Artificial Magnetic Conductor as Planar Antenna for 5G Evolution

A 5G wireless system requests a high-performance compact antenna device.This research work aims to report the characterization and verification of the artificial magnetic conductor(AMC)metamaterial for a high-gain planar antenna.The configuration is formed by a double-side structure on an intrinsic dielectric slab.The 2-D periodic pattern as an impedance surface is mounted on the top surface,whereas at the bottom surface the ground plane with an inductive narrow aperture source is embedded.The characteristic of the resonant transmission is illustrated based on the electromagnetic virtual object of the AMC resonant structure to reveal the unique property of a magnetic material response.The characteristics of the AMC metamaterial and the planar antenna synthesis are investigated and verified by experiment using a low-cost FR4 dielectric material.The directional antenna gain is obviously enhanced by guiding a primary field radiation.The loss effect in a dielectric slab is essentially studied having an influence on antenna radiation.The verification shows a peak of the antenna gain around 9.7 dB at broadside which is improved by 6.2 dB in comparison with the primary aperture antenna without the AMC structure.The thin antenna profile ofλ/37.5 is achieved at 10GHz for 5Gevolution.The emission property in an AMCstructure herein contributes to the development of a lowprofile and high-gain planar antenna for a compact wireless component.

Progress in ultra-wideband planar antennas

This paper introduces the advances of ultra-wideband （UWB） and super-wideband （SWB） planar antennas based on the printed monopole, microstrip slot and other planar antenna designs in the last decade. A brief history of the ultrawideband antennas is first provided. Several types of planar antennas for UWB systems with band-notched designs are reviewed. Special SWB planar antenna designs with the bandwidth ratio greater than 10：1 including metal-plate and printed monopole antennas and tapered slot antennas are presented and compared.

Research on novel multi-layer and multi-polarized slot-coupling planar antenna array

A novel multi-layer planar antenna array to achieve multi-polarized radiation is developed. U-shaped coupling slots are embedded in the ground plane to extend the bandwidth. The phase relation between adjacent elements in the radiation field is analyzed when adjacent elements are fed in opposite phase. Return loss and radiation pattern are measured for a 16-element antenna array at 12.5 GHz. The radiation pattern shows a good agreement with the calculated one in the shape of the main beam. The return-loss of the proposed antenna array is less than -20 dB in the 12.5 GHz frequency band （12.25-12.75 GHz）. Because of two feed ports the antenna can transmit arbitrary elliptic polarized waves if the two feed ports have different amplitude and phase. The main factors such as element spacing, substrate medium and manufacturing imperfection are analyzed and the corresponding conclusions are presented.

Beamforming and Angle-of-Arrival Estimation of Square Planar Antenna Array

This paper presents a dual-band planar antenna array for ISM band applications (2.4 GHz and 2.45 GHz). This antenna is proposed for indoor applications and enables adaptive beamforming and angle of arrival (AOA) estimation. An adaptive beamforming algorithm is applied for a planar antenna array, which is able to steer its main beam and nulls in azimuth and elevation planes over a wide frequency band. Planar antenna array operates as a spatial filter in 3D space, processing the received signals with weighting schemes. A planar antenna array is designed for AOA estimation in azimuth and elevation planes by using MUltiple SIgnal Classification (MUSIC) based on subspace algorithm. The Base Station (BS) equipped with this planar antenna is preferred to be at the center position on the room ceiling to cover all sectors of the room. It is designed to use four directional triangular elements arranged to form a square planar antenna array. Planar antenna with four elliptical slotted triangular elements (PAFESTE) is used to obtain optimal directivity in four directions in azimuth plane with specific orientation of 30? in elevation plane. It is characterized by half power beamwidth in elevation plane of about 60? and half power beamwidth in azimuth plane of about 90?.

