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Liao Shaowei Yan Ping Xu Jianhua Wang Ya 《Microwave and Wireless Components Letters, IEEE》2007,17(8):568-570
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. 相似文献
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《Microwave and Wireless Components Letters, IEEE》2008,18(11):731-733
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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。 相似文献
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《Microwave and Wireless Components Letters, IEEE》2009,19(7):434-436
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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。 相似文献
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《Microwave and Wireless Components Letters, IEEE》2006,16(11):585-587
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 相似文献
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《Microwave and Wireless Components Letters, IEEE》2006,16(11):624-626
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 相似文献
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Wenjia Tang Hongjoon Kim 《Microwave and Wireless Components Letters, IEEE》2009,19(4):221-223
In this letter, we present a frequency translator based on a left-handed nonlinear transmission line (LH NLTL). The proposed LH NLTL can achieve a very linear phase variation as a function of applied dc bias for a broadband frequency that facilitates a low spurious, broadband frequency translation. Our experiment demonstrates that the LH NLTL enables frequency shift with 30 dB maximum spurious suppression. For any frequency between 3 and 3.8 GHz, it was possible to achieve 100 KHz-1 MHz frequency shift while the range of spurious suppression is between 21 and 30 dB. Because of its compactness and possibility of low-cost monolithic fabrication, this circuit will be very useful for microwave instrumentation, or a coherent communication system where single sideband modulation is required. 相似文献
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Yu-Shin Wang Min-Feng Hsu Shyh-Jong Chung 《Antennas and Propagation, IEEE Transactions on》2008,56(3):675-683
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. 相似文献
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Jae-Gon Lee Jeong-Hae Lee 《Microwave and Wireless Components Letters, IEEE》2007,17(4):283-285
In this letter, a novel parallel coupled bandstop filter (BSF) using a double negative (DNG) coupled transmission line is presented. Between microstrip as a double positive (DPS) transmission line and mushroom structure as a DNG transmission line, strong coupling broadly arises in the cross range of dispersion curves of isolated microstrip and mushroom structure because of a complex propagation constant in the cross range. Strong coupling inhibits wave propagation, so that this kind of structure can be utilized as a BSF. This BSF utilizes coupled transmission line instead of coupled resonator, resulting in broad bandwidth (>30%), sharp-rejection, and high rejection level. The strong coupling between the DPS and DNG transmission line makes it possible to shorten the coupling length, resulting in compact size 相似文献
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《Microwave Theory and Techniques》1967,15(4):220-231
Theory and applications of coupled nonuniform transmission lines are described. Matrix representations of a general coupled nonuniform transmission line are presented, by means of which the behavior of any coupled nonuniform transmission line maybe completely described. Among a wide variety of applications of coupled nonuniform transmission lines, two typical networks, one the coupled nonuniform transmission-line folded all-pass network and the other the coupled nonuniform transmission-line directional coupler, are treated in detail. Equivalent circuit representatious of these two networks are presented, which enable the designer to synthesize them in a greatly simplified manner by making use of the theories now available for more conventional single nonuniform transmission lines. In addition, the properties of these two networks using coupled exponential line are investigated. Design procedure is also given for asymmetrical coupled exponential-line directional couplers having excellent characteristics. 相似文献
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《Microwave and Wireless Components Letters, IEEE》2009,19(12):804-806
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提出一种具有两组复合左右手通带的平面传输线结构.与传统左手微带线相比,本结构利用连有金属折线的矩形贴片和接地板上T形DGS(defected ground structures)结构形成一组新的左手通带和右手通带.为了使左右手通带间禁带闭合,用梯形贴片及接地板上交趾DGS结构代替上述结构,最终实现具有两个零级谐振频率点的平面传输线.结构的仿真结果与利用等效电路和Bloch-Floquet原理得到的理论结果及测量结构都符合较好.这种新颖的具有多通带的复合左右手传输线可应用于多通带微波器件设计. 相似文献
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Coupled Strip Transmission Line with Three Center Conductors 总被引:1,自引:0,他引:1
《Microwave Theory and Techniques》1966,14(10):446-461
An exact analysis is made for the shielded coupled strip transmission line with three center conductors. By means of the immittance matrices presented, the electrical behavior of the coupled strip transmission line of this type may be completely described. Design formulas which enable one to evaluate the cross-section dimensions from the desired values of characteristic immittances are derived for the two kinds of the line configurations. Equivalent circuits of the two-port networks for various port conditions are also presented. In addition, an application is discussed involving the asymmetrical coupled strip transmission line with two center conductors. The appendix gives the derivation of the design formulas by means of conformal mapping techniques. 相似文献
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