VSWR Research Articles

Theoretical study of sound absorption performance for Al2O3-polyurethane foam composite

To reveal the sound absorption property and mechanisms of Al2O3-polyurethane (Al2O3-PU) composite materials in theory, the impedance tube model is established by using the finite element method in this paper. Meantime, the theoretical modal and the calculation method adopt the Johnson-Champoux-Allard (JCA) modal and the standing wave ratio method, respectively. By comparing the experimental and simulation values of PU and Al2O3-PU composites from 0 to 1250 Hz, the results prove that the JCA predicted values can match the actual measured values. To further predict the sound property of Al2O3-PU composites in the medium and high frequency, the diameter of 29 mm and length of 600 mm for the impedance tube is installed. Finally, the sound pressure distribution diagram of the impedance tube is obtained.

A low sidelobe 77 GHz centre‐fed microstrip patch array antenna

AbstractA low sidelobe 77 GHz centre‐fed microstrip patch array antenna is proposed for automotive radar application. The proposed antenna comprises eight linear antenna arrays, each of which is centre‐fed by a coplanar waveguide with ground transmission line at the back of the microstrip patches. Each linear antenna array contains 10 patch antenna units, which are connected through a T‐type power divider network to achieve a −30 dB Taylor weighted distribution. The simulation results show that the designed phased array antenna has a good one‐dimensional phased scanning ability of ±45° with active voltage standing wave ratio less than 2 at 75–79 GHz, along with −20 dB low sidelobe symmetrical radiation patterns in the H plane. An antenna sample fed by a WR12 waveguide is fabricated and measured to verify its performance. The measured VSWR is less than 2 at 73.6–85 GHz. This design provides a new idea for millimetre wave automotive radar antenna design.

Prediction of Microwave Characteristic Parameters Based on MMIC Gold Wire Bonding

In this paper, a method based on deep learning is proposed to predict the parameters of bonded metal wires, which solves the problem that the transmission characteristics of S-parameters cannot be predicted. In an X-band microwave chip circuit, gold wire bonding technology is often used to realize bonding interconnection, and the arch height and span of the bonded metal wire will have a great influence on the microwave transmission characteristics. By predicting the S-parameters of the bonded metal wire, the relationship between the structure parameters of the single wire and the transmission performance of the microwave device can be deduced. First, the gold wire bonding model is established in HFSS simulation software. After parameter optimization, the simulation results meet the requirements of establishing data sets. Then the sampling range of S parameters is set, and the parameters are scanned to establish data sets. Second, the artificial neural network model is built. The model adds a dropout mechanism to the hidden layer to enhance the generalization of the neural network, prevent overfitting phenomenon, and significantly improve the model’s prediction performance. Finally, the model predicts the corresponding relationship between the arch height and span of the bonding wire and the insertion loss, return loss and standing wave ratio. The mean square error of the test set is less than 0.8. The experimental results show that compared with the traditional process measurement method, this method can quickly and accurately infer whether the microwave characteristics of the bonded product are qualified, which greatly reduces the time and economic cost of the engineer and improves the work efficiency.

A broadband dual‐polarised antenna with L‐shaped strips for long‐term evolution/5G application

AbstractA broadband dual‐polarised antenna with L‐shaped strips for long‐term evolution (LTE)/5th generation mobile networks (5G) is proposed in this article. Based on the principle of multi‐mode resonance, wide bandwidth is achieved with L‐shaped strips and H‐shaped strips. The metal strips and dipoles are printed on the same substrate, which also contributes to antenna miniaturisation. The short pins are designed for impedance matching and improving isolation. The metal reflector is designed to control beamwidth and increase gain. A prototype was fabricated using an easy Printed Circuit Board technique to verify the proposed design. Low‐profile of 0.2λ0 (λ0 is the free‐space wavelength at the centre frequency) is achieved. The measured results show that the relative bandwidth is 74% (2.3–5.0 GHz) at Voltage Standing Wave Ratio <1.8 while the isolation is more than 24 dB covering the LTE/5G modern band. In addition, the in‐band average gain is 9 dBi.