A PLANAR ANTENNA OF CONDUCTOR MODULATING PERIODIC STRUCTURE

A novel planar leaky-wave antenna of conductor modulating periodic structure formillimeter wave application is proposed.Using the theory of two-dimensional periodic admittancesurface,theoretical analysis,numerical calculation and experimental study are carried out for thiskind of antenna.A planar antenna of conductor modulating periodic structure is realized in 8mmwave band.It has an aperture area of 90×90mm^2.The measured performances of the antennaare good.

THEORETICAL STUDY OF A STRIPLINE PLANAR ANTENNA

Numerical results,of the aperture field,radiation pattern and directivity of a stripline planarantenna element are obtained by the moment method.The difficulty of singularities in the integral equationhas been overcome by a simple shift of the testing functions.

Simulation Analysis on Applicability of Meta Material and PBG Based mm-Wave Planar Antenna for Advanced Cellular Technologies

Metamaterials have got a unique identification in the field of electromagnetic. Left handed metamaterials have been recognized through its working at high frequencies with larger bandwidth in antenna design. The author has proposed a multi substrates LH metamaterials with an array of split triangular antennas for wideband as well as for larger bandwidth. FR4 is being used at frequency 42 - 26 GHz with thickness of 3 mm for substrate and matching circuit is inserted to get high gain with minimum reflections. The number of rods in PBG is 100, which is found to get high return losses and ideal behavior of VSWR. Obtained results have been in good agreement such as S11 is approximately ﹣30 dB, VSWR 1.8 dB and the bandwidth enhancement is 2 GHz at frequency 5 GHz. All results are plotted using commercial software CST microwave studio (Version 2012) and MATLAB.

Single-layer broadband planar antenna using ultrathin high-efficiency focusing metasurfaces

Phase gradient metasurfaces（PGMS） offer a fascinating ability to control the amplitude and phase of the electromagnetic（EM） waves on a subwavelength scale, resulting in new applications of designing novel microwave devices with improved performances. In this paper, a reflective symmetrical element, consisting of orthogonally I-shaped structures, has been demonstrated with an approximately parallel phase response from 15 GHz to 22 GHz, which results in an interesting wideband property. For practical design, a planar antenna is implemented by a well-optimized focusing metasurface and excited by a self-designed Vivaldi antenna at the focus. Numerical and experimental results coincide well. The planar antenna has a series of merits such as a wide 3-d B gain bandwidth of 15–22 GHz, an average gain enhancement of 16 d B, a comparable aperture efficiency of better than 45% at 18 GHz, and also a simple fabrication process. The proposed reflective metasurface opens up a new avenue to design wideband microwave devices.

Innovative design and optimization of a two-dimensional deployable nine-grid planar antenna mechanism with a flat reflection surface

With the development of the aerospace industry,space missions are becoming more complicated and diversified,and there is a demand for antenna mechanisms with a larger physical aperture.In this paper,a planar deployable mechanism is proposed,which can form a flat reflection surface with a small gap between plates.To this end,a novel large-scale two-dimensional deployable nine-grid planar antenna mechanism is designed.First,two antenna folding schemes and four supporting mechanism schemes are proposed.Through comparison analysis,the antenna configuration scheme with the best comprehensive performance is selected.A kinematic model of the deployable mechanism is established,and its kinematic characteristics are analyzed.Then,the correctness of the kinematic model is verified by comparing the analytical and simulation results of the kinematic model.Subsequently,a finite element model of the antenna is developed.Based on the response surface method,the structural parameters of the support rods of the antenna are optimized,and a set of optimized solutions with lightweight and high fundamental frequency characteristics are obtained.Finally,a prototype of the proposed nine-grid planar antenna is fabricated.The feasibility of the deployment principle and the rationality of the designed mechanism are verified by deployment experiments.

UWB planar antenna technology

Recent developments of the ultra-wideband(UWB)planar antennas are reviewed,where the progress in UWB plate monopole antennas,UWB printed monopole antennas and the UWB printed slot antennas is introduced and compared.In addition,the UWB printed antennas with the band-notched functions are also presented.

