Microwave power detectors

[摘要] The basic quantities of current and voltage are difficult to measure directly at microwave frequencies; therefore power becomes a crucial parameter. Design, operation and purchase of any RF or microwave equipment and measurement of microwave signals are enhanced by knowledge of the power [l]. So it is important to have accurate power-measuring standards at all frequencies. This thesis looks at the design of a waveguide bolometer that is suitable for a power detector. The bolometric method measures microwave power by using a resistance changing heat sensitive element that converts the power into heat and uses a bridge circuit to read out accurate resistance change, due to the absorbed power. Two heat sensing elements are modelled here; first an inductive metal post and secondly a thin film heat sensing element, both located at a specific position in a rectangular waveguide. The design parameters are determined by using analytical equations and transmission line theory. For both elements the design structure results validate the theory and show good power absorption at the center frequency of operation. The ultimate aim is to have a bolometer operating at the higher frequency bands; however in this thesis they are modelled at X-band (8.2-12.4 GHz).

[发布机构] University:University of Birmingham;Department:School of Engineering, Department of Electronic, Electrical and Systems Engineering

[关键词] T Technology;TK Electrical engineering. Electronics Nuclear engineering