一种Ku波段混合馈电频扫天线阵设计

研制了一种俯仰向波束固定,方位向频扫的Ku波段频扫平面天线阵.采用双层微带结构获得带宽约18%的宽带微带贴片天线作为阵列单元.天线阵俯仰向采用微带功分器及该种天线单元组成线阵.方位向为实现波束较大范围的频扫能力, 并提高天线阵的工作效率采用波导慢波线缝隙与线阵微带线电磁耦合结构进行馈电.在采用HFSS软件完成仿真设计的基础上,加工并测试了一套12×40规模的天线阵,结果表明该天线阵在工作频段内驻波比优于1.5,波束扫描范围大于80, 副瓣电平优于-20 dB,除中心频点外,增益大于26.5 dB.     

天线与天线阵

0623134宽带印刷天线与双极化微带及波导缝隙天线阵= Broadband printed antennas and dual-polarized microstrip and waveguide slot antenna arrays[刊,英]/汪伟//上海大学学报(英文版)．—2006,10(3)．—282(E) 0623135宽带超低副瓣天线阵设计[刊,中]/孙绍国//电讯技术．—2006,46(3)．—87-92(G)描述了由16元线阵组成的L频段宽带超低副瓣天线阵的设计,给出了设计过程中所解决的各项关键技术及所采用的技术途径,以及一些设计数据和测试结果。天线近场测试表明,所研制的天线在优于25%频带内天线峰值副瓣电平低于-38dB,垂直面扫描30±°时,天线峰值副瓣电平低于-35dB。参6     

一种Ka频段波束可捷变的低副瓣波导缝隙天线阵的设计

在传统的波导缝隙天线阵的基础上,设计了一种波束可捷变的低副瓣波导缝隙天线阵。采用巧妙的布阵设计,通过对子阵、等功分不等功分器、和差网络的优化设计等,实现了高增益、低副瓣、波束可捷变等特性,并进行了容差分析。仿真结果表明,在35.75GHz±50MHz的频带内,窄波束增益≥34.7dB,窄波束副瓣≤-25.6dB,所设计的天线在宽、窄波束两种模式下均可获得较好的方向图特性。     

Ka 波段宽带正交模耦合器设计

提出了一种覆盖Ka 卫星通信全频段带宽的正交模耦合器设计,实现了相对带宽54%的突破。该正交模耦合器基于turnstile 十字转门型结构,结合后端弯波导、Y 型合成头和45毅扭波导设计,能够满足两路正交极化信号等相输出,设计使用频率内双端口S11 <-20 dB,端口隔离达到50 dB,交叉极化低于-50 dB,插入损耗优于0. 4 dB。     

一种双极化微带天线阵的设计

给出一种双极化微带天线阵的设计,分别对单元和馈电网络进行了研究.设计、测试了一个X波段的天线阵.测试结果,两种极化端口的阻抗带宽均大于14.6%(电压驻波比小于1.6),端口之间的隔离度优于34dB.水平极化端口的交叉极化电平抑制优于-26dB,垂直极化端口的交叉极化电平抑制优于-24dB.该天线可以作为合成孔径雷达有源相控阵天线的子阵.     

箱型光谱响应聚合物阵列波导光栅的研制

通过减少奇数阵列波导的芯宽度,同时增加偶数阵列波导的芯宽度的技术,构造了箱型光谱-选用氟化聚芳醚FPE聚合物材料,设计并制备了17×17信道箱型光谱响应阵列波导光栅(AWG)波分复用器.测试结果表明,器件的中心波长为1550.87nm,波长间隔为0.8nm,3dB带宽约为0.476nm,串扰低于-21dB,插入损耗为13～15dB.     

箱型光谱响应聚合物阵列波导光栅的研制

通过减少奇数阵列波导的芯宽度,同时增加偶数阵列波导的芯宽度的技术,构造了箱型光谱. 选用氟化聚芳醚FPE聚合物材料,设计并制备了17×17信道箱型光谱响应阵列波导光栅（AWG）波分复用器. 测试结果表明,器件的中心波长为1550.87nm,波长间隔为0.8nm, 3dB带宽约为0.476nm,串扰低于-21dB,插入损耗为13~15dB.     

