一种三单元新型宽波束扫描电控无源阵列天线

通过电抗加载来控制方向图主瓣指向的天线称为电控无源阵列天线,简称ESPAR天线.提出了一种三单元H形缝隙耦合馈电贴片ESPAR相控阵天线,该天线通过分别改变加在两侧寄生辐射贴片馈电端的直流控制电压来改变相应的电抗加载值,从而使其实现宽波束扫描.给出了该天线的详细分析,以及电磁仿真结果,结果表明,该天线在H面上能实现-30°～30°的宽波束扫描.     

一种新型小型化宽带无人机机载智能天线研究

随着无人机系统的发展,无人机无线链路需要具有智能波束跟踪能力的小型化宽带高增益定向波束实现无线连接与组网。以电抗加载理论为基础,研究一款机载电控无源阵列天线(ESPAR),为了实现宽带效果,中心部位馈电的主振子以单锥天线作为激励,以寄生单元高度、单元间间距和加载电抗参量为优化参量,经过参数扫描、筛选和优化,给出了仿真结果,并进行了样机制作,给出了测试结果,实现了机载智能天线的小型化与宽带化。     

宽频带宽波束磁电偶极子天线设计

为了展宽天线的波束宽度,在磁电(ME)偶极子天线的基础上,该文设计出一种低交叉极化宽频带宽波束的新型磁电偶极子天线。通过将振子倾斜弯折,展宽了天线的波束宽度;结合6个寄生振子的对称加载,提高了辐射方向图的一致性。在型馈电结构基础上,优化天线的振子间距和振子长度,实现了天线58.5%的相对带宽(S11-10 dB),频带范围为2.3~4.2 GHz;对振子倾斜角度以及寄生振子的参数进行优化,在2.4~4.0 GHz的频带内实现了辐射方向图E面和H面同时达到120以上的半功率波束宽度(HPBW)。测试与仿真有较好的一致性,证明了所设计天线不仅具有宽频带宽波束特性,同时在整个频带范围内方向图的一致性得到了极大地提高。     

五元印刷单极子方向图可重构阵列天线*

设计制作了一种用于无线通信移动终端的方向图可重构阵列天线.该阵列天线由一个激励单极子和四个长度可调的寄生印刷单极子组成,可工作于两种模式,阵列波束在方位面内有八种不同的指向.通过控制PIN开关的状态,寄生单元可以在引向器和反射器之间切换状态,方向图的主瓣指向开关断开的阵元方向.阵列天线方向图可以以45°步长覆盖方位面,工作频带覆盖WiMAX (3.40-3.69GHz)频段,辐射增益大于6dBi.在两种模式中各选取了一个指向状态,对其回波损耗和方向图进行了实测,实测结果与仿真结果吻合较好.     

加载介质透镜的超宽带平面螺旋天线设计

针对乳腺癌检测、成像等医疗领域对天线高增益及宽频带的需求,研究设计了一款加载介质透镜的超宽带平面螺旋天线。该天线采用双臂平面阿基米德螺旋天线作为辐射单元,在辐射臂外围间隔一定距离处加载金属圆环以改善驻波性能,并由指数渐变式微带巴伦作为馈电结构。天线顶部加载介质透镜,底部设置金属圆台形反射背板,实现了调整波束形状和提高天线增益的目的。加装圆柱形天线罩后天线高度约为87.53 mm,直径约为46.50 mm。仿真结果显示,天线在3－12 GHz 工作频带内回波损耗小于-10 dB,辐射方向图呈现良好的定向辐射特性,实测结果与仿真结果基本一致。     

一种倾斜波束双极化天线

提出了一种具有倾斜波束辐射特性的新型双极化天线。该双极化天线由两个正交的纺锤形偶极子 组成,根据准八木天线原理,在偶极子两侧加载寄生振子作为反射器和引向器,用以实现倾斜波束辐射。这种纺锤 形偶极子可以增加电流长度从而减小天线的整体尺寸。同时在每个偶极子贴片上蚀刻两个梯形槽,以实现良好的 阻抗匹配。另外,通过连接到同轴线的金属短截线对纺锤形偶极子进行激励,简化了天线馈电结构。测试结果表 明,天线的阻抗带宽为3. 36~3. 69 GHz(S11 <-10 dB),两个极化端口之间的隔离度大于16 dB,波束倾斜度为30°,波 瓣宽度约为85°,可适用于单侧大角度扫描阵列。     