CubeSat-Based Observations of Lunar Ice Water Using a 183 GHz Horn Antenna: Design and Optimization

Technological advancements have revolutionized the space industry, facilitating deep space exploration using CubeSats. One objective is to locate potential life-support elements, such as water, on extraterrestrial planets. Water possesses a distinct spectral signature at 183 GHz, useful in remote sensing and environmental monitoring applications. Detecting this signature provides crucial information about water and ice presence and distribution on celestial bodies, aiding future exploration and colonization efforts. Mostly in space remote sensing uses corrugated horn antennae due to high gain and radiation patterns but fabrication of corrugated antenna is very challenging or even impossible in some cases. To ease this challenge, in our research we propose ideas to transform a corrugated horn antenna into a smooth-walled design by using MATLAB Cubic smoothing Splines algorithms. We compare simulation results between smooth-walled and corrugated antennas, and we can see some improvements in insertion losses, Voltage Standing Wave ratio (VSWR), and gain. We also manufactured this 183 GHz antenna using a commercially available 3D printer by utilizing Acrylonitrile Butadiene Styrene (ABS) material. The antenna surface was then coated with a thin layer of copper using conductive paint. In the end, we practically evaluate smooth-walled antenna functionality and compare it with the theriacal results. Validating the antenna’s functionality proposes a cost-effective and accessible production method to be used in a CubeSat engineering model or university students’ project.

Design and Characterization of a Compact Four-Element Microstrip Array Antenna for WiFi-5/6 Routers

The WiFi-5 band was the most popular WiFi band until the Federal Communications Commission (FCC) announced a new spectrum of 6 GHz WiFi (5.925–7.125 GHz) for unlicensed users. Our proposed work is about to cover both the 5 GHz and 6 GHz WiFi bands. These two bands have a great impact in the wireless communication field. A low-loss Rogers RT 5880 material is used as the substrate layer, which helps us to make the antenna compact ( 23 × 40 × 0.79 mm3) keeping a good performance profile over the latest high-speed WiFi-5/6 band. The proposed antenna covers a huge bandwidth (simulated BW: 2.85 GHz ranging from 4.50 to 7.35 GHz and measured BW: 2.83 GHz ranging from 4.50 to 7.33 GHz), which can be used for the latest WiFi-5 and WiFi-6 routers. The antenna also has omnidirectional properties. Besides that, the gain and directivity of the antenna are quite good, and the measured results buttress the simulated results. The presented different detail parametric studies indicate the antenna’s optimization level, which is excellent. The minimum values of reflection coefficient and voltage standing wave ratio make it a compatible candidate for the implementation of high-speed WiFi-5/6 routers.

Using Modeling to Select the Type of Microwave Field Emitter for Dense-Layer Grain Dryers

The microwave field is used for drying and disinfecting grains during the pre-sowing seed treatment. The use of a microwave field in these installations leads to an increase in their productivity and a decrease in the energy consumed by them. In grain dryers, where the grain moves in a dense layer without being loosened, one of the challenges in using microwave fields is ensuring sufficient uniformity of the field distribution. In this article, waveguide design options that introduce microwave radiation into the grain layer are discussed. The objective of this study was to use application software to find the optimum type of transmitter from the three options presented. A mathematical simulation of the electromagnetic field distribution was performed with the use of CST Microwave Studio software 2019 in order to evaluate and compare horn-type, rectangular, and semicircular waveguides. The data on the standing wave ratio and radiation efficiency of these types of waveguides have been reported. The specific features of the microwave electromagnetic field distribution and radiation power in the output of these waveguides have been described. The results of mathematical simulations revealed that semicircular waveguides with slot-type radiators are preferable for processing dense grain layers.

