An improved design method of Rotman lens antennas

A Rotman lens is used to feed a linear array antenna for wideband use. A relationship between design parameters for realizing a Rotman lens has been derived by introducing a new design variable. The design method which minimizes the phase error on the aperture of the linear array antenna has been shown. For large array length, the above phase error due to this method becomes considerably smaller than that due to a conventional method. This improved method makes it possible to design small and low-loss Rotman lens antennas.     

Compact wide-band multimode antennas for MIMO and diversity

This paper presents broadband multimode antennas for multiple-input multiple-output (MIMO) and diversity applications. The antenna system is not based on spatial diversity, as usual MIMO systems, but on a combination of pattern and polarization diversity. Different modes of self-complementary, thus extremely broadband, spiral and sinuous antennas are used to decorrelate the signals. It is shown that only one antenna is necessary to receive three uncorrelated signals, thus the space required to place the MIMO antenna is very small. Simulation results and measurements of a typical indoor scenario are given.     

毫米波Rotman透镜天线设计

设计了一个毫米波Rotman透镜天线,该天线也是一个同时多波束天线。用Rotman透镜作为馈电网路,运用准光学技术替代大量移相器,获得同时多波束扫描,并且使电路变得简单,减少了体积和重量。包括馈电网络在内的整个天线系统采用微带来实现,并且使用Ansoft Ensemble仿真软件进行辅助设计,仿真结果表明,该天线可以实现大角度窄波束扫描。     

基于多模滤波器概念的宽带天线设计

提出了一种基于多模滤波器概念的宽带天线设计方法.多模宽带滤波器的研究已有多年的历史.本质上讲,谐振天线的辐射单元也是谐振器,同样存在着多个模式.因此,多模滤波器的概念和方法完全可以应用于宽带谐振天线的设计.文中给出了所提出的多模宽带天线的原理,并通过支节加载偶极子演示了典型的设计方法.仿真和测试结果表明,所设计的天线在几乎不影响尺寸的情况下有效地实现了宽带特性.     

罗特曼透镜馈电的多波束阵列系统设计

多波束系统广泛地应用于电子战设备中。讨论了基于罗特曼透镜馈电的多波束阵列系统的设计理论和原则,给出了一个16元罗特曼透镜和凹口天线组成的多波束阵列系统,阐述了馈电透镜和阵列天线的设计过程以及设计中的难题及解决办法。     

A V-Band Beam-Steering Antenna on a Thin-Film Substrate With a Flip-Chip Interconnection

We propose a planar V-band beam-steering antenna based on a millimeter-wave (mm-wave) system-on-package technology using advanced thin-film technology on a silicon mother board. The thin-film substrate has the capability of integrated passive elements and flip-chip interconnection. Space-consuming components such as a microstrip Rotman lens and patch antennas are implemented on a low-loss, low-cost, and low-dielectric-constant material, benzocyclobutane. V-band monolithic microwave integrated circuits, a power amplifier, and a SP4T switch, are flip-chipped on the thin-film substrate while minimizing parasitic effects. The fabricated antenna module shows if-plane beam steering at four angles, plusmn6deg and plusmn20deg. The measured effective isotropic radiated power is in the range of 17.3-18 dBm. To our knowledge, this is the first demonstration of a planar mm-wave beam-steering antenna module on a thin-film substrate incorporating integrated terminating loads and flip-chip interconnections.     

宽带太赫兹偶极子光电导接收天线研究

太赫兹光电导天线广泛应用于宽带脉冲太赫兹波的检测,是太赫兹光谱和成像系统中的重要器件。偶极子光电导天线由于其结构简单、制作容易成为使用最广泛的一类太赫兹光电导接收天线。衡量太赫兹光电导探测天线的一个重要指标是其响应带宽。针对偶极子天线的探测带宽,分别对天线臂长为10、50、150 m的偶极子天线及一种作为对比的178 m的蝶形天线（Bowtie antenna）进行了实验及理论研究。结果显示其探测带宽随天线臂长增加而减小,与微波天线理论一致。进一步的,采用商用电磁场数值仿真软件进行建模仿真,仿真结果与理论及实验结果具有很好的一致性,证实数值仿真已在很大程度上模拟出实际天线的特性,从而为优化结构参数制作大宽带和高灵敏度的太赫兹天线提供支持。同时,对超半球硅衬底透镜对天线接收频谱的影响也进行了探讨。     

