Concepts and design of zero-bias Schottky detectors for millimetre wave applications

This work demonstrates sensitive low-power detectors with optimized performance for very particular applications. Whether it is about minimum video noise, maximum responsivity, bandwidth or linearity, the final detector performance always relies on optimization on multiple design levels. Accurate models are developed for zero-bias Schottky diodes, with DC, RF, temperature and noise behaviour. The main investigated detector design aspects are the proper choice between available diodes for optimum SNR, based on accurate video noise prediction for millimetre wave detectors. The detector designs require either broadband impedance matching for the envisaged power level with high linearity for radiometry, an extremely large bandwidth with an attenuated dipole approach and investigations on the material level for broadband detection, or most accurate impedance matching to achieve a maximum sensitivity in a very compact design for wireless communication networks. A low noise 89GHz waveguide coupled detector module is demonstrated. It complies with very stringent performance criteria in direct detection radiometer chains for space applications and has entered a pre-qualification stage for space components for the European Space Agency (ESA). A broadband EMC sensor with multi decade bandwidth is designed with an extended frequency range from 1GHz to more than 100GHz with flat frequency response. The third detector is a prototype of a planar folded dipole antenna, realized with integrated complex impedance matching to the diode, for maximum sensitivity. Several results in this thesis are the best ever achieved in the field of millimetre wave detectors, or published for the first time. Each presented detector has outperformed available solutions and state-of-the-art results.