VSWR Research Articles

Design of Inverted F-Shape Antenna at 2.35 GHz for S-Band Applications

In this work, a simulation model of planar inverted F antenna (PIFA) will be presented with the radiating plate that has been connected to ground plane that has been accompanied by shortening plate and the FR4 substrate between ground plane and radiating plate. Where PIFA was built using computer simulation technology (CST) for the studio microwave (2019 release). The simulation model has been studied for return loss (S-parameter), bandwidth (BW), voltage standing wave ratio (VSWR), and input impedance (Zin) which are −21.875406dB, 301MHz, 1.1752855, and 50, respectively. The simulation results showed that the PIFA component covers a wide frequency band ranging between 2.202 and 2.504GHz, which can be used in Bluetooth, Wi-Fi, and Long Term Evolution (LTE) applications that are used in the fourth generation cellulares communications.

A two-element planar multiple input multiple output array for ultra-wideband applications

<span>In this article, a planar monopole two-element multiple input multiple output (MIMO) array has been designed and characterized with the intention of ultra-wideband (UWB) applications. The array has a voltage standing wave ratio (VSWR) working bandwidth (BW) of 13.258 GHz between 3.394-16.652 GHz, with a fractional BW (FBW) of 132.28% with respect to a center frequency of 10.023 GHz. The two elements of the MIMO array are 900 polarizations mismatched for better isolation. Consequently, less than 20 dB of isolation has been achieved throughout the entire BW. Also observed was a good combined realized peak gain of up to 5.85 dBi and total efficiency of greater than 85%. For MIMO performance key parameters, the array exhibits the envelope correlation coefficient (ECC) <0.0033, diversity gain (DG) >9.983, total active reflection coefficient (TARC) <0.445, mean effective gain difference (MEG12) ≈0 dB, and the channel capacity loss (CCL) <0.4 bps/Hz. This design would encourage designers to create high-performance MIMO antennas for UWB frequency-related applications.</span>

Single Port Multimode Reconfigurable UWB-NB Antenna for Cognitive Radio Applications

In this paper, a compact, single port, multimode reconfigurable UWB-NB antenna with a novel feeding network is presented. The proposed antenna consists of a pentagonal-shaped monopole radiator, a beveled-shaped partial defected ground plane with a rectangular slot, and a reconfigurable bypass feeding network. The antenna realizes a wideband frequency range from 2.4 to 18 GHz and four narrow band frequency ranges, 5.3 to 6.8 GHz, 6.0 to 7.6 GHz, 7.2 to 8.8 GHz and 8.4 to 11.4 GHz. The antenna provides an omnidirectional radiation pattern with gain from 2.2 to 6.2 dBi maximum at 12 GHz and voltage standing wave ratio (VSWR) ranges from 1 to 2. The fabricated antenna has an overall dimension of 18×21×1.6 mm3. Sensing and tuning ranges of the fabricated antenna shows good agreement with the simulation results. The proposed antenna has an advantage of simple design, low profile, single port excitation and omnidirectional radiation pattern making it suitable for applications such as handheld mobile cognitive radio systems.

Development and design of wearable textile antenna on various fabric substrate for unlicensed ultra-wideband applications

In the area of wearable technology an enhancement of basic microstrip antenna is evolution of wearable textile antenna. A major requirement for wearable textile antenna is its flexible designed materials which incoprates of fabric in the structure. The parameters obtained from the wearable textile antenna are return loss (S-11), directivity, gain, voltage standing wave ratio (VSWR) as well as the specific absorption rate (SAR) value. All these parameters are mostly influenced by the value of substrate dielectric constant and its thickness. In this paper, the design of wearable dual band frequency microstrip antenna is presented for wireless communication services. When the federal communication commission (FSS) has allowed the operation of unlicensed ultra-wideband (UWB) thus it attracted research interest in realizing UWB antennas for wireless applications. The operating frequency of the proposed antenna ranges from 2.85 GHz to 7.3 GHz. For body-worn and wearable applications, the antenna is embedded on selected textiles (i.e. felt, denim, polyester and leather). The prorposed microstrip antenna is designed, simulated and analysed in computer simulation technology (CST) microwave studio.