Triple‐band circularly polarized conformal antenna for vehicular communication applications

AbstractVehicular communication presents a compact wideband implantable antenna for the best wireless transmission of information. The key role of the antenna is handled by the thickness of the substrate present in that antenna. Also, the shape of the antenna causes the performance characteristics. Now, vehicle‐to‐vehicle communication is the interesting task for designers to create successful and organized vehicular communication systems. This article presents a triple‐band circularly polarized conformal antenna for vehicular communication. An antenna is introduced as a triple‐band circular polarized conformal antenna and preserved a suitable mount on the vehicle surface for greater gain to provide well‐maintained operational performance characteristics. For getting circular polarization, circular cuttings are provided in the design of the proposed antenna. The radiation gives a fixed direction by providing 0.3 mm thickness. Here, use a circularly polarized antenna to rectify the signal absorption due to the contact material used in the antenna. A polyamide material is used as a substrate to get a probable successful link and improve the flexibility of the antenna. The triple‐band circularly polarized antenna is designed to operate in vehicular communication bands such as 2.4 GHz Wi‐Fi, 3.5 GHz WiMAX, and 5.9 GHz dedicated short range communication. The antenna is designed to resonate in a triple band to improve the antenna parameters like frequency response characteristics, gain, return loss, voltage standing wave ratio, left hand circularly polarization, right hand circularly polarization, axial ratio, fidelity factor, directivity, radiated power, and input impedance. Under the operating frequency bands of 2.4, 3.4, and 5.9 GHz, the efficiency of the proposed antenna is 98.48%, 97.31%, and 97.90%, respectively. The triple‐band circularly polarized conformal antenna is implemented in the high‐frequency structure simulator platform. The proposed tri‐band antenna is applicable in vehicular communication systems and healthcare for efficient wireless transmission.

New microstrip patch antenna array design at 28 GHz millimeter-wave for fifth-generation application

<span lang="EN-US">This paper presents a study and an array design consisting of two microstrip patch antennas connected in series in a 2×1 form. This antenna provides better performance for the fifth-generation (5G) wireless communication system. The microstrip line feeding technique realizes the design of this antenna. This feed offers the best bandwidth, is easy to model, and has low spurious radiation. The distance between the feed line and the patch can adapt to the antenna’s impedance. In addition, the antenna array proposed in this paper is designed and simulated using the high frequency structure simulator (HFSS) simulation software at the operating frequency of 28 GHz for the 5G band. The support material used is Rogers RT/duroid® 5880, with relative permittivity of 2.2, a thickness of h=0.5 mm, and a loss tangent of 0.0009. The simulation results obtained in this research paper are as: reflection coefficient: -35.91 dB, standing wave ratio (SWR): 1.032, bandwidth: 1.43 GHz, gain: 9.42 dB, directivity: 9.47 dB, radiated power: 29.94 dBm, accepted the power: 29.99 dBm, radiation efficiency: 29.95, efficiency: 99.83%. This proposed antenna array has achieved better performance than other antenna arrays recently published in scientific journals regarding bandwidth, beam gain, reflection coefficient, SWR, radiated power, accepted power, and efficiency. Therefore, this antenna array will likely become an important competitor for many uses within the 5G wireless applications.</span>

A 2.45 GHz microstrip patch antenna design, simulation, and anlaysis for wireless applications

This paper designs, simulates, and analyzes the S-band microstrip patch antenna (MPA) for wireless applications. FR-4 (lossy) and Rogger RT/duroid, whose dielectric permittivity is 4.3 and 2.2, respectively, have been used as substrate materials. Simulation is done by computer simulation technology (CST) suite studio 2019 software. Simulations with FR-4 material showed that the return loss was -20.405 dB, the gain was 2.592 dB, the directivity was 7.47 dBi, the voltage standing wave ratio (VSWR) was 1.221, the bandwidth (BW) was 0.0746 GHz, and the efficiency was 34.69%. Also, Rogers RT/duroid material gives results of a return loss of -12.542 dB, a bandwidth (BW) of 0.0349 GHz, a gain of 8.092 dB, a directivity of 8.587 dBi, and an efficiency of 94.24%. The main goal of this antenna is to have a low return loss while getting as close as possible to a VSWR of 1. This will improve the antenna's gain, directivity, and efficiency compared to other antennas. Copper was used to make the patch and the ground, which were 0.35 mm and 0.0077 mm thick, respectively. The results obtained from the proposed antenna were better than those previously published in various in modern scientific journal and conference papers.

