星载合成孔径雷达双极化天线阵研究

介绍了一种宽带双极化星载SAR有源相控阵天线阵,该天线以TR组件和双极化线阵组成的有源线阵为基础,并根据相控阵天线对雷达信号瞬时带宽的限制条件,选择合适的实时延迟子阵,结合结构安装的要求,构成电气独立的模块。在此基础上,根据雷达对天线孔径大小的需要,通过馈电网络激励拓展成大型有源相控阵天线,该天线可以通过波控灵活的控制和网络的合成,实现多极化、波束扫描、波束赋形和多通道等功能。其中对于双极化辐射天线,分别针对微带贴片天线阵和波导缝隙天线进行了分析和研究,并给出了实验验证结果。微带天线阵采用宽带的双层贴片辐射单元和并馈网络实现大带宽要求,两种正交极化模式分别由共面微带线和缝隙耦合来激励,其馈电网络居于开有耦合缝隙接地板的两侧,实现复杂网络空间安排和降低馈线耦合的功能。对于贴片单元的激励,采用对称、反相馈电和分组优化等方法,有效地提高了极化隔离度和极化纯度;而双极化波导缝隙阵中,以脊波导宽边纵缝谐振阵实现垂直极化,波导窄边非倾斜缝隙阵实现水平极化,在每种线阵中都通过分组馈电、过载技术和辐射/馈电波导一体化设计,实现了宽带和压缩横截面的目的。两种形式的天线阵比较,阵面剖面高度相当,微带阵具有宽带、轻质、易于加工和成本低等优势,而波导缝隙阵则具有高效、高隔离度和低交叉极化等性能,但是其缺点是结构复杂、加工难度大和重量大等。     

乐创-MPC2810高性能四轴运动控制器

特点： ·单轴／多轴独立运动、二／三／四轴线性插补运动、圆弧插补; ·提供立即运动和批处理运动两种运动模式; ·高速轨迹连续插补,速度平滑化处理;     

基于矩量法的小型化宽带线天线的仿真研究

研究了线天线的宽带化和小型化问题.针对目前通信技术的发展,各种电子设备均向小型化与微小型化方向发展,多频段和宽带跳频对带宽的需求,而常用的双极子天线由于带宽窄和物理尺寸大,无法满足天线小型化和宽带化的要求.提出了宽带匹配网络与加载相结合的方法设计了一种单极子加载天线,通过仿真详细分析了天线的电压驻波比和辐射特性,得出这种单极子加载线天线全面提高天线增益和降低电压驻波比的结果,经实验证明单极子加载天线基本满足小型宽带线天线要求.     

一种具有宽带双极化低散射特征的微带阵列天线

针对阵列天线宽带散射缩减设计进行研究,设计了一种基于无源对消技术的低散射阵列天线,该新型微带阵列天线在宽频带内具有双极化低雷达散射截面（RCS, Radar Cross Section）性能;对基于两种散射性能不同的单元组成阵列的RCS性能进行了理论研究,进行了单元的散射幅度和相位对阵列RCS的影响分析;提出了一种加载T型缝隙的新型微带天线结构,该单元结构的辐射性能与散射性能能够进行独立调控和综合优化,该单元与传统微带贴片单元具有相似的辐射特性,并可在宽频带（带内和带外）内与传统微带单元产生有效相位差;将传统微带单元和加载T型缝隙的新型微带单元组成4×4阵列天线,仿真结果表明,提出的阵列天线在3GHz～7GHz（相对带宽80%）频带内实现了同极化RCS缩减,在3.3GHz～7GHz（相对带宽71.8%）频带内实现了交叉极化RCS缩减,缩减峰值分别为16.3dB和36.3dB,带内RCS缩减均值分别为14.1dB 和17.6dB;与传统微带阵列天线相比,提出的阵列天线增益下降小于0.1dB;提出的微带阵列天线具有高效率辐射和宽频带双极化低散射性能,为低散射阵列天线设计提供了新的思路。     

Ku宽带正交模耦合器仿真设计

正交模耦合器(OMT)是实现天线馈源系统双极化工作的关键器件.为实现Ku宽带频率复用馈源网络,设计了一种宽带双脊OMT,由双脊波导、轴向阻抗变换器和功率合成器组成.用HFSS仿真设计了一个Ku全频段的OMT,工作带宽10.7GHz～ 14.5GHz,根据仿真优化后的尺寸,加工了实物样机,测试驻波小于1.16,隔离大于40dB,传输损耗小于0.15dB.结果表明,宽带双脊OMT具有频带宽、高性能的特点,能够满足需求.     

