Advanced Design System Simulation Research Articles

Dual-band low-power RF-to-DC signal converter circuits for energy harvesting

This article presents dual-band low-power, high-sensitive radio-frequency (RF)-to-direct current (DC) signal converter circuits, operating at 2.45 and 5.5 GHz bands, for radio frequency energy harvesting applications. In particular, it focuses on the lumped element and microstrip transmission line model circuits. The lumped element RF-to-DC converter circuit is composed of a dual-band impedance matching circuit, voltage-doubler rectifier, and DC-pass filter with a resistive load of 5 kΩ. This converter circuit gives a DC output voltage of 48 mV at 2.45 GHz and 25 mV at 5.5 GHz on −25 dBm input power. Maximum conversion efficiency is 47% at the 2.45 GHz band and 27% at the 5.5 GHz band when the input power is set to −10 dBm. Circuit design steps, matching conditions, performance parameters, and so on, are presented using Advanced Design System simulation. To validate the concept of the lumped element model, a microstrip transmission line RF-to-DC converter model is simulated and fabricated. It also composes of a dual-band matching network, voltage-doubler, and DC-pass filter with a load resistance of 5 kΩ. At a low input power of −18 dBm, it gives an output voltage of 21 mV in measurement. An appropriate match between the simulation and measurement is noted.

Compact lowpass filter with vast out-of-band rejection utilizing DGS

A unique low-profile microstrip lowpass filter (LPF) is introduced. It features a broad range of stopband and sharp roll-off. The suggested LPF is built utilizig a T-shaped configuration which includes a stub for resonance and utilizes open stubs as attenuator cells. To further improve the stopband, a double circular ring is engraved into the ground plane. The developed filter features a cut-off frequency of 3 dB at 3.4 GHz, a roll-off rate of 108 dB/GHz, and a stopband range from 3.7 to 22.8 GHz. The attenuation is less than −20 dB. The prospective LPF is designed using a lumped LC circuit model and validated using Keysight Advanced Design System (ADS) simulation and theory. The final design is realized using RT/Duroid 4003C, which boasts a small footprint of 12.4mm×8.69mm×0.8mm. The modelling findings and measurements of the suggested LPF are in fairly good agreement.

High-Sensitivity Chitin Nanofiber-Coated Series Piezoelectric Quartz Crystal Humidity Sensors

This paper fabricated a high-performance chitin nanofibers-coated interdigital electrode-piezoelectric quartz crystal (IDE-PQC) humidity sensor. Firstly, this paper investigated the influence of each Butterworth-Van Dyke equivalent parameter of the piezoelectric quartz crystal on the resonance characteristics of the IDE-PQC humidity sensor. Then, the results of MATLAB calculations revealed that the resonant frequency of the IDE-PQC humidity sensor changes larger (i.e., higher sensitivity) by increasing the PQC electrode area and decreasing the quartz wafer thickness. Next, the theoretical result was proved using advanced design system (ADS) simulation. Finally, the moisture-sensitive performances of IDE-PQC humidity sensors with different electrode areas and quartz wafer thicknesses were tested using chitin nanofibers as the moisture-sensitive material. The experimental results showed that the IDE-PQC humidity sensor with a larger electrode area and thinner quartz wafer thickness has higher sensitivity. This paper provides a new solution for building a high-performance series piezoelectric quartz crystal sensor.

An equivalent circuit for magnetoelectric composites operating in a longitudinal mode resonance: BAW-actuated mechanical antenna