A 2.45 GHz microstrip patch antenna design, simulation, and anlaysis for wireless applications

This paper designs, simulates, and analyzes the S-band microstrip patch antenna (MPA) for wireless applications. FR-4 (lossy) and Rogger RT/duroid, whose dielectric permittivity is 4.3 and 2.2, respectively, have been used as substrate materials. Simulation is done by computer simulation technology (CST) suite studio 2019 software. Simulations with FR-4 material showed that the return loss was -20.405 dB, the gain was 2.592 dB, the directivity was 7.47 dBi, the voltage standing wave ratio (VSWR) was 1.221, the bandwidth (BW) was 0.0746 GHz, and the efficiency was 34.69%. Also, Rogers RT/duroid material gives results of a return loss of -12.542 dB, a bandwidth (BW) of 0.0349 GHz, a gain of 8.092 dB, a directivity of 8.587 dBi, and an efficiency of 94.24%. The main goal of this antenna is to have a low return loss while getting as close as possible to a VSWR of 1. This will improve the antenna's gain, directivity, and efficiency compared to other antennas. Copper was used to make the patch and the ground, which were 0.35 mm and 0.0077 mm thick, respectively. The results obtained from the proposed antenna were better than those previously published in various in modern scientific journal and conference papers.

A novel octagonal slot circular compact ultrawideband antenna with detailed frequency and time-domain analysis

With time, the device's reliance on wireless communication and its users grows tremendously. The ultrawideband (UWB) technology offers a 7.5 GHz uncontrolled bandwidth. Because it allows for larger data rates over a short distance, UWB technology is the current and future requirement of new generation mobile networks. As a result, a novel octagonal slot circular compact UWB antenna with detailed frequency and time-domain analysis is proposed in this research. Throughout the UWB range, the hexagonal-shaped circular radiator aids in reaching better S11 parameters (S11-10 dB). The modified trapezoidal like partial ground plane allows for a wide bandwidth. The proposed UWB antenna operates at frequencies ranging from 3.2 to 13.1 GHz, allowing for a bandwidth of 9.9 GHz and a fractional bandwidth of 121.4%. Voltage standing wave ratio (VSWR) is seen to be in the range of 1 to 2 throughout this UWB range. Throughout the operational bandwidth, the antenna's gain ranges from 2.8 to 4.1 dB. The suggested UWB antenna has the advantages of being small, having superior impedance matching, a simple design, and having a high gain, all of which can be used to deploy the antenna for the aforementioned purposes.

Partial Discharge Wideband Full-Band High-Gain Resonant Cavity UHF Sensor Research.

To meet the real demand for broadband full-band high-gain antenna sensors in the process of partial discharge (PD) Ultra-High frequency (UHF) detection test and online monitoring of power equipment, this paper builds a resonant cavity monopole UHF antenna sensor based on Fabry-Perot resonant cavity antenna technology, conducts the sensor Voltage Standing Wave Ratio (VSWR) optimization study using curved flow technology, conducts the sensor gain optimization study using slot dual resonant structure, and, finally, tests the sensor performance using the built PD detection test platform. The resonant cavity monopole antenna exhibits outstanding VSWR performance in the frequency range of 0.37 GHz-3 GHz, according to simulation and test data: the average gain in the frequency range of 0.3 GHz-3 GHz is 4.92 dBi, and the highest gain at the primary resonant frequency of 1.0 GHz is 7.16 dBi, with good radiation performance over the whole frequency spectrum. The electromagnetic pulse signal sensed by the UHF sensor developed in this paper can demonstrate the energy spectrum distribution characteristics of PD radiation electromagnetic wave signal more comprehensively, laying a firm technical foundation for thoroughly understanding the electromagnetic wave radiation characteristics of various types of PD insulation defects of various power equipment and the selection of a specific direction for its supporting optimization.