岸基远程高频表面波雷达小型宽带天线系统的设计

从高频表面波雷达天线工程的角度出发,基于对数周期天线的设计理论,优化设计了一副小型 宽带发射天线;基于端射阵理论,优化设计了一副小型宽带、具有大前后比的双鞭天线,并以此作为阵列天线的基本单元组成六元均匀线阵。文中分析了收发天线的工作原理,并给出了计算机模拟结果。     

一种多波束面阵天线的分析与设计

介绍了二维多波束天线的特点和实现二维多波束的几种方法，针对空馈的Rotman透镜推导出了由它馈电的平面天线阵的相位计算公式及设计方法，在此基础上成功地实现了空馈透镜的平面天线阵样机，并给出了相应的测试结果。     

Permittivity of composites used for Luneburg lens antennas by drilling holes based on 3-D printing technique

Due to the attractive performances such as the ability of beam focus, broadband, multi-beam scanning and other features, Luneburg lens antennas are applied in multi-beam antenna, which overcomes the problem of gain loss produced by multi-beam parabolic antenna. Based on 3-D printing technique, Luneburg lens antennas by drilling holes are studied. Permittivity and loss tangent of the equivalent lens materials can be influenced by original materials, hole shapes, hole directions, and porosity. After tests, polystyrene with waxes may be the most appropriate materials for Luneburg lens with high strength. Permittivity with the shape of triangle is the lowest due to the homogeneity. Relative permittivities with the direction at a range of 15°-45° are lower while loss tangent at a range of 0°-30°. Radial directional holes are more appropriate for Luneburg lens. The relative permittivity is decreased with the increment of porosity. After calculations, the forecasts calculated by Looyenga and A-BG theory are more precise. Finally, Luneburg lens with two layers is fabricated by 3-D printing.     

An experimental completely overlapped subarray antenna

A completely overlapped subarray antenna was designed, fabricated, and tested to demonstrate its broad-band, low sidelobe, wide scan angle performance. It uses time delay steering at the inputs to a transform feed, which illuminates a phase-shifter steered objective lens. The transform feed is a Rotman lens and the objective is a cylindrical bootlace lens, both of which are parallel plate waveguide cavities with coaxial probe elements. The signal bandwidth goal of 20 percent (8.1-9.9 GHz) at55degscan was met easily, however, achieving the peak sidelobe goal of - 30 dB proved more difficult because of internal reflections in the Rotman lens beamformer. A brief summary is presented of the completely overlapped subarray antenna (COSA) concept to explain the detailed design of our experimental model. Antenna pattern and S-parameter measurements illustrate the operating principles, the difficulties encountered, and the results achieved.     

一种新型探地雷达天线的FDTD分析

探地雷达系统一般采用超宽带短脉冲信号,因而其天线系统也必须为宽带的。该文给出一种新型的探地雷达天线,该天线为置于镜像面上且具有离散指数电阻加载的单偶极子。通过FDTD法对该天线辐射特性的仿真计算表明,选择合适的电阻加载方式,可以消除由于天线末端阻抗不匹配而引起的二次反射,使天线具有较好的辐射波形和一定的带宽,从而满足实际探地雷达系统的需要。文中还分析了收发天线不同组合方式对直耦信号和目标回波信号的影响。     

一种小型化超短波单极子天线设计

超短波天线在舰船飞机上应用很广,天线的小型化有利于提升其隐蔽性、稳固性,因此对天线的小型化设计显得异常重要。采用加载集总元件和宽带匹配网络的方式,设计了一款新型超短波天线。将宽带匹配网络做成一个微带电路结构与天线辐射单元直接相连的一体化设计,进一步减小了天线的长度;采用 Matlab 和 HFSS 软件联合仿真,并运用遗传算法优化计算全部集总元件的具体数值。天线在100 MHz~400 MHz频段范围内的驻波系数 VSWR(电压驻波比)小于3,水平方向全向辐射。天线和匹配网络总的物理长度仅为255 mm,实现了小型化的要求。制作了天线实物并测量,实测天线参数与仿真参数吻合较好,达到了设计目标。     

宽带被动导引头天线系统性能分析

详细讨论了宽带被动导引头中的关键部件－超宽频带天线的性能，并在此基础上分析了三种具备大视角特性的被动测角方法。由于宽带天线没有确定的相位中心，因此不能采用通常的振幅和差式单脉冲法进行宽频带测角。本文提出的波束运算网络可用于一个宽带螺旋天线同时得到两个交叉波束的振幅－振幅式单脉冲系统中。此外，对比幅相干测向法中的测角模糊问题也进行了研究。     

