High Frequency Simulation Research Articles

Enhanced Electromagnetic Wave Absorption in Hexaferrite/LSMO Bilayers: Optimization of Structural Design Using a High Frequency Software Simulation

In this study, the electromagnetic (EM) wave absorption properties of a two-layered structure composed of La0.7Sr0.3MnO3-epoxy (10 wt.%) (LSMO) and SrFe9.5Co1.25Ti1.25O19-epoxy (10 wt.%) (SFCTO), both exhibiting distinct high-frequency magnetic and dielectric properties, were investigated using a High Frequency Simulation Software (HFSS) simulation tool. LSMO had a high dielectric constant (ε' >30) within the measurement range (0.1-18 GHz), indicating that dielectric loss mechanisms primarily contribute to EM wave absorption. In contrast, SFCTO is a material capable of significantly absorbing EM waves near 10 GHz due to ferromagnetic resonance (FMR). The simulations were validated by comparing the measured and simulated reflection losses (RL) of an unpatterned LSMO/SFCTO bilayer. The RL spectra were examined by varying the layer thickness and pattern size in three configurations: a continuous LSMO/SFCTO structure, a cross-patterned LSMO on SFCTO, and a square-patterned LSMO on SFCTO. In the continuous LSMO/SFCTO structure, tunable absorption frequency bands were achieved by adjusting the layer thickness. However, it was difficult to achieve broadband absorption due to the reflective characteristics of the high dielectric LSMO layer. The cross-patterned LSMO structure on SFCTO demonstrated broader bandwidth absorption, with layer thickness being more influential than pattern width. The square-patterned LSMO on SFCTO exhibited the best broadband EM wave absorption (max Δf = 7.39 GHz). These results suggest that broader absorption is achievable by partially covering the high-dielectric layer with patterns on a hexaferrite sheet.

Split ring hole metamaterial-enhanced pyroelectric detector for efficient multi-narrowband terahertz detection

Derived from infrared pyroelectric detection, typical terahertz (THz) pyroelectric detectors have low sensitivity at low-frequency THz bands. Based on the high-efficiency absorption of the metamaterial perfect absorber (MPA), a novel split ring hole metamaterial-enhanced pyroelectric detector is proposed to achieve efficient multi-narrowband THz detection. Using high frequency simulation software (HFSS), the dimensional parameters including ring radius, ring width, connection beam width, array period, and thickness, are optimized to enhance efficient multi-narrowband absorption. The as-optimized metamaterial-enhanced detectors are fabricated via micro-nano manufacturing technology. The voltage responsiveness and noise equivalent power of the metamaterial-enhanced detector are tested by THz focused optical path and compared with those of the typical pyroelectric detector and the simulated MPA absorptivity. The results indicate that the metamaterial-enhanced detector has a multi-narrowband detection capability at 0.245 THz, 0.295 THz, and 0.38 THz, which is close to the simulated MPA absorptivity. Compared to the typical pyroelectric detector, the split ring hole metamaterial-enhanced detector can simultaneously achieve thermal absorption, thermal conduction, and pyroelectricity in the same MPA structure, providing faster response speed above 100 Hz chopper frequency and two times higher detection sensitivity at multi-narrowband THz frequencies. This research can be used for THz sensing, absorption filtering, biological macromolecule detection, and other applications.

Design of a Dual-Band Printed Antenna for Modern Wireless Communications and Internet of Things Applications

Wireless technology is increasingly influenced by the advanced technological development of antennas. With the rapid expansion of Internet of Things ( IoT) application in the contemporary communication networks, the demand for small printed antennas is increasing, due to their small size and ease of design and manufacture to suit their various application. In this paper, the antenna is designed which is operating at two different frequency bands 2.40GHz and 5.78GHz. The design parameters of the antenna have been calculated using the transmission line model, and an antenna design program has been used for the simulation process is HFSS ( High frequency simulator structure ) tool, which is based on Finite Element Method (FEM). In this work, the proposed slot dual band patch antenna is implemented using FR4 substrate material with a thickness 1.6mm and relative permittivity 4.4. The size of the proposed antenna is just (28 × 27.7mm). The proposed antenna has Omni-directional radiation patterns on most of the operating band. The dual band antenna is designed by adding a slot to the top of the radiated patch. Therefore, the proposed dual- band antenna shows good performance, which is suitable for modern wireless communications and Internet of Things (IoT) applications. The measurements are found to be in good accordance with the simulated results.