Low‐profile broadband circularly polarized short‐circuited dipole antenna with backed cavity

AbstractA broadband circularly polarized (CP) dipole antenna with a backed cavity is presented in this letter. The proposed antenna consists of a pair of rotational symmetric short‐circuited branches and a Γ‐shaped feed structure. Each branch is designed to be axe‐shaped so that the antenna can achieve a broad 3‐dB axial ratio (AR) bandwidth. The coupled feeding method assures the antenna is wideband, and the shorting‐to‐the‐ground technique miniaturizes the lateral dimensions of the antenna. The profile of the proposed antenna is around 0.16λL (λL denotes the wavelength of the lower bound frequency). The introduction of a back cavity effectively enhances the boresight gain and improves the isolation level if the antenna is used to form an array. Finally, the design is prototyped, and the measurement results agree well with the simulation. The fractal voltage standing wave ratio (VSWR)<2 bandwidth and 3‐dB AR bandwidths are 61.15% (2.725–5.125 GHz) and 45.9% (3.15–5.03 GHz), respectively. The antenna's efficiency exceeds 91.5% over the target frequency band.

TEM-камера открытого исполнения для испытаний малогабаритных радиоэлектронных средств на электромагнитную совместимость

This paper presents the design and fabrication of an open TEM cell. It allows you to measure the radiated emission and immunity of radioelectronic devices. The size of the EUT should not exceed 184×162×30 mm. Performed analytical and quasi-static analysis of the regular part of the TEM cell. In the frequency range up to 1.4 GHz the reflection coefficient |S11| of the regular part does not exceed minus 45 dB. The electrodynamic model of the TEM cell is developed and the geometric parameters are optimized using a genetic algorithm. Analysis of the electrodynamic model showed that in the frequency range up to 920 MHz the voltage standing wave ratio (VSWR) does not exceed 1.3. The inequality of the electric field in the area of EUT placement is not more than 6 dB in the frequency range up to 875 MHz. The validity of the obtained results is checked using the numerical methods of finite elements and the transmission line matrix. A solid-state model of the TEM cell is developed to evaluate the effect of the design features of the assembly. The frequency dependences of |S11| of the solid‑state model do not exceed minus 17.69 dB in the frequency range up to 916 MHz. The TEM cell is fabricated by laser cutting and bending aluminum sheet metal. Using a vector circuit analyzer Micran R4M-18 measured S‑parameters of the fabricated TEM cell. The transmission coefficient |S21| of the fabricated TEM cell in the frequency range up to 936 MHz does not exceed minus 2.2 dB. The reflection coefficient |S11| does not exceed minus 17.69 dB. The results of radiated emission measurements of the Altera Cyclone IV FPGA debug board in the frequency range up to 1 GHz with a fabricated TEM cell is presented.

Velocity and Direction Adjustment of Actuated Droplets Using the Standing Wave Ratio of Surface Acoustic Waves (SAW)

Droplet actuation using surface acoustic wave (SAW) technology has recently been widely employed in “lab-on-a-chip” applications. In this article, SAWs generated by interdigital transducers (IDTs) were used to actuate microdroplets, where their velocity and direction could be adjusted by changing only the excitation phase shift, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</i> , of the voltage applied to the two IDTs. Specifically, the equation of the vibration of the mixed traveling surface acoustic waves (TSAWs) and standing surface acoustic waves (SSAWs) formed on the substrate surface operating in the exciter–exciter mode has been reported by the authors. An analytical expression for the acoustic standing wave ratio has been derived and given as a function of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</i> and the spatial phase difference. It can be seen from the expression that the directions of the TSAWs will be opposite to each other, in the range of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</i> given by (0, π) and (π, 2π), and the component of the TSAWs can be adjusted by changing <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</i> in each direction. Following the theoretical analysis discussed here, two IDTs have been excited to generate a mixture of TSAWs and SSAWs. A series of experiments was carried out to control the velocity and direction of the actuated droplets, by changing only <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">θ</i> . In addition, an experiment performed to compare the techniques shows that the upper limit of the velocity of the actuated droplets can be significantly increased using the exciter–exciter mode, showing that it has the potential to be an alternative method to the traditional exciter–absorber mode.

