Two-port Network Analyzer Research Articles

Design of a novel split-recessed-gate β-Ga2O3 MOSFET-based maximum-gain microwave amplifier

In this study, a split-recessed-gate Ga2O3 MOSFET has been proposed for high-frequency applications. Extensive simulations have been carried out using TCAD Silvaco to examine the analog characteristics as well as the critical high-frequency metrics of the proposed device. A comparison has been drawn with conventional recessed-gate β-Ga2O3 MOSFET, and it is demonstrated that the proposed device outperforms the conventional device in terms of the high-frequency metrics due to its significantly lower parasitic capacitances and higher intrinsic gain. In addition, it was also demonstrated that the proposed device exhibits a substantial increase of 127.7% in the Johnson’s figure of merit, significantly higher, i.e. 134.7% higher, than Baliga’s high-frequency figure of merit, as well as a 3.25% increase in Baliga’s figure of merit as compared to the conventional device. Furthermore, a two-port network analysis has been carried out for both the devices and it has been shown that the proposed device offers higher gain with a slight trade-off in the reflections at the input/output ports. The scattering parameters have also been extracted and used to perform the stability analysis. It was observed that the proposed device exhibits higher stability for the entire frequency range. Furthermore, a maximum gain amplifier was designed using the proposed device. An impressive gain of 11.04 dB was demonstrated at an ultra-high frequency of 3 GHz.

A Modular Circuit Synthesis Oriented Modelling Approach for Non-Isolated DC-DC Converters in CCM

The continued commissioning of DC microgrids in an effort to achieve net-zero carbon levels in the atmosphere demands the large-scale deployment of converters to make the power from renewable energy sources, such as solar PV, usable. To control these inherently non-linear converters using classical linear control methods, averaged modelling techniques are employed. These methods are laborious and easily become intractable when applied to converters with increased energy storage elements. A modular modelling approach is proposed. This approach is based on the synthesis of converters using refined basic building blocks. The refined basic building blocks are independently modelled as two-port networks and used in a circuit synthesis-oriented manner to derive power stage models of commonly used DC-DC converters. It is found that most of the converters considered in the study can be described as a cascade combination of these basic building blocks. As such, transmission parameters are mainly used to model the two-port networks. Moreover, it is also found that using this modelling technique enables the computation of generalized expressions for all power stage models of interest. The use of two-port networks curtails the size of the matrices describing the basic building blocks to 2 × 2, and thus simplifies the entire modelling procedure. Additionally, two-port network analysis makes this modelling technique modular, thus making it more suited to be employed in DC microgrids. The independence of the two-port models on the circuit topology and functionality makes it possible to even model new converters containing the described basic building blocks solely based on circuit connection.

Impedance Compressing Matching Network Based on Two-Port Network Analysis for Wireless Power Transfer System

This article proposes a new design method of impedance matching networks for wireless power transfer (WPT) systems. In WPT systems, the input impedance of resonator varies over a wide range rather than having a fixed value due to coupling variation. In conventional systems, tunable matching networks have been commonly used to match the variable impedance to a fixed impedance. Three-port impedance compression networks have also been proposed to eliminate the mechanical tuning processes. In this article, a two-port impedance compressing matching network (ICMN) is proposed that addresses the load variations without the need for any mechanical tuning. In impedance matching, a two-port network can have a low design degree-of-freedom for load variation. In order to overcome this limitation, this article analyzes the general model of a two-port network and proposes a systematic design procedure. The effectiveness of the proposed method is verified with a design example that constructs an ICMN <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> .