It brings new design perspectives to study mechanical antenna in the view of circuit rather than the electromagnetic field. In this paper, an equivalent circuit of bulk acoustic wave (BAW) antenna is constructed by using constitutive relation of magnetoelectric composites and Newton’s governing equation. Based on this circuit, series and parallel resonant frequencies of two phases for BAW antenna are simulated in advanced design system (ADS) and magnetoelectric coupling coefficient is calculated. The results show that the electromechanical coupling coefficient is about 6%, the magnetomechanical coupling coefficient is about 86%, and the magnetoelectric coupling coefficient is about 5.2% under the existing material system (AlN and FeGaB). The magnetoelectric voltage gain is derived based on Kirchhoff’s Current Law, which contributes to studying the influence of the two phases thickness ratio on the performance of BAW antenna. The results show that BAW antenna has the optimal energy coupling and conversion when the thickness ratio of the two phases is 1:1. The input and the output impedances of BAW antenna are calculated by T-parameter matrix, which are perfectly matched with the results in ADS simulation. Relevant experiments have been carried out by preparing the magnetoelectric antenna based on PZT and Terfenol-D materials to verify the universality of the model.

The dynamics analysis of the two-stage chaotic Colpitts oscillator for secure communication systems

This abstract presents a novel study of the two-stage chaotic Colpitts oscillator which is intended to secure communication systems. This study is divided into two important parts, the first one is to solve the mathematical model of the studied chaotic oscillator under Matlab simulator using the fourth-order Runge-Kutta method, where the results show that this model goes through many different behaviors to reach the chaotic one (doubling of periods), which is obtained in the case where the value of g is greater than 1.5. The second part of this work consists on the simulation of the oscillator circuit under Advanced Design System simulator adopting the BFG520 bipolar junction transistor, and this is for the purpose of verifying the obtained mathematical results, as well as to study the frequency properties of this circuit. Based on the results of this electrical simulation, it has been demonstrated that the two-stage Colpitts oscillator is capable to generate chaotic oscillations in the range of (0.9 to 5.6 GHz).

An efficient wideband cascode class FF−1 Doherty power amplifier with control harmonic impedance inverter for X‐band applications

SummaryThis paper presents an efficient Doherty power amplifier (DPA) with optimized harmonic impedance inverter. The proposed design consists of carrier and peaking power amplifiers designed for class F‐ and class F−1‐based operations. Also, multiharmonic non‐uniform stepped‐impedance transmission line‐based input–output matching network is designed for the proposed circuit. The new design maximizes the operating bandwidth by optimizing the control harmonic impedance inverter. The DPA circuit is implemented using the advanced design system simulator, and the chip is made of GaAs 0.25‐μm PHEMT on silicon nitride monolithic microwave integrated circuit die. The fabricated chip exhibits drain efficiency (DE) of 41%–51.5%, power added efficiency of 36.4%–41%, gain of 10.9 dB, and adjacent power leakage ratio of −34.6‐dBc at 30‐dBm peak power. The size of the chip is 2.8 × 1.9 mm2, and it occupies less die area as compared to the existing DPAs.

An improved 2×2 array antenna using both-sided microwave integrated circuit technology for circular polarization

<span lang="EN-US">A circularly polarized microstrip patch array antenna using both-sided microwave integrated circuit (MIC) technology with a triple feed network has been proposed in this article. The antenna elements, feed structure and both-sided <a name="_Hlk112828933"></a>MIC technology are used and arranged in such a way to obtain circular polarization alongside high gain without using an external matching circuit. The 50 Ω microstrip line is used to energize the antenna where the antenna’s total feed network is made up of both series and parallel combinations of microstrip and slot line. The antenna was realized using Teflon glass fiber substrate </span><em><span lang="EN-US">(ε<sub>r</sub>)</span></em><span lang="EN-US">=2.15 with a thickness of 0.8 mm. The antenna has some splendid parameters including S<sub>11</sub> of less than -35 dB, a gain of 12 dBi with an omnidirectional pattern and an axial ratio of 0.7 dB at the operating frequency. The antenna possesses a bandwidth of 430 MHz (4.22%) after operating at X-band in the frequency spectrum. The antenna’s simulated parameters were investigated with the help of advanced design system (ADS) simulation software in microwave momentum mode.</span>

