Differential tunable phase shifter

The author presents an effective method for computation of the transient response of multiple nonuniform transmission lines. This time-domain analysis technique can predict reflections and crosstalk. The proposed spectral technique is used to transform partial differential equations describing a system of transmission lines into a set of linear ordinary differential equations, which can be solved with one of the many well-developed integration techniques. Numerical experiments performed with the prototype program showed that the method can solve specific problems (lossless, uniform lines) just as fast as less general methods based on modal analysis exploiting the particular properties of lines.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The Matching Impedance (MI) design method using Non-Uniform Transmission Line (N.U.T.L.) is a design method that offers more advantages over the 1/4 transformer method, the 1/4 multisection method, and the stub method. In this study, the Matching Impedance system is designed to match the WLAN antenna load with a line impedance of 50 Ohm at the 2.4 GHz. The Matching Impedance system is designed using a transmission line with a Characteristic Impedance (Zo) value that is triangular (Triangular Taper) distributed. This study also examines the effect of the number of cutting sections on a transmission line if the line with the Triangle distribution is implemented on a Microtsrip. From the test results, it is found that the number of sections used to form the Non Uniform transmission line has a significant effect on the bandwidth of the system working frequency for the required value of the Reflection Coefficient.

The vast majority of nonuniform transmission lines are no analytical solution except for a few special forms of transmission line. Dividing nonuniform transmission line into several equal parts, then each part can be regarded as uniform transmission line approximately. Using the theory of uniform transmission line to analyze nonuniform transmission line's transient response is the commonly used method. Composite Simpson's rule for transient analysis of nonuniform transmission lines is proposed in this paper. The exponential transmission matrix of nonuniform transmission line's equation is transformed into a general algebraic equation, which greatly simplifies the analysis on transient response for nonuniform transmission line. The simulation results illustrate the accuracy of the presented approach with examples.

Controllable microstrip transmission line phase shifters employing the membrane actuated ground plane are investigated. Simulated data are included for a uniform air gap transmission line phase shifter, as well. A single 10.4 mm diameter membrane had showed phase shifts of 37.07/spl deg/ and 55.48/spl deg/ at 11.01 GHz and 14.25 GHz, respectively, which can be further duplicated and put as an array to cover the desired length of the microstrip line, to achieve a desired phase shift in a particular application. This phase shifter may find applications in phased arrays, and as discrete phase shifter components.

A study on the maximum size reduction percentage of 5G Hairpin Bandpass filter nonuniform transmission line resonator is presented in this paper. Size reduction is obtained by applying Nonumiform Transmission Lines theory on each λ/2 uniform transmission line resonator of the filter. To get the required compact-sized filter, some constraints should be applied to satisfy the matching condition in addition to meet the uniform transmission line filter design specifications. High Frequency Structure Simulator (HFSS) software and Computer Simulation Technology (CST) software are used in this study. At the best size reduction percentage, the designed filter shows good return and insertion loss : S 11 = S 22 12 = S 21 is approximately -0.29 dB (CST) and -0.46 dB(HFSS) at center frequencies, Fc = 6.9 GHz and 6.67 GHz , respectively.

A new method is derived for computing the wave propagation constant γ of a uniform transmission line. The new method is based on the properties of a similar and unitary matrix, and allows us to minimize the errors due to connection repeatability. These matrices are obtained from the wave cascade matrices (computed from scattering parameter measurements) of two different length lines of identical but unknown characteristic impedance. The usefulness of the new method is demonstrated by assessing the dispersion of the dielectric constant eeff and the attenuation constant α of an ultra-low-loss transmission line in the frequency range of 0.040–65 GHz. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 268–271, 1999.

An algorithm based on an extended scattering matrix formulation is presented for time-domain simulation of lossy dispersive multiconductor transmission lines with arbitrary linear or nonlinear terminations. At each point in time, both sides of the transmission line structure are represented by an extended Thevenin equivalent. This general transmission line model was implemented in a SPICE-like simulation program, and the results are presented. >

Three types of differential phase shifters using composite right/left handed (CRLH) transmission line (TL) are presented. Type 1 uses two CRLH-TLs. Type 2 uses a CRLH-TL combined with a conventional delay TL and the differential phase is designed at the medium operating frequency. Type 3 is the same as type 2 except that the differential phase is designed both at the lower and upper operating frequencies. Design methods for the three types phase shifters are given. From simulated results, it can be seen that type 1 is hard to work out of radiation area and types 2 and 3 can be easily designed to work out of radiation area. Compared with type 2, type 3 has a better broadband phase response.

