平板微波炉均匀性提升研究

提出了一种平板微波炉新型曲面天线结构,与平面天线结构相比,其加热均匀性具有明显改善,同时消除采用平面天线的平板微波炉产生的微波盲区。该曲面天线由曲面金属片和内导体构成。根据微波天线理论,首先设计平面天线和曲面天线初始尺寸,然后运用电磁仿真软件HFSS实体建模,通过仿真空载和负载条件下,对比验证曲面天线能够提升均匀性和消除微波盲区,最后再通过天线手板测试验证。研究表明新型曲面天线相对平面天线,加热均匀性提升10.3%,且消除微波盲区。     

金属地平面尺寸对超宽带单极天线性能影响

研究了金属地平面对无线移动终端超宽带单极天线性能的影响。当天线金属地平面的长度和宽带改变时,考察了包括阻抗带宽和辐射方向图在内的天线主要特性,尤其是地平面尺寸改变较大时对回波损耗的影响。并对40×60mm2的金属地平面尺寸对应的天线特例进行了样品加工和测试,结果表明其反射系数和方向图测试情况与实验仿真基本一致。     

随机误差对超低副瓣天线平面近场测量的影响

导出了平面近场测量中近场幅相随机误差所引起的误差谱的解析表达式。利用计算机模拟和统计平均的方法研究了近场幅相随机误差对超低副瓣天线平面近场测量结果的影响 ,并给出不同口径尺寸的超低副瓣天线的平面近场测量 ,为保证- 5 5 d B副瓣± 5 d B的测试精度 ,所能允许的近场幅相随机误差的最大起伏度     

一种高频电大尺寸天线测试的新方法

文章提出一种简单可行的高频电大尺寸天线辐射测量新方法.该方法基于天线形面光学精密测量,将形面分为多个区域,每个区域带入实际光学测试采样点数据,采用电磁场数值计算得到天线的辐射方向图.光学测试系统提供了足够高的测试精度可以满足微波、毫米波甚至太赫兹等频段天线的测试要求.该方法还可以解决超大型可展开天线测试以及模拟星载环境实验条件下天线辐射测试难题.     

一种用于蓝牙终端的小型天线设计

针对蓝牙天线发展的要求,结合目前天线小型化技术,在研究平面倒F天线(PIFA)的基础上,采用曲流技术对PIFA天线进行了小型化设计。与同类型的PIFA天线相比,在相同工作频率(f0=2.45 GHz)的条件下,设计天线的回波损耗S11<-50 dB,相对带宽提高了0.7%,达到了3.7%,同时有效地缩小了天线的尺寸(11 mm×9 mm×6 mm)。对天线进行加工并测试,回波损耗为-10 dB的带宽为120 MHz,各项指标均满足蓝牙技术需要。     

Miniaturized Antenna for Application of Bluetooth Terminal

针对蓝牙天线发展的要求,结合目前天线小型化技术,在研究平面倒F天线(PIFA)的基础上,采用曲流技术对PIFA天线进行了小型化设计.与同类型的PIFA天线相比,在相同工作频率(f0 =2.45 GHz)的条件下,设计天线的回波损耗S11＜-50 dB,相对带宽提高了0.7％,达到了3.7％,同时有效地缩小了天线的尺寸(11mm×9mm×6mm).对天线进行加工并测试,回波损耗为- 10 dB的带宽为120 MHz,各项指标均满足蓝牙技术需要.     

一种基于缝隙结构的小型双频段射频能量接收天线

随着超低功耗芯片技术的发展,无线传感器节点的功耗已进入微瓦（μW）级范围,使低功耗传感器利用周围环境中的射频无线能量为自身供电成为可能。提出了一种用于无线传感器节点的小型射频能量接收天线。该天线采用微带缝隙结构,基于缝隙天线设计理论,应用全波电磁场工具对其进行了设计及仿真优化,并获得了该结构谐振点随尺寸变化的一般规律。在常用FR4材料的小尺寸双面PCB板上,通过开槽加载和微带线馈电方法使天线可以同时工作在GSM和ISM两个频段。在1．9GHz和2．4CHz频率点上,天线的回波损耗分别为-39．4dB和-20．8dB,最大增益分别达到1．4dBi和2．9dBi,测试与仿真结果基本吻合。该天线含地平面在内的尺寸为5cm×5cm,实现成本低,可同时接收两个频段的射频能量,有效地扩展了频率适应范围,提高了能量接收效率。     

