A vector field measurement system for 150 GHz

The paper describes the design and realization of a heterodyne vector field measurement system. The system is designed to work in a frequency range from 148 GHz to 152 GHz with a dynamic range of about 75 dB and a phase uncertainty better than 3 degrees. It uses two channels for the measurement of the magnitude as well as the phase characteristics of an electromagnetic field. Two fundamental mixers at 150 GHz have been installed, which are both pumped by a 150 GHz phase locked solid-state oscillator unit. The system can be extended to the 300 GHz and 450 GHz frequency range by replacing these mixers by subharmonically pumped mixers. The mixers and two dielectric antennas, used as distortion minimized field probes, are mounted on a high precision 3D scanning platform. At the IF frequency of 160 MHz the vector analysis of the measured signals is done by an IF processing unit with considerably enhanced measurement accuracy by software corrections with a personal computer.