一种全向共形微带贴片天线阵的设计

设计制作了一款新结构的垂直极化全向微带天线。天线利用分布于立方体侧面上的四个对称性天线单元的单向辐射实现全向辐射,通过单元辐射结构上加载两臂,增加天线的谐振点,展宽设计天线的带宽,对该天线进行了仿真和测试。结果表明,仿真与测试结果基本吻合。设计的天线带宽覆盖了1.7~2.8 GHz,反射系数S11<–10 d B的相对带宽达到49%,在整个频带内实现了全向辐射。天线结构简单且紧凑,易于加工,可用于移动通信领域。     

一种全向圆柱共形螺旋阵列天线

基于圆柱共形阵列天线的基本理论,提出了一种螺旋圆柱阵列天线,该阵列由两层沿圆柱外壁交错排列的螺旋单元组成,采用矩量法分析了天线的辐射特性。通过优化螺旋单元的个数及分布,得到最优的单层单元数N=18,层间距H=60 mm,使阵列天线在实现高增益的同时,在θ=90°平面上产生360度全向辐射,最大增益Gmax可达7.5 dBi,不圆度C<1.6 dB。     

Wideband omnidirectional microstrip array

A compact broadband antenna having a far-field pattern similar to that of a magnetic dipole with horizontal polarisation has been designed and tested. The dimensions of this printed antenna, etched on low permittivity substrate, are 130×130 mm. The measured bandwidth, which is 52% for a VSWR of less than 2, is achieved through the utilisation of nonresonant elements     

Large-bandwidth flat cylindrical array with circular polarisation and omnidirectional radiation

Experimental properties of a flat cylindrical array with circular polarisation and omnidirectional radiation are presented. The thickness of the array wrapped on a perfect conducting cylinder is 0.04?0. A bandwidth of 10% has been obtained. It is now possible to decrease the thickness by a factor 2 (i.e. to 0.02?0), when using a short-circuited elementary source instead of a flat folded dipole, and yet retain the same band-width.     

柱面共形蝶形微带天线的阻抗特性和方向图研究

研究了小曲率半径有限长度圆柱体上共形蝶形微带天线的阻抗特性和方向图.给出了不同曲率半径下的柱面共形蝶形微带天线反射损失和方向图的仿真结果.实际制作和测试了柱面共形微带天线的单元和二元阵列天线,仿真结果与实测结果比较吻合.研究表明:当圆柱半径较小时,不但方向图改变,而且谐振频率下降、阻抗带宽明显减小;当圆柱长度缩短时,方向图的起伏增大.     

用FE-BI法分析圆柱上共型P波段微带天线

采用有限元／边界元法（ＦＥ－ＢＩ）分析了内嵌在圆柱体上的微带天线,着重讨论了该类天线应采用的基函数和权函数以及柱面单元的编码方法。给出了该类天线在三种不同圆柱半径,辐射单元数目分别为一元、二元时的阻抗特性和辐射特性的理论值和测试值,实测结果与数值结果吻合甚好。     

Photodiode-integrated microstrip antenna array for subterahertz radiation

The radiation characteristics of subterahertz (sub-THz) electromagnetic waves emitted from an antenna array integrated with photodiodes are investigated. The element of the fabricated array antenna was a 300-GHz microstrip antenna integrating a uni-traveling carrier photodiode. It was observed that the beamwidth of a 3 /spl times/ 1 antenna array is about half that of the single microstrip antenna. We also confirmed that the radiation direction changed by 20/spl deg/ when 2/spl pi//5 of phase difference was added to the input optical signal for each antenna element. These results demonstrated that sub-THz waves emitted by each element of the array were coherently superimposed and the power combining of the sub-THz radiation occurred in the microstrip antenna array. The measured output power of each radiation element is about 120 /spl mu/W, and a total output power of 1 mW can be estimated for a fabricated 3 /spl times/ 3 array in an ideal radiation condition.     

