Electric-controlled metasurface antenna array with ultra-wideband frequency reconfigurable reflection suppression

The electric-controlled metasurface antenna array(ECMSAA)with ultra-wideband frequency reconfigurable reflection suppression is proposed and realized.Firstly,an electriccontrolled metasurface with ultra-wideband frequency reconfigurable in-phase reflection characteristics is designed.The element of the ECMSAA is constructed by loading the single electric-controlled metasurface unit on the conventional patch antenna element.The radiation properties of the conventional patch antenna and the reflection performance of electric-controlled metasurface are maintained when the antenna and the metasurface are integrated.Thus,the ECMSAA elements have excellent radiation properties and ultra-wideband frequency reconfigurable in-phase reflection characteristics simultaneously.To take a further step,a 6×10 ECMSAA is realized based on the designed metasurface antenna element.Simulated and measured results prove that the reflection of the ECMSAA is dynamically suppressed in the P and L bands.Meanwhile,high-gain and multi-polarization radiation properties of the ECMSAA are achieved.This design method not only realizes the frequency reconfigurable reflection suppression of the antenna array in the ultra-wide frequency band but also provides a way to develop an intelligent low-scattering antenna.

Frequency Reconfigurable Antenna for Portable Wireless Applications

In this paper,the design and experimental evaluation of a hexagonalshaped coplanar waveguide(CPW)-feed frequency reconfigurable antenna is presented using flame retardant(FR)-4 substrate with size of 37×35×1.6 mm3.The antenna is made tunable to three different modes through the status of two pin diodes to operate in four distinct frequency bands,i.e.,2.45 GHz wireless fidelity(Wi-Fi)in MODE 1,3.3 GHz(5G sub-6 GHz band)in MODE 2,2.1 GHz(3G Long Term Evolution(LTE)-advanced)and 3.50 GHz Worldwide Interoperability for Microwave Access(WiMAX)in MODE 3.The optimization through simulation modeling shows that the proposed antenna can provide adequate gain(1.44∼2.2 dB),sufficient bandwidth(200∼920 MHz)and high radiation efficiency(80%∼95%)in the four resonating frequency bands.Voltage standing wave ratio(VSWR)<1.5 is achieved for all bands with properly matched characteristics of the antenna.To validate the simulation results,fabrication of the proposed optimized design is performed,and experimental analysis is found to be in a considerable amount of agreement.Due to its reasonably small size and support of multiple frequency bands operation,the proposed antenna can support portable devices for handheld 5G and Wireless LAN(WLAN)applications.

Multi-Mode Frequency Reconfigurable Conformal Antenna for Modern Electronic Systems

The article presents a miniaturized monopole antenna dedicated to modern flexible electronic systems.The antenna combines three fundamental properties in a single structure.Firstly,it is characterized by a compact size compared to the state-of-the-art literature with an overall size of 18×18×0.254 mm3,secondly,the proposed antenna integrates the reconfigurability function of frequency,produced by means of a Positive-IntrinsicNegative(PIN)diode introduced into the radiating element.Thus,the antenna is able to switch between different frequencies and different modes,making it suitable to meet the ever-changing demands of communication systems.third,the antenna is equipped by the property of flexibility.In fact,a conformability test is performed and has demonstrated the stability of the antenna performance under normal and bending conditions.Finally,in order to demonstrate the potential of the proposed antenna,a comparison between the simulated and measured results is made and turned out to be a strong agreement,making the antenna an excellent candidate for future miniaturized rigid and conformal devices.

Cactus-Shaped Frequency Reconfigurable Antenna for Sub 10 GHz Wireless Applications

This paper presents,a novel cactus shaped frequency reconfigurable antenna for sub 10 GHz wireless applications.PIN diode is utilized as an electrical switch to achieve reconfigurability,enabling operation in four different frequency ranges.In the switch ON state mode,the antenna supports 2177-3431 and 6301-8467 MHz ranges.Alternatively,the antenna resonates within 2329-3431 and 4951-6718 MHz while in the OFF state mode.Radiation efficiency values,ranging from 68%to 84%,and gain values,ranging from 1.6 to 4 dB,in the operating frequency bands.the proposed antenna satisfy the practical requirements and expectations.The overall planner dimensions of the proposed antenna model is 40×21 mm^(2).Moreover,the measurement results from the prototype support the simulation results.Based on the frequency ranges supported by the antenna,it can be used for multiple wireless standards and services,including Worldwide interoperability and Microwave Access(WiMAX),Wireless Fidelity(Wi-Fi),Bluetooth,Long Term Evolution(LTE)and satellite communications.This increases its applicability for use in mobile terminals.