Design of compact transition from conical to coaxial transmission lines with a low return loss

ABSTRACT In this paper, a simple design method for compact transition from conical to coaxial lines with a uniform impedance and low reflection in the standard ASTM D4935 jig for shielding measurement of planar materials is introduced. The proposed structures with even a short conical line exhibit a more uniform impedance and lower return loss and consequently expand the measurable frequency range. By two-port network analysis using a full-wave numerical simulator, the proposed structures are examined and validated in terms of the voltage standing wave ratio that indicates the reflection of the coaxial and conical junction. In addition, a time-domain reflectometry analysis is performed using the simulated S-parameters. Through this, the distributed characteristic impedances at the conical and coaxial lines are calculated and the difference from the theoretical values is analysed. To verify the accuracy of simulation analysis, the simulation results are compared with the measurement results using a commercial ASTM jig.

Characterization of silicon microstrip sensors for space astronomy

Silicon microstrip detectors are widely used in experiments for space astronomy. Before the detector is assembled, extensive characterization of the silicon microstrip sensors is indispensable and challenging. This work electrically evaluates a series of sensor parameters, including the depletion voltage, bias resistance, metal strip resistance, total leakage current, strip leakage current, coupling capacitance, and interstrip capacitance. Two methods are used to accurately measure the strip leakage current, and the test results match each other well. In measuring the coupling capacitance, we extract the correct value based on a SPICE model and two-port network analysis. In addition, the expression of the measured bias resistance is deduced based on the SPICE model.

Research on the harmonic in new continuous cable traction power supply system and its transmission characteristic

This study does research on resonance and harmonic transmission problems in a new continuous cable traction power supply system (CCTPSS), CCTPSS can realise long-distance co-phase power supply and effectively reduce phase separation and is applicable for extended power supply in areas with the weak power grid. Firstly, the system structure is introduced, a cable traction network is divided into three kinds of subnets for its complicated topology and huge system scale. The equivalent circuit model and mathematical model of each subnet are established with distribution parameters, especially the cable capacitance effect be considered. Then, according to the two-port network analysis theory, the system equivalent circuit is constructed by considering the electrical connection relationship, system harmonic impedance expression is calculated. Resonance influence factors and harmonic transmission mechanisms are analysed. Finally, theoretical analysis validity is verified in simulation; harmonic transmission characteristics CCTPSS including traction cable and overhead catenary, are studied. The new system shows better resonance performance compared with the existing AT traction power supply system.

Deterministic Noise Analysis for Single-Stage Amplifiers by Extension of Indefinite Admittance Matrix

This article presents two methods, the block approach indefinite admittance matrix (BA-IAM) and the estimation-by-inspection, to analyse the effects of deterministic noise on single-stage, single-ended amplifiers by extending the indefinite admittance matrix. The proposed methods are used to develop a generalised two-port network analysis for the commonly used amplifier topologies, in the presence of the supply, ground, bulk, and input noise sources. Various illustrative case studies (common-source, common-gate, and push-pull amplifiers) are considered to validate the analytical method of different CMOS technology nodes (180 nm, 110 nm, and 28 nm) and foundries (Lfoundry, UMC, and TSMC). Both the proposed methods are compared with the relevant existing methods in terms of mean percentage error (MPE), and computational complexity. The mathematically derived expressions using two methods show less than 4% MPE when compared with the schematic simulation results, obtained by the SPICE based simulations. Also, the post-layout simulations (PLS) results for all the examples (designed in CMOS 180 nm Lfoundry technology) show excellent matching with schematic simulations. The proposed methods can be further applicable to antennas, complex circuits, digital circuits, etc.

An Efficient Modeling for Underwater Wireless Power Transfer Using Z-Parameters

Wireless power transfer (WPT) technvvology can be employed for the wireless charging of unmanned underwater vehicles. However, in an underwater WPT (UWPT) system, the eddy current loss (ECL) caused by the conductivity of seawater must be considered. Designs that do not properly consider the ECL can cause the unpredictable efficiency decrease of the system. In this article, we propose an efficient modeling for the UWPT system using Z -parameters. Utilizing the electromagnetic analysis and two-port network analysis, we can derive an impedance model of coils considering the frequency and the conductivity of seawater. The impedance model can be used to make an equivalent circuit of an UWPT system. The ECL can be predicted accurately by using the proposed equivalent circuit. For validation, an UWPT system was implemented and measured to compare with theoretical calculated results and electromagnetic simulation results. The calculation, simulation, and measurement results were in good agreement.