Design and Analysis of Impulse Radio (IR) Based UWB Transmitter with Antenna

The use of ultra-wideband (UWB) in target detection, radar and wireless connectivity, specifically in the medical world, has attracted a lot of attention. The concept that the IR-UWB system does not necessarily require carrier signals is one of its most appealing features. IR-UWB can transmit information using short Gaussian monocycle pulses. In light of these advantages, this paper proposes a novel UWB transmitter system which consists of UWB signal generating circuits and UWB antenna, which work together to create entire UWB transmitter. It is based on impulses and has a simple architecture with low power consumption. The proposed transmitter is realized in Cadence tools with 90nm CMOS technology and proposed UWB antenna is simulated using Advanced Design System (ADS) simulator software. In addition, the transmitter circuit and the antenna are co-simulated using ADS software. The illustrated UWB transmitter uses a low-power supply and generates pulse amplitude with pulse duration of for the Gaussian monocycle pulse. Due to its increased output voltage swing and reduced power consumption when comparing to other circuits, the proposed architecture is functional and suitable for use in short-range wireless networks and medical applications.

Design and characterization of an RF reused energy system for nano-devices

In this work a simple, high conversion efficiency, and high output voltage energy harvesting device was designed and simulated. The harvesting device consists of microstrip antennas, matching and rectifier circuits. Both mono patch and array antennas are designed to be operated at 5.8 GHz. The simulation work was implemented using central standard time (CST) studio. Results showed an accepted return loss and high gain. To more elevate the device gain and then to obtain greater output energy, an array of microstrip antennas was designed. To convert the radio frequency (RF) energy to dc output voltage, a rectifier, which consists of a voltage doubter and schottky diodes was designed using advanced design system (ADS) simulator. Furthermore, to achieve 50 Ω impedance, a matching circuit was designed by adjusting the microstrip line patterns. The output voltage of the device was 6.2 V at input power 20 dBm and 560 Ω load resistance.

Accurate Crosstalk Noise Modeling and Analysis of Non-Identical Lossy Interconnections Using Convex Optimization Method

Recent studies on integrated circuits interconnections are mainly concentrated on the analysis of crosstalk and delay, by taking the trade-off between accuracy, speed, and complexity into consideration. The new idea of this paper is to apply the convex optimization method to analyze crosstalk and delay of the lossy coupled interconnections in identical and non-identical forms. For this purpose, a simple and comprehensive model is proposed to cover the functional and dynamic crosstalk in a computationally-effective way. More specifically, various case studies are determined to analyze the transient response of the coupled transmission lines with arbitrary excitation sources in the presence of both capacitive and inductive coupling characteristics. To validate the model, the numerical and Advanced Design System (ADS) simulation results are compared to indicate the desired accuracy. The calculated crosstalk percentage error of the proposed model with respect to ADS and HSPICE are less than 1.03% and 1.19%, respectively. In addition, the computational speed of the proposed method is about twice higher than ADS and HSPICE. The proposed model is extendible to handle <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${N}$ </tex-math></inline-formula> coupled lines, making it appropriate to model complex integrated circuit interconnections.

Design of 90° Hybrid Coupler With Nonequal Outputs [Educator’s Corner

A direct theoretical analysis of a 90° hybrid coupler, as the function of the frequency, is carried out by modeling the transmission line sections as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ABCD</i> matrices. This approach enables combinations of different numbers of sections (to enhance the bandwidth) and different nonequal power division at the outputs. The theoretical results are compared with Keysight Advanced Design System (ADS) simulations, showing perfect compliance at a frequency band of 1–3 GHz.

