Design Study.
Abstract
This study shows that AM-PM conversion can be obtained over a wide instantaneous bandwidth by using a broadband circuit with the proper dispersion characteristics. Circuits having the prescribed characteristics have been used for several years in high power coupled cavity tubes at Litton Industries. The circuits were not developed to provide low AM-PM but to provide high power operation over wide bandwidths. The low AM-PM characteristics are an additional attribute discovered quite accidentally. This study shows why tubes using these circuits have the low AM-PM conversion demonstrated. Although the study utilized an X-band circuit (7.0 to 11.0 GHz) the results are applicable in other frequency bands. The circuit can be scaled directly so that the values of phase velocity and impedance are the same. The loss parameter, which increases at higher frequencies due to skin effect losses, can be decreased by choosing a solenoid design utilizes an all OFHC copper circuit to minimize losses. The study shows how the tube parameters b, QC, and d affect AM-PM conversion. An understanding of the effects of these parameters is essential in designing low AM-PM tubes.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 15, 1978
- Accession Number
- ADA074437