Validation of a functional principle for a broadband millimeter-wave power detection structure in a recent BiCMOS technology

In this paper, a functional principle for a broadband thermal detector suited for a monolithical integration is shown. Two tantalum load resistors are heated by an input signal, while the temperature at a fixed distance is recorded on chip with a differential temperature sensing bridge. An integrated differential to single-ended stage amplifies the bridges differential voltage and provides an output voltage proportional to the input power of the detector. The thermal resistance and capacitance between the load resistor and the sensing cell act as a low pass filter in the electrical regime. Based on this concept, a detector chip has been designed, which has been analyzed in thermal simulations. The realized detector has been characterized on-chip and bonded to a microwave substrate for a system performance estimation. Its input impedance is tuned to 50 Ohms and measured matching is better than -15 dB from 150MHz to 110 GHz. With a low supply voltage of 1.5V and its active area of around 80×36μm², the detector is suitable for an integrated power measurement solution.