Plus Shape Slotted Fractal Antenna for Wireless Applications

Fractal antennas are characterized by space filling and self-similarity properties which results in considerable size reduction and multiband operation as compared to conventional microstrip antenna. This paper outlines a multiband antenna design based on fractal concepts. Fractal antennas show multiband behavior due to self-similarity in their structure. The plus shaped fractal antenna has been designed on a substrate of dielectric constant €r = 4.4 and thickness 1.6mm. The proposed antenna is characterized by a compact size and it is microstrip feed fractal patch of order 1/3. It is observed that the antenna is radiating at multiple resonant frequencies. The resonant frequency is reduced from 2.2 GHz to 900 MHz after I & II iterations respectively. Thus considerable size reduction of 81.77% & overall bandwidth of 12.92% are achieved. The proposed antenna is simulated using the method of moment based commercial software (IE3D) and it is found that simulated results are in good agreement with the experimental results.

Ultra-Wideband Log Periodic Dipole Antenna (LPDA) for Wireless Communication Applications

This paper proposes a printed log-periodic dipole antenna (LPDA) for ultra wide bandwidth (UWB) applications. The antenna comprises of cascading four U shaped elements of different line lengths with balun circuit to improve the antenna impedance matching. The proposed antenna dimensions are 50 × 50 mm2 with FR4 substrate thickness 0.8 mm. Full-wave EM solver HFSS (High Frequency Structure Simulator) is used for modeling the proposed antenna. The pulse distortion is verified by the measured the proposed antenna performance with virtually steady group delay. The simulation and experimental results show that the proposed antenna exhibits good impedance matching, stable radiation patterns throughout the whole operating frequency bands, acceptable gain and stable group delay over the entire operating band. An UWB extended from 1.85 GHz to 11 GHz is obtained, and the average antenna gain is about 5.5 dBi over the operating band with peak gain around 6.5 dBi and 70% average radiation efficiency.

On the Design of Circular Fractal Antenna with U-Shape Slot in CPW-Feed

A new ultawideband circular fractal antenna with notched-band characteristics is presented. A notched-band characteristic is achieved by employing a U-shape slot in 50 Ω feed lines. The ultra-wideband impedance matching and compact size have been obtained by using CPW-feed technique and the fractal concept. The measured result of proposed fractal antenna exhibits the ultra wideband characteristics from 3.0 to 18.0 GHz at VSWR 2:1 except notched-band frequency. The proposed antenna has been analyzed theoretically and experimentally with respect to design parameters. The measured radiation pattern of fractal antenna is nearly omnidirectional in azimuth plane throughout the operating frequency. This antenna is useful for UBW communication system.

Tri-Band Fractal Antennas for RFID Applications

The RFID is a rapidly developing technology. It’s used in many applications such as logistics, ticketing, security, employee attendance record and others. Also, fractal technology is used in many areas, and recently in antenna design because it allows making multi-band and wide-band antennas. In this paper, two tri-band fractal antennas are studied for the Radio Frequency Identification (RFID) applications using the Method of Moment (MoM). The first one is designed for the RFID readers and it operates at 3.85 GHZ, 5.80 GHZ and 8.12 GHZ. The second one is designed for the RFID Tags and it operates at 3.94 GHZ, 5.65 GHZ and 8.20 GHZ.

Frequency reconfigurable antenna actuated by inflated triangular structure:Design and analysis

This paper proposes a frequency reconfigurable triangular antenna actuated by an inflated triangular structure.The open path antenna is transformed from an open type to a closed structure by inflating.Inflatable structures are easy to manufacture by fusing 2 inextensible membranes together along a defined pattern of lines.However,the prediction of their deployed shape remains a challenge.To solve the pattern changed problem,guided by geometric analyses and local buckle characteristics,the inflated triangular structure has been designed and verified by experiment and simulation.In the process of transformation of the antenna,the resonant frequency of the antenna is changed because this frequency is determined by the conformational change.The resonant frequency changes from GHz to kHz when the design of initial structure sizes is from millimeter to meter.The measured peak gains,the frequency,and the radiation direction are also reconfigurable by the initial size.Finally,the reconfigurable resonator array is presented,which is coupled to electric fields to absorb all incident radiation.In this work,the changed pattern design by inflating is applied to the antenna design,and its frequency reconfigurability is achieved.Through the electricity performance analysis of the reconfigurable antenna,precise manufacturing will be possible and provide guidance for manufacturing frequency reconfigurable antennas.

Reconfigurable Microstrip Double-Dipole Antennas for Personal Wireless Communications

In this paper, a number of reconfigurable antennas are designed to support multiband and wideband wireless applications in different frequency bands in the range between 1 GHz and 6 GHz. The proposed designs consist of microstrip-fed two dipoles through simplified balun. By controlling the lengths of the dipoles by connecting or disconnecting slots, we are able to change the antenna operating frequency as well as the operation mode. Two modes are supported by all of the proposed antennas: Multiband and Broadband modes.