Self-Heating Characterization and Thermal Resistance Modeling in Multitube CNTFETs

The thermal resistance, thermal capacitance, and thermal time constant have been experimentally extracted for the first time for a multi-tube multi-finger carbon nanotube FET (CNTFET) from trap-free high-frequency characteristics by following a methodology based on temperature-dependent two-port network analysis. The extracted short thermal time constant confirms the thermal stability for this emerging technology. A lumped-element electro-thermal model for multi-tube CNTFETs has been developed and proven with experimental data.

Coupling Coefficient Measurement Method with Simple Procedures Using a Two-Port Network Analyzer for a Multi-Coil WPT System

In this paper, we propose a measurement method with a simple procedure based on the definition of the impedance parameter using a two-port network analyzer. The main advantage of the proposed measurement method is that there is no limit on the number of measuring coils, and the method has a simple measurement procedure. To verify the proposed method, we measured the coupling coefficient among three coils with respect to the distance between the two farthest coils at 6.78 and 13.56 MHz, which are frequencies most common for a wireless power transfer (WPT) system in high-frequency band. As a result, the proposed method showed good agreement with results of the conventional S-parameter measurement methods.

Time-efficient fault detection and diagnosis system for analog circuits

Time-efficient fault analysis and diagnosis of analog circuits are the most important prerequisites to achieve online health monitoring of electronic equipments, which are involving continuing challenges of ultra-large-scale integration, component tolerance, limited test points but multiple faults. This work reports an FPGA (field programmable gate array)-based analog fault diagnostic system by applying two-dimensional information fusion, two-port network analysis and interval math theory. The proposed system has three advantages over traditional ones. First, it possesses high processing speed and smart circuit size as the embedded algorithms execute parallel on FPGA. Second, the hardware structure has a good compatibility with other diagnostic algorithms. Third, the equipped Ethernet interface enhances its flexibility for remote monitoring and controlling. The experimental results obtained from two realistic example circuits indicate that the proposed methodology had yielded competitive performance in both diagnosis accuracy and time-effectiveness, with about 96% accuracy while within 60 ms computational time.

Research on two-port network of wavelet transform processor using surface acoustic wavelet devices and its application

The goal of this research is to study two-port network of wavelet transform processor (WTP) using surface acoustic wave (SAW) devices and its application. The motive was prompted by the inconvenience of the long research and design cycle and the huge research funding involved with traditional method in this field, which were caused by the lack of the simulation and emulation method of WTP using SAW devices. For this reason, we introduce the two-port network analysis tool, which has been widely used in the design and analysis of SAW devices with uniform interdigital transducers (IDTs). Because the admittance parameters calculation formula of the two-port network can only be used for the SAW devices with uniform IDTs, this analysis tool cannot be directly applied into the design and analysis of the processor using SAW devices, whose input interdigital transducer (IDT) is apodized weighting. Therefore, in this paper, we propose the channel segmentation method, which can convert the WTP using SAW devices into parallel channels, and also provide with the calculation formula of the number of channels, the number of finger pairs and the static capacitance of an interdigital period in each parallel channel firstly. From the parameters given above, we can calculate the admittance parameters of the two port network for each channel, so that we can obtain the admittance parameter of the two-port network of the WTP using SAW devices on the basis of the simplification rule of parallel two-port network. Through this analysis tool, not only can we get the impulse response function of the WTP using SAW devices but we can also get the matching circuit of it. Large numbers of studies show that the parameters of the two-port network obtained by this paper are consistent with those measured by network analyzer E5061A, and the impulse response function obtained by the two-port network analysis tool is also consistent with that measured by network analyzer E5061A, which can meet the accuracy requirements of the analysis of the WTP using SAW devices. Therefore the two-port network analysis tool discussed in this paper has comparatively higher theoretical and practical value.

