COUPLED CAVITY SLOW WAVE CIRCUIT AND TUBE USING SAME

• US 3,668,459 A
• Filed: 09/08/1970
• Issued: 06/06/1972
• Est. Priority Date: 09/08/1970
• Status: Expired due to Term

• Current Assignee: Armand Staprans, Robert J. Butwell, Robert S. Symons
• Original Assignee: Armand Staprans, Robert J. Butwell, Robert S. Symons
• Inventors: Butwell, Robert J., Staprans, Armand, Symons, Robert S.
• Primary Examiner(s): Saalbach, Herman Karl
• Assistant Examiner(s): Chatmon, Jr., Saxfield
• Application Number:
  US05/070,173
• Time in Patent Office: 637 Days
• Field of Search: 315/3.5,3.6,39.3,5.41,5.42
• US Class Current: 315/3.5
• CPC Class Codes: H01J 23/24 Slow-wave structures , e.g. delay systems

Abstract

A coupled cavity slow wave circuit, such as a cloverleaf circuit, and a microwave tube using same are disclosed. The slow wave circuit includes an array of cavity resonators arranged successively along the beam path with adjacent ones of the cavities having a common end wall structure. A plurality of generally radially directed coupling slots are cut through the common wall between adjacent resonators to form a plurality of axially aligned arrays of coupling slots angularly displaced around the beam path. Each array of slots is angularly displaced about the beam path from the adjacent array by (360/N) degrees where N is the number of axially aligned arrays of slots. Each axially aligned array of coupling slots includes means for interrupting the flow of electrons through the slots such as a blocking member or the slots are staggered or offset in radial or angular position such as to block off a line-of-sight path parallel to the beam through at least a portion of each array of coupling slots to inhibit cumulative electromagnetic interaction between undesired beamlets in the arrays of slots and the fields of the slow wave circuit, whereby the efficiency and stability of the tube are increased.

Claims

1. In a tube employing a coupled cavity slow wave circuit, means for projecting a beam of electrons over an elongated beam path, slow wave circuit means disposed along the beam path in electromagnetic energy exchanging relation with the beam, said slow wave circuit means including an array of cavity resonators arranged successively along the beam path with adjacent ones of said cavity resonators having common end wall structures, said common end wall structures having a plurality of generally radially directed elongated open inductive coupling slots therein providing wave energy communication through said common end walls, said coupling slots being arranged in N angularly displaced arrays around the beam path, each array being angularly displaced by (360/N) degrees where N is an integral number greater than 2, THE IMPROVEMENT COMPRISING, means disposed intermediate the ends of said slow wave circuit for interrupting the flow of electrons along a secondary beam path parallel to the primary beam path through at least an inner radial portion of each of the arrays of coupling slots, whereby undesired beam paths through said coupling slots are blocked to inhibit cumulative electromagnetic interaction between undesired beamlets in said array of slots and fields of the slow wave circuit.

2. The apparatus of claim 1 wherein said means for interrupting the flow of electrons along a secondary beam path includes means for blocking a line-of-sight path parallel to the primary beam path through at least an inner radial portion of each of the arrays of coupling slots.

3. The apparatus of claim 2 wherein said beamlet blocking means comprises a successive radial displacement of the geometric centers of the coupling slots of each array along a path through each array of coupling slots for blocking a line-of-sight path parallel to the beam path through at least an inner radial portion of said slots.

4. The apparatus of claim 2 wherein said beamlet blocking means comprises a successive angular displacement of the geometric centers of the coupling slots of each array along the beam path through each array of slots for blocking a line-of-sight path parallel to the beam path through at least an inner radial portion of saiD slots of each array of slots.

5. The apparatus of claim 2 wherein said beamlet blocking means comprises an electron barrier structure disposed in a plurality of said cavity resonators for blocking a line-of-sight path for the electrons parallel to the beam path through at least an inner radial portion of said slots of each array of slots.

6. The apparatus of claim 5 wherein said electron barrier structure comprises an electrically conductive vane structure dimensioned to block off at least a portion of a line-of-sight path parallel to the beam path through one of said arrays of slots, said vane structure being disposed generally midway along the length of each of said cavity resonators.