Microwave propagation mode transformer

• US 4,636,689 A
• Filed: 03/14/1984
• Issued: 01/13/1987
• Est. Priority Date: 03/18/1983
• Status: Expired due to Fees

• Current Assignee: Thomson-CSF (Thales SA)
• Original Assignee: Thomson-CSF (Thales SA)
• Inventors: Mourier, Georges
• Primary Examiner(s): Chatmon, Saxfield
• Application Number:
  US06/589,565
• Time in Patent Office: 1,035 Days
• Field of Search: 315/3, 315/4, 315/5, 372/2, 372/99, 333/21 R, 333/21 A
• US Class Current: 315/4
• CPC Class Codes: H01J 23/027 Collectors
• CPC Class Codes: H01J 23/36 Coupling devices having distributed capacitance and inductance, structurally associated with the tube, for introducing or removing wave energy
• CPC Class Codes: H01J 25/02 Tubes with electron stream modulated in velocity or density in a modulator zone and thereafter giving up energy in an inducing zone, the zones being associated with one or more resonators

Abstract

This transformer (9) is formed by a waveguide, of approximately elliptical cross-section, and with increasing eccentricity (e) along the axis (z) of the transformer. This transformer (9) is connected on one side to the cavity (1) of a gyrotron (11) and on the other side to a section of guide (13) having the same cross-section as the final cross-section of the transformer and of which the cross-section is constant along the axis (z) of the transformer.

The transformer receives from the gyrotron cavity a complex mode, of TE_on type, and changes said mode into a mode in which the electrical field is approximately parallel to a given direction (z). A system of two mirrors (M₃ and M₄) enables a single beam of plane waves (19) to be obtained from the two beams of plane waves (14 and 15) obtained at the output of the section of waveguide (13).

Claims

1. A gyrotron which includes means forming an electron beam along a beam axis, a circular cavity into which the beam is projected for interacting with electromagnetic wave energy and creating oscillating wave energy in the cavity, an output wave guide essentially rectangular in cross section in which the electric field is parallel to the major wall of the guide, and an intermediate mode conversion means having one end coupled to the cavity and the other end coupled to the output wave guide comprising a transforming wave guide essentially elliptic in cross section whose eccentricity varies from about zero at said one end to about one at said other end and having a pair of mirrors oppositely disposed along the axis of the beam with openings therebetween, a pair of beam collectors oppositely disposed along the axis of beam at said openings, and means for directing the electron beam after it has traversed the cavity through said openings onto said collector means.

2. A gyrotron in accordance with claim 1 in which the radius of the circular cavity matches the minor axis of the transforming wave guide at its one end.