The common-base differential amplifier and applications revisited

In this paper, the common-base (or -gate) differential amplifier is revisited and presented. A variant of the same amplifier is also presented and both are analyzed using standard two-port network analysis. Their high frequency behavior, differences in biasing details and noise analysis are also compared and contrasted. New differential input-output filters are derived for the common-base (or -gate) differential amplifier as well as a new low impedance Norton amplifier. Simulations using Spectre in a 90nm UMC CMOS process of several of the filters as well as experiments conducted using discrete transistors confirm the theoretical results.

A Virtual RLC Damper to Stabilize DC/DC Converters Having an LC Input Filter while Improving the Filter Performance

The $LC$ filter at the input of a dc/dc converter may cause instability when the converter is controlled as a constant power load (CPL) and one of the effective solutions is to reduce the output impedance of the $LC$ input filter with different stabilization dampers. In this letter, the impact of these dampers on the $LC$ filter is analyzed with two-port network analysis and it is found that the existing dampers all degrade the performance of the original $LC$ input filter to some extent. In order to overcome this drawback, an $RLC$ damper is proposed to stabilize the whole system while improving the performance of the $LC$ input filter. In addition, this $RLC$ damper is also designed to achieve high robustness against the parameter variations of the $LC$ input filter. Furthermore, in order to avoid the power loss when implementing the damper physically, a control strategy for the CPL is proposed to implement the $RLC$ damper as a virtual $RLC$ ( $VRLC$ ) damper. The actual effectiveness of the $VRLC$ damper and its impact on the CPL are fully evaluated via two-port network analysis as well. Finally, experimental results from a 100-W 48–24-V buck converter with an $LC$ input filter are presented to demonstrate the proposed $VRLC$ damper.

Mode error analysis of impedance measurement using twin wires**Supported by Natural Science Foundation of China (11175193, 11275221)

Both longitudinal and transverse coupling impedance for some critical components need to be measured for accelerator design. The twin wires method is widely used to measure longitudinal and transverse impedance on the bench. A mode error is induced when the twin wires method is used with a two-port network analyzer. Here, the mode error is analyzed theoretically and an example analysis is given. Moreover, the mode error in the measurement is a few percent when a hybrid with no less than 25 dB isolation and a splitter with no less than 20 dB magnitude error are used.

Measurement Technique for Symmetrical Reciprocal Three-Port Devices Using Two-Port Vector Network Analyzer

A measurement technique is proposed to conduct S-parameter measurements on symmetrical reciprocal three-port devices using a two-port vector network analyzer. The technique takes the effects of reflection from an unmeasured port terminated with a non-ideal 50-Ω load into consideration. These reflected signals cause errors in S-parameter measurements, especially at higher frequencies where the reflection is too large to be ignored. The errors have been overlooked in the traditional three-port measurement using two-port network analyzers. In this paper, analytic equations are presented for some common symmetrical reciprocal three-port devices to improve the accuracy of their S-parameter measurements. The improvement is justified by comparing the data before/after applying the proposed technique with the measured data from four-port vector network analyzers. In addition, error analysis is conducted to ensure that the errors introduced by vector network analyzers would not be deteriorated by the proposed equations.