Synthesis of a Multiband Microstrip Patch Antenna for 5G Wireless Communications

This paper presents a multiband microstrip patch antenna for future 5G Millimeter Wave (mm-wave) wireless technologies. The synthesized antenna is designed to be based on the genetic algorithm (GA) optimization tool in the high frequency simulation software (HFSS). The optimized dimensions of the engineered antenna are 24 × 24 × 0.203 mm3, comprising of a ground plane. The antenna design simulated results have been implemented via (HFSS) and microwave studio (CST) tools. The proposed antenna structure is engineered using Rogers RT-Duroid 4003 substrate as a dielectric medium. The Conformist rectangular and circular patches are modified to get multiband operation in the mm-wave band 25–32 besides 40–60 GHz frequency ranges. The input reflection coefficient (S11\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\mathrm{S}}_{11}$$\\end{document}) simulation results were compared with the measurements to check the validity of the design. The fabricated antenna radiation efficiency and gain values are also measured over the desired bandwidths. The measured gain and radiation efficiency values reached up to 9.75 dBi, 0.85%, and 10.75 dBi, 0.84%, for both bandwidths, respectively.

Design and validation of frequency reconfigurable multiband antenna using varied current distribution method

Modern communication technologies require systems that can function at a wide range of frequencies, with diversity of radiation patterns, and with different types of polarization. In communication systems, the antenna serves as a filter; hence the ability to reconfigure the antenna is essential. The performance and design of a frequency band reconfigurable antenna are discussed in the paper, along with a comparison of the outputs of simulated and the fabricated design. Three PIN diodes are utilized to switch between various frequency bands. To increase selectivity, two ring resonators were added to the antenna's ground structure. As the current distribution changes in various switching instances, it is seen that the antenna operates at various resonant frequency bands. Connecting the diodes would change the current and field distribution in the chip design and thus change the resonant frequency. The antenna structure was designed and obtained results using High Frequency Simulation Structure (HFSS) software. The simulated and fabricated antenna is found to be operating in S band (2–4 GHz) and C (4–8 GHz) band of IEEE frequency bands with a gain in the range of 2.59 dB–9.54 dB. Typically the antenna resonates at various frequencies specifically, 2.38 GHz, 2.48 GHz, 3.98 GHz, 4 GHz, 4.45 GHz, 6.99 GHz, 7.2 GHz, 8.25 GHz. Under different switching cases of the diodes, the antenna is found to be radiating in different frequency ranges. By switching the PIN diodes under different cases, the current distribution path can be altered and as result of it, the antenna operates at variable frequencies.

Design of Microstrip Antennas Array for Wireless Applications by Using HFSS

The modern wireless communication desires high gain, wide bandwidth and minimal size antennas that are efficient to provide improved performance over a wide range of frequency spectrum. This requirement leads to the design of microstrip patch antenna. This paper presents the design of compact 1X2 microstrip patch antenna array which uses the corporate feed technique for excitation. The proposed antenna is designed on FR-4 substrate with dielectric constant 4.4 and thickness 1.6mm. Dielectric constant and parameters like Return Loss, Gain and Radiation pattern are calculated using high frequency simulation software. The fabricated antennas results are to be compared with Simulation results. The antenna has been designed for the range 2.4 GHz. Keywords: Microstrip antenna, corporate feed, FR-4 substrate, Microstrip antenna array

Investigation on the Electromagnetic Surface Waves for Single-Wire Power Transmission

Single-wire power transmission (SWPT) is a power transmission method that uses only one wire to realize long-distance transmission of power. For deep insight, the theory of electromagnetic surface waves in this article is applied to reveal the principle of a long-distance large-scale SWPT system. Maxwell's equations under two different media in this system are established, based on them and the boundary conditions on the interface of the media, the propagation law of electromagnetic field energy in the SWPT system is analyzed. A simulation model is built by high frequency simulator structure (HFSS). The distribution law of the Poynting vector in different situations is studied to verify the correctness of the theoretical analysis. Moreover, long-distance transmission experiments are carried in the campus. It is shown that the transmission power can reach 300 W or 135 W when the transmission distance is 100 m or 200 m, respectively.