Full-Wave Analysis of Monopulse Dielectric Lens Antennas at W-band

Lens antenna is a good substitute for the Cassegrain antenna at millimeter-wave frequencies, especially at W-band. On one hand, the antenna design, which is bulky and heavy at low frequencies, becomes compact and light-weighted at W-band. On the other hand, without the blockage caused by the sub-reflector and the feed horns which are unavoidable in a Cassegrain antenna, the lens antennas show better radiation characteristics. In this paper, several lens antennas fed by metal horns are analyzed using a full-wave method-finite element method based on the weak form of the Helmholtz equation (WF-FEM). Numerical results show that the lens antennas presented have low side lobe level (SLL), and good sum and difference performances.     

混合遗传算法优化设计宽带加载螺旋天线

研究了遗传算法和模拟退火法相结合的方法来快速优化设计宽带加载螺旋天线.采用该算法对加载螺旋天线上的加载集总元件的值、加载位置以及匹配网络参数进行一体化优化设计.采用一种简单有效的方法来快速求解加载元件值和加载位置改变后的阻抗矩阵方程,提高了优化设计的效率.利用该方法成功地设计了两副宽带小型化加载螺旋天线.     

Microwave hyperthermia induced by a phased interstitial antennaarray

An interstitial microwave antenna array for hyperthermia cancer treatment is investigated. The purpose is to generate both uniform and controlled nonuniform temperature distributions in biological tissue by modulating the phases of the signals applied to each antenna. The array has four antennas positioned on the corners of a 2 cm square. The distributions of absorbed power within the arrays are computed and then converted into temperature distributions through a heat conduction simulation. The temperature patterns over phantom muscle are presented in both the lateral plane (perpendicular to the antennas) and the axial plane (parallel to the antennas). It is found that by proper phase modulation of radiofrequency signals applied to each antenna, a uniform heating can be produced in the entire array volume     

The leaky lens: a broad-band fixed-beam leaky-wave antenna

A novel type of leaky-wave antenna is presented. Differently from previously reported leaky-wave antennas, it is characterized by a constant beam direction over a very wide range of frequencies. The radiation originates at a slot etched at the interface between air and a dense dielectric, which is shaped to form a cylinder of elliptical cross sections of decreasing dimensions. Two prototypes have been designed, manufactured, and tested. The measurements are in very good agreement with the expectations, demonstrating the potentials of the leaky lens concept to realize integrated transmitters or receivers that are extremely broadband and directive.     

Dielectric Lens Antennas for Wireless Broadband Communications

Dielectric lens antennas are proposed for wireless broadband communication systems in the mm-wave range. Two lens antenna configurations for base station applications are presented and evaluated in terms of radiation characteristics, feeding system, input reflection loss, bandwidth and fabrication tolerances. The system requirements to provide optimum power distribution over the cell and good control of the cell boundaries are achieved. These lens antennas are designed for circular symmetric cell coverage and use a circular waveguide as the feed targeting typical applications at 60 GHz and 40 GHz range. The same concept is applicable for non- symmetrical cells with other feeds. Simulations are performed using Geometrical and Physical Optics codes as well as Finite Elements codes. Theoretical results are verified by measurements, showing good agreement.     

Numerical analysis of dielectric lens antennas using a ray-tracing method and HFSS software

In this paper, we use for the first time the ray-tracing method combined with the HFSS software to analyze lens antennas. HFSS is a very popular commercial tool that can provide very accurate results for the simulation of antennas. However, because of limitations on computational resources, it is hard to apply to solving large electromagnetic problems. In this paper, HFSS is used to simulate the fields of the feed part of a lens antenna. The ray tracing method is adopted for the lens part. This treatment makes the combined method feasible for solving large lens antennas. In using the ray-tracing method, cubicspline interpolation is exploited to fit the face of the lens and to solve for the derivatives at each point on the curved surface. Newton's method is applied to find the intercept between the ray and the curved surface. The numerical method proposed in this paper is very suitable for the analysis of dielectric lens antennas with arbitrary feeds and lens shapes. The validity of the idea is demonstrated by comparing the simulation results of this new method with those from using CST (Computer Simulation Technology) software. Very good agreement is achieved.