1310nm大功率高偏振度量子阱超辐射发光二极管

设计并制备了一种斜条脊波导结构压应变高偏振度多量子阱超辐射发光二极管.设计的脊波导出光面TiO2/SiO2四层宽带增透膜的TE模式反射率约为10-6,分析了脊波导角度偏差和膜层厚度偏差对增透膜反射率的影响.实验结果表明,在250 mA直流电流驱动下,所设计的超辐射发光二极管芯片单管输出功率可达22.7 mW,出射光谱FWHM约为37.3 nm,光谱纹波系数低于0.15 dB,TE模式输出光强占主导,偏振度约为19.2 dB.     

宽频带膜片激励波导窄边非倾斜缝隙阵天线

文中提出一种新型宽频带低交叉极化的波导缝隙线阵设计，辐射单元是由波导内膜片激励的窄边非倾斜缝隙。线阵划分成多个子阵，并由功分器馈电。设计、加工了一个16单元X波段的均匀直线波导缝隙阵，测试得到7．2％阻抗带宽（VSWR≤1．5），天线辐射方向图最高副瓣电平低于-11．8dB，并且具有低于-39dB的交叉极化特性。     

聚合物热光可变光衰减器

提出一种旁路结构聚合物热光可变光衰减器(variable optical attenuator,VOA)的设计,采用旁路波导可提高衰减效率并降低串扰.软件模拟验证,无间距旁路VOA衰减可达28dB,比未加旁路波导的相同结构VOA增加10dB,但同时插入损耗增加0.3dB,串扰低于-44dB,理论功耗为40mW.采用倒脊形结构研制了原理性的热光聚合物VOA,测得衰减大于11dB,相应输入电流为66mA,具有明显的热光效应.     

An improvement of parasitic dipole array using suppressor elements

A novel configuration of parasitic arrays is introduced. The characteristics of the array in both forward and backward radiation are improved by using a new element, the suppressor. The suppressor elements are aligned parallel to a radiating dipole or to a conventional endfire array such as a Yagi-Uda array. Radiation in the unwanted direction is reduced by the suppressors, and the forward gain is effectively increased. Design of the optimum antenna parameters was achieved using the moment method, and results were compared to measured values, with good agreement obtained. New arrays were compared to well-designed Yagi-Uda arrays. A new array which is aligned with two broadside suppressors and with three endfire elements had an improved forward gain of 1.5 dB and a reduced backward gain of -4 dB compared to a conventional, well designed Yagi-Uda array with five endfire elements     

Nonuniformly spaced linear and planar array antennas for sidelobe reduction

The material discussed can be divided into two parts. In the first part, an iteration method is presented for calculating the distances between the elements of a symmetrical nonuniformly spaced linear array antenna for sidelobe reduction. The amplitude of the excitation is assumed to be constant. The iteration method is applied to linear array consisting of 24 elements. After a few iterations, the sidelobe-to-mainlobe power ratio was reduced to over 22 dB from its value of 13.2 dB for uniform array spacing. In the second part, several symmetrical nonuniformly spaced planar array antennas have been designed, using the nonuniform linear array spacings of part one. The planar arrays include square-shaped and circular structures, with the number of elements ranging from 284 to 576. The iteration method discussed can be applied to linear arrays with any number of elements to obtain nonuniform grid spacings for sidelobe reduction. A number of planar grid structures can be constructed using the nonuniform linear grids. The nonuniform linear and planar arrays utilize fewer radiating elements and result in desirable sidelobe structures.     

Low-cost X-polarised broadband PCS antenna with lowcross-polarisation level

A broadband personal communication system (PCS) antenna concept, based on a low cost stacked patch approach is presented. The manufactured single element shows an insertion loss bandwidth (-14 dB) of 15.9% and is dedicated to the established PCS 1800 system including the DECT frequencies. The base station array antenna, a 1×8 element column array, is fabricated using dual ±45° polarised single elements. Within the 13.9% bandwidth of the array (-14 dB) the measured level of cross-polarisation is below -16.5 dB over all angles in both principal planes     

高增益低副瓣X波段宽带圆极化Vivaldi天线阵设计

设计了一种新型的覆盖X波段的宽带圆极化2×2天线阵,具有高增益、低副瓣和良好的圆极化性能.该阵列以Vivaldi天线为基本单元,采用旋转对称的十字形结构,四端口等幅馈电且相位依次为0°,90°,180°和270°.此天线阵在整个X波段内阻抗匹配良好,轴比均低于3dB.采用矩形栅栏和底部扼流环结构将天线地板上的表面电流集中在槽线附近并降低后向辐射,从而获得低副瓣和高增益.频段内的峰值增益为10.7 dB,前后比大于20 dB.两个主平面的方向图对称性良好且基本重合.各天线单元间的低耦合使得天线阵的交叉极化很低.实物测试结果与仿真结果基本吻合.     

