Analysis of Modified Square Sierpinski Gasket fractal microstrip antenna for Wireless communications

In this paper, the slot loaded microstrip antenna has been developed with Sierpinski gasket technique. The proposed Modified Square Sierpinski Gasket (MSSG) fractal antenna involves a square patch utilizing Sierpinski gasket (triangular) structure. Four triangular slots are loaded at each iteration. The structure is then simulated using commercially available Ansoft HFSS simulator. The multi-band operation has been achieved by the proposed antenna at 15.915 GHz, 20.045 GHz, 23.077 GHz, 27.77 GHz frequencies with −20 dB, −25 dB, −22 dB, −28 dB return loss respectively which works well for Ku (12–18 GHz) and K (18–27 GHz) band. The consistent result is obtained after simulation and the validity of fabricated design is checked by the measured result. The designed antenna is an attractive candidate for applications like wireless multi-band communication systems.     

A novel wide-band circular patch antenna

In order to overcome the narrow-bandwidth of the patch antenna, one kind of configuration which can widen the bandwidth significantly is discussed in this letter. Analyzed by the equivalent-circuits method and simulated by HFSS, a rule derived from simulated results that can aid to design the microstrip antennas is found. Finally, the structure parameters are optimized out, which reaches 44.67% impedance bandwidth. Furthermore, this kind of configuration can also be applied to the multi-layer patch antenna.     

A COMPACT QUADRATURE FEEDING CIRCUIT FOR CIRCULARLY POLARIZED ANTENNA

A novel compact quadrature feeding circuit for a circularly polarized antenna is described. The equivalent circuit method in microwave network theory is used and the conventional directional coupler is converted to a new quadrature feeding circuit. This feeding circuit has the same characteristics as the conventional directional coupler but its size is only about one fourth of that of the latter. The formulas for designing the feeding circuit are given. The optimized results obtained by using the software ENSEMBLE are also reported.     

Reconfigurable dual-band circularly polarized microstrip patch antenna for wireless applications

A new design of reconfigurable single-feed circular patch microstrip antenna for dual-band circular polarization application is proposed. The dual-band functionality is realized through incorporating cross-slots of equal slot length in the circular patch and utilizing two PIN diodes to switch the slots on or off. A pairs of tuning stubs are used to tune the circular polarization performance. The design process is presented and good results were obtained.     

Miniaturization of microstrip loop antenna for wireless applications based on metamaterial metasurface

The metamaterial and fractal techniques are two main methods for antenna miniaturization and in this paper, we have modeled an especial shape of the antenna based on loop formation with metamaterial load for this aim. The metamaterial layer is made by multi parallel rings and the result shows that the final antenna size reduced drastically while the frequency shifts from 7 to 4 GHz. The antenna has Omni-directional pattern with the gain of 3.5 dBi, so the size is reduced around 40%for 4.5 GHz and another resonance is made at 2.5 GHz with a return lossless than −6 dB with more than 60% frequency shift. The reflection and transmission have been utilized for showing the left hand characteristic based on two port periodic simulations in HFSS full wave software. We show that how the metamaterial load can provide the circular polarization (CP) by controlling the current distribution. We also presented that by making slots we obtained the better Axial Ratio (AR) and miniaturized the antenna with reconfigurable qualification. As a result of fact, we show that by using metasurface we able to miniaturized the antenna and simultaneously achieved the circular polarization.     

共面耦合馈电小型化E-E形及半E-E形宽带微带天线

提出并设计了一种可应用于多频段无线通信的小型化宽带微带贴片天线.天线采用共面容性耦合的馈电方式补偿探针的分布电感,应用FR4高频介质板与空气层组成的层叠介质、E-E形和半E-E形辐射贴片缩减天线的尺寸.结果表明,E-E形微带天线和半E-E形微带天线的阻抗带宽分别为1.85～2.57 GHz(相对带宽32.6％)和1.85～2.50 GHz(相对带宽29.9％).和普通E形微带天线相比,E-E形和半E-E形微带天线的贴片面积缩小了47％和61％.     