Two-port network analysis and modeling of a balanced armature receiver

Models for acoustic transducers, such as loudspeakers, mastoid bone-drivers, hearing-aid receivers, etc., are critical elements in many acoustic applications. Acoustic transducers employ two-port models to convert between acoustic and electromagnetic signals. This study analyzes a widely-used commercial hearing-aid receiver ED series, manufactured by Knowles Electronics, Inc. Electromagnetic transducer modeling must consider two key elements: a semi-inductor and a gyrator. The semi-inductor accounts for electromagnetic eddy-currents, the ‘skin effect’ of a conductor (Vanderkooy, 1989), while the gyrator (McMillan, 1946; Tellegen, 1948) accounts for the anti-reciprocity characteristic [Lenz's law (Hunt, 1954, p. 113)]. Aside from Hunt (1954), no publications we know of have included the gyrator element in their electromagnetic transducer models. The most prevalent method of transducer modeling evokes the mobility method, an ideal transformer instead of a gyrator followed by the dual of the mechanical circuit (Beranek, 1954). The mobility approach greatly complicates the analysis. The present study proposes a novel, simplified and rigorous receiver model. Hunt's two-port parameters, the electrical impedance Ze(s), acoustic impedance Za(s) and electro-acoustic transduction coefficient Ta(s), are calculated using ABCD and impedance matrix methods (Van Valkenburg, 1964). The results from electrical input impedance measurements Zin(s), which vary with given acoustical loads, are used in the calculation (Weece and Allen, 2010). The hearing-aid receiver transducer model is designed based on energy transformation flow [electric→ mechanic→ acoustic]. The model has been verified with electrical input impedance, diaphragm velocity in vacuo, and output pressure measurements.This receiver model is suitable for designing most electromagnetic transducers and it can ultimately improve the design of hearing-aid devices by providing a simplified yet accurate, physically motivated analysis.This article is part of a Special Issue entitled “MEMRO 2012”.

Modeling and simulating the nerve axon as a thin-film microstrip

Since Hodgkin and Huxley described the nerve axon as a cable (H–H model), many efforts have been made to find more approximated transmission line models representing the nerve axon. This paper describes a simple model that represents the nerve axon in two parts: the internodal space as a lossy thin-film microstrip line and the node of Ranvier as an active complex load. The complex load terminating the transmission line is given by the variable impedance of a tunnel diode. First, the internodal space is circuitally analyzed and electromagnetically simulated as a lossy thin-film microstrip line terminated on a complex fixed load. The transmission line circuit theory, the two-port network analysis, and a two-dimensional finite difference time domain method are used for such a task by forcing a strip subatomic metallization. Then, the transfer function of the internodal space, cascaded with the node of Ranvier, is equated to the transfer function of a transmission line section that includes a tunnel diode. This procedure is carried out in order to obtain the diode's variable impedance. The diode was introduced by Nagumo, Arimoto, and Yoshizawa for simulating the nerve axon as an active transmission line. The active transmission line is represented by the FitzHugh simplified H–H model known as the Bonhoeffer–van der Pol model.

A 15–50-GHz Quasi-Optical Scalar Network Analyzer Scalable to Terahertz Frequencies

A 15-50-GHz two-port quasi-optical scalar network analyzer consisting of a transmitter and receiver built in a planar technology is presented. The network analyzer is based on a Schottky-diode multiplier and mixer integrated inside a planar antenna and fed differentially by a coplanar waveguide transmission line. The antenna is placed on an extended hemispherical high-resistivity silicon substrate lens. The local oscillator signal is swept from 3 to 5 GHz and high-order harmonic mixing in both the up- and down-conversion mode is used to realize the RF bandwidth. The network analyzer has a dynamic range of >;50 dB in a 1-kHz bandwidth, and was successfully used to measure frequency-selective surfaces with <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> =20, 30, and 40 GHz and a second-order bandpass response. Furthermore, the system was built with circuits and components for easy scaling to millimeter-wave frequencies, which is the primary motivation for this work.

On the two‐port network analysis of common amplifier topologies

AbstractUsing two‐port network transmission parameters, we derive exact expressions for the voltage/current gains and the input/output impedances of common amplifier topologies. The derived expressions are valid both for BJT and MOS‐based amplifiers and are independent of any particular small signal transistor model. Copyright © 2009 John Wiley &amp; Sons, Ltd.