Two-port Network Analyzer Research Articles

Motivating Two-Port Network Analysis through Elementary and Advanced Examples

We seek to motivate the use of two-port network circuit analysis techniques by proposing two examples: one is elementary, the other is advanced. In particular, we start by deriving the transmission matrices for small-signal equivalent models of the BJT and MOS transistors. We then proceed to the first example where we explain the function of a Gyrator in a very clear way aided by Spice simulations. In the second more advanced example, we show how to systematically analyse the classical Cascode amplifier in a general way that is independent of whether it is realized using a BJT or a MOS transistor. The two examples highlight the strength and generality of the not-so-popular two-port network analysis which is usually introduced to undergraduate students much later than other circuit analysis techniques. This delay results in a preference for using mesh and nodal techniques to model and analyse electronic circuits.

0.7-dB Insertion-Loss D-Band Lange Coupler Design and Characterization in 0.13 μm SiGe BiCMOS Technology

Design, measurement, and characterization of a low-loss Lange coupler on Si-substrate up to 170 GHz are presented in this paper. How to determine the value of the even number of the strip lines according to the process design rules is illustrated carefully based on odd- and even-mode impedance theory and calculation. The deembedding procedures of GSG pads and 50 Ω termination resistors are illustrated in details. Simulation and measurement results indicate that the fabricated on-chip 50 Ω resistors can be used for characterization of four-port Lange coupler by two-port network analyzer within expected measurement errors. Measurement results show that the minimum insertion loss of 0.7 dB at central frequency of 140 GHz is achieved, which is in excellent agreement with simulated data.

Measurement of high data rate performance in perpendicular magnetic recording

Two-port network analysis is used to probe the dynamics of the perpendicular recording head. Two identical heads are aligned to each other with poletip to poletip on their air-bearing-surface sides, while the spacing is about the typical flying height. With two-port network analysis, forward transmission coefficient measurement shows the nonuniformity of the frequency response across the footprint of the poletip. It is suggested that the spatial distribution of the fast-field pulse can be optimized by constructing the fast write pulse with proper frequency components. In addition, the head-to-media recording performance is characterized by contact scanning recording tester. A single 0.15 ns/50 mA current pulse is good enough to complete the recording.

Identifying the Structure of Nonlinear Perturbations in Mixers using Multisine Signals

The objective of this paper is to identify the position of the nonlinearity, a custom designed multisine signal that can be used to excite the signal path of the mixer. This special random-phase multisine signal with a random harmonic grid contains several carefully selected spectral lines that are left unexcited. These "holes" in the spectrum of the signal act as detectors for the presence and the location of the nonlinearities that deviate from the ideal. First the proposed detection algorithm was tested in a simulation to show that it can work in an ideally controlled environment. Afterwards, measurements are performed on a real mixer excited with a special odd random-phase multisine with a two-port large signal network analyzer (LSNA) and detect the position of the unwanted nonlinearities in the device model.

Novel algorithms for the characterization of n-port networks by using a two-port network analyzer

Abstract. The measurement of the scattering matrices of n-port networks is an important task. For this purpose two ports of the n-port network are connected with the network analyzer and the remaining ports are connected to reflecting terminations. In order to specify the scattering matrix of a n-port network with the multi-port method (Rolfes et al., 2005), n reflecting terminations are required from which at least one reflection factor needs to be known. There are some cases, in which the multi-port method shows weak convergence properties. For example, a T-junction cannot be identified if the reflecting terminations used are short circuits and if the line length is equivalent to a multiple of a half wavelength. This is due to the fact that the two ports connected to the network analyzer become isolated. Two new algorithms, named the sub-determinant method and the wave-identification method, respectively, which employ a second set of reflection terminations that have to differ from the first set, allow to identify every n-port network without the necessity to distinguish different cases. Both methods are based on least square algorithms and allow to determine all scattering parameters of a n-port-network directly and uniquely.

Vector network analyzer ferromagnetic resonance of thin films on coplanar waveguides: Comparison of different evaluation methods

We have carried out two-port network analyzer ferromagnetic resonance measurements on a coplanar waveguide. We present a detailed description on how to calculate from the raw measurement data a value proportional to the complex susceptibility and permittivity of the ferromagnetic material. Necessary corrections for errors due to imprecise sample placement on the waveguide and the sample dimensions are presented. Evaluated data up to 15 GHz are provided for two model samples: a 40 nm Co80Fe20 layer showing a large linewidth (≈900 MHz) and a 40 nm Co72Fe18B10 layer yielding a small linewidth (≈360 MHz). Using these experimental data the presented evaluation scheme based on all four scattering parameters is then compared to commonly used approximate evaluation schemes relying on only one S parameter. These approximate methods show close agreement for the ferromagnetic resonance frequencies (the relative error is below 1%). However, the resonance linewidths show a relative error that can reach 10% in comparison with the presented evaluation method.