Rectangular and circular antennas design for Bluetooth applications

The most researched and examined aspect of the communication system is the wireless connection. Without learning how to operate and use different types of antennas, your knowledge is incomplete. Microstrip patch antenna research has advanced significantly in recent years. When compared to standard antennas, microstrip patch antennas provide additional advantages and opportunities. It is of low volume, light weight, low cost, low appearance, compact and easy to manufacture. This study investigates the differences between rectangular and circular patch antennas. For Bluetooth applications, the center frequency of 2.4 GHz was chosen as the optimal resonant frequency. On a flame retardant (FR-4) epoxy substrate, the antenna dielectric constant is 4.4. Above the ground the base rises 3.6 mm. For the simulation process, high frequency simulation software (HFSS 15) is used as the program design. Antennas 1×1, 1×2, and 1×4 are designed for both circular and rectangular antennas. A comparison was made for both types of antennas and voltage standing wave ratio (VSWR), return losses, gain, directivity and half power beam width (HPBW) were found, and the feature of the rectangular antenna was shown.

Design and optimization of pi-slotted dual-band rectangular microstrip patch antenna using surface response methodology for 5G applications

Modern wireless network antenna technologies are designed to meet the ever-increasing needs of emerging applications. Hence this paper investigates potential antenna impedance bandwidth performance enhancement techniques based on optimizing independent geometrical parameters of pi-shaped slotted dual-band rectangular microstrip patch antenna (DBRMSPA). The antenna considered in the optimization process is with a slotted patch which improves impedance bandwidth of the antenna. And independent factors are geometrical parameters that influence the antenna's impedance bandwidth (BW) and operating frequency (Fr). The factors are substrate height (Hs), patch length (L), and slot (s2) length (Ls), and the experiment is designed using Computer Simulation Technology (CST) suite 2019 to generate a dataset by varying these parameters in a specific range. Then based on the dataset, response surface methodology (RSM) is applied to develop mathematical models that relate the responses Fr and BW with independent variables. Using analysis of variance (ANOVA), the effects of varying independent factors on both responses and model validation were investigated. Then constrained numerical optimization is applied to determine optimum design parameters. The optimized parameters, substrate height, patch length, and slot (s2) length (Ls) are 0.648 mm, 3.048 mm, and 1.325 mm, respectively. The optimized dual-band antenna, designed with optimized parameters, achieved a target impedance bandwidth (≥4 GHz), 7.2 GHz and 4.17 GHz at 28 GHz and 38 GHz, respectively. Similarly, the antenna's radiation efficiency at 28 GHz and 38 GHz is 75.457% and 88.6237%, respectively. The proposed antenna also gives a gain of 6 dBi at 28 GHz and 4.15 dBi at 38 GHz. And VSWR is less than 2 throughout its impedance bandwidth. All of these results were generated using the CST EM solver and validated using the Ansys High Frequency Simulation Software (HFSS) with good agreement. As a result, the proposed potential performance enhancement techniques provide an antenna with a wide impedance bandwidth suitable for 5G mobile communication applications.

Design and analysis of the output windows of a doorknob structure for high-power P-band klystron

This article presents the design, analysis, and simulation for the klystron coaxial radio frequency (RF) output windows. Three new RF windows (Type-2, 3, and 4) are proposed based on the coaxial RF window with a doorknob structure (Type-1) to improve its performances. The proposed RF windows are simulated in high frequency simulator structure. At the operating frequency, the return loss are obtained as −49, −60, −56, and −52 dB, and the insert loss as −0.003 62, −0.002 51, −0.002 74, and −0.003 dB, respectively, for Type1, 2, 3, and 4. Moreover, for Type-1, the E-field near the short-circuit surface is significantly greater than that near the output port side due to the asymmetrical structure of RF window. However, this phenomenon has been greatly improved in the proposed RF windows. The heat load because of RF power absorption over the ceramic has been calculated. The distribution of heat load in three new windows is more uniform and less than that in Type-1, and the heat load in Type-2 is about half of that in Type-1. The thermal and structural analyses of RF windows predict the lower temperature and less mechanical deformation for the three new RF windows. Multipactor analysis is carried out to determine the safety at the operating power level.