Design of Vivaldi array antenna with low sidelobe for Monopulse tracking application

The article will present the array antenna system for Monopulse tracking application. The Antenna includes 3 parts: monopulse comparator, unequal power divider, and antenna array. The monopulse comparator and unequal power divider are designed by microstrip line on PCB. Antenna array consists of 244 Vivaldi elements. Conducted simulation of the antenna system and obtained the following results: The bandwidth of the antenna system is greater than 10% with Voltage Standing Wave Ratio smaller than 1.6 (VSWR ≤1.6); Realized gain of the sum beam (radiation pattern) at the central frequency reaches 26.2 dBi; Sidelobe level of sum beam is less than -20dB in the whole frequency range; The peak and null of two difference beams are smaller than 20dB. With the results obtained, the Antenna Monopulse system is mentioned as completely suitable for use for tracking applications and arrangement in narrow space locations with compact size.

A Compact Broadband Monopole Tapered Slot Antenna With High Field Uniformity for Vehicle EMC Test From 20 to 220 MHz

A compact broadband monopole tapered slot antenna (MTSA) for vehicle electromagnetic compatibility (EMC) tests in the semi-anechoic chambers (SAC) is proposed and investigated. The proposed MTSA takes the metal ground of the SAC as part of an antenna. With the mirroring effect of the ground plate in the SAC, the proposed MTSA acts as a conventional tapered slot antenna (TSA) but with only a half size of the conventional TSA, and also avoids the adverse effect of the ground reflections on the field uniformity effectively. Moreover, the MTSA has a slot on its flaring plate that reduces its weight by 30%. Both the simulated and the measured results show that the proposed MTSA achieves a standing wave ratio (VSWR) below 2:1 from 20 MHz to 220 MHz, and a good uniformity, with radial uniformity better than 3 dB, transverse uniformity better than 4 dB. The simulated gains are from 6 dBi to 13.5 dBi with radiation efficiencies over 90% across almost the entire bandwidth.

Survey on performance parameters of planar microwave antennas

Planar antennas, which include microstrip antennas and printed circuit board antennas, are used in telecommunications. This study aims to provide an overview of microstrip antennas for diverse applications. Microstrip patch antenna design is a new study topic that has been established for usage in 5th-generation communication applications. An antenna is a group of connected devices that serve as a single antenna to broadcast or receive radio waves. Antennas come in a variety of designs and sizes. The paper discusses several printed microstrip antenna designs, such as rectangular to circular, broadband, dual-band, millimeter-wave and microstrip arrays. The microstrip patch is an antenna layout that is lightweight, low-profile, and results-oriented. Microstrip patch antennas may be employed in various 6G communication system applications in the future. This paper examines antenna geometric structures, antenna analysis methodologies, antenna dimensions and many different types of antennas. It will also go over the substrate materials, loss tangent, thickness, return loss, bandwidth, voltage-standing-wave-ratio (VSWR), gain, and directivity so that an optimized antenna can be designed and fabricated having excellent characteristics for use in modern applications by the promising academic researchers in the near future.

Monopole Antenna for Experimental Flight Applications

A monopole dual band antenna for experimental flight applications on a small scale Unmanned Aerial Vehicle available in the Aero modeling lab of Department of Aeronautical Engineering at Manav Rachna International Institute of Research and Studies is presented in this paper. Radiating patch of proposed antenna consists of concentric circle at resonance frequency of 1.35 GHz and 5.25 GHz. The minimum reflection constant at 1.5 GHz is -20 dB and 5.2 GHz is -36 dB. The bandwidth of 300 MHz and 830 MHz achieved during the design process is considered adequate for efficient and effective utilization of the designed antenna. Radiation pattern of proposed antenna show Omnidirectional pattern. Designed antenna provides solutions for L and C band aviation application for early reported geometry. Various parameters like return loss, gain, radiation pattern surface current and Voltage Standing Wave Ratio (VSWR) have been studied and analyzed using the application software CST Microwave Studio. The experimental antenna designed for experimental flight evaluation can also be used as Global System for Mobile Applications (GSM), Worldwide Interoperability for Microwave Access (WiMAX), Wireless Local Area Network (WLAN), Walkie-Talkie and Air Traffic Control (ATC) antenna. In the overall perspective, the proposed antenna can also be utilized for ground communication and other airport facilities in addition to the experimental role envisaged.