Ultra low phase noise and high output power monolithic microwave integrated circuit oscillator for 5G applications

novel structure of low phase noise and high output power monolithic microwave integrated circuit (MMIC) oscillator is presented in order to use it in 5G applications. The oscillator is based on the ED02AH process which allows us to design a microwave oscillator keeping a minimum size which is impossible to have it using other technologies since microwave oscillators are sensitive components above 20 GHz. The oscillator is studied, designed, and optimized on a GaAs substrate from the OMMIC foundry using the advanced design system (ADS) simulator in order to obtain a miniaturized oscillator (1.1×1.3 mm&lt;sup&gt;2&lt;/sup&gt;) generating two signals of different frequencies f&lt;sub&gt;o1&lt;/sub&gt;=26 GHz and f&lt;sub&gt;o2&lt;/sub&gt;=30 GHz. The objective is to design an oscillator with high output power and low phase noise while respecting its specifications. The optimization of the proposed microwave oscillator shows satisfying results. Indeed, at 26 GHz and 30 GHz, the output powers are respectively 13.33 dBm and 14.89 dBm. The oscillator produces a sinusoidal signal of 1.5 V and 1.75 V amplitude respectively at 26 GHz and 30 GHz. The oscillator phase noise at f&lt;sub&gt;o1&lt;/sub&gt; and f&lt;sub&gt;o2&lt;/sub&gt; resonance frequencies using the liquid crystal (LC) resonator shows respectively -109 dBc/Hz and -110 dBc/Hz at 10 MHz offset.

Modified Coptic Cross Shaped Split-Ring Resonator Based Negative Permittivity Metamaterial for Quad Band Satellite Applications with High Effective Medium Ratio.

This research article describes a modified Coptic cross shaped split ring resonator (SRR) based metamaterial that exhibits a negative permittivity and refractive index with a permeability of nearly zero. The metamaterial unit cell consists of an SRR and modified Coptic cross shaped resonator providing quadruple resonance frequency at 2.02, 6.985, 9.985 and 14.425 GHz with the magnitude of −29.45, −25.44, −19.05, and −24.45 dB, respectively. The unit cell that was fabricated on a FR-4 substrate with a thickness of 1.6 mm has an electrical dimension of 0.074λ × 0.074λ; the wavelength (λ) is computed at the frequency of 2.02 GHz. The computer simulation technology (CST) microwave studio was employed to determine the scattering parameters and their effective medium properties, i.e., permittivity, permeability and refractive index, also calculated based on NRW (Nicolson–Ross–Weir) method through the implementation of MATLAB code. The frequency range of 2.02–2.995 GHz, 6.985–7.945 GHz, 9.985–10.6 GHz, and 14.425–15.445 GHz has been found for negative permittivity. An effective medium ratio (EMR) of 13.50 at 2.02 GHz shows that the proposed unit cell is compact and effective. The lumped component based equivalent circuit model is used to validate with simulation results. The proposed unit cell and its array were fabricated for experimental verification. The results show that the simulation result using CST and high-frequency structure simulator (HFSS) simulator, equivalent circuit model result using advanced design system (ADS) simulator and measurement results match each other better. Its near zero permeability, negative permittivity, negative refractive index, high EMR and simple unit cell design allow the proposed metamaterial to be used for S-, C-, X- and Ku-band satellite applications.

Wide bandwidth enriched symmetric hexagonal split ring resonator based triple band negative permittivity metamaterial for satellite and Wi-Fi applications