多媒体光电混合网络线

产品特色：·适合智能家居布线及光纤到户之用·配合三网融合的布线大趋势．以一或二根超五类局部区域网络电缆引入千兆位以太网·以FDDI技术等级多模或单模纤芯引入千兆位以太网．以一或二根同轴电缆引入公用天线电视、直播卫星、闭路电视和影像／话音等应用·易于处理,具弹性及可靠     

施迈赛－电磁安全锁TZM／TZF系列

特点： ·热塑外壳; ·手动、紧急开关或紧急; ·寿命长,机械寿命可达200万次; ·双绝缘; ·锁紧力达1500N;     

数字发现

±800千伏 6月18日,世界上第一个±800千伏直流输电工程、我国特高压直流输电示范项目——云南至广东±800千伏特高压直流输电工程顺利建成,实现双极投产。工程西起云南省楚雄彝族自治州,途经广西壮族自治区,东至广东省广州市,输电距离1373公里,额定电压±800千伏,额定容量500万千瓦。2006年,工程获得国家发改委核准,被确定为我国特高压直流输电自主化示范工程．并于同年12月19日开工建设。     

信捷电子-全新XCM系列运动控制型PLC

特点： ·运动控制专用PLC; ·直接在XCP Pro软件中调用控制代码; ·容量更大,处理速度更快; ·可扩展模块和BD板,支持MODBUS通讯。     

研华-Intel Celeron M嵌入式触屏平板电脑TPC-870H

特点： ·Celeron M低功耗处理器; ·8寸带触屏的TFT LCD显示器; ·TPC-870H的设计符合工业级的顶级要求,如构造紧凑,整机铝制外壳,无风扇系统和无转动零件的无轴承存储设计等,确保其在严苛工业环境下可靠耐用;     

A novel computational intelligence method for broadband dual-polarized base station antenna design

Broadband dual-polarized base station antenna requires wide impedance matching bandwidth, high-polarization isolation, stable radiation patterns, small gain variations, and high-cross polarization discrimination level. For antenna designers, it usually takes much computational time to design broadband base station antenna because there are extensive structural parameter analysis and multiple performance characteristics to be synthesized one by one. In this paper, a novel population-based computational intelligence optimization method is proposed for broadband base station antenna design. The proposed optimization method is based on self-adaptive weight vector strategy and could speedup searching through adjusting weight vectors and decreasing the number of full-time objective function evaluations. To verify its high efficiency of the proposed optimization method, a compact broadband dual-polarized base station antenna operating at 3.3–5.0 GHz is designed. From measurement results, it is observed that polarization isolation is higher than 27 dB, gain variation is smaller than 0.4 dB, and half-power beamwidth (HPBW) is within 65° ± 3°. In addition, XPD level is better than 24 dB at boresight direction and better than 13 dB within a sector of ±60°. Therefore, the designed antenna is promising for 5G broadband cellular base station applications.     

Novel single‐fed broadband circularly polarized antenna for GNSS applications

This letter presents the design of a broadband microstrip CP antenna using single‐fed technique. The feeding network is integrated within the coupling feed patch to simplify the structure. The proposed antenna is designed for Global Navigation satellite System (GNSS) operating at 1575.42 ± 10.23 MHz (GPS: L1 band), 1559～1592 MHz (Galileo: E2‐L1‐E1 band), 1602 ± 5.625 MHz (GLONASS: L1 band) and 1559.052～1591.788 MHz & 1610～1626.5 MHz (BeiDou Navigation Satellite System B1 and L band). Another advantage of this antenna is the much wider bandwidth in both VSWR and 3 dB axial‐ratio compared with traditional single‐fed CP antennas. Details of design, simulated and experimental results of this CP antenna are presented and discussed. The measured results confirm the validity of this design which meet the requirement of GNSS applications.     

