Passive Two-ports Research Articles

Analytical Review of Two-Signal Methods for Measuring the S-Parameters of Two-Port Networks

In this paper, we consider two-signal and modified two-signal methods for measuring the S-parameters of passive two-ports and a method for adequately measuring the S-parameters of two-ports, such as transistors, developed on their basis. The methods are implemented using a coaxial simulator-analyzer of microwave amplifiers and oscillators in its measuring channels matched or mismatched with loads. The field of application and the interrelation between these methods are investigated, and their advantages and disadvantages are discussed. Data on the maximum measurement error of the methods are presented.

On Passive Symmetrical Two-Ports, Impedance Conversion and Power Transfer

The theory of linear passive symmetrical two-ports is reviewed. Many results of practical interest can be derived from the very compact analytical basis of this model. However, such derivations are scattered in the literature. In addition, the demonstrations do not always take advantage of the generality that can be obtained by avoiding implementations built on particular applications. A complete, self consistent analysis is presented here. Attention is focused on power transfer and the relations between the impedances at each port. The specific case of transmission lines is finally addressed.

Invariant Properties Of Similar Hybrid Matrix Coefficients

abstract Two-ports in hybrid connections are considered. The transfer and sensitivity properties of similar two-ports are considered. The transform of connections for passive two-ports and changes of their internal structures have been noticed. Two types of similarity and their sensitivities are given. Sensitivities are considered with respect to corresponding elements of networks or with respect to parameters of two-ports. For these sensitivity analysis, sensitivity invariants of networks function of similar networks with two-ports are derived. Sensitivity invariants of networks with two-ports (in hybrid connections) can be used to test and find fault in electronic networks with active two-ports.

CAD technique for designing microwave transistor active filters

A CAD method for designing microwave active filters, based on an extension of the simplified real frequency technique, is presented. This approach is analogous to the design of the matching networks in microwave amplifiers: the filter is developed by cascading active devices with passive two-ports which have a particular form of the transfer function. The potential of the method is illustrated by a computer simulated design of bandpass active filters.

Noise power sensitivities and noise figure minimization of two-ports with any internal topology

A theoretical foundation is presented for efficient CAD-oriented computation of first-order noise power sensitivities of networks with respect to network parameters. Application to the CAD of low-noise circuits with a minimum noise figure using efficient gradient optimization methods is envisaged. The approach is applicable to circuits with any internal topology composed of any number of passive linear multiports and active linear two-ports. It is based on the scattering matrix description for circuit elements and wave representation for noise. >

De-embedding two-port noise parameters using a noise wave model

Equations are presented, suitable for computer or calculator, for accurately de-embedding the noise parameters of both the first and the second two-port in a cascade of noisy two-parts from known values of the noise parameters of the cascade. The derivations are presented in terms of a noise wave model for two-ports, using transfer scattering small signal parameters. A numerical example is presented in which the noise parameters of two cascaded passive two-ports having unequal physical temperatures are individually de-embedded from the noise parameters of the cascade. As a check on the analysis presented, the noise parameters of each two-port are also calculated directly from its scattering parameters and physical temperature. >

SC simulators of passive two-ports

Abstract A method for synthesizing switched capacitor circuits that simulate passive LC ladder networks is proposed. The circuits are developed by cascading lower order SC active subnetworks which serve the purpose of two port simulators. Experimental results from two circuits that are proposed as examples, are also given.

A method for embedding network characterization with application to low-loss measurements

A method of parameter identification for linear passive two-ports is proposed. It uses load, short circuit, and sliding short as primary standards and also open circuit as a redundant magnitude standard. A normalizing transformation is applied to the measurement data in order to simplify and speed up its processing. An error analysis and an optimal choice of sliding-short positions are also presented. High accuracy of the dissipative loss determination has been achieved using statistical methods. Experimental results have demonstrated very high precision of the method and also its usefulness as a calibration method for one-port network analyzers.

Error analysis of the measurement of microstrip effective dielectric constant for the characterisation of passive two-ports

The current method for evaluating the effective dielectric constant εe f of microstripline (or coaxial line) has been found to be error susceptive. The error analysis has shown the limitations on the bandwidth of measurements and physical restrictions to be imposed on the test jigs to avoid anomalous values of propagation constant. The practical measurement of εe f has been carried further to characterise OSM–244–4ASF connectors and HI–Q 100pF DC block chip capacitor in the 2–4 GHz range.

Noise equivalent circuit of linear passive two-ports with applications to transmission lines

A new representation of the thermal noise of linear passive two-ports, expressed in terms of the Thevenin equivalent circuit and convenient to circuit designers, has been derived. This representation is applied to the determination of the contribution of the noise of a transmission line (a special case of a two-port) to the total noise of a noise thermometer system. Preliminary experimental results from measurement of temperature with a noise thermometer connected via a long transmission line encourages further development of practical noise thermometers.

Impedance Transformations of Cascaded Active or Passive Identical Twoports

The number of iterative impedances for any active or passive twoport is one, two or infinite, the first and last cases being of only limited significance and application. For the second case, a previous article determined which of the two impedances (called stable) was ultimately approached by the sequence of input impedances to cascades of identical networks (active or passive) with ever-increasing numbers of sections. It was also noted that this convergence was in general nonmonotonic. This article provides a solution to the problem of determining the impedance values which, when used as terminations for such a cascade, will generate a sequence of input impedances which steadily approaches the stable iterative impedance. To facilitate the proofs involved, it also presents a resume of the relatively obscure geometric interpretation, the isometric circle method of construction, and the classification of the underlying bilinear transformations. The theorems presented could have important application in the estimation of error in approximation problems involving artificial lines and filters working into varying terminating impedances and even, perhaps, over wide frequency ranges. Secondary results include 1) the passive iterative impedance for a cascade of passive networks is the stable one when the other is active, and 2) conditions on, and examples of, networks which generate periodic sequences of input impedances.