Design investigation of dual-band dual-circularly polarized hybrid antenna array using semi-hexagonal HMSIW cavity

This paper presents a novel dual band, dual Circularly Polarized (CP) hybrid antenna consisting of a microstrip patch radiator and semi-hexagonal half mode substrate integrated waveguide (HMSIW) cavity. The hexagonal HMSIW cavity operates at its fundamental TM010 mode and excites two rectangular radiating patches with different sizes to provide multiband operation. An inclined slot with suitable size and position is placed on top of each patch to provide CP with different types including right-handed CP (RHCP) wave at the first band and a left-handed CP (LHCP) wave for the other band. Antenna structure is numerically simulated using High Frequency Simulator Structure Simulator (HFSS) and results including reflection coefficient, axial ratio (AR), and radiation patterns are reported. Moreover, a linear array of two elements of the proposed hybrid antenna is designed and simulated. A prototype of the proposed single element and two elements array is made and successfully tested. The measured results show that for the proposed two elements array 3 dB AR bandwidth and peak gain for the low- and the high-band are 1%, 9.2 dBi and 3.1%, 8.8 dBi respectively, which agrees well with those obtained by simulation.

Improved Multiband Rectangular Microstrip Patch Antenna for 5G Application

In this work, a multiband microstrip patch antenna for 5G mobile applications was designed and simulation was conducted using HFSS (High Frequency Simulation structure) software. The frequency range of 3.5 GHz through 11.65 GHz was considered and the antenna dimensions were obtained from a well-established design equations. During simulation, the designed antenna was considered for an antenna without an inset feed and an inset fed antenna using layers of RT/Duroid 5880 substrate with a patch size of 33 mm × 28.8 mm and height of 1 mm. The antenna performance was analyzed in terms of S11 parameters, return loss, Voltage standing wave ratio (VSWR), reflected power, and forwarding power. The result showed that the antenna radiates at a frequency of 3.5 GHz, 5.93 GHz, 7.49 GHz, 10.07 GHz and 11.65 GHz with an S11 value of -19.33, -17.40, -25.84, -32.94, -26.25 dB and VSWR of 1.88, 2.35, 1.68, 1.78 and 1.03. The designed antenna can be used for 5G applications that require the frequencies obtained in this research work.

Simulation Design of Low-Profile Equilateral Triangle Microstrip Patch Antenna Operating at 28 GHz

This study is established for designing an Equilateral Triangular Microstrip Patch Antenna (ETMPA) operating at 28GHz suitable for 5G application technologies. The design procedure is performed by considering inset fed techniques and implementing both Computer Simulation Technology (CST) and High Frequency Simulator Structure (HFSS) in order to assess their performance through the computation of antenna parameters. In order to arrive at the aforementioned objectives, different substrate materials with different heights and various conductor patch material types are utilized and their effect on the antenna radiation performance is investigated. The simulation results reveal that a minimum low-profile (ETMPA) of the order of (4.59 mm3) with reliable radiation performances is generally achieved by Taconic-TLX-9 dielectric substrates of height (h=0.2mm) and with copper patch material. Based on the specifications provided above, the results show that the S11, VSWR, efficiency, directivity, gain and bandwidth with both CST and HFSS techniques are, respectively, (-26.24, -14.60), (1.102, 1.53), (81%, 87.6%), (6.31, 6.52) dB, (5.39, 5.94) dB and (0.708 GHz, 0.503 GHz). Besides, a good agreement between the presented optimum antenna parameters is also observed as compared to the ones previously obtained experimentally or theoretically by other researchers for different patch shapes operating at 28 GHz. In addition, the computed results of the antenna parameters display generally that the CST provides better results than HFSS as compared to the ones experimentally obtained by previous researchers. Finally, the proposed antenna design has the advantage of size reduction in comparison to most of the other works and it is one of the 5G technology requirements.

Simplified Model and Simulation Analysis of Ferrite Hollow Bead Coating Based on Computer Aided Design Method

When ferrite hollow beads were made into coating materials, because ferrite hollow beads had hollow internal structure and conductive and magnetic ball wall, ferrite hollow beads have typical resonant ball characteristics in structure. The absorbing coating composed of numerous ferrite hollow beads could be considered as a resonant absorber. With the rapid development of information technology, especially computer technology, the introduction of computer simulation technology can often save experimental costs and reduce the blindness of experiments. Therefore, in order to comply with this development trend, this chapter will establish the absorber model of ferrite hollow bead coating based on HFSS (high frequency simulator structure) electromagnetic simulation software, and qualitatively analyze the relationship between the thickness of ferrite hollow bead coating and the resonant frequency of absorber and the distribution state of electromagnetic field inside the coating through the of computer simulation software.

