A Broadband CPW-to-Microstrip Modes Coupling Technique

A broadband vertical transition from coplanar waveguide (CPW)-to-microstrip modes is presented. The transition has a double resonance and can be tuned for very wide-band operation. The CPW-to-microstrip modes coupling technique is useful for the vertical integration of multi-layer millimeter-wave circuits, packaging and antenna feeding networks. A vertical transition has been fabricated on 100 m silicon substrate for operation at W-band frequencies and shows less than 0.3 dB of insertion loss and better than 12 dB of return loss from 75 to 110 GHz. A 94 GHz CPW-fed microstrip antenna showing a 10-dB bandwidth of about 30 % has been built using the same transition technique.     

超宽谱电磁脉冲辐射场测量系统

 介绍了一套自行研制的高功率超宽谱电磁脉冲辐射场测量系统，该系统主要由TEM喇叭接收天线、同轴传输线、宽带示波器及微型计算机组成。其中，TEM喇叭上极板为等腰三角形金属板，顶角14°，高60 cm，下极板为80 cm×30 cm矩形金属板，两金属板间夹角为7°，采用同轴线直接馈电方式，馈电点高度1 mm。分析了测量系统的基本理论，采用时域有限差分和离散傅里叶变换相结合的方法对TEM喇叭接收天线的传递函数进行了计算，建立了信号衰减补偿方法。实测了抛物反射面脉冲辐射天线的辐射场，测得主轴上远区辐射场主脉冲波形与辐射天线的激励信号近似成微分关系，当激励信号的前后沿变快时，测得的辐射场也相应增大。测量结果表明，该系统能够反映脉冲辐射场的变化特性，具有良好的波形保真性和宽频带特性。     

100MW重复频率超宽带脉冲辐射源的实验研究

 介绍了利用充氮气自击穿开关产生双极脉冲, 并通过同轴双锥天线辐射的实验研究。实验获得电压约±100kV, 脉冲宽度小于等于3.6ns, 工作频率单次、10Hz和100Hz的双极脉冲;同轴双锥天线带宽150MHz～1GHz, 峰值功率辐射效率达65%。     

一种新型的ECRF天线—Vlasov天线及其逆过程的实验研究

本文描述一种新颖的ECRF天线,简述了它的原理及所进行的实验。基于互逆性原理,首先利用Vlasov天线的逆过程获得了一个圆模式输出的测试用微波源。在此基础上,对该天线的正过程进行了实验与测试,得到了几乎完全线极化的天线辐射场分布。并将实验结果与理论结果进行了比较与分析。     

Phased array for millimeter wave frequencies

A phased array is presented at a frequency of 70 GHz, consisting of a corporate feed, ferrite phase shifters and dielectric rod antennas. Metal waveguides were utilized to construct the feed network, whereas a special dielectric waveguide structure was employed for the ferrite phase shifter and dielectric rod antenna. Beam scanning can be performed electronically controlled in the horizontal plane.     

35GHZ Patch Antenna Array Based on the Electromagnetic Band‐Gap Structure

The electromagnetic bandgap (EBG) structure, also called photonic bandgap structure, consisted by triangular arrays of air columns on the dielectric structure is designed and studied by using the FDTD method. According to the simulated and measured results, the EBG structure effectively suppressing surface wave for TE and TM modes is designed. The optimized EBG structure is presented.The proposed EBG structure is applied to the fourelement microstrip patch array antenna. As results of simulation and measurements, the impedance bandwidth and the gain of proposed EBG patch array antenna are improved.     

Electromagnetic crystals in microstrip technology

Recently, new promising periodic structures called photonic crystals (PCs), or more appropriately electromagnetic crystal (ECs), for the microwave and millimetre wave range, have been considered for both microwave and photonic applications. Planar microstrip waveguides are very attractive in microwave engineering and several innovative designs have been proposed for them to expand the scope of application of the new PC concepts to the microwave domain. We review some of these microstrip EC structures looking at them as counterparts of their analogues in optical wavelengths. Moreover, very recent solutions that open new promising applications both in microwave and millimetre wave integrated circuits and antennas are presented.     

HL—1M装置等离子体软X射线的锯齿和模行为

用高灵敏、高时空分辨的软Ｘ射线诊断系统，诊断ＨＬ－１Ｍ装置中等离子体的锯齿振荡。对观测到的四种主要锯齿作了介绍，对出现最多的有模经典锯齿和有模非经典锯齿作了详细描述和分析。结果表明，后者（主要在低ｑａ放电中出现）具有比前者低的中心ｑ（０）值，在物理机制上与前者不同，属湍流模型范畴。     

小型宽带短波对数周期天线的设计

利用对数周期天线（LPDA）设计的基本理论和电磁场数值方法，详细分析了LPDA各参数与电性能之间的关系．针对传统方法设计LPDA纵向长度大和频带超过10个倍频程后次激励区明显破坏其宽带性能的问题，采用增大LPDA张角的方法来缩短纵向长度，提出了两种抑制次激励区的方法。同时寻找最佳的结构参数优化LPDA的性能．结合工程实际要求设计了一副1．5～30MHz的大张角LPDA．计算机模拟结果表明；该天线在20：1的超宽频带内驻波比小、方向图不分裂，纵向长度比传统方法设计的LPDA缩短一半以上．     

Active Frequency-Tune Beam-Scanning Leaky-Wave Antenna Arrays

X-band active beam-scanning leaky-wave antenna arrays, including 1 × 1,1 × 2 and 1 × 4 prototypes, have been demonstrated. These antennas integrated one or several microstrip leaky-wave antenna elements with a single varactor-tuned HEMT VCO as an active source. Measured results on experimental antennas indicate that the beam scanning angle of the 1 × 1 antenna close to 40° can be achieved and the scanning range of 1 × 2 and 1 × 4 antenna arrays are both close to 32°. Furthermore, reflected wave due to the open end of each leaky-wave antenna element has been suppressed by the symmetric configuration of this antenna array and the antenna efficiency increases. When comparing with the measured radiation pattern of the single element antenna, we found that the 1 × 2 and 1 × 4 antenna arrays can effectively suppress the reflected power by more than 5.5 dB and 10.5 dB, respectively, at 10.2GHz. The power gain are more than 2 dB and 3.16 dB higher than the single element antenna with a measured EIRP of 18.67 dBm.