An Effective Optimization Methods for the Suppression of Edge Effects in Ultrawideband Tightly Coupled Antenna Arrays

An effective optimization method is proposed for the suppression of edge effects in finite ultrawideband tightly coupled antenna arrays (TCAAs). By designing a practical finite TCAAs, the influences of edge effects on active voltage standing wave ratio (VSWR) are analyzed. Meanwhile, both the active VSWR and the array gain pattern are formulated as analytical expressions with respect to amplitude and phase excitations for analyzing the design freedom of edge effects. Aimed at suppressing the edge effects within an ultrawideband operation band, a nonconvex optimization problem is established for the synthesis of tightly coupled dipole arrays (TCDAs), where array gains at considered scanning angles and frequencies satisfying given maximum active VSWR and amplitude dynamic range ratio (DRR) are maximized. The nonconvex problem is transformed into an iterative convex optimization problem by the use of an iterative way, and the amplitude and phase excitations are efficiently solved by the convex optimization algorithm accordingly. By comparing to the traditional uniform amplitude and progressive phase excitation (UAPPE) method, the simulated and measured results of the ultrawideband TCDA show that the proposed method can slightly improve array gains at most frequencies, while the active VSWRs are suppressed to 3 over a 10:1 bandwidth when scanning up to 45°.

Design and characterization of frequency reconfigurable honey bee antenna for cognitive radio application

<span lang="EN-US">In this article, a frequency reconfigurable honey-bee compact microstrip monopole antenna is proposed which is fed by a microstrip line (50 Ω) having the capability of providing dual-band as well as triple-band operation in eight distinct modes. By embedding three PIN diodes overs the honey bee arms, the effective current distribution is controlled hence resonant frequency is also changed in eight distinct modes in real-time. This is the reason the proposed antenna is portrayed as a frequency reconfigurable antenna in this paper which is suitable for cognitive radio application. This proposed antenna can be used for various wireless application such as Bluetooth, Wi-Fi, worldwide interoperability for microwave access (WiMAX), wireless local area network (WLAN), C-band, and X-band applications. The proposed antenna possesses a planner geometry of 39×34×0.87 mm<sup>3</sup> which is printed on a substrate as flexible FR-4 (lossy) (ε<sub>r</sub>=4.4 and tanδ=0.019). The proposed antenna exhibits voltage standing wave ratio (VSWR)<2 for all 19 resonant frequencies of interest and perceptible radiation pattern over entire frequency bands with a positive gain. CST microwave studio is used to find out all simulated results of antenna parameters.</span>

Design of an Effective Antenna for Partial Discharge Detection in Insulation Systems of Inverter-fed Motors

Partial discharge (PD) measurements under repetitive impulse voltages are critical for the qualification of inverter-fed motor insulation systems. Severe electromagnetic interference due to high frequency switching from power electronic devices can cause the traditional PD detection techniques of sinusoidal voltage unfeasible. This article presents the design of an Archimedes spiral antenna that can work effectively for PD detection under fast rise time repetitive impulse voltages. The antenna structure is optimized by a media superstrate with a high dielectric constant over the radiant surface. Through the optimized design, both the gains of the antenna in the 0.5–1.5 GHz frequency range and the signal-to-noise ratio for PD detection are increased substantially. Modeling and experimental results prove that the gain of the antenna can reach 2.5 dB in the frequency range of 500–900 MHz and become higher than 7.0 dB in the frequency range of 900–2.0 GHz, with a voltage standing–wave ratio smaller than 1.4. This seems to be a significant achievement for PD detection under fast rise time impulse voltages.

Design of a high-gain dual-band LI-slotted microstrip patch antenna for 5G mobile communication systems

The microstrip patch antenna has been successfully used in modern wireless communication systems including the fifth generation (5G) applications. The focus of this paper is on the high-band millimeter waves of the 5G, particularly the 26 and 28 GHz as widely used frequency bands. The main goal of this study is to provide a significant improvement in the microstrip patch antenna gain by adding slots with L and I shapes to a single rectangular patch, being very common structure used in 5G antennas. It is worth noting that this is an empirical study carried out using the CST Studio Suite simulator for simulating and optimizing the slot dimensions. The results presented in the paper show that a very high gain could be achieved by inserting a couple of symmetric LI slots and a rectangular slot located in the middle. To validate our results, the paper presents a detailed comparison between the proposed and previously developed microstrip patch antennas, and demonstrates that the proposed ones outperform the others in achieving high gain and directivity while providing great Voltage Standing Wave Ratio (VSWR) and efficiency measures, and wide enough bandwidth at the two frequency bands selected.