Ultrahigh frequency tunability of aperture-coupled microstrip antenna via electric-field tunable BST

A composite ceramic with nominal composition of 45.0 wt%（Ba0.5Sr0.5）TiO3–55.0 wt%MgO（acronym is BST–MgO） is sintered for fabricating a frequency reconfigurable aperture-coupled microstrip antenna. The calcined BST–Mg O composite ceramic exhibits good microwave dielectric properties at X-band with appropriate dielectric constant εr around85, lower dielectric loss tan δ about 0.01, and higher permittivity tunability 14.8% at 8.33 k V/cm. An ultrahigh E-field tunability of working frequency up to 11.0%（i.e., from 9.1 GHz to 10.1 GHz with a large frequency shift of 1000 MHz）at a DC bias field from 0 to 8.33 k V/cm and a considerably large center gain over 7.5 d B are obtained in the designed frequency reconfigurable microstrip antenna. These results demonstrate that BST materials are promising for the frequency reconfigurable antenna.

RF MEMS Based Reconfigurable Rectangular Slotted Self Similar Antenna

Wireless communication systems which require flexibility and reconfigurability in antenna systems faces main problems like antenna performance, size, weight and cost. A wide band Frequency Reconfigurable Rectangular Slotted Self Similar Antenna has been proposed in this paper. The rectangular slotted patch is repeated for two iterations at different scales and is separated by means of Radio Frequency Micro Electro Mechanical Systems (RF MEMS) switches in order to provide reconfigurability. The antenna can operate in three frequency bandsi.e. K-band, Ku-band and Ka-band by altering the states of RF MEMS switches. To avoid fringing effects and to improve antenna performance, quarter wavelength (λ/4) spacing is required between the antenna and the ground plane. However, a Reconfigurable Antenna requires different λ/4 spacing which is difficult to achieve using a common ground plane. So the Frequency Reconfigurable antenna is integrated with high impedance surface (HIS) like Electronic Band Gap (EBG) structures to suppress standing waves and surface waves with a unified profile thickness of 1.75 mm. The overall dimension of the proposed antenna along with RF MEMS Switch, feed element and HIS is about 8 mm × 8 mm × 1.75 mm. The simulated results of the proposed antenna reveal enhancement in antennas performance like Voltage Standing Wave Ratio (VSWR), Front to Back Ratio (FBR) and bandwidth when it is placed over HIS EBG. Also the radiation patterns of the proposed antenna when placed over EBG shows the suppression of side lobe and backward radiation.

Wideband Reconfigurable Millimeter-Wave Linear Array Antenna Using Liquid Crystal for 5G Networks

The advanced design of a 10 × 1 linear antenna array system with the capa-bility of frequency tunability using GT3-23001 liquid crystal (LC) is pro-posed. The design for this reconfigurable wideband antenna array for 5G ap-plications at Ka-band millimeter-wave (mmw) consists of a double layer of stacked patch antenna with aperture coupled feeding. The bias voltage over LC varies from 0 V to 10.6 V to achieve a frequency tunability of 1.18 GHz. The array operates from 25.3 GHz to 33.8 GHz with a peak gain of 19.2 dB and a beamwidth of 5.2° at 30 GHz. The proposed reconfigurable antenna ar-ray represents a real and efficient solution for the recent and future mmw 5G networks. The proposed antenna is suitable for 5G base stations in stadiums, malls and convention centers. It is proper for satellite communications and radars at mmw.

Multiband Monopole Antenna with Sector-Nested Fractal

A kind of novel multi-frequency monopole antenna with sector-nested fractal is proposed and designed, which is nested with a series of similar circular sector elements. By means of the trapeziform ground plane with the tapered CPW (coplanar waveguide) feeder in the middle, the antenna’s radiation performance is greatly improved. The antennas can synchronously operate in three frequencies, covering the working frequency bands of WLAN/WiMAX, 2.44 GHz/3.5 GHz/5.2 GHz - 5.8 GHz. The pattern and impedance measurements of antenna show a good performance over the WLAN/WiMAX band;it possesses a near omni-directional characteristic and good radiation efficiency. Moreover, the antenna is miniature and its design idea can be easily applied into other types of nested structure, the features of which make the proposed antenna have a promising application in other fields.

Researches on Reconfigurable Antenna in CEMLAB at UESTC

This paper summarizes the achievement and progress in the research on reconfigurable antenna since 2001, in Computational Electromagnetics Laboratory （CEMLAB） at University of Electronic Science and Technology of China （UESTC）. Several typical reconfigurable antennas are introduced, which can realize frequency, pattern or frequency-pattern reconfigurability by electrically controlling methods. Some techniques involved in the design and analysis of reconfigurable antennas are reported. At last, the development trend of reconfigurable antenna is predicted in the conclusions.

