| 摘要 |
PURPOSE:To widen the variable range of the degree of coupling by inserting a coupling loop from a coupling hole into a cavity while mounting said loop on the inward end of a coaxial line, and making the degree of the insertion of said loop variable by making use of the forward and backward movement or rotation of a flange. CONSTITUTION:A variable input coupling part 36 is provided on the first cavity (input cavity) 25 facing to a tuner 32, and a coupling hole 56 extending in the axial direction of the cavity is bored in the wall 50 of the cavity 25. And, a coupling loop 57 bent in approximately ? character-shape is arranged in the cavity 25 such that said loop passes in a non-contact manner through said coupling hole. An RF terminal 58, a coaxial line 58c, and a coupling loop 57 are fixed on a RF terminal mounting flange 60, and although the flange 60 is attached to the cavity wall 50 via a bellows 61 to keep its airtightness, it is movable prependicularly to a tube axis as shown by an arrow P. Accordingly, when the flange 60 is brought near to the tube axis, the effective area of the coupling loop 57 within the first cavity 25 becomes large, thus allowing the coupling to become large. On the contrary, when it is moved away from the tube axis, the coupling becomes small. |