Bandwidth is a vital factor for the transmission phase of satellite data that plays an important role in satellite performance. This paper presents a wide bandwidth enriched metamaterial consisting of symmetric hexagonal split ring resonator (SRR) with triple band negative permittivity and refractive index and near zero permeability for satellite and Wi-Fi applications. The electrical dimension of the designed metamaterial unit cell is 0.17λ × 0.17λ where wavelength (λ) is computed at a first resonance frequency and developed on a cheap dielectric material FR-4 (lossy) with a thickness of 1.6 mm. The proposed metamaterial contributes triple resonances for the transmission coefficient (S21) at the frequencies of 5 GHz, 6.88 GHz and 8.429 GHz with the magnitude of −33.79, −21.7 and −25.18 dB, respectively covering C and X bands through the numerical execution of CST microwave studio 2019. The effective bandwidth of the unit cell are 1.67 GHz (3.89 to 5.56 GHz), 0.52 GHz (6.59 to 7.11 GHz) and 0.98 GHz (7.98 to 8.96 GHz) where the value of S21 less than −10 dB. The first resonance frequency is used to high speed-bandwidth enriched Wi-Fi and satellite band. Wi-Fi is usually faster using 5 GHz frequency band. The rest of the resonance frequency can be used in satellite applications. A negative permittivity has been perceived at frequencies of 5 – 6.066 GHz, 6.88 – 7.409 GHz, 8.429 – 10.061 GHz using Nicolson-Ross-Weir (NRW) methods with MATLAB code. The dependence of the resonance frequencies on the design parameters, substrate thickness, dielectric materials, the influence of the different structure of unit cell has also been examined. The designed unit cell structure with equivalent circuit diagram are analyzed and validated using Advanced Design System (ADS) simulator that exhibits similar to the S21 of the proposed structure. Furthermore, measurement results and Ansys high-frequency structure simulator (HFSS) simulator results are also employed to verify the outcome. Due to the overall performance, such as wide bandwidth, excellent effective parameters of the designed structure, the proposed research can be very suitable for satellite and Wi-Fi applications.

A novel 0.2–7 GHz microwave hyperchaotic generator based on Hartley oscillator

In this paper, a miniaturized microwave-band hyperchaotic generator prototype has been designed and realized. By improving the topology of Hartley oscillator, the proposed single-stage common-collector structure oscillator enables us to generate a microwave 0.2–7 GHz smooth spectrum signal with a power around −30 dBm. Using BFP650 SiGe transistor as a non-linear component, the proposed circuit has been implemented and simulated then experimentally approved. Introducing the parasitic capacitors C BC and C BE and using the exponential model to describe the active component non-linearity, a simplified electrical model for the developed circuit has been proposed. To exhibit the deterministic chaotic character of the mentioned circuit, mathematical and schematic implementation results using Matlab and Advanced Design System (ADS) simulations have been presented. The concordance between the two simulation results permits us to adopt the simplified state equation model to describe the circuit behavior. The Lyapunov spectrum exponents representation allowed us to verify the hyperchaotic behavior in the presented generator. Finally, an autonomous simple prototype architecture of the generator using the PTFE (Polytetrafluoroethylene) substrate with ε r = 2.2 has been realized and experimentally validated. The achieved performances made the proposed circuit suitable for various fields of telecommunications.

A Closed-Form Transient Response of Coupled Transmission Lines

There is a growing interest in analysis of crosstalk noise and delay in coupled transmission lines in various fields. Due to the large number of interconnections and associated compression, this analysis is particularly significant in large integrated circuits. There are various ways to analyze crosstalk noise and delay considering the compromise between accuracy and complexity. This article presents closed-form expressions in the Laplace domain based on transmission line theory to obtain crosstalk noise and delay of identical and nonidentical coupled interconnections. To this end, a simple model is proposed, which encompasses both capacitive and inductive coupling features in coupled interconnections. Moreover, it serves to handle both functional and dynamic crosstalk. The crosstalk noise voltage and propagation delay at the far-end of coupled lines are observed. The transient response of coupled transmission lines is demonstrated for various case studies. The obtained results are compared with Advanced Design System simulations indicating that the proposed model computes crosstalk noise and captures waveform shapes with desired accuracy. Moreover, the derived form is scalable for the analysis of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> coupled multiconductors, opening new horizons to analyze the complex integrated circuit interconnections with decent accuracy and high computation speed.

