亚毫米波对角喇叭天线的GA优化设计及其性能测试

Genetic algorithm design and measurement of sub-millimeter wave diagonal horn

应用遗传算法(GA)对工作于150GHz的亚毫米波对角喇叭天线的辐射特性进行优化,并对优化结果进行了实验测试.针对亚毫米波波段的特点,采用口径积分法(AI)分析天线特性并由此构成GA的适应度函数,通过与Johnsson测量值和Virginia Diodes Inc公司实际产品的增益参数相对比,检验了适应度函数的正确性.根据GA优化后的对角喇叭天线结构,制作了实验样品,利用俄制返波管(BWO)和热膨胀式太赫兹波功率探测器,在准光实验平台上测试了该优化结构的增益范围和E面方向图.实验结果与GA优化所期望的目标相符合,证实了该优化软件在准光辐射器设计与研制中的可靠性.实验方案为亚毫米波乃至太赫兹波段电磁器件的参数测试、性能评估提供了一种便捷、有效的途径.

The genetic algorithm（GA） is applied to the optimization of a sub-millimeter wave diagonal horn operating at 150GHz and the measurement is carried out to validate the performance of the optimized antenna.The fitness function is established by the aperture-integration（AI） method for its accuracy in sub-millimeter wave antenna analysis.The computations of AI are compared with the measured results provided by an available literature and the gains of diagonal horn products manufactured by Virginia Diodes Inc.,validating the correctness of the fitness function in GA.A diagonal horn is fabricated according to the GA-optimized horn＇s geometry and its radiation property is measured employing BWO（backward-wave oscillator） with a thermal-expansion-type terahertz detector.The possible variation range of the gain and the E-plane radiation pattern of the horn are measured by a set of quasi-optical instruments.The measured results conform to the prescribed objective of GA,verifying the reliability of the developed GA software which contributes to the quasi-optical radiators design and research.The measurement procedure presented in this paper provides a convenient and efficient scheme for the parameter testing or the performance prediction of components in sub-millimeter wave and terahertz engineering.