Design of a sensor for measuring average power in the frequency band 110 GHz – 170 GHz

Measuring the average power of high-frequency electrical signals is essential in a number of major fields, including civil security, the military and industry in general. This thesis is dedicated to designing and realization of a sensor for average power measurement, ensuring SI traceability in the D-band frequency range between 110 GHz and 170 GHz. The calibration of a transfer power sensor against a primary standard allows the determination of two parameters: its efficiency and its calibration factor, which depend on the efficiency and the return loss of the power sensor.

The thermoelectric power sensor developed through numerical simulations using CST Studio Suite software, consists of three parts: the high-frequency part (HF), the thermal part, and the direct current part. The high-frequency part is made up of a rectangular waveguide and a transition between the waveguide and a coplanar line ending in a resistive load. The thermal part includes a series of thermocouples intended to measure the heating of the load. The DC part allows for power transposition between HF and DC to determine the HF power.

The results obtained showed a return loss lower than -15 dB, an efficiency greater than 0.8, and a sensitivity between 0.08 and 0.09 mV/mW for the sensor. These results are very encouraging and demonstrate a successful sensor design. We fabricated the sensor housing, manufactured the chip, and constructed the measurement circuit. We also prepared the assembly of the components in the sensor housing and installed the required connectors for sensor’s calibration in preparation for its subsequent characterization.

D band, efficiency, electromagnetic and thermal simulations, metrology, return loss, sensitivity, thermoelectric power sensor

Full document (FR) : TEL-04935745