一种空气同轴馈电的X波段低副瓣阵列天线

设计了一种应用于雷达系统中的低成本低副瓣阵列天线, 该天线阵包含256个辐射单元, 由四个64单元的子阵组成, 采用波导合成网络进行功率合成.天线单元采用空气同轴馈电的角锥喇叭, 空气同轴馈线内外导体呈方型结构, 其终端为短路馈电方式, 实现了内导体的自支撑设计和较低的传输损耗, 并依据综合幅度分布采用若干数量的不等功分器进行低副瓣设计.测试结果表明, 小于2的驻波带宽为0.5 GHz, 相对带宽为7.5%.另外, 中心频率的增益为30 dB, 增益大于29.5 dB的带宽为0.2 GHz, E面和H面的旁瓣电平为28.5 dB和29 dB.     

A 7-25 MHz high-power ten-element electronically scanned array for ionospheric backscatter measurements

A ten-element array of log-periodic monopole antennas with a power gain of about 20 dB is described. The individual elements are designed for input continuous wave (or peak) powers of 200 kW and differ somewhat from previous monopole configurations. The array element spacing is adjusted so that when it is electronically scanned in synchronism with the associated receiving array all side and grating lobes of the two-way pattern are down at least 20 dB. Element, array, and ground screen designs are discussed, as well as the model array mutual coupling measurements, electronic scanning systems and the associated coaxial transmission lines.     

Parallel-series feed network with improved G/T performance for high-gain microstrip antenna arrays

A 16 x 8 microstrip antenna array with 28 dB of gain at 18 GHz using a parallel-series feed with reduced conductor traces is presented. The feed network connects antenna elements with about 50% reduction in conductor traces compared to conventional arrays with equal numbers of radiating elements. It also enhances the gain-bandwidth performance of the array and maintains a broadside radiation pattern in a wider frequency band. The full-wave simulation results are verified by means of measurements that demonstrate a relative gain-bandwidth of 4.4% with less than 1 dB of gain ripple.     

基于CVT 排布的非周期栅格密度加权阵设计

相比传统周期栅格密度加权阵,非周期排布密度加权阵有很多优点,但对非周期排布密度加权阵的设计方法却不完善。该文提出了一种利用质心Voronoi 图设计密度加权阵的新方法,这种方法可以按照预期幅度加权设计非周期排布的密度加权阵,得到的单元排布具有非周期性和匀称性的特点。作为例子分析了一个直径为32.8 的圆形阵,分别计算了按圆口径泰勒分布25 dB, 30 dB, 35 dB 和40 dB 副瓣设计的阵列方向图。相比已有文献中的计算结果,用该方法能获得更好的副瓣性能和口面效率。      

Metamaterial Insulator Enabled Superdirective Array

Metamaterial EM insulators are shown to suppress mutual coupling between densely packed array elements. This technique allows for array element design in isolation, without consideration of adjacent elements and mutual coupling effects. Suppressing mutual coupling allows for denser packing and enhanced directivity in antenna arrays approaching the superdirective theoretical maximums. Metamaterial isolation walls 0.05lambda₀ thick exhibit 20 dB peak isolations with 10 dB isolation bandwidths of 2-6% and very low losses. These insulators achieve lower than -30 dB coupling levels for 0.2lambda₀ periodicity arrays. A simulated 1.18lambda₀ five element broadside array exhibits a superdirective 65 degree first-null beamwidth with -9.5 dB side-lobes and when physically fabricated, experiment validates theory with a squinted 75 degree first-null beamwidth and only slight degradation of sidelobe levels. The main beam of the metamaterial insulated array is steerable over a full +/-90 degree horizon with little scan loss and no instances of scan blindness, a null can be placed to any angle including broadside, and as narrow as 25 degree peak-to-null separation is possible     

The peak sidelobe of the phased array having randomly located elements

A formula is derived for the peak sidelobe level of a phased array in which the elements are randomly located. The parameters of the formula are the number and size of the array elements, size of the array, wavelength, beamsteering angle, and signal bandwidth. The theory is tested by measurement of the peak sidelobe of several hundred computer-simulated random arrays. Unlike the case for the conventional array the effect of spatial taper (nonuniform density of element location) upon the peak sidelobe level is minor. The peak sidelobe of the two-dimensional planar array is approximately 3 dB higher than that of the linear array of the same length and same number of elements.