This paper presents an optimization circuit model of multiconductor transmission lines in the time domain. Several methods allow calculation of the currents and the tensions distributed on the uniform transmission line. Most of these methods are limited to lines with constant losses, and only for linear loads. The macro-model we propose, using Pade approximant, employs more variables and allows it to reduce the necessary cells' number in modelization than the traditional cells cascade method. This macro-model, using the Modified Nodal Analysis method (MNA), is suitable for an inclusion in circuit simulator, such as Esacap, Spice, and Saber. The MNA method offers an efficient means to discretize transmission lines on real and complex cells compared to the conventional lumped discretization. In addition, the model can directly handle frequency-dependent line parameters in the time domain. An example, with experimental measures taken from literature, is presented to validate the model we propose, and show its importance. It is necessary for assuring the results validity obtained from Pade macro-model to study its stability and passivity.

In this paper, a finite-difference time-domain (FDTD) analysis of the transmission line equations for a general circuit simulator is presented. A two-port circuit representation is derived for integrating a dispersive transmission line network within a circuit/system simulator. The circuit model consists of resistive elements and dependent current sources, which are updated at every time step by the FDTD algorithm. The frequency dependence of the conductors' parameters is taken care of by a recursive integration that employs the Vector Fitting algorithm. The application of this model is presented for several examples, such as nonuniform transmission lines, plane wave excitation of the line, and determination of overvoltages induced by a nearby lightning stroke.

This paper proposes a transmission line tower model in frequency domain for back‐flashover analysis, which has a uniform characteristic impedance and a uniform propagation constant. Most conventional tower models are constructed as a constant and uniform parameter transmission line that is independent of frequency. However, the authors' models have the frequency dependency of the characteristic impedance and the propagation constant to express the frequency characteristic of the transmission line tower.Two models, a cylinder model and a four‐frames model, were investigated to simulate the tower. Their surge responses were computed by numerical electromagnetic field analysis based on the moment method. From the results, the two‐port circuit constants were calculated in the frequency domain, and the characteristic impedance and the propagation constant are derived from them. The complex artificial oscillations appeared in frequency dependency of the parameters because the parameters were calculated numerically. The equations with analytical form were obtained by approximating with a smooth curve to the oscillations. It is possible for the equations to represent the transmission line constants as a function of geometrical parameters such as the tower height and the radius. Close agreement was found between the surge response computed by the numerical electromagnetic field analysis and the result calculated by inverse Laplace transformation of the analytical equations. To prove the model, the experimental results were compared with the computed ones of the cylinder model that has arms, and it was shown that the new model agrees closer with the experiment than conventional transmission line models.

In this paper, the equivalent circuit for modeling the thin wire array in metamaterial is proposed. The macro effect of the thin wire array can be clearly described by the equivalent circuit method, while a plane wave is propagating through it, according to the response of the thin wire array to the incident electromagnetic wave and the equivalence relation of uniform medium and uniform transmission line. In addition, the effective permittivity model of the asymmetric wire array is derived based on the transmission line theory. The validity of the model is proven by numerical simulations. The description of mathematical derivation exhibits clear physical concepts and provides a new approach for better understanding of the negative permittivity effect of the thin wire array

Fault recognition on branched and meshed electrical transmission line networks can be simplified by comparing the measured digital reflectogram with a simulated one. The synthetic reflectogram is built up in the frequency domain, making use of models that describe attenuation and dispersion of a pulse propagating on a uniform transmission line. A new method to accurately model any line type in the frequency domain is considered. It is shown how the parameters of this model can be determined from noisy time-domain-reflectometer (TDR) measurements. An example application involving the RG58C/U coaxial cable shows the use of simulation in prefault detection. >

This paper examines time domain methods for characterizing signal propagation in uniform transmission lines. The impact of the limitations associated with time domain instrumentation and methodologies are examined and guidelines for minimizing errors are presented.

Impedance autotransformers based on canonical nonuniform transmission lines are considered. Their advantages over autotransformers based on uniform transmission lines (UTL) in overall dimensions/broadbandness are shown.