On the design of inscribed triangle circular fractal antenna for UWB applications

In this article, an ultrawide band inscribed triangle circular fractal antenna is presented. The antenna has been designed on FR4 substrate dielectric constant ?_r = 4.3 and thickness of substrate 1.53 mm with initial dimension of 30 mm diameter. The experimental result of fractal antenna exhibits the excellent ultra bandwidth from 2.25 GHz to 15 GHz corresponds to 147.83% impedance bandwidth at VSWR 2:1. This ultrawide band characteristcs of antenna has been achieved by using the CPW-fed and fractal concept. The measured radiation pattern of fractal antenna is nealy omnidirectional in azimuth plane and bidirectional in elevation plane. The measured group delay of proposed antenna is almost constant throughout the band. Such type of antenna is very useful for UWB communication system.     

Microstrip Sierpinski fractal carpet for slot antenna with metamaterial loads for dual-band wireless application

The compact microstrip antennas with the dual-band characteristic and reconfigurable qualification have been noticed and investigated in this paper. We have developed the slot microstrip antenna with Sierpinski carpet and Minkowski formations and then the metamaterial loads are placed on this antenna in the slot area. The reflection/transmission method has considered to obtain the permittivity and permeability of the split ring resonator (SRR) as a metamaterial. Finally, we show that by using some junction in the metamaterial layer, we can obtain reconfigurable characteristic. Both antennas have dual-band characteristic where the first antenna has two resonances at 3.2 and 4.5 GHz and in the second antenna by altering the metamaterial layer both resonances are occurring at 3.5 and 5.8 GHz. We show that the antenna has two resonance frequencies that matched with the metamaterial Double Negative (DNG) characteristic. Both antennas are printed on FR-4 also we compared measurement and simulation results together. Aforementioned antennas cover the main wireless, WiMAX and LTE bands with sufficient gain and high efficiency (more than 80% typically) with a bi-directional radiation pattern for the indoor application. Here, the metamaterial is used for controlling the resonances and Sierpinski carpet is developed for matching.     

An offset CPW-fed triple-band circularly polarized printed antenna for multiband wireless applications

An offset coplanar waveguide (CPW)-fed triple-band circularly polarized tilted asymmetrical E-shaped printed antenna for multiband wireless applications is presented in this paper. The antenna mainly consists of a tilted asymmetrical E-shaped patch and excite by a 50 Ω offset CPW feed line using a transformer for impedance matching to generate wide quad operating bands. By properly embedding rectangular slots in the tilted asymmetrical E-shaped patch and triangular stubs loaded modified CPW ground plane, the antenna reveals triple-band circular polarization (CP) features. Numerical analysis and experimental validation of the antenna structure have been carried out and results are presented. The mechanism of triple-band CP operation, analysis of surface current distributions, design procedure, and parametric study of the design is discussed in details. It is well suited for the application of UMTS-2100, 3.5/5.5 GHz WiMAX, 5.2/5.8 GHz WLAN, ITS, downlink of X-band satellite communication, and ITU 8 GHz bands.     

W-shaped enhanced-bandwidth patch antenna for wireless communication

In this paper a novel form of the familiar E-shaped patch antenna is presented. In the presented approach, by using the genetic algorithm (GA) based on fuzzy decision-making, some modifications have been implemented to the incorporated slots which lead to even more enhancement in the antenna bandwidth. The MOM (Method of Moment) is employed for analysis at the frequency band of 1.8GHz–2.6GHz by the optimization parameters of supply locations and slot dimensions. In the implemented fuzzy system, inputs are parameters like population, and outputs are parameters like recombination to produce the next generation. Fuzzy inference system (FIS) is used for the control of GA parameters. The design is also optimized by successive iterations of a computer-aided analysis package and experimental modifications. Prototype antenna, resonating at wireless communication frequencies of 1.88 and 2.37 GHz, has been constructed and experimental results are in relatively good agreement with the analysis. Dimensions of the modified slots for bandwidth enhancement, while maintaining good radiation characteristics, have been determined and the obtained antenna bandwidth of 36.7% is larger than that of a corresponding unslotted rectangular microstrip antenna or a conventional E-Shaped patch antenna. Details of the antenna design approach and experimental results are presented and discussed.     