Comprehensive Investigation and Comparative Analysis of Machine Learning-Based Small-Signal Modelling Techniques for GaN HEMTs

A number of machine learning (ML) algorithm based small signal modeling of Gallium Nitride (GaN) High Electron Mobility Transistors (HEMTs) have been reported in literature. However, these techniques rarely provide any inkling about their suitability in modeling GaN HEMTs under varied operating conditions. In this context, this paper thoroughly investigates various ML based techniques and identifies their suitability for specific application scenarios. At first, an array of commonly employed modeling techniques based around Artificial Neural Network, RANdom SAmple Consensus, Support Vector Regression, Gaussian Process Regression, Decision Tree, and Genetic algorithm assisted Artificial Neural Network are used for development of modeling framework to exploit the bias, frequency and geometry dependence on S-parameter based outputs. Subsequently, the ensemble techniques namely Bootstrap aggregating, Random Forests, Extremely Randomized Trees, AdaBoost, Gradient Tree Boosting, Histogram-based Gradient Boosting, and Extreme Gradient Boosting are also explored to understand the capability of these algorithms in the development of GaN HEMT small signal models. Thereafter, an exhaustive analysis of bias and variance is carried out to figure out the most appropriate algorithms for specific applications. The discrepancies during model development are removed by tuning the hyperparameters of the respective models using Random search optimization with 5-fold cross validation technique. Post tuning, the models are evaluated in terms of generalization capability, Advanced Design System compatibility, computational efficiency, training and simulation time, models’ capacity and parameters’tuning time.

Power Conversion Using Analytical Model of Cockcroft–Walton Voltage Multiplier Rectenna

A voltage multiplier rectenna is a combination of a voltage multiplier rectifier and an antenna used for the conversion of AC to DC. It is an essential part of the system of RF energy harvesting. Conventional rectennas are characterized by low conversion efficiency. This study presents an analytical novel mode designed for RF energy harvesting systems to study the voltage and current output of rectifier stages for efficiency optimization. The design contains a voltage multiplier rectification circuit with seven stages. The Schottky diode HSMS 285-C was selected for the circuit modeling voltage multiplier circuit. Advanced Design System (ADS) simulation was used to validate the equations of the theoretical model solved with MATLAB code. The fabricated system was tested for an input power range of 10 μW to 100 mW; the maximum output power is 0.2577 mW with maximum efficiency of 29.85%.

Optimized Design of Low Power Complementary Metal Oxide Semiconductor Low Noise Amplifier for Zigbee Application

An optimized high gain low power low noise amplifier (LNA) is presented using 90 nm CMOS process at 2.4 GHz frequency for Zigbee applications. For achieving desired design specifications, the LNA is optimized by particle swarm optimization (PSO). The PSO is successfully implemented for optimizing noise figure (NF) when satisfying all the design specifications such as gain, power dissipation, linearity and stability. PSO algorithm is developed in MATLAB to optimize the LNA parameters. The LNA with optimized parameters is simulated using Advanced Design System (ADS) Simulator. The LNA with optimized parameters produces 21.470 dB of voltage gain, 1.031 dB of noise figure at 1.02 mW power consumption with 1.2 V supply voltage. The comparison of designed LNA with and without PSO proves that the optimization improves the LNA results while satisfying all the design constraints.

Theoretical Analysis and Novel Simulation for Single Shunt Rectifiers

Rectifiers are essential for microwave wireless power transfer (MWPT). RF-DC conversion efficiency must be improved for the practical use of MWPT. The focus of this research is related to single shunt rectifiers. Former research explained the operations of single shunt rectifiers in the frequency domain. Currently, we are using a harmonic balance method for the circuit simulations. These analyses focus on the frequency domain and transient phenomena were not directly analyzed. Also, the differences between experiments and their simulations are still issues in designing rectifiers. Therein, we analyzed an ideal rectifier with transient analysis and simulation. We also propose a novel simulation for single shunt rectifiers. Our simulation method is based on simple theories focusing on the steady-state condition of transient phenomena. In our analysis method, the output DC voltage is a fixed parameter and the DC current with the voltage is calculated. Therefore, this method is suitable for analyzing I-V characteristics. First, theoretical solutions are compared with Advanced Design System (ADS) simulations and they show the good agreement. Next, we created the novel simulation with our analysis method. Their results are also compared with ADS simulations. These analyses showed good agreement. Therefore, our novel method is consistent with former researches and commercial simulations. As a result, this research shows a novel analysis method for single shunt rectifiers and its consistency.