Ansoft HFSS Research Articles

Uwb Bpf using Quad Section Stepped Impedance Resonator

Ultra wide band (UWB) frequency range is from 3.1 to 10.6 GHz with a bandwidth of 7.5 GHz. UWB bandpass filter(BPF) is an essential component of any UWB communication system. Design of UWB BPF with extremely high bandwidth is a challenge task. In this paper a simple method is developed for the design of UWB BPF. A quad section stepped impedance resonator (QSSIR) is used as the basic element of the filter. QSSIR has four impedance sections connected in cascade. Ultra wide bandwidth is realized by appropriately selecting impedance ratio and electrical length ratio of the SIR. Two transmission zeros are introduced in the insertion loss response by folding the QSSIR. Designed filter has bandwidth extending from 3.73 to 9.93 GHz with a fractional band width (FBW) of 91% and center frequency 6.83 GHz. There are five transmission poles in the obtained frequency response. Simulation is performed using ANSOFT HFSS. Designed filter was fabricated using FR4 substrate. Test results are found to be in good agreement with simulations. Proposed filter has a simple planar structure. Fabrication is easy. It can be used in UWB systems as band pass filter

Implementation of Compact Ultra wide Band Antenna Design for Breast Cancer Tumor detection

One of the applications of UWB antenna is for detecting a cancer tumor according to breast cancer model system. The absolute dimensions of antenna are 44x30mm2 having a thickness of 1.6 mm. It involves Ultra wide band of 80% frequency range of 3 GHz–12 GHz for the FCC band. The proposed antenna resulted high gain and omni-directional radiation patterns and a considerable impedance matching. The optimized functioning of the antenna is illustrated by the simulation results. This antenna has been implemented in a designed system model with dielectric properties of a human breast capable to detect peculiar bodies. The tumor is detected and examined by the received Proportions and Positional coordinates, accessed by the application of UWB antenna. The accurate position coordinates of the tumor inside the breast are obtained at the places with the least Specific absorption rate (SAR). The antenna was used to localize the tumor precisely which shows the excellent functioning of the antenna and device. The proposed device is simulated by using Ansoft HFSS software and also CST Microwave studio simulator developed the breast model.

Miniaturized Ring Resonator Wideband Bandpass Filter with Wide Stop Band

In this paper miniaturized quarter wavelength rectangular shaped multimode ring resonator bandpass filter with extended diagonal corners and internally located high impedance perturbation stubs, is proposed. Input/output open stubs are tightly coupled to the extended diagonal corners running parallel to the two sides of the ring resonator, implemented to generate wide passband and wide stop-band. Cut-off frequencies can be shifted to the higher side by increasing the length of the sides of resonator. By inserting the perturbation stubs, rectangular ring resonator produces three degenerate modes out of which first two form a wide passband. Small square patch is attached to the opposite interior corners of the ring resonator and T-shaped stub attached to the opposite longer side of the resonator are tightly coupled with feeder line to improve the return loss, insertion loss and skirt-characteristics. Shorter sides of the rectangular ring resonator are bent in U-shaped to increase the effective length of the resonator eventually the bandwidth is widened. Filter is designed and simulated for the center frequency of 3.2 GHz, bandwidth from 2.0 GHz to 4.0 GHz, on dielectric constant 3.38 and thickness 0.508 mm. Electromagnetic simulator Ansoft HFSS is used to optimize the filter dimensions.

Miniaturized Ring Resonator Wideband Bandpass Filter with Wide Stop Band

In this paper miniaturized quarter wavelength rectangular shaped multimode ring resonator bandpass filter with extended diagonal corners and internally located high impedance perturbation stubs, is proposed. Input/output open stubs are tightly coupled to the extended diagonal corners running parallel to the two sides of the ring resonator, implemented to generate wide passband and wide stop-band. Cut-off frequencies can be shifted to the higher side by increasing the length of the sides of resonator. By inserting the perturbation stubs, rectangular ring resonator produces three degenerate modes out of which first two form a wide passband. Small square patch is attached to the opposite interior corners of the ring resonator and T-shaped stub attached to the opposite longer side of the resonator are tightly coupled with feeder line to improve the return loss, insertion loss and skirt-characteristics. Shorter sides of the rectangular ring resonator are bent in U-shaped to increase the effective length of the resonator eventually the bandwidth is widened. Filter is designed and simulated for the center frequency of 3.2 GHz, bandwidth from 2.0 GHz to 4.0 GHz, on dielectric constant 3.38 and thickness 0.508 mm. Electromagnetic simulator Ansoft HFSS is used to optimize the filter dimensions.