High-gain planar TEM horn antenna fed by balanced microstrip line

A printed TEM horn antenna with high gain fed by balanced microstrip line is proposed. The radiation part of the antenna consists of two symmetrical triangular metal slice branches printed on the FR-4 substrate with 15 mm thickness. The two branches are fed by balanced microstrip line. The antenna is simulated by software CST MICROWAVE STUDIO and the equivalent adopted dipole model is proposed to describe the radiation characteristic of the antenna. The simulation results indicate that the frequency range is from 164 GHz to 5 GHz with reflection coefficient less than -6 dB, and the typical gain value is 8 dB in the operating bandwidth. In order to improve antenna gain without influencing the bandwidth, the length of the dielectric slab should be extended appropriately in the main radiation direction. By extending the length of the dielectric slab appropriately in the main radiation direction, the antenna gain can be improved significantly without the influence on the bandwidth. Besides, a metal disc loaded in the radiation direction makes the gain in band be more stable. The prototype has been fabricated and measured in microwave anechoic chamber which is coincident with the simulation results. This antenna can be widely applied in the UWB field.

A Comprehensive Parametric Study of Planar Inverted-F Antenna

This paper presents a comprehensive numerical and experimental study of Planar Inverted-F Antennas (PIFA) involving all the parameters which may affect the characteristics of PIFA. It is found that PIFA characteristics are affected by a number of parameters including the dimensions of the ground plane, length, width, height and position of the top plate, positions and widths of shorting pin/plate and feed pin/plate. It is also found that the width of feed plate plays an important role in broadening the antenna bandwidth. It is shown that a fractional impedance bandwidth up to 65% can be obtained using an optimized design. Furthermore, a new empirical formula is introduced for the estimation of the central operational frequency of PIFA. These results are very useful for aiding PIFA design in practical applications.

Impact of Element Spacing on the Radiation Pattern of Planar Array of Monopole Antenna

In recent years, several attempts have been made in designing planar array antennas with high directivity. This paper is aimed at investigating the impact of element spacing on the directivity of planar array of monopole antenna. The directivity of antenna with reduced grating lobes can be obtained by carefully varying the inter-element spacing of array antenna. Based on this conception, this paper presents the investigation carried out on the relationship between inter-element spacing and the directivity of planar array of monopole antenna. It went further to highlight the effect on the total fields radiated by the antenna. The inter-element spacing is one of the most important antenna parameters that determine the directivity of the antenna. For a planar array of monopole, the directivity can be improved by varying the inter-element spacing. Four elements uniform planar array antenna and Hadamard matrix method was used to determine element positioning in the array matrix. The simulated results obtained using Matlab, showed that good directivity was obtained by using element spacing between 0.1λ - 0.5λ. Increasing the spacing beyond 0.6λ - 1.0λ also improved the directivity, but generated many grating lobes. As inter-element spacing increased, the grating lobes increased in size, number and levels. The study, therefore, inferred that the best directivity (radiation pattern) can only be obtained when the element spacing is within 0.1 - 0.5λ.

Bandwidth optimization of a Planar Inverted-F Antenna using binary and real coded genetic algorithms

With the exponential development of mobile communications and the miniaturization of radio frequency transceivers, the need for small and low profile antennas at mobile frequencies is constantly growing. Therefore, new antennas should be developed to provide larger bandwidth and at the same time small dimensions. Although the gain in bandwidth performances of an antenna are directly related to its dimensions in relation to the wavelength, the aim is to keep the overall size of the antenna constant and from there, find the geometry and structure that give the best performance. The design and bandwidth optimization of a Planar Inverted-F Antenna (PIFA) were introduced in order to achieve a larger bandwidth in the 2 GHz band, using two optimization techniques based upon genetic algorithms (GA), namely the Binary Coded GA (BCGA) and Real-Coded GA (RCGA). During the optimization process, the different PIFA models were evaluated using the finite-difference time domain (FDTD) method-a technique belonging to the general class of differential time domain numerical modeling methods.