Design and Analysis of Novel Antenna for Millimeter-Wave Communication

At present, the microwave frequency band bandwidth used for mobile communication is only 600 MHz. In 2020, the 5G mobile Communication required about 1 GHz of bandwidth, so people need to tap new spectrum resources to meet the development needs of mobile Internet traffic that will increase by 1,000 times in the next 10 years. Utilize the potentially large bandwidth (30∼300 GHz) of the millimeter wave frequency band to provide higher data rates is regarded as the potential development trend of the future wireless communication technology. A microstrip patch implementation approach based on electromagnetic coupling feeding is presented to increase the bandwidth of a dual-polarized millimeter-wave antenna. To extend the antenna unit's impedance bandwidth, coplanar parasitic patches and spatial parallel parasitic patches are used, and a 22 sub-array antenna is developed using paired inverse feed technology. The standing wave at the centre frequency of 37.5 GHz is less than 2 GHz. The antenna array's relative bandwidth is 6.13 percent, the isolation is >30 dB, the cross-polarization is −23.6 dB, and the gain is 11.5 dBi, according to the norm. The proposed dual-polarized microstrip antenna has the characteristics of wide frequency bandwidth, large port isolation, low cross-polarization, and high gain. The antenna performance meets the general engineering requirements of millimeter-wave dual-polarized antennas.     

Design of 4-element microstrip array of wideband reflector antenna with stable high gain characteristics

In this paper, three microstrip antennas with and without reflector are proposed with stable and high gain characteristics. The proposed antennas are simple to design and do not involve loading of any active elements on the patch or ground plane. The designed antennas cover the total frequency range of 10.5–44.5 GHz and operate well within the 5G communication frequency band of 27–30 GHz; consequently, making proposed antennas suitable for upcoming wireless technology. Furthermore, a 2 × 2 antenna array with phase diversity is proposed which offers an almost stable gain of about 14 dBi within the operating band. The proposed antennas are analyzed by finite element method based Ansys HFSS simulator. The fabricated prototypes of the optimized designs are made and simulated results are found in good agreement with the measured results.

     

蝶形天线的计算机仿真设计

蝶形天线是在脉冲型探地雷达中广泛采用的一种宽带天线。本文采用时域有限差分算法(FDTD)结合PML吸收边界条件分析了蝶形天线在高斯脉冲激励下的时域特性,通过傅立叶变换,计算出天线的方向图和在不同频率下的输入阻抗,结果表明FDTD算法用于分析蝶形天线是有效的。     

正方形嵌套分形多频印刷对称振子天线

设计了一类具有正方形嵌套结构的新型分形多频对称振子天线.振子由一系列相似的正方形单元嵌套组成.天线能够同时工作于多个频率,这些频率涵盖了WLAN系统所要求的2.4 GHz/5.2 GHz/5.8 GHz三个频率,采用三维电磁仿真软件CST MWS(R)软件进行了仿真研究,得到了平衡微带线馈电的对称振子天线的模型.制作了...     

A meta-surface loaded,low profile 28 GHz phased array antenna

A low-profile wide-scan phased array for 28 GHz 5G band operation, based on the current sheet array (CSA) concept, is presented in this work. The array is dual-polarized with horizontally and vertically polarized dipoles are placed in close proximity to leverage intentional capacitive coupling. A meta-surface based on fully split rings is printed on the top of the matching layer, contributing to wide-scan performance. A capacitive metallic plate is placed below the cross-section formed between orthogonal dipole elements to subdue the in-band coupled-loop modes. The design is demonstrated to operate at 26–30 GHz with voltage standing wave ratio (VSWR) <3 for ±60° scanning in principal planes, with a low-profile 0.26λ_h. The simulations are validated by measuring an 8 × 8 array prototype, which shows good agreement with the simulated predictions.     

Novel miniaturized multiband antenna and applications for smart navigation media

This article presents a novel low‐cost integrated multiband antenna design customized for navigation media applications. The distinctive feature of the design consists in using a broadband planar dipole with four arms and a miniaturized feeding‐point, easy to deploy inside the tracking devices, and cost‐effective for supply chain industry. The article first introduces the main challenges and the benefits of miniaturizing antennas for supply‐chain and particularly for navigation media system which is the case‐study. Further the parametric study and final dimensions of the design and the simulation results are discussed. The proposed design is fabricated and the measurements of the radiation pattern and the return loss are performed proving that the antenna with maximum gain up to 10 dBi and S₁₁ up to ?30 dB, exhibits excellent performance for all the frequencies required in the navigation media systems such as 1.6, 1.8, 2.3, 2.4, 2.6, 3.6, and 5.8 GHz. The proposed design was implemented and tested inside a tracking device mounted on a vehicle and compared with existing commercial antennas. This study showed that the proposed antenna is suitable for tracking devices as it is miniaturized for internal integration and it has better 4G and GPS signal detection and low power consumption comparatively with existing commercial antennas.