Multiport S-Parameter Measurements of Linear Circuits With Open Ports

A simple technique to measure the S-parameters of a linear multiport with a two-port network analyzer is evaluated. Just two probes and a single specimen are required. All two-port combinations are measured with the other ports left open. Special care was taken to estimate the maximum measurement uncertainties and to identify critical parameter values. Results can be further improved by using a simplified weighting scheme or by correcting for open-port capacitances. The technique is especially suited for wafer probes.

Measurement of Soil Thermal Properties by Spherical Probe

The thermal resistivity of the soil surrounding a power cable is a very important factor in evaluating the load-carrying capability of underground cable. This paper presents a method for measurements of soil thermal properties with a spherical probe along the cable installation routes. On the basis of two-port network analysis, equations for the temperature response of the hollow spherical probe are obtained. The paper offers a mathematical model for calculation of the soil thermal parameters, including the related standard deviations, using the least square method. The propagation time of thermal flux is calculated, and it is shown that the transient stage of the spherical probe can be used for measurements in infinite as well as limited samples of soil. Thermal self-capacity and contact thermal resistance between probe and surroundings are taken into the calculations. The realization of the probe with electrical heater and temperature detector, as well as additional measuring devices, is described.

Influence of the ground line position on the signal integrity of product-related interconnects in the frequency and time domain

The impact of the ground line position on the line parameters of signal interconnects built in a 110-nm CMOS technology is investigated in the presence of a conductive substrate. Characteristic line parameters obtained from simulations are validated with two-port network analyzer measurements of specially designed test structures in a frequency range up to 50 GHz. In addition, the influence of the ground line position on time-domain signals in product-related bus systems is explored. It is shown that the impact of substrate effects on the line parameters, and consequently on the signal shape in the time domain, strongly depends on the relative position of the ground line with respect to the signal lines and, as expected, on the length of the line system. The authors show that for short on-chip bus systems (shorter than 2 mm), the influence of the ground line positioning on time-domain signals is negligible. However, for long bus systems (e.g., 5 mm), this influence becomes significant and can no longer be neglected.

On the High-Frequency Characteristics and Model of Bulk Effect in RF MOSFETs

The new design with minimum loop inductance suitable for the measurements at high frequencies with substrate bias is described. These test structures allow characterizing 4-tenninal MOSFETs with a standard two-port Network Analyzer. The high-frequency behavior of bulk effect in MOSFETs is studied at different bias conditions for a 0.18 μm RF CMOS technology. The BSIM3 extension RF MOSFET modeling with bulk effect is verified and analyzed from two-port Y-parameter results. The result of RF NMOSFET shows that a good accuracy of the 4-terminal RF MOSFET modeling is achieved.

Multiport scattering matrix measurement using a reduced-port network analyzer

A novel method for acquiring the scattering matrix of an n-port network from measurements using a reduced-port network analyzer is developed. This method can obtain the scattering matrix of a nonreciprocal or reciprocal n-port network with the use of a three- or two-port network analyzer. The formulation of this method considers the imperfection of terminators used in the measurement, and only two of the terminators are required to be known. Experimental results from a four-port microstrip circuit show good accuracy using the developed method.

How to calibrate through balun transformers to accurately measure balanced systems

Balun transformers are used in front of network analyzers to measure the balanced- and common-mode characteristics of transmission lines and electronic networks. The nonideal nature of real baluns will cause measurements made with this technique to be in error. This paper shows that by following a calibration procedure similar to the conventional network analyzer calibration of Kruppa and Sodomsky, where known standards are measured, and these measurements are used to correct measurements of unknown devices, one can compensate for the nonideal nature of the measurement baluns. In this procedure, a conventional two-port network analyzer is connected to the balun transformer and, without disconnecting the network analyzer, inaccuracies in the balun can be calibrated out. Balanced mode, common mode, and mode conversion parameters can be accurately measured. This paper applies the previously published method of Silvonen for conventional network analyzer calibration to correct the measurement errors when using balun transformers.

Port reduction methods for scattering matrix measurement of an n-port network

The port reduction method (PRM) is a method to acquire the scattering matrix of an n-port network from the scattering matrix measured at a reduced port order by terminating certain ports. This then relaxes the instrumentation requirement and calibration procedure. As the port order is reduced to two, the scattering matrix of an n-port network can be obtained from the measurement using a conventional two-port vector network analyzer. In this paper, we describe two novel PRMs, which can reduce the order of measured ports to two. The experimental results show good accuracy. These two PRMs can provide a simpler calibration procedure and instrumentation than those directly using an n-port network analyzer. In addition, they give more accurate results than those measured by a two-port network analyzer with the assumption of using ideal terminators.