Perancangan Antena Pesawat Tanpa Awak Menggunakan ANSYS High-Frequency Structure Simulator

<p class="Abstract"><span lang="EN-US"><em>Using crewless aircraft or Unmanned Aerial vehicles </em>(UAV)<em> is rife in the civil and military world. The problem that often occurs is that the </em>UAV<em> has disconnected from the control center. One of the reasons was that the aircraft was operating outside the radio control center's range. This study aims to design a control antenna with a higher gain than the previous research antenna, which is used as a reference. The method we used is designing a </em>2×8<em> circular array microstrip antenna using the Ansys high-frequency structure simulator </em>(HFSS)<em> software. The result gives a return loss value of -30.25 dB, a voltage standing wave ratio </em>(VSWR)<em> of </em>1.11<em>, and a bandwidth of </em>512,1 MHz<em>. The amount of gain is </em>12.94 dB.<em> The magnitude of the reflection coefficient of the designed antenna is </em>0.017.<em> This value means that the amount of power reflected by the designed antenna is </em>1.7%,<em> or the antenna is capable of capturing signals of up to </em>98.3%.</span></p>

A planar antenna array with wide frequency band and wide end‐fire beam

AbstractA planar antenna array with wide frequency band and wide end‐fire radiation beam is proposed in this letter. The antenna element is composed of periodic structure, and its feeding position deviates from the center of symmetry, so end‐fire radiation is obtained. The measurement results show that the antenna array operates in the frequency range of 6.11−10.38 GHz with voltage standing wave ratio less than 2, and the corresponding impedance bandwidth is 51.7%. It exhibits a wide radiation beam of more than 80° at end‐fire direction and achieves realized gain of more than 8 dB in measured band.

Solar Cell Integrated Wearable Patch Antenna on Artificial Magnetic Conductor for On-Body and In-Body Communications

This paper presents a patch antenna on a jeans textile with an artificial magnetic conductor (AMC) structure stacked on a solar cell for wearable applications in the Industrial, Scientific, and Medical (ISM) band. Meanwhile, the loading of the AMC reflector increases the radiation efficiency and antenna gain and also results in a reduction in specific absorption rate levels. As examination cases, two textile antenna designs loaded on 7 × 8 patches of AMC plane with the ground plane of both fully copper conductor and partially copper aided with solar cells were fabricated and tested, presenting a strong agreement between simulation and measurement. Its measured impedance bandwidth is 13.79% (2.16 GHz–2.48 GHz) with good return loss and voltage standing wave ratio features in the operating band where it is being used. Besides being a source of electricity, the silicon solar cells are also used as a radio frequency ground plane for the AMC plane. They can produce363.08 mW.

Wideband and dual-band antennas with band-notched using electromagnetic band-gap structure

This paper presents a single-element microstrip spade-shaped patch antennas with a partial ground plane, integrated with an electromagnetic band-gap (EBG) structure, and fed with a microstrip feedline to achieve wideband, dual-band and band-notched characteristic. Two similar mushroom-like EBG structures built into the wideband antenna were used to suppress a specific band, resulting in dual-band. The wide-band antenna achieved a broad bandwidth of 9GHz from 5-14GHz, with a maximum gain of 6.8dBi. Based on the simulation and measured results, the wide-band antenna offers 89% fractional bandwidth for a voltage standing wave ratio less than 2 (VSWR < 2). The EBG provides a band-notch with a bandwidth 3GHz from 8-11GHz, leaving dual-band with bandwidths of 2GHz and 1.5GHz centred at 7GHz and 11GHz, respectively. Surface current distribution and parametric studies were conducted to better understand the behaviour and influence of the EBG parameters. The simulation results were validated through experimental measurement, and both agreed well. The antennas could be used for 5G wireless communication and filtering.

"Design of Compact Circular Microstrip Patch Antenna by Using Metamaterial Structure"

In today’s modern communication industry, antennas are the most essential components required to create a communication link. Micro strip antennas are the most suited for aerospace and cellular applications because of their low cost, light weight and low power handling capacity. The paper provides a detailed study of the design of compact circular microstrip patch antenna by using metamaterial structure.The metamaterial antenna is designed in FR4 Epoxy substrate with dielectric constant of 4.4, height of the substrate is 1.6 mm with a circular patch. Metamaterial analysis and simulation was done using HFSS 2022 R2 Software yields a best results of gain at their operating frequency (fr) and return loss. Desirable voltage standing wave ratio between 1 and 2 is achieved, after introducing artificial magnetic unit cell metamaterial on the circular patch antenna. Hence multiband antenna is obtained used for Sub-6 GHz 5G applications, operates in S, C, X, Ku bands.