同相馈电十字振子圆极化天线的设计

通过对同相馈电十字振子圆极化天线的分析,提出了用振子等效长度缩短模型来定性,分析其实现圆极化的原理.同时利用时域有限差分法对十字振子天线进行仿真.并在2个波长长度范围内找到了实现圆极化的振子尺寸,在满足一定轴比带宽条件下,在垂直于十字振子平面通过十字振子中心的轴线上圆极化轴比可以达到1.166 8.分析了当大线尺寸改变时,圆极化特性的变化规律.为同相馈电十字振子圆极化天线的设计提供了参考.     

舰载平面相控阵天线安装倾角的设计方法

利用舰载惯性导航系统提供的姿态信息,对处于静态和动态姿态下的舰载平面相控阵天线的波束指向变换进行了分析,得到了平面相控阵天线的扫描角。在此基础上,以相控阵天线最大扫描角度最小为目标,给出了天线随舰载安装平台处于运动姿态条件时的安装倾角的设计方法。该方法能够在给定的舰船纵摇和横摇范围内,针对相控阵天线需求的空域扫描覆盖范围,实现对任意多面旋转布阵的平面相控阵天线安装倾角的计算。由该方法计算得到的天线安装倾角能够使平面相控阵天线有最小的最大扫描角,从而提高相控阵天线的电气性能。     

电场传感器校准的等效天线系数法

针对电场传感器在1 GHz以上频段高于200 V/m场强的校准需求,提出了等效天线系数法.该方法借用了天线系数的概念,在混响室中首先通过现有场强标准装置传递得到小场强时接收天线的等效天线系数,再利用等效天线系数对混响室中的大场强定标,从而实现电场传感器的大场强校准.混响室中采用等效天线系数法定标的大场强与采用统计方法计算得到的大场强相比较,场强偏差满足系统不确定度要求,说明了等效天线系数法的合理性.该方法借助混响室的特点和天线系数概念,将电场传感器校准幅度提升至200 V/m以上,为大场强测量的准确性提供了依据.     

平面相控阵天线极限扫描空域分析

基于平面相控阵天线单元间距由设定的扫描空域中不出现栅瓣条件确定，分析了在选定矩形栅格和三角形栅格的阵列单元间距后，平面相控阵天线的极限扫描空域，揭示了相控阵天线尚未被充分利用的扫描资源。     

一种减小相控阵天线球面近场测量截断误差的方法

在相控阵天线球面近场测量中,有限扫描面和相控阵天线波束扫描将会引起较大的截断误差.为了解决这一问题,提出利用基于遗传算法参数优化的余弦窗函数对近场数据进行加权处理的方法来有效减小截断误差.以半波振子组成的矩形平面阵作为待测天线,对相控阵天线球面近场测量进行了计算机模拟.模拟结果表明,通过对近场数据进行加余弦窗的处理并用遗传算法对参数进行优化能够大大减小相控阵天线波束扫描时的有限扫描面截断误差,从而证实了文中所提出方法的正确性和有效性.     

锥体共形相控阵天线的特性分析

基于电磁场理论推导了锥体共形相控阵天线的阵因子。与平面相控阵天线相比,锥体共形相控阵天线单元间的空 间相位差既与阵元的轴向位置有关,又与阵元的周向位置有关。因此,在进行锥体共形相控阵天线设计时,除采用二维相 控阵形式外,尽量避免采用一维相扫锥体共形相控阵天线。     

A sectored phased array for DBF applications

In this paper, we present the idea of using switching techniques in phased arrays in order to reduce the size and cost of the RF/IF circuitry on a smart array system with a given number of array elements. The principle is illustrated using a sectored phased array antenna working on the 5.2 GHz industrial, scientific and medical (ISM) band. The antenna is a four-element dipole array, with two active and two parasitic elements. The array uses a reflective 2P4T switch to route the RF signals to consecutive elements of the array and four pin diode SPST switches for short or open circuiting the antenna elements. The performance of the proposed antenna system surpasses the performance of traditional two-port phased array systems and is comparable to that of four-element planar arrays. Simulated results of the antenna performance and beam-forming capabilities are presented.     

