A COAXIAL-WAVEGUIDE TYPE BROADBAND IMPATT OSCILLATOR

摘要

This invention relates to a coaxial-waveguide IMP ATT oscillator having a coaxial-waveguide cavity, an IMPATT diode adapted to be placed inside the said coaxial-waveguide cavity and tuning arrangement for maximizing the output power. The coaxial-waveguide cavity comprises a reduced height rectangular waveguide with iris in the bottom broad-wall of the waveguide with which the coaxial line is integrated by means of two coaxial spacers having central hole. A stepped impedance transformer is used to match the impedance of the reduced height waveguide of the coaxial-waveguide cavity with the full height waveguide delivering power to the load. The IMPATT diode is reverse biased with a power supply that feeds d.c. power to the diode through a bias-post. The designed coaxial-waveguide IMPATT oscillator is capable of generating millimetre-wave power of 1.0 Watt using GaAs IMPATT diode and operates at 34.25 GHz having a bandwidth of 20% of the operating frequency.