wave can be accomplished by subjecting it to a constant rate of phase shift or by applying an ideal repetitive sawtooth phase function which snaps to zero at 360 degrees (serrodyne modulation). The DIGILATOR is a new type of frequeucy translator which employs a multibit latching ferrite phase shifter with a suitable digital switching driver to obtain a multiple-step approximation to the serrodyne phase function. This paper reviews the theory of an N-step DIGILATOR and describes the design of a 16-step, X-band device. Experiments showed that performance is independent of microwave frequency over the design frequency band of the phase shifter. The carrier and close-in sidebands were suppressed by 39 dB and predicted far-out sidebands were within 1 dB of theoretical amplitudes.     

Coaxial Waveguide Based Left-Handed Transmission Line

In this letter, a new realization of left-handed transmission line (LHTL) is presented; the proposed structure is realized by periodically loading the coaxial waveguide with gaps in the inner conductor and wires between the inner and outer conductors, the gaps and wires act as series capacitors and shunt inductors. The dispersion characteristic of this new LHTL is analyzed by means of high frequency structure simulator (HFSS) eigenmode simulation and microwave network theory, which exhibits LH behavior over a 60% bandwidth. A backward wave behavior is unambiguously demonstrated from HFSS driven modal simulation. The phase front is observed to be in the opposite direction with respect to the energy one for a finite nine-unit cell prototype.     

A Broadband Quadrature Power Splitter Using Metamaterial Transmission Line

A broadband quadrature power splitter (QPS) is developed using the metamaterial transmission line (MM TL). It consists of a Wilkinson power divider and two phase-adjusting TLs, namely a MM TL and a microstrip (MS). The slope of the phase-response curve of the MM TL is synthesized to be the same as that of the MS along with the 90deg phase increment at two design frequencies. Hence, the broadband quadrature phase difference over the desired frequency range can be obtained. In this letter, the QPS is developed at the center frequency of 2 GHz. Over the frequency range of 1.1-3.5 GHz, an amplitude imbalance of less than 0.9 dB and a phase error of less than plusmn5deg have been experimentally demonstrated.     

Switchable Composite Right/Left-Handed (S-CRLH) Transmission Line Using MEMS Switches

This letter presents a novel switchable composite right/left-handed (S-CRLH) metamaterial transmission line (TL) using MEMS switches. The proposed TL is based on a general CRLH TL with switchable capacitors and switchable shunt inductive stubs. The LH mode of the S-CRLH TL ranges from 7.5 GHz to 10.4 GHz. In these frequencies, the S-CRLH TL is able to switch from a negative phase response (phase lag) to a positive phase response (phase lead), or vice versa. This phase modulation can be obtained through a voltage, due to the use of MEMS switches. The size of the fabricated S-CRLH TL, including bias networks, is $4941 mu{rm m}times 2076 mu{rm m}$ and is compact thanks to the LH mode.      

Suppression of Unwanted Harmonics Using Integrated Complementary Split-Ring Resonators in Nonlinear Transmission Line Frequency Multipliers

Inspired by the distributed nature of nonlinear transmission lines (NLTLs), a novel filtering method that integrates the filter stages within the NLTL periodic structure is introduced to suppress unwanted signals. To implement the filter, compact complementary split-ring resonators are designed and included in a coplanar waveguide-based NLTL frequency doubler. Analytical derivations for the filter design and prediction of the dispersion characteristics are presented. Measurement results are reported to validate the efficiency of the method demonstrating improvement in third harmonic suppression and reduced sensitivity to the variation of the input voltage level.     

Left-Handed Transmission Line Based on Resonant-Slot Coupled Cavity Chain

In this letter, a novel realization of left-handed transmission line is presented; the proposed structure is based on identical symmetrical resonant-slot coupled cavity chain. The dispersion characteristic of the resonant-slot coupled cavity chain is analyzed by means of field theory and finite element method (FEM) eigenmode simulation, and a left-handed passband is proved to exist. A backward wave behavior is demonstrated unambiguously from FEM driven modal simulation. The phase front is observed to be in the opposite direction with respect to the energy one for a finite nine-unit cell prototype     

Dual-Band Mixer Using Composite Right/Left-Handed Transmission Lines

The concept of composite right left-handed transmission lines provides for one additional degree of freedom in realizing arbitrary dual-band frequency response devices. In this letter, an arbitrary dual-band operation mixer, based on the classical balanced mixer topology is proposed. The prototype demonstrates the mixer performance for a ratio of 2.5 between the two operation bands (860 MHz and 2,150 MHz). The conversion losses are better than 8.5 dB in both bands.     

A Broad-Band Frequency Translator with 30-dB Suppression of Spurious Sidebands (Correspondence)

The theory and design of a broad-band microwave frequency translator using diode-switched coupled-line phase shifters is discussed. Results indicate spurious sideband suppression greater than 30 dB out to the 30th harmonic of the translation frequency.     