一种圆形共形相控阵天线的设计与分析

矩形栅格平面相控阵天线经常受到圆柱形设备的约束,本文研究设计了一种阵元非均匀分布排列的圆形口径相控阵天线方向图,建立数学模型并对其进行了公式推导和计算机仿真。同时与同等规模的矩形栅格平面相控阵天线方向图进行对比分析。分析表明,前者的半功率点波束宽度要小于后者,主瓣能量利用更加集中,提高了扫描性能,辐射能量大致相同的情况下,前者所需要的阵元数要少,节约了成本。     

77 GHz汽车角雷达宽波束平坦增益阵列天线设计

设计了一款基于波束赋形技术的宽波束、平坦增益平面阵列天线,用于汽车角雷达系统.该阵列天线由三个1×10串馈线阵组成,串馈线阵采用单元不等间距分布的Dolph-Chebyshev天线综合法进行设计以降低副瓣.为了满足汽车角雷达宽视场角(field of view,FOV)的需求,对平面阵列天线采用波束赋形技术以展宽方位面...     

Optical techniques for reconfiguring microwave phased arrays

Very large phased array antennas, particularly in radar and adaptive receive applications as opposed to communications usages, require large amounts of digital data processing for beamsteering, null-formation, imaging, and signal correlation computations. Such processing requires a computational capability which is effectively proportional to the square of the antenna size, and can readily become one of the main design drivers. This processing bottleneck problem is addressed for large phased array antennas. An approach in terms of parallel processing in the optical domain is presented as a potential solution. The defining equations for a phased array antenna system are given, along with the transfer functions for an embedded optical spatial filter control element. Such a control element is shown to have the potential of rapidly reconfiguring a large phased array antenna without the speed penalties associated with conventional sequential addressing methods. A hypothetical phased array antenna, with optical spatial filter control elements, is simulated in a computer model and performance results are presented     

An affordable millimeter-wave beam-steerable antenna using interleaved planar subarrays

Design and fabrication aspects of an affordable planar beam steerable antenna array with a simple architecture are considered in this paper. Grouping the elements of a phased array into a number of partially overlapped subarrays and using a single phase shifter for each subarray, generally results in a considerable reduction in array size and manufacturing costs. However, overlapped subarrays require complicated corporate feed networks and array architectures that cannot be easily implemented using planar technologies. In this paper a novel feed network and array architecture for implementing a planar phased array of microstrip antennas is presented that enables the fabrication of low-sidelobe, compact, beam-steerable millimeter-wave arrays and facilitates integration of the RF front-end electronics with the antenna structure. This design uses a combination of series and parallel feeding schemes to achieve the desired array coefficients. The proposed approach is used to design a three-state switched-beam phased array with a scanning width of /spl plusmn/10/spl deg/. This phased array which is composed of 80 microstrip elements, achieves a gain of >20 dB, a sidelobe level of <-19 dB and a 10-dB bandwidth of >6.3% for all states of the beam. The antenna efficiency is measured at 33-36% in X band. It is shown that the proposed feeding scheme is insensitive to the mutual coupling among the elements.     

Predicted performance of magnetized semiconductor phase shifters for millimeter-wave microstrip array antennas

The tunable phase shift of a planar magnetized semiconductor phase shifter is presented, suitable for an integrated environment due to its miniature size, low-biasing requirements, and lower material related problems at millimeter-wave frequencies. A linear microstrip phased array antenna with an integrated semiconductor phase shifter is designed and the calculated beam steering properties are tabulated. The design process is verified by simulating similar ferrite-based linear phased array antennas.