Design of a Low temperature cofired ceramic wideband WideScan antenna array for millimetre‐wave applications

The design, fabrication, and measurement of a 7 × 7 mm-wave array antenna have been presented for 5G communications. The substrate integrated waveguide (SIW)-fed antenna element is formed of four parts: a rectangular radiating patch, a coupling slot cut onto the broadwall of the SIW, a transition layer, and a feeding layer at the bottom. The bandwidth and radiation efficiency has been improved by embedding an air cavity below the radiating patch, as the effective dielectric constant of the substrate is reduced. Moreover, a prototype has been fabricated and measured to verify the design principles. The finite array operating over 23–28 GHz has achieved active voltage standing wave ratios of less than 2 and 2.5 in the E- and H-planes while scanning up to 45° respectively. Compared with the theoretical ideal gain, the average gain drop of the measured embedded element gain is 0.73dB.

Circular slot antenna for triband application

We recommend a circular monopole antenna (CMPA) with a central feed to operate in three bands. The antenna is circular and has an 8cm diameter. The suggested antennas' resonance frequency ranges are 2.43 GHz, 5.24 GHz, and 9.61 GHz. The planned CMPA is made up of two circle-shaped slots cut into the radiating patch. The whole structure is supplied via a microstrip feed line and analysed using CST Studio's electromagnetic simulator, which is based on finite integral technique (FIT). To check the structure, the return loss, radiation pattern, voltage standing wave ratio (VSWR), and gain are all examined. The structure's ideal dimensions are determined using a parametric study of three factors: feed position, feed breadth, and ground size. The proposed CMPA is capable of operating in several bands and has good matching impedance in all of them.

Wideband L/X-Band Shared-Aperture Phased Array Antenna for SAR Applications

In this article, a wideband shared-aperture phased array antenna is proposed for synthetic aperture radar (SAR) applications. A metal cavity-backed slot antenna and a slot antenna are used as the L- and X-band antenna elements, respectively. Notably, the X-band antenna elements are mounted on top of the L-band ones, and their interactions are successfully isolated by loading a layer of frequency selective surface (FSS). The FSS layer reflects the electromagnetic waves in X-band and allows transmission of the L-band electromagnetic waves, making the shared-aperture antenna work properly in L- and X-bands. Furthermore, a circular patch is designed to improve the bandwidth of the X-band antenna. Simulations indicate that the proposed antenna has impedance bandwidths of 46% in X-band (7.5–12 GHz) and 21% in L-band (1.7–2.1 GHz). Moreover, the X-band antenna can scan up to ±60° in the E-plane and ±30° in the H-plane with voltage standing wave ratio (VSWR) below 3. To verify the design method, a shared-aperture antenna prototype, which consists of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6\times6$ </tex-math></inline-formula> X-band elements and one L-band element, has been fabricated and measured. Finally, the measured results agree well with the simulated ones.

Shared-Aperture Dual-Polarized Ku-Band and Single-Polarized Ka-Band Phased Array Antenna With Scanning Coverage Enhancement

A dual-polarized Ku-band and single-polarized Ka-band shared-aperture phased array antenna is proposed in this article. The endfire dipole antenna is designed as the radiating element of both bands. To eliminate the shading effect of the horizontal-polarized Ku-band antenna caused by the common ground, the director is loaded on the Ka-band antenna to increase the height of the equivalent phase center of the Ka-band antenna. The high-order mode of the horizontal-polarized Ku-band antenna is excited when the Ka-band antenna scans to a wide angle in H-plane within the frequency range of 33–34 GHz. An etched square ring is loaded on the Ku-band radiating arm to induce the reverse current to prevent such a high-order mode. The scanning blind spots occur at 33 and 35.8 GHz when the Ka-band antenna scans to 50° in E-plane owing to the mutual coupling between the Ka-band antenna and the vertical-polarized Ku-band antenna. A metallic strip is loaded on the vertical-polarized Ku-band antenna to eliminate the blind spot at 33 GHz. The feeding position of the vertical-polarized Ku-band antenna is elevated to eliminate the blind spot at 35.8 GHz. The periodic cell and finite array are simulated to verify the design proposed in this article. The results demonstrate that the design is effective and the beam-scanning coverage reaches <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pm \mathrm{50}^{\circ }$ </tex-math></inline-formula> at both bands. The active voltage standing wave ratio (VSWR) is not greater than 3.5 at 15–17 and 33–36 GHz in the whole beam-scanning coverage. A prototype of the 4 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 4 Ku-band and 8 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 8 Ka-band shared-aperture array is fabricated and measured. The measured results agree well with the simulated ones.