Th-Shaped Tunable Multi-Band Antenna for Modern Wireless Applications

A compact,reconfigurable antenna supporting multiple wireless services with a minimum number of switches is found lacking in literature and the same became the focus and outcome of this work.It was achieved by designing a Th-Shaped frequency reconfigurable multi-band microstrip planar antenna,based on use of a single switch within the radiating structure of the antenna.Three frequency bands(i.e.,2007–2501 MHz,3660–3983MHz and 9341–1046 MHz)can be operated with the switch in the ON switch state.In the OFF state of the switch,the antenna operates within the 2577–3280MHz and 9379–1033MHz Bands.The proposed antenna shows an acceptable input impedance match with Voltage Standing Wave Ratio(VSWR)less than 1.2.The peak radiation efficiency of the antenna is 82%.A reasonable gain is obtained from 1.22 to 3.31 dB within the operating bands is achieved.The proposed antenna supports UniversalMobile Telecommunication System(UMTS)-1920 to 2170 MHz,Worldwide Interoperability and Microwave Access(WiMAX)/Wireless Broadband/(Long Term Evolution)LTE2500–2500 to 2690 MHz,Fifth Generation(5G)-2500/3500 MHz,Wireless Fidelity(Wi-Fi)/Bluetooth-2400 to 2480 MHz,and Satellite communication applications in X-Band-8000 to 12000 MHz.The overall planar dimension of the proposed antenna is 40×20mm2.The antennawas designed,along with the parametric study,using Electromagnetic(EM)simulation tool.The antenna prototype is fabricated for experimental validation with the simulated results.The proposed antenna is low profile,tunable,lightweight,cheap to fabricate and highly efficient and hence is deemed suitable for use in modern wireless communication electronic devices.

Two Types of Compact UHF Antennas for Partial Discharge Measurement

To investigate the partial discharge (PD) online monitoring of transformers by ultra-high-frequency (UHF) approaches,high-qualified UHF antennas are focused on as one key technique. The size of UHF sensor used for PD UHF online monitoring in transformer is excessively large,therefore,it is not convenient for internal installation of transformer. Two types of compact UHF antennas with small sizes,a Hilbert fractal antenna and a small loop antenna are presented. PD experiments of three typically artificial insulation defects are executed and both antennas are used for PD measurement. The spectra of power via frequency of detected PD signals are analyzed and compared. The experimental results show that the Hilbert fractal antenna and small loop antenna are qualified for PD online UHF monitoring.

Frequency-,radiation pattern-and polarization-reconfigurable antenna for wireless applications

In this communication,a frequency-,radiation pattern-and polarization-reconfigurable antenna employing liquid metal is presented.Two crossed dipole antennas are surrounded by four independent reflectors and directors to realize multi-beam switching.The length of dipole arms can be adjusted by extracting the liquid metal from the needle tube to achieve frequency reconfiguration.The polarization can be switched by injecting liquid metal into different dipole microfluidic channels.It is simple in design and has multiple reconfigurable capabilities.An antenna with a relative frequency tuning range of 35.8%extending from 2.43 GHz to 3.49 GHz is fabricated.It also can perform 6 kinds of beam steering over a 360°coverage and switch between two different polarizations.The antenna has potential to employ cognitive radio(CR)and base station in wireless systems.

用于油气井RFID扶正器激活的阅读器共形天线设计

基于油气井井下环境的特点,为实现井下扶正器的远程控制,同时改正射频识别(RFID)阅读器天线电磁波强度衰减过大、辐射性能差等缺陷,设计一种共形于井下管道的RFID扶正器阅读器偶极子天线。依据天线设计的基本理论,利用天线弯折技术,将该天线结构设计为倒“U”型,实现与套管相共形;通过仿真扫频分析优化天线参数,分析天线主要结构对性能的影响。结果表明,设计的天线最终的中心频率为860 MHz,在该频率下天线输入端口反射系数为-21.05 dB,增益为2.2 dB,天线尺寸为11 mm×148.44 mm,天线的性能满足设计需求,可用于套管扶正器等井下工具的无线控制。

基于新型共面波导的频率可重构MIMO天线设计

设计了一种基于新型共面波导(CPW)频率可重构多输入多输出(MIMO)天线。在天线中使用开关元件,通过控制开关改变CPW的电流长度来实现6.17~9.38 GHz与19.53~25.48 GHz离散频率可调。转换模式不需要额外的匹配电路,使得结构更紧凑。天线单元采用CPW馈电方式,蚀刻在F4B的介质基板上,MIMO配置无需额外的解耦装置便能实现良好的隔离效果。仿真和测试结果表明,单个天线与MIMO天线均可实现频率可重构特性,天线单元之间的隔离度<-20 dB,相关包络系数<0.05,分集增益接近10 dB,满足设计要求。