Tailoring double-negative metamaterial responses to achieve anomalous propagation effects along microstrip transmission lines

The design of a double-negative metamaterial loaded microstrip transmission line (DNG MTM-TL) to tailor the propagation characteristics at S- and C-band frequencies is presented. Guided-wave propagation along this DNG MTM-TL was studied numerically. The scattering parameters of the DNG MTM-TL were obtained with Ansoft's High Frequency Structure Simulator. A two-port network realization of the DNG MTM-TL is established. The effective permittivity and permeability for the DNG MTM-TL is extracted using this two-port network representation. It is shown that both a negative permittivity and a negative permeability and, hence, a negative index of refraction exist in the design frequency range. These material parameters are dispersive and conform to a two-time derivative Lorentz material model type of resonance behavior. This form of the index of refraction may be very suitable for applications dealing with phase and dispersion compensation along a microstrip transmission line.     

Pulse propagation along certain lumped nonlinear transmission lines

A lumped RGC transmission line having a switch in series with G (switch open for voltages greater than some fixed threshold; switch closed otherwise) and a shunt battery-resistor combination in each section is considered. It is shown that, although there exist two distinct resting states for each section, it is not always possible to switch the entire line from one state to the other, and it is never possible to propagate a pulse along such a line. Modifications are suggested in order to obtain pulse propagation.     

CHARACTERISTICS OF MICROSTRIP TRANSMISSION LINES

An efficient hybrid field solution to microstrip transmission lines is presented byusing SLE and SLM modes in spectral domain.It by-passes the lengthy process of formulatingthe determinant equation for the unknown propagation constant.Compared with spectral domainadmittance approach,this method is clear in both physical and mathematical senses and may beapplied to a variety of structures.     

Full-wave analysis of radiation effect of microstrip transmission lines

A full-wave analysis of radiation effects produced by discontinuities in microstrip and buried microstrip transmission lines is presented. Beginning with the dyadic Green's function for a dielectric slab, with an embedded source, an integral equation is formulated. This equation is then solved by the method of moments to obtain the current distributions along the transmission line, in particular, near the discontinuities. Employing these results, the near- and far-zone fields, as well as radiation patterns are computed. The results from our method showed good agreement with those of previous publications in complex reflection and transmission coefficients, and equivalent capacitance values. It is found that under resonance conditions the radiation efficiency of a simple structure can exceed 41%, which may cause a potential problem in electromagnetic compatibility. Our analytic result also shows that the maximum radiation occurs when the source is located at the height of from the bottom ground plane, which should be prevented.     

Network analysis of microwave oscillators using microstrip transmission lines

A network and computer-aided-design approach is discussed which is useful in designing microstrip oscillators to operate between 10 and 20 GHz. The analysis is applied to GaAs m.e.s.f.e.t. active devices.     

A broadband transition between microstrip and coplanar stripline

A design for a broadband microstrip-to-coplanar-stripline transition using broadside-coupled strips is proposed in this letter. Two transitions are designed in back-to-back configuration and the insertion loss is optimized in X-band (8.2 GHz/spl sim/12.4 GHz). Both simulation and measurement are in good agreement. The measured bandwidth for 1 dB insertion loss and 20 dB return loss is from 6.9 GHz to 12.4 GHz.     

Crosstalk between microstrip transmission lines

Methods for prediction of crosstalk between microstrip transmission lines are reviewed and simplified for the weak-coupling case. Classical coupled transmission line theory is used for uniform lines, and potential and induced EMF methods are used for crosstalk between nonuniform lines. It is shown that the potential method is equivalent to classical coupled transmission line theory for the case of uniform lines. An experiment was performed for uniform coupled microstrip lines for frequencies from 50 MHz to 5 GHz, and good agreement between theory and measurement was obtained for both near- and far-end crosstalk     

A wideband coplanar stripline to microstrip transition

A wideband coplanar stripline (CPS)-to-microstrip line was developed. The transition has a simple structure for the ease of fabrication with low cost. The measured performance of two back-to-back transitions exhibits an insertion loss of less than 3 dB and a return loss of better than 10 dB over a bandwidth from 1.3 GHz to 13.3 GHz (1:10.2). For narrower bandwidth, an insertion loss of less than 1 dB with a return loss of better than 10 dB was achieved from 1.4 GHz to 7.3 GHz (1:5.2)     

Shunt posts in microstrip transmission lines

Shunt posts in microstrip transmission lines are analyzed by employing the planar waveguide model. A multiple expansion method with greatly enhanced efficiency and accuracy has been achieved with the development of very fast algorithms for the computation of Schloemilch-type series. The method applies to perfectly conducting imperfectly conducting, and composite shunt posts. This approach is compared with the standard point matching technique for perfectly conducting posts. The two methods are found to be in excellent agreement in regions of overlapping applicability. A fairly wide range of computed data is utilized to develop the tools needed to incorporate the post into various microstrip circuit applications. As one application, a procedure is developed for using this post to obtain effective short-circuiting qualities over a broad frequency range. As a second application, the possibility of creating filtering devices is explored using both multiple metallic post structures and single dielectric posts     

Analysis and synthesis of tapered microstrip transmission lines

The input voltage reflection coefficient on a tapered microstrip transmission line is analyzed and a new Fourier transform pair is derived which introduces echo time and frequency as variables. Calculations of the input reflection coefficient take into account the frequency dispersion-characteristics of the effective permittivity. An efficient method is proposed for analysis and synthesis of microstrip tapers and numerical results are presented for microstrip exponential tapers and microstrip Chebyshev tapers     

