Capacitive Model and S-Parameters of Double-Pole Four-Throw Double-Gate RF CMOS Switch

In this paper, we have analyzed the Double-Pole Four-Throw Double-Gate Radio-Frequency Complementary Metal-Oxide-Semiconductor (DP4T DG RF CMOS) switch using S-parameters for 1 GHz to 60 GHz of frequency range. DP4T DG RF CMOS switch for operation at high frequency is also analyzed with its capacitive model. The re-sults for the development of this proposed switch include the basics of the circuit elements in terms of capacitance, re-sistance, impedance, admittance, series equivalent and parallel equivalent of this network at different frequencies which are present in this switch whatever they are ON or OFF.

Effect of Process Parameters on S-Parameter of Fabric-Based Embroidered Transmission Line

This paper presented a method of fabricating radio frequency( RF) transmission lines by embroidering conductive thread on fabric. A digital embroidery machine was selected to fabricate transmission lines. Effects of the typical process parameters on the S-parameter of these RF transmission lines were tested and discussed. And the results showed that embroidery process parameters such as stitch direction,stitch spacing,stitch length and embroidered tension had significant effects on the RF performance of embroidered transmission lines,of which stitch type was the most important factor for the measured S-parameter of transmission lines.

Reduction of signal reflection along through silicon via channel in high-speed three-dimensional integration circuit

The through silicon via （TSV） technology has proven to be the critical enabler to realize a three-dimensional （3D） gigscale system with higher performance but shorter interconnect length. However, the received digital signal after trans- mission through a TSV channel, composed of redistribution layers （RDLs）, TSVs, and bumps, is degraded at a high data-rate due to the non-idealities of the channel. We propose the Chebyshev multisection transformers to reduce the signal reflec- tion of TSV channel when operating frequency goes up to 20 GHz, by which signal reflection coefficient （$11） and signal transmission coefficient （$21） are improved remarkably by 150% and 73.3%, respectively. Both the time delay and power dissipation are also reduced by 4% and 13.3%, respectively. The resistance-inductance-conductance-capacitance （RLGC） elements of the TSV channel are iterated from scattering （S）-parameters, and the proposed method of weakening the signal reflection is verified using high frequency simulator structure （HFSS） simulation software by Ansoft.

A Computer-Aided Tuning Method for Microwave Filters by Combing T-S Fuzzy Neural Networks and Improved Space Mapping

A computer-aided tuning method that combines T-S fuzzy neural network(TS FNN)and offers improved space mapping(SM)is presented in this study.This method consists of three main aspects.First,the coupling matrix is effectively extracted under the influence of phase shift and cavity loss after the initial tuning.Second,the surrogate model is realized by using a T-S FNN based on subspace clustering.Third,the mapping relationship between the actual and the surrogate models is established by the improved space mapping algorithm,and the optimal position of the tuning screws are found by updating the input and output parameters of the surrogate model.Finally,the effectiveness of different methods is verified by an experiment with a nine order cross coupled filter.Experimental results show that,compared to a back propagation neural network method based on electromagnetic simulation and an SM method based on a least squares support vector machine,the proposed method has obvious advantages in terms of tuning accuracy and tuning time.

Extrinsic equivalent circuit modeling of InP HEMTs based on full-wave electromagnetic simulation

With the widespread utilization of indium-phosphide-based high-electron-mobility transistors(InP HEMTs)in the millimeter-wave(mmW)band,the distributed and high-frequency parasitic coupling behavior of the device is particularly prominent.We present an InP HEMT extrinsic parasitic equivalent circuit,in which the conductance between the device electrodes and a new gate-drain mutual inductance term L_(mgd)are taken into account for the high-frequency magnetic field coupling between device electrodes.Based on the suggested parasitic equivalent circuit,through HFSS and advanced design system(ADS)co-simulation,the equivalent circuit parameters are directly extracted in the multi-step system.The HFSS simulation prediction,measurement data,and modeled frequency response are compared with each other to verify the feasibility of the extraction method and the accuracy of the equivalent circuit.The proposed model demonstrates the distributed and radio-frequency behavior of the device and solves the problem that the equivalent circuit parameters of the conventional InP HEMTs device are limited by the device model and inaccurate at high frequencies when being extracted.