基于共面波导的全角度频率波束扫描天线

为满足平面集成系统、雷达等领域对宽角度频率波束扫描天线的需求,提出了一种低剖面、小型化、全角度频扫天线的设计方案.天线通过在共面波导上刻蚀周期性孔阵列,形成人工表面等离子体激元结构,利用其高次模辐射的特性产生频率扫描波束.通过在共面波导一侧金属地上刻蚀周期性的梳状结构,并由共面波导为其馈电,产生低频反向端射波.仿真结果表明,天线在9.1～53 GHz频带内平均增益为12.75 dBi,频率波束扫描范围为180°.由于矢量网络分析仪频率量程限制,实测结果在9.1～40 GHz与仿真结果具有较好的一致性.该天线具有加工易、剖面低、成本低、全角度扫描的特点,为平面集成系统、雷达等领域宽角度频扫天线提供了一种新的设计思路.     

一种用于5G MIMO 系统的宽带高增益圆极化天线

为提升5G无线通信系统容量,设计了一款基于V 形缝隙耦合馈电的宽带高增益圆极化天线。该天线采用双层辐射贴片结构,拓展天线的阻抗带宽,并分别在辐射贴片和寄生贴片上刻蚀一对半径不等、位置正交的双圆形缝隙,有效改善了天线的圆极化特性。通过加载平板反射器提高天线的前后比,实现良好的定向辐射。实测结果表明,驻波比小于2的阻抗带宽为53.55% (2.27~3.93 GHz),在半功率波束宽度范围内轴比小于3 dB,轴比带宽为27.38%(2.9~3.82 GHz),在工作频带内实测的天线平均增益达到8.22 dBi。该天线适合作为5G多天线系统中的智能天线单元进行自适应波束赋形。     

一种宽波束相控阵天线单元

对于宽角扫描相控阵天线,天线单元的宽波束特性是保证相控阵天线宽角扫描的前提条件。该文介绍了一种在E面和H面都具有宽波束特性的U形贴片相控阵天线单元。用腔模理论分析了该天线单元,并用HFSS8.0仿真软件对该天线单元进行了有效的优化。对加工的天线单元作了测试,结果显示测试值与仿真值吻合较好。实测波束宽度在E面和H面都达到110°,验证了该天线单元的宽波束特性,说明其适用于二维宽角扫描相控阵天线。     

手持终端波束成形天线阵列的优化设计

设计了一款适用于移动手持终端的低剖面波束成形天线阵列。该天线阵列由八个结构相同的倒F天线组成,可以工作在GSM1900(1880~1920 MHz)、LTE2300(2300~2400 MHz)和LTE2500(2540~2620 MHz)三个频段。通过功率传输效率最大化理论,可以优化出该阵列在所需方向上的最佳激励。通过馈电电路板给8个天线单元提供优化的激励,可以将天线波束偏转到所需方向,并且保证天线在该方向上获得最大可能增益。天线阵列工作在2.45 GHz时,在x、y、z方向上的增益分别为7.80、6.03和7.20 dBi;相应地,在1.9 GHz时分别为6.67、5.27和6.05 dBi。     

Direction-of-Arrival Estimation (DoA) Using Switched Parasitic Planar Arrays and the Method of Genetic Algorithms

An electronically controllable, switched parasitic planar array can be used for the purpose of direction finding. The method proposed in this paper exploits the electronic beam steering, achieved by simply inserting an appropriate digital word in the antenna feeding circuit, to resolve two signals. A genetic algorithm was used to determine the strengths and the angular positions of the incoming signals in the azimuth plane. The results obtained concentrate on wideband signaling in a multipath environment, with and without the presence of noise. The antenna design and the reliability of the direction-finding method are presented. The proposed method is strongly dependent on the type of the receiving antenna (a switched parasitic planar array is superior to a ``uniform' antenna with identical radiation patterns). Increasing the number of radiation patterns available improves the reliability of the method. The reliability of the method slightly deteriorates, as the angular discrimination of the incoming signals becomes smaller, but the results remain quite satisfying.     