Implementation of slow wave characteristics in a microstrip antenna and its implementation with substrate integrated waveguide

In this article, a planar slow wave long-wire-antenna (LWA) is proposed for RF and microwave applications. Mathematical design equations of transformation of cylindrical LWA into planar microstrip antenna are presented. Slow wave effect produced by LWA is demonstrated in terms of group delay in a square slot aperture antenna and the same is compared with the proposed LWA embedded with square slot in the ground plane. Furthermore, substrate integrated waveguide is embedded with the proposed structure which further enhance the antenna gain and group delay. Group delay of about 2 ns is enhanced to the value of 26.7 ns after the integration of substrate integrated waveguide with LWA. Finite element method is used to investigate the design through Ansoft HFSS simulator, which is further validated by measured results of fabricated prototype.

Probe Feed Multi-Element Multi-Segment Triangular Dielectric Resonator Antenna with RCS Analysis

The aim of the paper is to propose a design and analysis of multi-element multi-segment triangular dielectric resonator antenna (MEMS TDRA) with Radar Cross-Section (RCS). The proposed antenna has been excited through coaxial probe feed. The coaxial probe feed excites TM[Formula: see text] dominant mode fields within the TDR elements. A general guideline for wide bandwidth and high gain has been prepared for designing of MEMS TDRA. The model of the proposed MEMS TDRA has been studied through simulation (Ansoft HFSS software) and fabricated for measurement. The simulated antenna performance has good agreement with the measured one. The proposed MEMS TDRA performance has been compared with some similar type of previously published structure and found wider bandwidth and higher gain. The proposed MEMS TDRA provides monopole-like radiation pattern with nearly 39% bandwidth ([Formula: see text] dB). The average gain of 6.0 dBi has been found over the entire bandwidth. The RCS analysis has been performed for monostatic and bistatic modes at different frequencies and angles. The proposed antenna is appropriate for WLAN and WiMAX applications.

Multiband Microstrip Patch Antennas using Heterogeneous Substrate for Wireless Applications

A heterogeneous substrate multiband microstrip patch antenna with various shapes fed by a rectangular microstrip feed line is proposed in this paper with a total area of 73.3 x 127.85 x 3.2 mm3. The antennas are printed on a heterogeneous substrate with the combinations of easily available materials like FR4_epoxy, Air and Taconic RF-30 with relative permittivity of 4.4, 1 and 3.The multiband characteristics are achieved by choosing a proper selection of positions and dimensions of slot in the substrate below the patch. The various structures of microstrip patch antennas like rectangular, square, circular, elliptical and triangular covers L (1-2 GHz), S (2-4 GHz), C (4-8 GHz) and X (8-12 GHz) bands and used for various applications like Low Density Radio Communications Link (LDRCL), Communication satellites, Wireless LAN-802.11b, 802.11g, Bluetooth and WiMAX applications. All the antennas are designed and imitated using Ansoft HFSS 13.0 antenna software. The prototype of various shapes of proposed antennas are fabricated and measured and results in good return Loss, VSWR, resonant frequency, radiation pattern and the antenna gain.

Double-Elliptical Micro-Strip Patch Antenna for Higher Design Flexibility and Miniaturization

Micro-Strip Patch Antenna (MSPA) finds large scale applications in various fields of communication. Elliptical shaped patch antenna is a prominent category among MSPAs. Possibility of circular polarization and dual resonant frequencies makes the Elliptical Micro-strip Patch Antenna (EMPA) widely accepted in modern communication devices. The present work aims to identify the constraints in further advancements in the design of EMPA and propose a novel shape to overcome these constraints. Minimizing the patch area and increasing the number of degrees of freedom in design were found to be the challenges. To overcome these challenges, a newly shaped patch called ‘Double-Elliptical Patch (DEP)’ is proposed for designing ‘Double-Elliptical Micro-strip Patch Antenna (DEMPA)’. A double-ellipse is a combination of two half-ellipses either with the same minor axis and different semi-major axes or with the same major axis and different semi-minor axes. The DEP has an additional degree of freedom in design compared to elliptical patch, which leads to greater design flexibility. In the present work, a DEP with the same horizontal major axis and centrally given feed was designed using Ansoft HFSS software. The semi-minor axis of upper half-ellipse was varied by keeping the semi-minor axis of lower half-ellipse a constant. The radiation properties of DEMPA were found to be similar to that of corresponding EMPA and this was achieved with less patch area. The maximum percentage reduction in patch area was 10.714%. The DEMPA covered the entire frequency range of Ultra Wide Band (UWB).