EQUIVALENT TWO-PORT MEASUREMENT EQUATIONS FOR RECIPROCAL MULTIPORT NETWORK AND THEIR APPLICATIONS

Equivalent two-port measurement equations for reciprocal n-port network are de-rived.As an example,applications of these equations,measurement details and data-processingmethods are discussed for any three-port network.To realize rapid and automatic measure-ments of S-parameters of any reciprocal multiport network,a set of measurement system whichis composed of auto-slotted line and program controlled movable shorts is presented in this paper.Experimental data are given for an H-plane Tee three-port network.

COMPUTER-AIDED OPTIMUM SOLUTION FOR SCATTERING PARAMETER MEASUREMENTS OF TWO-PORT LOSSLESS NETWORK

A new constrained eigenvalue method for scattering parameter measurements oftwo-port lossless reciprocal network is developed.The non-linear S-curve problem is easily trans-formed into a simple linear one by this method.All formulas are programmed on the IBM-PCdigital computer.Some examples are given.

Measurements of Balun and Gap Effects in a Dipole Antenna

In the present paper, design and analysis of a 2.4 GHz printed dipole antenna for wireless communication applications are presented. Measurements on return loss and radiation pattern of this antenna configuration are included in this investigation. The printed dipole is combined with the feeding structure of a microstrip via-hole balun and is fabricated on an FR-4 printed-circuit-board substrate. Two inevitable discontinuities are introduced by this antenna architecture in the form of right-angle bends in the microstrip feed line and in the dipole’s gap, respectively. The impact of mitering these bends in the reflection coefficient, resonance bandwidth and radiation pattern of antenna has been investigated by means of simulation and experiment.

Analysis and Impact of Surface Acoustic Wave Filter in-Band Ripple on Testing and Measurement of High Data Rate Communications

In this paper, we present a background and theory of the effect of Surface Acoustic Wave (SAW) Filter Module (SFM) in-band ripple on high data rate communications parameters such as the Error Vector Magnitude (EVM). In addition, we present analyses and statements for the choice of unbalanced S-parameters set of the SFM over balanced S-parameters set of the SFM in measurements and Agilent’s Advance Design System (ADS) Ptolemy simulations. A test and measurement setup using Agilent’s equipment will be presented.

Optimum Design for a Low Noise Amplifier in S-Band

An optimum design of a low noise amplifier （LNA） in S-band working at 2-4 GHz is described. Choosing FHC40LG high electronic mobility transistor （HEMT）, the noise figure of the designed amplifier simulated by Microwave Office is no more than 1.5 dB, meanwhile the gain is no less than 20 dB in the given bandwidth. The simulated results agree with the performance of the transistor itself well in consideration of its own minimum noise figure （0.3 dB） and associated gain （15.5 dB）. Simultaneously, the stability factor of the designed amplifier is no less than 1 in the given bandwidth.

Attenuation characteristics of monolayer graphene by Pi-and T-networks modeling of multilayer microstrip line

The impedances of Pi- and T- networks are obtained from the measured S-parameters of the multilayer microstrip line by modeling as an attenuator. The changes in impedances have been analyzed for the properties of various superstrates at the microwave ranges. With graphene on glass and graphene on quartz loadings, the impedances have increased and shifted towards lower frequency more in Pi-network than T-network modeling. This shift has become more prominent at higher frequency for the graphene on glass than graphene on quartz. A little increase in attenuation is found for graphene on glass or quartz than bare glass and quartz. The present study can be extended to obtain attenuation characteristic of any thin film by simple experimental method in the microwave frequencies.