宽波束柱面共形毫米波微带天线设计

提出了一种利用保距变换设计宽波束圆柱共形毫米波微带天线的方法,并利用保角变换设计了该天线的馈线.作为实例设计了一个宽波束柱面共形毫米波微带天线单元以及一个由八个该天线单元组成的天线线阵,ANSOFT HFSS软件的模拟结果证明了该设计方法的可靠性.与传统的微带天线和阵列相比,本文提出的微带天线单元具有较大的波束宽度,由其构成的线阵在大角度扫描时,具有低副瓣以及较宽的周向波束.     

MUSIC算法在柱面共形天线阵DOA估计中的应用研究

由于柱面共形天线阵所具有的特殊性质,使得其在利用经典MUSIC算法进行DOA估计时,性能会受到较大影响.通过将柱面共形阵划分为多个子阵的方法,可以有效地解决此类问题.仿真结果表明,该方法能应用于柱面共形阵的DOA估计,并容易推广到任意曲面共形阵.     

A retrodirective microstrip antenna array

A Van Atta retrodirective reflector was designed and developed, using an aperture-coupled microstrip antenna array. This reflector possesses the advantage of reflecting high fields to the source point over a wide range of incidence angles and, owing to the low cost and conformability of the structure, is suitable for applications in intelligent vehicle highway systems (IVHS). An approximate theory associated with the reradiation and scattering principles of the reflector is presented for the purpose of understanding and designing the reflector. The utility of the retrodirective reflector was demonstrated by comparison with a plate reflector and a microstrip antenna array without a feed structure. Finally, a reflector with switches in the middle of the microstrip feed lines was investigated for possible applications in communications and remote identification     

A cylindrical multiconductor stripline-like microstrip transmissionline

An analytical expression for the Maxwell capacitance matrix of a class of cylindrical inhomogeneous, multiconductor transmission lines is provided. This class includes cylindrical structures symmetrical with respect to the circuit circle and having a symmetry axis. The effective dielectric constant of the line is found to be the arithmetical mean of the dielectric constants of the two media. Hence, this structure enjoys the main advances of the planar stripline-like microstrip systems. It is also pointed out how to obtain elliptical stripline-like microstrip transmission lines     

A shared-aperture dual-band dual-polarized microstrip array

This paper describes the design and testing of a prototype dual-band dual-polarized planar array operating at L- and X-bands. The primary objectives were to develop new antenna technology with dual-band and dual-polarization capability in a shared aperture, featuring low mass, high efficiency, and limited beam scanning. The design of a prototype planar microstrip array of 2×2 L-band elements interleaved with an array of 12×16 X-band elements that meets these requirements is discussed in detail and measured results are presented. The array is modular in form and can easily be scaled to larger aperture sizes     

A dielectric-coated circumferential slot array for omnidirectional coverage at microwave frequencies

The design and development of a resonant array of circumferential shunt slots cut into the broad wall of a ring waveguide are presented. This antenna, which is recessed into a metal cylinder and dielectric coated, provides nearly omnidirectional coverage. Calculations using an idealized model consisting of a dielectric-coated flush-mounted array on a metal cylinder were performed and used as the primary basis for design. The array recess design was experimentally determined and shown to control the elevation pattern when the recessed array is mounted on a variety of spacecraft shapes. The tolerance problems and the related trapped wave effects encountered in the development of the array are discussed.     

电小尺寸锥台上双馈圆极化共形微带天线阵设计

在电小尺寸锥台上,设计并实现一款锥台共形水平全向双馈圆极化微带天线阵。该天线的工作频率覆盖GPS L1频点(1.575 GHz)和北斗导航系统B1频点(1.562 GHz)。基于HFSS软件仿真,分析了锥台共形对天线阵单元的S11、轴比和增益等参数带来的影响,通过调整辐射贴片尺寸,减小了锥台共形对天线的影响,改善了圆极化性能,提高了天线的圆极化增益。加工天线阵并进行测试,测试结果表明,该天线阵在1.55～1.60 GHz频段内,S11参数≤-10 dB,在GPS L1频点和北斗B1频点,水平全向增益最大值达到了1.73 dB,1.25 dB,增益不圆度≤2.5 dB,实测结果表明该天线具有良好的水平全向圆极化辐射性能。     