Broadband modeling and measurement of the signal behavior in S/390 MCM packages

In this work, we investigate the electrical performance of critical signal paths in IBM's S/390 MCM packages. We present lumped RLC-models suitable for standard circuit simulators like e.g. SPICE. The models are developed from finite element simulations of typical signal path segments. By comparing S-parameters from simulations of the models to two-port network analyzer measurements we validate the models in a frequency range up to 3 GHz.

A homodyne multiport network analyzer forS-parameter measurements of microwaveN-port circuits/systems

A homodyne multiport network analyzer is proposed for the characterization of N-port microwave devices, circuits, and systems. The single six-port junction used as a wave correlator is operated as a two-channel wave receiver. The use of an additional test set, which comprises two switching matrices and N bidirectional couplers, allows the measurements of complete S-parameter matrices of N-port devices. By comparison to existing network analyzers, the proposed system is homodyne in the sense that it does not require any frequency down-conversion to determine the phase information, and uses only one single six-port junction to obtain complex S-parameter measurements from only scalar measurements. A detailed description of the proposed system is presented. Two- and three-port structures are measured, and the results are compared to the data obtained by a two-port commercial network analyzer. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 63–67, 2000.

Implementation and calibration of a two-port electrooptic network analyzer

A novel bidirectional electrooptic network analyzer has been demonstrated which enables the full S-parameter characterization of both electrooptic (E/O) and optoelectronic (O/E) components using a single connection of the device-under-test to the test ports. A combined two-tier E/O and O/E calibration is proposed. Measurement results which validate both the analyzer architecture and the calibration are presented.

S-parameter measurements yielding the characteristic matrices of multiconductor transmission lines

A frequency-domain method is presented, which yields accurate characteristic matrices of uniform multiconductor transmission lines (MTLs). It uses simple two-port network analyzer S-parameter measurements of a set of open-circuit and short-circuited MTL configurations. The method eliminates the need for voltage and current probes, which introduce errors. Transversely inhomogeneous MTLs can be accurately characterized in their quasi-TEM propagation regime. The influence of the skin effect on the inductance matrix is taken into account. The technique was used to determine the inductance and capacitance matrices of a low-loss three-conductor ribbon cable above a ground plane. Comparisons with numerically and analytically obtained data are given. Measurements are found to be repeatable for lines of length /spl Lscr/</spl lambda//4. The /spl lambda//4 requirement is not found to be a restriction in the megahertz regime and only plays a role as line-end effects become significant at gigahertz frequencies. The obtained accuracy is significantly better than previously reported results.

Simulation and implementation of lightwave component characterization using a bilateral electro-optic network

The simulation and implementation of a bilateral electro-optic network has been demonstrated. The advantage of the proposed network is that it can be used as a black box to convert a microwave network analyzer into a two-port lightwave network analyzer. Simulations have been carried out to determine the sensitivity of the bilateral network to optical reflections. Measurement results on one-port optical structures are more accurate than those obtained with commercial lightwave analyzers and indicate the viability of this approach for full two-port lightwave measurements.

Microwave propagation and optimization in 0-3 particulate composites consisting of multilayer structures

Abstract Composites with 0–3 connectivity comprised of ceramic powders in a polymer matrix were evaluated for their dielectric properties in the X-band (8–12 GHz) frequency regime with the emphasis on 10 GHz. Ferroic ceramic, ferroelectric Pb(Mg1/3Nb2/3)O3 (PMN), and polymer epoxy were evaluated in this study. The ferroelectric material was chosen for their high dielectric constants and loss at 10 GHz which enhance absorbance, and as an alternative to ferrite absorbing composites because they have less magnetic induction and coupling associated with them.1 The powder loading in the composites was varied between 0 and 45 volume percent. The scattering parameters S 11* (reflectance) and S 12* (transmittance) were obtained directly from an HP8510 two-port network analyzer. Absorbance and complex dielectric permittivities were then obtained at 10 GHz for the above epoxy composites. With the information obtained from single layers, a multilayer configuration was predicted and analyzed by a user friendly comput...

Improved sensitivity for measuring surface resistance of superconducting thin-films

We have measured the surface resistance R S of Nb and NbN thin-films with better than ±20% reproducibility for R S down to 1 μΩ at 6 GHz. The technique is based on Q-factor measurements of a coplanar waveguide resonator improved by modern microwave design and packaging practices. The design minimizes extraneous losses, such as radiation and dielectric losses, and no correction for them is necessary. Unloaded Q-factor data are determined from the transmission and reflection frequency response of the resonator which is weakly coupled to a two-port network analyzer. The measured surface resistance of a NbN film deposited on silicon is 1.3 μΩ at 4.2 K and 6 GHz, and its temperature dependence is consistent with BCS theory.