Broadband Feed for Low Cross-Polarization Uniplanar Tapered Slot Antennas on Low-Permittivity Substrate

A broadband feeding technique for the uniplanar tapered slot antenna (TSA) is presented. The TSA operates at a center frequency of 6.5 GHz with a 7 GHz bandwidth (107 percent). The antenna and feed are realized with a broadband microstrip-to-slotline transition on a low permittivity high frequency substrate, Rogers RT/Duroid 5880. The input impedance of the system is designed for 50 Ω compatibility with other system components, and the cross polarization is kept below –30 dB. The developed TSA system was simulated with commercially available electromagnetic software and manufactured. Measured results validate the design process and the antenna’s performance.

平面端射圆极化天线进展综述

全面总结了平面端射圆极化天线的发展历程和重要突破。以正交磁偶极子和平面互补振子两大核心工作原理为主线,深入剖析平面端射圆极化天线的一般性设计方法,阐明其形态演变规律,详细介绍了平面端射圆极化天线的宽带设计技术、波束调控技术以及高增益设计技术等研究现状,最后探讨平面端射圆极化天线的可能发展方向,用于指导该领域的科学研究和工程设计。

双线偏振全数字相控阵天气雷达设计与试验

基于极端灾害性天气对高时空分辨率的探测需求,提出了一种采用平板阵列天线和全数字收发组件,并具有双线偏振功能的S波段相控阵天气雷达系统的实现方法,并对涉及的关键技术进行了研究分析,提出了基于脉内频相扫多波束的扫描策略设计,以及基于机内标定系统的在线标定设计思路。最后采用研制的工程样机开展了强对流天气观测试验,并与CINRAD/SAD雷达的观测数据进行了对比,对比结果表明采用该方法设计的工程样机对强对流天气的观测具有一定优势。

Improving the uniformity of RF-plasma density by a humped variable-gap spiral antenna

This paper develops a humped spiral antenna of top inductively coupled plasma with variable gap. Comparing with planar spiral antennae, it investigates the performance of humped spiral antennae in the calculated electromagnetic configurations and experimental results. It finds that the humped antenna has the improved uniformity of plasma density in the radial direction and the decreased electron temperature in the top inductively coupled plasma. By experimental and theoretical analyses, the plasma performance in the case of humped antennae is considered to be the combined results of the uniform electromagnetic configurations and the depressed capacitively coupling effect.

New band-notched UWB antenna

A simple and compact ultra wideband （UWB） printed monopole antenna with band-notched performance is proposed in this paper. The antenna is partially grounded so that the Q value is depressed and the impedance bandwidth is broadened. A small strip bar is loaded on each arm of the similar U-shaped radiator. The impedance bandwidth of the antenna overlap with IEEE 802.11a is rejected consequently. The geometry parameters of the antenna are investigated and optimized with HFSS. The measured bandwidth of the proposed antenna occupies about 7.89 GHz covering from 3.05 GHz to 10.94 GHz with expected notched band from 4.96 GHz to 5.98 GHz. A quasi-omnidirectional and quasi-symmetrical radiation pattern in the whole band is also obtained. As a result, a UWB wireless communication system can be simplified with the band-notched UWB antenna presented.

GIS局部放电检测用小型化平面螺旋天线研究

随着变电站中气体绝缘金属封闭开关设备(GIS)的广泛应用,局部放电检测逐渐成为发现故障隐患的重要手段。基于超高频(UHF)局部放电的检测原理,设计了一种工作于UHF频段的小型化天线。该天线基于传统阿基米德平面螺旋天线,利用一种振幅随着幅角线性增加的新型正弦波加载方式对天线进行进一步的小型化处理。通过HFSS软件进行仿真和试验验证,结果表明该天线在端口性能、方向性能以及增益等方面均满足局部放电检测的要求;同时天线尺寸较小,使用时易于安装,后续在GIS设备局部放电现场检测中有较大应用前景。