基于人工表面等离子激元传输线的宽带圆极化频率扫描天线

提出了一种由椭圆形人工表面等离子激元(SSPPs)馈电的新型宽带圆极化频率扫描天线.天线以椭圆结构单元SSPPs传输线为基础,沿传输线两侧周期性地加载开口环贴片,利用表面波的慢波特性实现天线的频率扫描,并且通过加载贴片偏移四分之一波导波长产生90°相移,实现圆极化辐射.仿真和实测结果均表明,所提出的天线在4.5～8.0...     

Dual Composite Right/Left-Handed (D-CRLH) Transmission Line Metamaterial

The novel concept of dual composite right/left-handed (D-CRLH) transmission line metamaterial is introduced. The D-CRLH is the "dual" of the conventional CRLH in the sense that it has a series parallel (instead of series) LC tank and a shunt series (instead of parallel) LC tank. This topological duality results in dual properties. The D-CRLH indeed exhibits its left-handed (LH) band at high frequencies and its right-handed (RH) band at low frequencies and is of stop-band nature, in opposition to the CRLH which is low-frequency-LH/high-frequency-RH and pass-band. The so-called balanced condition is still valid in the D-CRLH for broadband matching. However, phase origin is at dc and infinity instead, as at the LH-RH transition, and the gap between the RH and LH bands cannot be closed up in practical implementations. In contrast, the D-CRLH provides an unlimited LH bandwidth. This letter presents the homogeneous and LC-network transmission parameters and the fundamental dispersion/impedance properties of the D-CRLH     

基于左右手传输线的小型天线设计

基于复合左右手传输线技术研究设计超小型的天线,通过对复合左右手传输线结构的适当调整获得一个零阶谐振天线,此时天线的工作频率不再依赖于天线的几何尺寸,而只与构成左手传输线的电感与电容相关,从而可大大降低天线的几何尺寸。文中基于复合左右手传输线设计了一款小型天线,使其可以工作在ISM频段,能够满足无线局域网(2.4~2.4835GHz)的要求。     

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     

A K-Band CMOS Voltage Controlled Delay Line Based on an Artificial Left-Handed Transmission Line

A K-band voltage controlled delay line based on a left-handed transmission line (LHTL) with cascaded metal-oxide-semiconductor (MOS) varactors and shunt inductors using CMOS technology is demonstrated for the first time. A variable time delay can be obtained by changing the capacitance of MOS varactors without any power consumption. The figure of merit is 10.9 $^{circ}$/dB at 18 GHz. This result is better than other variable LHTL in similar frequency band. A time delay ranging from 56.8 ps to 76.4 ps is achieved at 18 GHz. It allows about 30 times longer time delay than that of a traditional right-handed one with the same length. The chip size, including the pads, is 410 $mu{rm m}times,$640 $mu{rm m}$.      

传输线在宽带匹配中的应用

提出了一种宽带匹配网络设计的新思路。文中以任意输入阻抗的匹配为分析模型,详细分析了传输线在宽带匹配中的各种应用,并从宏观角度定性分析了传输线在阻抗匹配中的应用原理。在此基础上分析设计了一副工作在30～88 MHz频段、电压驻波比小于3．0的实用单极子天线,其实测结果良好地满足了要求。     

低相噪、低杂散数字锁相频率合成器

本文分析了数字锁相频率合成器的相位噪声,用控制论方法对低相噪、低杂散锁相环的环路滤波器进行了设计,并通过某L波段频率合成器的成功研制得到了验证.     

A Compact Slot Antenna Utilizing a Right/Left-Handed Transmission Line Feed

A novel compact planar antenna utilizing cascaded right/left-handed transmission lines is proposed. The significance of layout planning with respect to radiation is investigated and discussed in this paper. Two segments of transmission lines of the same electrical length with opposite signs are cascaded to provide zero phase at the operation frequency. The closed-form formulas for the equivalent circuit of a transmission line are used for circuit design. Both antenna layout and radiation mechanism are discussed. For experimental demonstration, the proposed antenna operating at 2.45 GHz was implemented on an FR4 substrate. The topology using several patches has quite smaller size than the conventional patch antenna. Besides, a fairly omnidirectional radiation pattern was measured.     

基于复合左右手传输线的超宽带滤波器设计

本文基于复合左右手传输线理论提出了一种设计超宽带滤波器的新方法。该方法从传输的幅度和相位出发,利用微带线结构构建复合左右手传输线,通过控制复合传输线的左手响应频率和右手响应频率来构建微波带通结构。通过在微带线上采用缺陷地板结构物理上实现负等效介电常数,得到低通特性;采用微带线加载交指电容实现负等效磁导率,得到高通特性。最终通过将两种情况组合,构建具有较强左手特性和较弱右手特性的复合传输线,完成基于微带线结构的超宽带滤波器设计。文中给出的仿真结果和实测结果吻合良好,有利的证明了该方法的有效性和实用性。