Fast and accurate synthesis of frequency reconfigurable slot antenna using back propagation network

In this work, the synthesis of a hexagonal shaped frequency reconfigurable antenna based on the back-propagation network (BPN) is presented. Initially, two dimensions of the antenna are selected as the input of BPN and the best solution is considered as the optimal parameters of antenna design. The proposed antenna resonates at eight different bands of frequency, one at a time, using four p-i-n diodes for the variation between 2.36 GHz and 3.92 GHz. In this work, the Ansoft HFSS software is used for antenna design and simulation whereas BPN algorithms are implemented in Scilab software. The Proposed design is fabricated and validated. The frequency tuning ratio is found to be 1.66:1. In this design, the biasing circuit is incorporated into the ground plane of the antenna which reduces the parasitic effects and this design can be used for cognitive radio system applications. Moreover, the simulated and measured results are found to be in fine concurrence with each other.

A diamond-shaped patch microstrip antenna with L-shaped stub for WLAN applications

This article proposes a Dual-band microstrip antenna with Diamond-shaped patch and L-shaped stub for two frequency bands of Wireless Local Area Network (WLAN) application. The combination of 50 Ω microstrip feed line and L-shaped stub, the upper frequency band of WLAN is obtained. This frequency band can be controlled by the length of ground plane. The proposed antenna benefits from omnidirectional radiation patterns for both frequency bands. The intended antenna is simulated by Ansoft HFSS v.15 and CST Microwave Studio and the results are compared. Also, the proposed antenna is implemented on an FR4 substrate with a thickness of 1.6 mm. According to measured results, S11 of less than -10 dB for frequency ranges of 2.3–2.7 GHz and 5–5.7 GHz with impedance bandwidths of 16% and 13%, respectively are achieved.

On the Design of Patch Antenna Array

Abstract In this paper, a coaxial fed patch antenna array for application in the 2.4GHz ISM band was implemented using the Ansoft HFSS software. Standard formulas were used to calculate different parameters of the antenna. These were just used as a basis of design as some parameters varied considerably during simulation. A good extent of the antenna design was hence done through trial and error. The proposed antenna was designed to work at 2.44GHz frequency band. A fractional bandwidth of 2.62%, which was not close to the desired 10% and a reflection coefficient of -18.2131dB were attained. This may have been brought about by poor impedance matching and a high level of spurious feed radiation and surface waves. A way of improving the bandwidth would have been to use proximity coupling feeding method which offers the highest bandwidth (as high as 13%) and is somewhat easy to model and has low spurious radiation. However, its fabrication would have been more difficult. A directivity of 8.53dB was achieved. This was a fairly high though directivity increase could have been studied through use of different substrate material and thickness.

Review Design of Slot Antenna Based on Ansoft HFSS Software

Abstract In this paper, a micro-strip fed slot antenna array for application in the 2.4GHz industrial, scientific and medical(ISM) band is implemented using the Ansoft HFSS software. Standard formulas are used to calculate different antenna parameters. The proposed antenna is designed to work at 2.4GHz frequency band. A half power beam width(HPBW) of 57°. A bandwidth of around 7.7% is attained. This may have been brought about by poor impedance matching and a high level of surface waves. A way of improving the bandwidth would have been to use proximity coupling feeding method which offers the highest bandwidth and is somewhat easy to model and has low spurious radiation. However, its fabrication would have been more difficult. A directivity of 2.01 dB is achieved. This is a fairly high though directivity increase could have been studied through use of different substrate material and thickness. Adjusting length and width of narrow slot loop antenna will influence on the resonance frequency and bandwidth. By using HFSS software, the characteristics of antenna are investigated and analyzed, including voltage standing wave ratio (VSWR), return loss and far field radiation patterns.

