COUPLED CAVITY SLOW WAVE CIRCUIT AND TUBE USING SAME

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.