MQWC BPFS WITH IMPROVED HORMONIC REJECTION FOR RADAR APPLICATIONS

In this paper, the design and realization of optimized microstrip quarter wave coupled bandpass filters for 1.8-6.2 and 5.8-10.2 GHz frequency bands with improved harmonic rejection are discussed with the center frequencies (f<sub>0</sub>) of 4 and 6 GHz. The designed microstrip quarter wave coupled bandpass filters reject the second and third harmonics at the higher frequencies and having the improved insertion loss of < 1 dB and return losses of 36 and 38 dB, respectively. For the proposed optimized bandpass filters implementation Rogers substrate material with the relative dielectric constant of 3.55, a standard thickness of 0.020 is used and the simulation performed on high frequency simulation software. The proposed filters are fabricated and tested in a vector network analyzer, and obtained test results are compared to the simulated results.

Design and Simulation of Rectangular Microstrip Patch Antenna with Triple Slot for X Band

Abstract: In the present work an attempt has been made to design and simulation of rectangular microstrip patch antenna with triple slot for X band using microstrip feed line techniques. HFSS High frequency simulator is used to analyse the proposed antenna and simulated the result on the return loss, radiation pattern and gain of the proposed antenna. The antenna is able to achieve in the range of 8-12 GHz for return loss of less than -10 dB. The operating frequency of the proposed antenna is 8.4 GHz & 11 GHz with dielectric substrate, ARLON of = 2.5 and h= 1.6mm. Keywords: ARLON substrate material, FEM, Microstrip Feed Line, X band

Resonance analysis using a high frequency simulation method for dc-SQUID amplifiers

We performed high-frequency simulation to optimize the geometric size of dc-SQUID amplifiers and to remove their intrinsic resonance characteristics from the operating range. The aim is to eliminate distortions in the IVΦ characteristics that ensures low noise and stable operation over a large range of bias current. With this method, we designed and fabricated a dc-SQUID amplifier with two series-connected octagonal loops to achieve a robust operating performance. The measured results not only show smooth IVΦ characteristics without any distortion, but also demonstrate that the swing voltage is much larger than the corresponding voltage realized without this method at the same bias current. In addition, the white flux noise level as low as 1.7 μΦ0/√Hz was achieved at 0.1 K corresponding to a low current noise level of 15 pA/√Hz.

Design and Simulation of Rectangular Microstrip Double Patch Antenna for X Band

Abstract: In the present work an attempt has been made to design and simulation of rectangular microstrip double patch antenna for X band using microstrip feed line techniques. HFSS High frequency simulator is used to analyse the proposed antenna and simulated the result on the return loss, radiation pattern and gain of the proposed antenna. The antenna is able to achieve in the range of 8-12 GHz for return loss of less than -10 dB. The operating frequency of the proposed antenna is 8.7 GHz with dielectric substrate, ARLON of = 2.5 and h= 1.6mm. Keywords: ARLON substrate material, FEM, Microstrip Feed Line, X band

Fabrication and modeling of antenna integrated uni-traveling-carrier photodiodes

The fabrication and modeling of bow-tie antenna integrated uni-traveling carrier photodiodes (UTC-PD) are presented. The experimental results show that a −10.68 dBm RF power can be obtained from the 4 × 50 μm2 area UTC-PD at 100 GHz. The device is modeled by high frequency simulation software. The trend of variation of the measured terahertz (THz) power with frequency matches well with the simulation results. Based on the model, the effects of the shape and the contact pads of the antenna on the THz power emission properties of the device are studied numerically, which helps to further optimize the device design.

Development of an analytical method to determine the propagation characteristics of microstrip line on artificial perforated substrates

This paper presents an analytical method to investigate the propagation characteristics of a uniform microstrip line placed on porous substrates. The structure is periodic with a specified unit cell and the substrate is made of cascaded multi-layer dielectric slabs. The proposed method is started by solving wave equation by decomposing Helmholtz operator using appropriate eigen-functions and applying the associated boundary conditions of tangential electromagnetic fields of the unit cell. Then, using Floquet theorem, the equivalent propagation constant of a one-dimensional (1-D) periodic structure is obtained. In addition to, the proposed method is developed for two-dimensional (2-D) structures by a suitable transformation. Several practical structures are considered to verify the accuracy of the proposed method. The comparison of the proposed analytical model and measurement results and those obtained using simulation process provided by High Frequency Simulator Strctures (HFSS) are reported. It is shown that our method can be used for a wide variety of structures to quickly estimate the required parameters with a good accuracy.