Characteristics of microstrip transmission lines withhigh-dielectric-constant substrates

An efficient numerical code is developed from a full-wave analysis in the Fourier transform domain to determine the characteristics of a single-strip or multistrip coplanar transmission line. Modes of both even and odd symmetries are included. The impedance of the transmission line is calculated using the power-current equivalent model. Coupling constants between the even and the odd modes are also calculated. Results are provided for a shielded two-strip coupled microstrip transmission line on high-dielectric-constant substrate such as lanthanum aluminate with applications to superconducting transmission lines     

An accurate calculation of uniform microstrip transmission lines

An analytical program for calculating the field distribution about a microstrip transmission line bounded by a shielding wall is used to calculate the impedance, velocity, and attenuation parameters. The program input parameters are the dimensions of the strip and shielding wall and the relative dielectric constant of the substrate material. The field distribution about the strip is integrated to find the charge density on the strip and walls with and without the dielectric substrate. From these two calculations, the relative velocity and impedance can be calculated.     

传输线中脉冲信号传输特性的联合时频分析

用联合时频分析方法将一维时域或频域脉冲信号扩展到时间 -频率的二维平面 ,通过时间窗、频率窗和 Wigner- Ville分布的时频平面对矩形和高斯脉冲信号在传输线 (双导线和同轴线 )中的传输瞬态特性进行比较分析对比。联合时频分析可以更直观、更全面地了解脉冲信号在传输线任意时间和任意位置的瞬态变化。     

The propagation of signals along a three-layered region: microstrip

The tangential components of the electric field on the air-substrate surface of a three-layered region such as microstrip are determined for the case when the source is a unit electric dipole on that surface. This is done by integrating the rigorous Hankel transforms subject to the condition k²₀<|k ²₁|≪|k²₂|, where k₀ is the wavenumber of air, k₁ of the substrate, and k₂ of the conductor. It is found that the field consists of lateral-wave terms and direct-wave terms with different wavenumbers and phase velocities with each term consisting of two components. These terms determine the coupling between vertical currents in connections from the air surface to the conducting plane. It is concluded that distortion of signals as they propagate along the surface of microstrip is not due to dispersion in the ordinary sense that the permittivities of the air or the substrate are frequency-dependent; rather it is due to the fact that each signal separates into two parts, the one traveling in the air, the other in the dielectric with different phase velocities. If the permittivity of the substrate is frequency-dependent, the part of the signal traveling in it will suffer dispersion; the lateral-wave part in the air will not     

Radiation from picosecond photoconductors in microstrip transmission lines

Signals radiated in the microstrip autocorrelation circuit are investigated using ion-bombarded InP photoconductors. A model and empirical data are presented which suggest that this circuit radiatively couples to itself, giving rise to what appears to be a "slow" signal in the autocorrelation data. It is demonstrated that with a judicious choice of electrode geometry, a subpicosecond signal radiated by the photoconducting gap can be separated from the slower signal radiated by the microstrip electrodes.     

Electromagnetic propagation along a multiconductor transmission line in a tunnel--approximate analysis

A general approximate formalism is presented which enables one to calculate in a simple manner the electromagnetic propagation characteristics of a multiconductor transmission line in an underground tunnel. This approach circumvents the tedious task of locating the complex roots of the exact mode equation. The formalism is based on an approximate treatment of the single-wire case due to Wait.Lambda, Omega, andZ_{s}in Wait's single wire formula for the propagation constant are replaced with corresponding quadratic forms in the eigenmodal wire currents to generalize the formula to an arbitrary number of wires. The foundations of this approximate approach in standard perturbation theory are indicated, lending physical meaning to the approximations. A simple example involving a two-wire line is presented to establish the order of accuracy to be expected in using this formalism.     

Full-wave analysis of aperture-coupled microstrip lines

Two methods are presented for the analysis of aperture-coupled microstrip lines. Assuming a quasi-transverse electromagnetic traveling wave incident on the feeding line, an expression for the wave on the coupled line is derived. First, the moment method is used and the current on the coupled line is represented by a traveling wave propagating away from the slot. In the second method, the reciprocity theorem is applied to the coupled line. Both the moment method and the reciprocity method make use of the exact Green functions and produce results that are in very close agreement. An equivalent circuit is derived and the S-parameters are computed. Theoretical results are verified with measurements     

Square-wave propagation along coupled coplanar transmission line

Results of modelling square-wave propagation along coupled coplanar transmission line with grounded centre strip conductor are presented. Improved agreement between numerical and experimental data for the near- and far-end crosstalk voltages has confirmed practical significance of inclusion of multimode propagation in non-ideally grounded coplanar lines.     

Moment models of general transmission lines with application tointerconnect analysis and optimization

In this paper, we present new moment models for uniform, nonuniform and coupled transmission lines. The moment model of a line is based on the relationships between the two port currents (KCL) and the two port voltages (KVL) of the line. The parameters of the model depend on the mean values of the voltage moments and the weighted voltage moments of the line. Simple formulas are given to compute these mean values efficiently. By using such models and moment matching techniques, interconnects modeled as transmission line networks can be efficiently simulated. In addition, by using moment sensitivities, we demonstrate that wire sizing optimization can be carried out for layout design