Small signal modeling of AlGaN/GaN HEMTs with consideration of CPW capacitances

Given the coplanar waveguide （CPW） effect on A1GaN/GaN high electron mobility transistors at a high frequency, the traditional equivalent circuit model cannot accurately describe the electrical characteristics of the device. The admittance of CPW capacitances is large when the frequency is higher than 40 GHz; its impact on the device cannot be ignored. In this study, a small-signal equivalent circuit model considering CPW capacitance is provided. To verify the model, S-parameters are obtained from the modeling and measurements. A good agreement is observed between the simulation and measurement results, indicating the reliability of the model.

High peak-to-valley current ratio In_(0.53)Ga_(0.47)As/AlAs resonant tunneling diode with a high doping emitter

An In0.53Ga0.47As/AlAs resonant tunneling diode （RTD） with a high doping emitter is designed and fabricated using air bridge technology. The RTD exhibits a high peak-to-valley current ratio （PVCR） of more than 40 at room temperature, with a peak current density of 24 kA/cm2. The extraction of device parameters from DC and microwave measurements is presented together with an RTD equivalent circuit. The high PVCR RTD with small intrinsic capacitance is favorable for microwave/THz applications.

Impedance matching for the reduction of signal reflection in high speed multilevel three-dimensional integrated chips

In high speed three-dimensional integrated circuits （3D ICs）, through silicon via （TSV） insertion causes impedance discontinuities along the interconnect-TSV channel that results in signal reflection. As demonstrated for a two-plane interconnect structure connected by a TSV, we incorporate an appropriate capacitance at the junction to mitigate the signal reflection with gigascale frequencies. Based on 65 nm technology and S-parameter analysis, the decrease of signal reflection can be 189% at the tuned frequency of 5 GHz. Extending this method to the five-plane interconnect structure further, the reduction of signal reflection can achieve 400%. So we could broaden this method to any multilevel 3D interconnect structures. This method can also be applied to a circuit with tunable operating frequencies by digitally connecting the corresponding matching capacitance into the circuit through switches. There are remarkable improvements of the quality of the transmitting signals.

Design,analysis and test of high-frequency interconnections in 2.5D package with silicon interposer

An interposer test vehicle with TSVs（through-silicon vias） and two redistribute layers（RDLs） on the top side for 2.5D integration was fabricated and high-frequency interconnections were designed in the form of coplanar waveguide（CPW） and micro strip line（MSL） structures. The signal transmission structures were modeled and simulated in a 3D EM tool to estimate the S-parameters. The measurements were carried out using the vector network analyzer（VNA）. The simulated results of the transmission lines on the surface of the interposer without TSVs showed good agreement with the simulated results, while the transmission structures with TSVs showed significant offset between simulation and test results. The parameters of the transmission structures were changed,and the results were also presented and discussed in this paper.

A simple method of measuring differentially-excited on-wafer spiral inductor-like components

This paper proposes a simple method of measuring differentially-excited on-wafer RF CMOS spiral inductor-like components.This method requires only two common ‘G-S-G＇ probes and an ordinary two-port VNA.Using a network instead of a detailed equivalent circuit, this method completes the de-embedding with only one ‘Through＇ dummy, and thus the measurements are greatly simplified.By designing the ports ‘Open＇ or ‘Shortcircuited＇ deliberately, a multi-port transformer can be transformed into three two-port networks with different terminators.Then, couplings between the two coils can be solved, and the differentially-excited scattering parameters（S-parameters） can be constructed.Also, a group of differential inductors and transformers were designed and measured, and then comparisons between simulated and measured electromagnetic results are performed to verify this method.

RF measurements of a C-band cavity beam position monitor

RF cold test of a novel C-band cavity beam position monitor （PBM） to be used in the SDUVFEL Test Facility is described. The test results are presented and some characteristics discussed. The main parameters obtained are in reasonable agreement with the analytical estimations. Effective suppression of the common mode has been demonstrated. The position sensitivity over the test region of μ0.5 mm is about -21.58 dB/10 μm for the TM110 mode and is linear in the central region of the BPM cavity.