Design and Simulation of Duplexer Based on Terahertz Technology

In this paper, a broadband polarization isolation device suitable for the terahertz band is designed by combining optics and electromagnetics. The 3D simulation software Ansoft HFSS is used to simulate the parameters of the polarization isolators and polarization converters in the module, and the final result graph is given. Finally, the polarized isolators and polarization converters were processed by the soft material processing technology and terahertz absorbing materials at home and abroad, and the assembly test was carried out. The test results prove that the transceiver isolation combined device has the advantages of high isolation and small transmission loss in the 450 ± 15GHz frequency band, which meets the technical specifications and has broad application prospects.

A Metallic WBAN Dielectric Resonator Antenna for ISM Band Applications

A compact cylindrical dielectric resonator antenna (CDRA) for Industrial, Scientific and Medical (ISM) applications is proposed in this article. The simple microstrip feeding system can be used to stimulate a certain CDRA. An implemented dielectric resonator delivers the functionalities for an efficient radiator with the feeding specifications. The permitted band can be accumulated by varying the design specifications. The standardized design comprises the resonator to attain frequency of 2.4 GHz. The ISM band is used in wireless body area networks (WBAN) technology for transmission of real time traffic such as video and information to monitor the health conditions. A U-shaped metal strip is located over the dielectric resonator material in order to miniaturize the size and enhance the resonator appearance. The consequences on antenna appearance for various radio wire specifications are explored. The intended model has competitive prices, lower volumes, and adequate containment. The evaluation of antenna illustrates the optimal bandwidth, coefficient of reflection (< -10 dB) as well as substantial gain across the specified bands. Coefficients of reflection, voltage standing wave ratio (VSWR) and radiation structure were discovered in each scenario. Architecture content and simulated results of Ansoft's HFSS are demonstrated. For ISM band implementations, the constructed antenna is sensible.

Modal Analysis of Directional Coupler and Its Equivalent Circuit

A modal analysis for the directional coupler is presented in this paper. The analysis is based on the mode-matching technique. The theory is verified by Ansoft HFSS software at a directional coupler with standard X-band (WR 90) rectangular waveguide ports. Element values of equivalent circuit model are computed by using the S-parameters obtained from the presented method in this paper. In addition this paper has corrected two formulations used in two previous works which have been published.

Wideband and Wide-Angle Single-Layered-Substrate Linear-to-Circular Polarization Metasurface Converter

A wideband and wide-angle linear-to-circular polarization converter (LCPC) based on a single-layer dielectric substrate is proposed. The converter element consists of a metal strip cross backed by a strip horizontally and centrically located on the other metallic layer. The vertical arm of the strip across the whole surface performs as a high- pass filter with a wide passband above a low cutoff frequency. Meanwhile, the horizontal strip resonates at a high out-of-band frequency and also offers a wideband response below the resonant frequency. Another two short strips vertically and horizontally placed around the crosses increase the phase shift caused by the crosses and improve both the passbands. Using equivalent circuit models and ANSOFT HFSS, an example of LCPC is designed with the overall element size of only $0.11\lambda _{0}\times 0.21\lambda _{0}$ for a 90° phase difference and wide-angle stability over the wide operation band. The prototype shows the simulated / measured axial ratios (ARs) below 3 dB over the bandwidth of 69%/74% for a normal incidence wave and 54% for the oblique incident angle of 55° in yz plane, respectively. With the insertion loss of less than 3 and 2 dB, the measured 3 dB AR bandwidth keeps 70% and 55%, respectively.