Design of compact fractal patch antenna for X/Ku/K-band applications

This paper presents a fractal-based compact new monopole antenna for wideband applications. The miniaturization has been achieved by incorporating Minkowski and Koch-snowflake fractals. The proposed antenna design is etched on top of Rogers RT/5880 dielectric material with a dimension of $8.10\times 8.10$ mm². The antenna is designed, analyzed, fabricated, and tested in the laboratory. The proposed geometry operates over a 8.62–22.40 GHz with fractional bandwidth (FBW) of 88.84% and VSWR is less than 2. The proposed monopole antenna exhibits nearly omnidirectional radiation patterns over the entire resonating band with a gain of 1–2.91 dBi and a radiation efficiency of more than 60.5%. Also, the measured results of the prototype make an excellent agreement with the simulated counterpart. Further, the antenna gives good time-domain characteristics. Therefore, the proposed miniaturized antenna can be used in X/Ku/K-band applications.     

Design of CPW-fed asymmetric slot UWB antenna for wireless application

A compact Ultra-WideBand(UWB) slot antenna is presented in this paper. The slot is modified rectangular in shape and asymmetrically cut in the ground plane. A hexagonal patch with two stepped CoPlanar Waveguide(CPW) feed is used to excite the slot. Wider impedance bandwidth is achieved due to the extra inductive reactance created by the asymmetric slot which neutralizes the capacitive reactance of the hexagonal patch. The measured impedance bandwidth of the proposed antenna is 11.85 GHz(2.9–14.75 GHz). The radiation patterns of the proposed antenna are obtained and found to be omni-directional in H-plane and bi-directional in E-plane.     

Split ring resonator based multiband hybrid fractal antennas for wireless applications

In this paper, initially two Moore Antennas are designed which are different from each other in terms of 50 Ω microstrip transmission line only. Same size Feed line is applied at right and left side of the substrate and termed as Left Side Feed Line (LFL) and Right Side Feed Line (RFL). To improve the multiband behavior of Moore Antenna, it is being fused with Koch curve and resultant antenna is named as Moore – Koch Hybrid Fractal Antenna (MKHFA) where Koch curves are superimposed on Moore curve. Two distinct MKHFA’s are designed as MKHFA with LFL and MKHFA with RFL. In order to attain the more number of frequency bands, improved gain, better impedance matching and improved bandwidth, both the MKHFA’s are loaded with Split Ring Resonator (SRR). Proposed antennas are designed on FR4 glass epoxy substrate with thickness 1.6 mm, relative permittivity 4.4. Results of Moore Antenna has been compared with MKHFA and found that MKHFA exhibits multiband behavior. A comparison between unloaded MKHFA using LFL/RFL and loaded MKHFA using LFL/RFL has been made and found that later case exhibits better results in terms of increase in number of frequency bands, bandwidth enhancement and improvement in gain. Prototypes of proposed MKHFA using LFL loaded with SRR and MKHFA using RFL loaded with SRR have been fabricated and tested for their results. The comparison between the simulated and measured results have been done and found in good agreement with each other. The overall dimensions of proposed MKHFA using LFL/RFL loaded with SRR is 25 mm × 25 mm and can be useful for different wireless applications such as Bluetooth (2.41–2.49 GHz) for ISM band, IEEE 802.11 g/b (2.40–2.48 GHz), WiMAX (2.5–2.69 GHz), WLAN (5.15–5.35 GHz), X-band satellite communication (7.1–7.76 GHz). Proposed MKHFA using LFL loaded with SRR also reports peak gain 5.76 dB and bandwidth 770 MHz, whereas, MKHFA using RFL loaded with SRR confirms peak gain 8.56 dB and bandwidth 750 MHz.     

Higher order mode excitation for high gain microstrip patch antenna

Higher order mode excitation in the microstrip patch has been achieved to alleviate the low gain problem associated with this particular class of antennas. This higher order mode excitation is achieved by geometric modification of the radiating patch. The designed antenna structure is simple in nature, provides easy fabrication and manufacturing while exhibiting high gain characteristic. The proposed antenna has a measured gain of 10.21 dBi at the operating frequency of 16 GHz. The half power beam width is approximately 36° and 34° in the H- and E- planes respectively. The antenna can be used in the different applications related to the Ku band.     

A wideband linear U-slot microstrip patch antenna array for wireless application

Microstrip antennas suffer an inherent disadvantage of narrow impedance bandwidth, normally within 5%. In this article, a single layer linear U-slot microstrip patch antenna array is designed, fabricated and characterised. The measured results agree well with the simulated, showing an enhanced impedance bandwidth (voltage standing wave ratio < 2) of 10.6%, ranging from 5.35 to 5.95 GHz, on an FR4 substrate. The antenna array has high efficiency and gain. Only a pair of sidelobes appear in the E plane radiation pattern. The reported linear array design can provide a method of expanding to 4 × N antenna array for satellite to ground communication operating at C band.     

