Ka-band E-plane Beam Steering/Shaping Phased Array System Using Antipodal Elliptically-tapered Slot Antenna

In this letter, we present a Ka-band 8-element E-plane beam steering/shaping phased antenna array (PAA) using antipodal elliptically tapered slot antenna (AETSA). The power feeding network, phase shifter and antenna element were fabricated on a single low cost PCB substrate to avoid the extra loss caused by connection of different circuit pieces and for easier integration and easier fabrication. The system achieved wide scanning angle, which is from −21° to +24° and the 3 dB beamwidth is widened by 10°, the latter being the requirement for plasma imaging application.     

Fabrication of Refractive Microlens Array with no Dead Area

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Signal Level Simulation Modeling for Antenna Array of Aperture Synthesis Radiometer Based on the Equivalent Complex Baseband Representations

This paper presents a signal-level simulation model for simulating the process that antenna array of Aperture Synthesis Radiometer (ASR) collecting thermal radiation and transforming thermal radiation signal into radio frequency (RF) signal. By using the equivalent complex baseband signals to represent the practical thermal radiation and RF signals, simulation efficiency is improved significantly. The statistic characteristics of simulation results are found to match the corresponding theoretical analysis well. Results of an imaging simulation experiment show that this model can be employed in ASR system-level simulator design.     

考虑互耦的半波振子线阵辐射和散射方向图综合

对于半波振子阵列天线,可用感应电动势法算得其阻抗矩阵,依据等效电路原理计入单元间的互耦计算辐射场.将其推广至考虑互耦的散射场计算,基于此辐射场和散射场的计算公式,提出一种考虑互耦同时综合半波振子阵列天线辐射和散射方向图的新方法.运用粒子群优化算法,通过优化振子的间距,同时综合指定辐射和散射方向图.运用该方法,通过对中心工作频率处的辐射和散射特性以及在威胁角度给定频带内的散射特性优化,有效降低半波振子阵在中心工作频率处的辐射和散射方向图的副瓣电平,并减小其在威胁角度给定频带内的雷达散射截面.计算结果与FEKO仿真结果吻合良好,验证方法的正确性.     

双峰远场结构的激光二极管阵列光场传输特性

提出了一种描述激光二极管阵列(Laser Diode Array,LDA)双峰远场结构的光场新模型,该模型同时考虑了激光二极管阵列垂直于结平面大发散角的传输特性,基于亥姆霍兹方程的远场解,运用非傍轴光传输理论分析,得到描述激光二极管阵列远场光分布模型,其结果与实验测量结果吻合较好.     

Measurement of the Mutual Coherence Function of an Incoherent Infrared Field with a Gold Nano-wire Dipole Antenna Array

The first direct measurement of the mutual coherence function of a spatially incoherent infrared beam was performed at 10.6 μm using a pair of infrared dipole nano-wire antennas that were connected to a common bolometer in the center of the pair by short lengths of coplanar strip transmission line. A spatially incoherent source was constructed by dithering a BaF2 diffuser near the focus of a CO2 laser beam. The distance from the diffuser to the nano-wire antenna pair was held constant while the distance from the focus of the laser beam to the diffuser was varied to control the effective diameter of the source. The measured bolometer signal was proportional to the magnitude of the mutual coherence function at the plane of the antennas. The experimental results were found to match the predicted performance closely. If this technology can be extended to large arrays, a form of synthetic aperture optical imaging based on the Van Cittert-Zernike theorem is possible, similar to that performed at microwave frequencies now by astronomers. This has the potential to greatly increase the angular resolution attainable with optical instruments.     

精确控制大数值孔径微透镜列阵面形的显影阈值方法

提出了一种可对大矢高、非球面微透镜阵列面形进行精确控制的新方法。针对不同面形的微透镜阵列，该方法首先对光致抗蚀剂表面的曝光分布进行设计，然后，利用光致抗蚀剂显影过程中的阈值特性，对微透镜的面形实行控制。当抗蚀剂显影速率接近0时，即可获得设计的微透镜面形。该方法不仅大大提高了微透镜阵列矢高的加工范围，而且还减小了光刻材料显影特性对微透镜面形的影响，提高了微透镜阵列的面形控制精度，在实验中获得了矢高达114μm的微透镜阵列。最终实现了大浮雕深度、大数值孔径、非球面微列阵光学元件的面形控制。     

Beam Profile Improvement of a LD Array by an External Cavity with Photorefractive Phase Conjugate Mirror

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Talbot Images of an Array Source with Correlated Phase Fluctuation Using the Propagation Law of a Gaussian Beam

Talbot images of a two-dimensional array source such as a surface-emitting array laser are investigated with the help of the propagation law of a Gaussian beam. The effect of the phase fluctuation existing between the elements of the source on the formation of Talbot images is revealed by computer simulation. In the study, the correlation extent of the phase fluctuation is taken into consideration together with its magnitude (standard deviation), and Talbot images of good quality are found to be formed when the correlation extent is larger than the extent of the diffraction of a Gaussian beam in the observation plane. It is further shown that the contrast of Talbot images is governed, in a statistical sense, not by the magnitude of the phase itself but by the phase-fluctuation slope in the array source.     

采用单元进化限制策略的RWCE算法优化换热网络

针对强制进化随机游走算法（RWCE）优化换热网络时后期进化缓慢的不足,提出一种采用单元进化限制策略的改进RWCE算法（RS-RWCE）优化换热网络.通过限制每次迭代个体中参与进化的换热单元数,在保持进化前期年综合费用收敛速度较快的同时,保证进化后期的精细搜索能力.通过对两个经典算例的比较验证,证明改进后的算法应用于换热网络优化问题时兼顾了整型变量与连续变量的优化,使计算效率和精度均得到提高,同时获得了较好的换热网络优化结果.