微波黑体发射率计量标准装置的准光照射天线设计

微波黑体发射率计量标准装置拟通过双站测量的方式，获取微波黑体的电磁散射信息，进而基于基尔霍夫热平衡定律获取其发射率信息。在有限的测量空间和较高的测试频段条件下，需要对照射天线进行优化设计，以实现对微波黑体散射特征的有效测量。针对此应用，在毫米波和亚毫米波段基于准光学技术，开展了照射天线仿真设计工作。并结合装置实测场景，对准光照射天线的散射测量收发链路进行仿真，结果表明：通过准光天线设计，可以使得发射天线在目标区形成相位平坦，边缘衰减的照射场分布，可以降低收发天线-目标间的电磁能量传输衰减，同时近似测得目标的远场散射特性已便于反射率积分。综合而言，通过仿真分析，验证了微波黑体发射率计量标准装置中高频段收发天线的设计原理和应用价值，同时也对其它近场测试系统的研制和应用提供了参考。

Quasi-Optical Antennas Design in the Standard Measurement#br# Facility on the Emissivity from Microwave Calibration Targets

The aperture antenna design in the near field scattering measurement is addressed, for developing the standard measurement facility on the microwave emissivity of calibration targets.In this standard facility, the emissivity from calibration targets is to be obtained based on the Kirchhoff′s laws of thermal equilibrium, that means by obtaining electromagnetic scattering in a bi-static measurement configuration the electromagnetic reflectivity is inferred for determining the emissivity.Actually, to fulfill the task within a limited measurement space and in high frequency bands, the antennas to be used as transmitter and receiver have to be optimistically designed.The Quasi-Optic antennas are introduced for the scattering measurements of calibration targets.Furthermore, with help of commercial simulation software FEKO, the full-link simulations from the transmitter to targets then to the receiver are conducted for analysis.The results show that: by using antennas of Quasi-Optic design, the illumination at the target zone can be focused with an edge attenuation, also to be flat in phase distribution.As a result, the power transmitting attenuation can be greatly reduced, and it is allowed to approximately obtain the far-field scattering characteristics of the calibration targets which is very important to infer the reflectivity based on limited measured scattering. After all, the simulation results verified the design principle and application performance of the antenna designs for the standard facility of the microwave emissivity.Also the proposed design can be a reference for antenna designs in general near-field test system developments.