Analysis and fabrication of a small-scale radio-frequency balun for magnetic resonance imaging amplifier.

In this study, the authors report the design and fabrication of a small mixed-integrated balun for magnetic resonance imaging (MRI). The device was designed by using the positive anti-symmetric coupling method, which applies the lump surface-mount technology capacitors as well as mirror-symmetric coupling strips that were etched on the top and bottom layers of a printed circuit board. The capacitors reduced the length of the coupling strips and compensated for imbalances in the phase and gain due to errors in the fabrication process. The structure and equivalent even-odd circuit model of the device was modeled and examined using commercial software to optimize the design parameters. Following this, the device was fabricated and its performance was assessed through measurements using a network analyzer. The results showed that imbalances in the gain and phase were lower than 0.1 dB and 1°, respectively, and the insertion loss and the input voltage standing-wave ratio (VSWR) were lower than 0.4 dB and -25 dB, respectively. More importantly, the device was small, with dimensions of 50 × 60 × 1.5mm. This makes it suitable for MRI applications involving highly integrated miniaturized systems. The proposed device was integrated into a 3.0T radio-frequency power amplifier (RFPA) and reduced the dimensions of its power modules by 20% compared with the traditional balun. Finally, the RFPA module was used in an 3.0T MRI system for imaging experiments, and the results showed that the balun can help obtain high-quality scanning images.

Compact Tri-Band Antenna with Double Winding Structures for 3G/4G/5G Base Station Applications

This paper presents a compact tri-band antenna with double winding structures for 3G/4G/5G base station applications. The proposed compact tri-band antenna design with double winding structure fed by a coplanar waveguide (CPW) reduces the installation space and mutual coupling between close frequency operation bands suitable for base band applications. The proposed antenna design can be configured for step-up and step-down transformer operation using double winding structures on either side of the central resonator with an ability to attain reversibility of transformer operation. The proposed compact tri-band antenna performance is evaluated for both with and without windings in the antenna structure. The proposed design without the winding structure achieves a dual band of operation whereas the design with a winding structure achieves tri-band operation with improved S11 performance and very less voltage standing wave ratio (VSWR). Two prototypes of tri-band ultra-wideband (UWB) antenna with double winding structures of high design specifications are fabricated and tested to validate the proposed design principle. The effectiveness of the projected design is evident from the excellent association between simulated and measured results. It is shown that the proposed design is very effective with low cost and the fabricated prototypes of the antenna with double winding structures are very compact with the dimensions of 18.6 X 15.6 mm2 achieving three frequency bands of operations at 2.9 GHz, 6.5 GHz, and 11.3 GHz with improved return loss < -10db and VSWR < 1.8.

Diversity performance of band notched ultra-wideband MIMO antenna

Like other wireless networks, UWB systems suffer from multipath fading. By fully using the abundant scattering circumstances and enhancing the shared connection between multi-antenna components, MIMO technique was known to improve the enormous data rate transmission and bandwidth limitation. A compact multiple-input-multiple-output (MIMO) antenna is proposed which has high seclusion and band-reject qualities for ultra-wideband (UWB) applications. It comprises two monopole micro-strip elliptical patch radiating elements. The fabricated MIMO antenna having a dimension of 18 × 36×1.6 mm3. To enhance isolation between two monopole antennas, a T- molded stub is extruded in the ground plane. To achieve band indented function for Wireless LAN (4.92–6.1 GHz), a dumbbell (I) molded stub is extruded. The Proposed antenna possesses a high seclusion of < −18 dB over the entire operating band frequency (2.9–18 GHz). The simulation results and structure analysis are studied on the basis of improved-isolation between two ports, radiation patterns, current distribution on surface, realized gain is more than 2.8 dBi, Correlation Coefficient of Envelope (ECC) is less than 0.1, Total Active Reflection Coefficient (TARC) is less than − 10 dB, Mean Effective Gain (MEG) is less than − 3 dB, Channel Capacity Loss (CCL) is less than 0.29 bps/Hz and Diversity Gain is less than 9.95 dB which shows high diversity performance. For this design, except at the notch-band range, the Voltage-standing-wave-ratio (VSWR) is less than 2.