A compact high gain microstrip antenna for wireless applications

In this article, we describe a novel type of defective ground surface (DGS) microstrip antenna that achieves higher gain, multi resonant frequency with compact size. The proposed antenna consists of a hexagonal shaped patch with small volume. Six triangular slots have been cut on the ground plane, just below the six corners of the hexagonal radiating patch. Antenna is circularly polarized one and it has the measured peak gain of 7.2 dBi. The antenna shows multi frequency behavior and more than 57% compactness compare to the conventional hexagonal patch antenna. The simulated results are confirmed experimentally. The proposed antenna is simple in structure compared with the regular stacked or coplanar parasitic patch antennas. It is highly suitable for wireless communications.     

基于分形的特异媒质层设计及应用于提高天线增益

根据分形原理,设计了一种新颖的分形图案。通过在印刷板(PCB)上周期性地蚀刻该分形图案制作了一种微带结构的特异媒质层。仿真计算表明,随着一些分形结构参数变化,该特异媒质层对电磁波具有连续变化的反射系数幅度和相位。依据部分反射层理论,将该特异媒质层加载在矩形贴片天线前方,在天线的工作频点、带宽和定向辐射特性基本保持不变条件下,矩形贴片增益得到不同程度提高。加工制作了特异媒质层和矩形贴片天线,测试结果验证了设计和仿真计算的正确性。     

Transparent and conformal wheel-shaped fractal antenna for vehicular communication applications

In this article, a low cost, compact conformal antenna is proposed for vehicular communications applications. The concept of fractal geometry is applied in this design to make the model more attractive in its appearance as well as to attain desired bands in the vehicular communication spectrum. It is fabricated on a transparent and flexible poly vinyl chloride material of size 55 mm × 40 mm × 3 mm. The proposed antenna is intended to operate in GSM-1800/1900, Digital Communication System (DCS-1800), Personal Communication Service (PCS-1900), Universal Mobile Telecommunications System (UMTS), Long-Term Evolution (LTE2600), Industrial, Scientific, and Medical radio band (ISM 2.4G), Wireless local area network (WLAN), Bluetooth, World Interoperability for Microwave Access (WiMAX), IEEE802.11p protocol based Vehicle-to-everything, Dedicated short-range communications (DSRC) and Wireless Access in Vehicular Environments (WAVE) communications bands. The prototype of the antenna in its planar and conformal versions exhibit the wideband characteristics and their measured results show good agreement with that of obtained simulation results. The virtual analysis of platform mounted characteristics of the proposed antenna at two different locations of the vehicle (vehicle roof-top and on side-view mirror) are performed in ANSYS Savant simulation tool and the corresponding far-field radiation performance is characterized.     

Fractal based ultra-wideband antenna development for wireless personal area communication applications

This paper presents a bandwidth enhanced, compact planar ultra-wideband antenna design for wireless personal area communication (WPAN) applications. The proposed antenna has fractal based geometry and is constructed using several iterations of a pentagon slot inside a circular metallic structure. The partial ground plane of the basic radiator is tapered, defected and a U slit is etched out from the microstrip feed to improve the −10 dB |S11| bandwidth. The proposed fractal based antenna has an impedance bandwidth from 2.9 GHz to 15 GHz with low profile configuration and is fabricated on FR4 substrate with dimensions of 32 mm × 32 mm × 1.6 mm. To authenticate the designed prototype, the antenna is fabricated and tested for impedance and radiation characteristics. The designed antenna has stable radiation characteristics in the operating band. Furthermore, the antenna is validated for its applicability in WPAN, by calculating fidelity factor through time domain analysis along with the transmission coefficient and group delay measurements.     

分形开槽减缩微带天线RCS

分形由于其独特的结构及性能早已在天线的设计中有所应用,但较少地应用于天线雷达散射截面减缩。本文首次将分形思想应用到开槽微带天线中。设计了一副分形开槽微带天线,与常规微带天线相比,在辐射性能降低不多的同时较好地实现了整个频带RCS减缩。