In this configuration, a calibrated noise tube is used as a standard noise source to calibrate the system over the entire V-band before the actual noise measurement of the IMPATT source can begin.
This prototype is self contained and does not need an external power supply to generate noise at V-band, in contrast to a noise tube that requires a bulky and relatively expensive power supply to provide the high voltages necessary to start the gas discharge process.
The purpose of these investigations was to propose workable and stable IMPATT-loaded waveguide cavities at V-band to replace the existing high cost, relatively cumbersome gas discharge noise tubes.
As a result of these investigations, noise tubes to a large degree may be replaced by IMPATT-loaded RH-RH waveguide cavity mounts, with good stability of operation in time and temperature.
The current noise tube consists of an argon-filled glass tube that is positioned at an approximate angle of 10 [degrees] to the broad face of the waveguide.
Actually, such a solid-state noise source is expected to have several advantages over conventional noise sources, such as temperature-limited thermionic diodes or a gas discharge noise tube. These advantages, summarized in Table 1, make avalanche noise sources, such as IMPATT diodes, good noise sources for all applications with critical restrictions in size, weight, power consumption, reliability, output noise level and bandwidth.
In this configuration, a calibrated noise tube is used as a standard noise source to calibrate the system before the actual noise measurement of the IMPATT source can begin.
Such a solid-state noise source has shown to be superior to the state-of-the-art noise sources, such as a gas discharge noise tube. These advantages can be briefly summarized as higher noise output, higher reliability, lower power consumption, subns pulsed operation without the use of a modulator, smaller size and lower weight.
Nevertheless, no substantial work or result leading to the actual production of noise sources in lieu of gas discharge noise tubes in mm-wave regions has been reported.