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.     

A Two-Dimensional Optical True Time-Delay Beamformer Consisting of a Fiber Bragg Grating Prism and Switch-Based Fiber-Optic Delay Lines

A two-dimensional optical true time-delay (TTD) beamforming system for a planar phased array antenna (PAA) is proposed and demonstrated. The optical beamforming system consists of a fiber-Bragg-grating-prism-based wavelength-dependent TTD (WD-TTD) unit for azimuth beam steering and a microelectromechanical-system-switch-based wavelength-independent TTD (WI-TTD) unit for elevation beam steering. The time delays generated by the WD-TTD and WI-TTD are measured. The results show that the proposed system can achieve the required time delays with the time-delay errors for the WD-TTD and the WI-TTD at 1 GHz less than 11.8 and 3.6 ps, which correspond to radiation direction errors of less than 1.5deg and 0.4deg for a planar PAA with the adjacent array elements spaced by a half radio-frequency wavelength.     

差分馈电双极化四波束方向图可重构天线

提出了一种平面差分馈电双极化四波束方向图可重构天线. 该天线由两个相互正交的偶极子和四个带PIN二极管的寄生单元构成,有两个差分馈电端口,通过短截微带线给两个相互正交的偶极子馈电. 两个偶极子正交摆放、异面垂直,与寄生单元蚀刻在同一基板上,整体结构简单. 切换PIN二极管的不同状态得到四个波束的方向图可重构和两种方式的极化可重构. 实验表明,?10 dB阻抗带宽为8.9%,覆盖3.27～3.58 GHz频段,平均增益为5.6 dBi,前后比约为10 dB,平均辐射效率为68%. 该天线结构紧凑、成本低、易加工.     

基于开窗结构和寄生单元的双陷波超宽带天线

设计了一种具有双陷波特性的平面超宽带天线。超宽带基础天线的馈电采用渐变式阶梯阻抗匹配结构作,使得天线具有了宽阻抗匹配能力。通过在椭形辐射器内进行开窗,以及在地面添加矩形寄生单元,实现了天线的双陷波特性。测试结果表明,该天线的工作带宽(VSWR<2）为3.1~10 GHz,工作在超宽带(UWB)频率范围,两个陷波分别在3.3~4.0 GHz和5.0~5.85 GHz,可以应用于WiMAX和WLAN频段的信号抑制。仿真与实测结果表明,该天线结构简单、实现了良好的陷波功能,能够较好地应用于超宽带通信系统中。     

箭载共形相控阵天线波控系统设计分析

为完成适用于天基测控的箭载共形相控阵天线对波束指向控制的需求,分析了箭载天线波控系统的设计要求与任务,论述了平面相控阵天线波控系统的实现方法,并根据波控系统基本原理推导出基于阵因子函数的箭载共形相控阵天线波控算法。针对运载火箭天基测控这一新需求提出了基于查表法的集中式波控设计方案,给出了系统设计方法。样机测试结果表明,该波控系统方案正确、可行,满足工程需求。     

Planar antenna for directive beam steering at end-fire using an array of surface-wave launchers

A planar surface-wave antenna (SWA) that achieves radiation at end-fire by surface-wave (SW) excitation is presented for millimetre-wave frequencies of operation. The 2D SWA is fed by a two-element array of printed SW launchers for controlled beam steering in the far-field. Measured results demonstrate a highly directive beam pattern with a 3 dB beamwidth less than 5 at 22.71 GHz. Such a planar low-cost and low-profile SWA design may be advantageous for surveillance systems and radar applications where beam steering at end-fire is of interest.     

A Self-Steering Two-Dimensional Planar Array for Nonsinusoidal Waves

The principle of a one-dimensional self-steering array system for beam forming with nonsinusoidal waves has been developed previously. In this paper, an adaptive antenna system consisting of a two-dimensional planar array of sensor elements and a real-time adaptive receiver processor is described. The sensor elements of the planar array are arranged into rows and columns so that the steering commands for the azimuth ald elevation directions can be generated separately. The array system electronically steers a beam in the direction of the source from which the waves are arriving without prior knowledge of the source location.