A Metamaterial-Coupled Wireless Power Transfer System Based on Cubic High-Dielectric Resonators

In this paper, a metamaterial-coupled, highly efficient, miniaturized, and long-range wireless power transfer (WPT) system based on a cubic high-dielectric resonator (CHDR) is explored. The proposed WPT system consists of two CHDR metamaterials separated by a distance and excited by two rectangular coils. Initially, this WPT system is analyzed by considering the cube dielectric permittivity, $\varepsilon _{r}$ = 1000, and loss tangent, tan $\delta$ = 0.00001. From the Ansoft HFSS simulation, it is observed that the system operates in the hybrid resonance mode resonating as a horizontal magnetic dipole providing more than 90% power transfer efficiency at a distance of 0.1 $\lambda$ . In addition, parametric studies regarding the transmitter and receiver sizes, loss tangent, receiver misorientation, cube periodicity, etc., are carried out. One of the significant findings of this parametric study reveals that the suggested WPT system is less sensitive to the displacement of the receiver coil, and the WPT efficiency due to misorientation of the receiver can be increased by changing the CHDR cube rotation. Due to inaccessibility of the very high $\varepsilon _{r}$ = 1000, 18 microwave ceramic samples of EXXELIA TEMEX E5080 (Oxide composition: Ba Sm Ti), which has a permittivity, $\varepsilon _{r}$ = 78, permeability, $\mu _{r}$ = 1, and a loss tangent, tan $\delta$ = 0.0004, was made for experimental verification. These cubes are surrounded by Teflon to make the CHDR resonators. From simulations and measurements, it is found that the proposed system outperforms the most recent high-dielectric or copper-based WPT systems in terms of efficiency, range, size, and specific absorption rate.

Optimized planar terahertz Yagi-Uda antenna using hybrid GSA-PSO optimization algorithm

In this paper, a planar Yagi-Uda antenna design for Terahertz applications is presented and optimized. The lengths of Yagi-Uda antenna elements beside the spaces between directors’ elements are optimized seeking for obtaining high gain and minimum return loss simultaneously at 300 GHz. Thus, the directivity enhancement enables to overcome the high atmospheric attenuation influence that faces the high frequency range and limit its communication capabilities, and the return loss minimization enables to minimize the return loss to improve the impedance matching besides, reducing the mismatching losses. The Gravitational Search Optimization Algorithm with Particle Swarm Optimization algorithm (GSA-PSO) as a hybrid technique is applied on the antenna elements using an offline link between MATLAB program and Ansoft HFSS simulation program. To show the convergence capability of the GSA-PSO, the results are compared with those obtained by other algorithms such as gradient local algorithm and genetic global algorithm (GA). The optimized antenna showed high gain of 15.84 dB with a return loss of -45.27 dB compared to 15.4 dB and -15.6 dB for the conventional counterpart design, and with gain of 15.8 dB, and return loss of -21 dB for the genetic algorithm, and finally with 15.75 dB, and -28 dB for the gradient algorithm. Furthermore, the GSA-PSO algorithm improves the search capability by 30%, compared with the GA algorithm.

A Novel Compact Microstrip UWB Rectangular Stair Slot Antenna for the Analysis of Return Losses

This article deals with the various designs of a novel compact microstrip fed UWB antenna to investigate the corresponding return losses of different structures. The dimension of the designed antenna is 33 x 19 x 1.9 mm3 with FR4 substrate and it can be operated from 2.846 - 11.7458 GHz. The effects of varying the structure of antenna are to exhibit the investigation of corresponding return losses. Different structures of antenna are simulated in Ansoft HFSS simulator. The results of return losses and radiation patterns are explored with the ultra wide band (UWB) rectangular Stair slot antenna. The modified structure of antenna shows the minimized return loss with an enhanced bandwidth that satisfies good UWB characteristics. Antenna performance can also be explored from the radiation behavior of the antenna which is relatively omni-directional pattern for rectangular Stair slot antenna

Multifrequency rectangular microstrip antenna with array of L-slots

A rectangular microstrip antenna containing an array of narrow L-slots and inverted L-slots is described for multifrequency operation. The patch was designed for TM010 mode of excitation at 2.1 GHz and is fed with a coaxial probe from the ground plane. The slots are cut on the patch at two opposite corners. The widths and lengths of these slots are varied to obtain the optimum performance at multiple frequencies. The performance parameters of this antenna are reflection coefficient (S11), radiation pattern, gain, and efficiency. A simple slotted structure without any additional electronic circuit was designed for multifrequency operation. The Ansoft HFSS software tool was used for the simulation and optimum design of the antenna on a FR-4 dielectric substrate above a ground plane. It is observed that the final configuration produces very good performance at penta frequencies: 1.25, 1.48, 1.8, 2.25, and 2.9 GHz with reasonable gain. The simulation results are verified with the experimental results and are found to be in good agreement.