A reciprocity approach for calculating radiation patterns of arbitrarily shaped microstrip antennas mounted on circularly cylindrical platforms

The paper presents a convenient and efficient approach, based on the reciprocity theorem, for calculating the radiation patterns of arbitrarily shaped microstrip antennas with dielectric substrate and superstrate layers mounted on circularly cylindrical platforms. A detailed theoretical development followed by examples with numerical and graphical results illustrate the versatility of the technique. The reciprocity approach presented is very flexible and may be used in conjunction with any of the commonly employed computational electromagnetics modeling approaches such as the method of moments, finite-element methods, and finite-difference time-domain techniques.     

A cylindrical array for the TACAN system

A new cylindrical array has been developed for the TACAN ground antenna application. The technical requirements are unique since the circumferential radiation pattern is quasi-omnidirectional with multiple lobes and must be rotated at a precise rate. This is accomplished by electronically modulating the azimuth aperture distribution. Thus the antenna is a system including a specialized cylindrical array, a modulating RF feed network, and the associated electronic generator providing the required modulation and reference signals. Theoretical and practical design considerations are presented using a mathematical model of the antenna. This model describes the characteristic behavior and actual performance of the cylindrical array. The antenna's physical characteristics and design features are described, and measured array performance is presented in detail and compared to the system requirements. Operational performance data accumulated during actual flight test evaluation is presented briefly.     

A 7.5-GHz microstrip phased array for aircraft-to-satellite communication

The demand for high-gain full-hemisphere coverage for aircraft-to-satellite communications is ever increasing. Many approaches to this problem have been investigated, including a parabolic dish under a radome and the more conformal hybrid-scan array under a radome. Both are heavy and protrude a significant distance from the aircraft skin. An alternative solution to the problem may be a completely conformal lightweight microstrip phased array.     

A microstrip array feed for land mobile satellite reflectorantennas

A circularly polarized feed array for a spacecraft reflector antenna is described that was constructed by using linearly polarized microstrip elements. The array has seven subarrays which form a single cluster as part of a large overlapping cluster reflector feed array. Each of the seven subarrays consists of four linearly polarized microstrip elements. The array achieved a better than 0.8-dB axial ratio at the array pattern peak and better then 3 dB antenna gain to 20° from the peak, across a 7.5% frequency bandwidth. A teardrop-shaped feed probe was used to achieve wideband input impedance matching for the relatively thick microstrip substrate. The low impedance and axial ratio bandwidths were achieved using a relatively thick honeycomb substrate with the impedance-matching feed probes     

Miniature and near-3D omnidirectional radiation pattern RFID tag antenna design

A planar and miniature (0.09lambda times 0.13lambda) radio frequency identification (RFID) tag antenna is described whose radiation pattern is near omni-directional in three dimensions, with less than 2.6 dB gain deviation in all directions. The antenna is comprised of an open-loop radiating element, which is excited by a small loop. The minimum and maximum read ranges of the implemented RFID tag are approximately 2.3 and 2.6 m, respectively. Comparison between the simulated and measured results for the radiation and read patterns are shown to be in good agreement.     

A novel radiation pattern and frequency reconfigurable single turn square spiral microstrip antenna

This paper presents a novel pattern and frequency reconfigurable microstrip antenna that uses switched connections. The basic antenna operates with linear polarization around 3.7 GHz. One set of connections provides a re-directed radiation pattern while maintaining a common operating impedance bandwidth with the baseline configuration. The second set of connections results in operation at a higher frequency band at 6 GHz with broadside patterns. Measured results of the three antenna configurations are provided. Potential applications of this reconfigurability and directions for future work are discussed.