A Multi-Band Free Space Test System For Automatic Focal Length Calibration

This paper proposes a multi-band free-space test system with automatic focus calibration. The test system consists of two parts, one is the automatic focal length calibration system, which combines the laser distance sensor, the focal distance calculation formula and the computer, and finally realizes the automation of the test process of the free space test system by controlling the guide rail; the second is the multi-frequency band In the process of testing the electromagnetic parameters of materials, this paper divides the traditional 8-18GHz wide-band test into five small frequency bands, namely 8-10GHz, 10-12GHz, 12-14GHz, 14-16GHz, 16-18GHz multi-band test, and use the automatic focal length calibration system to adjust the focal length to the focal length of the center frequency of each sub-band in the test of each frequency band, and then perform data collection. The experimental results show that the final measured data is averaged and compared with the data obtained from the test regardless of frequency band, and it is concluded that the system can improve the accuracy of the electromagnetic parameter test of dielectric materials.