JPS6472445A - Output circuit for magnetron - Google Patents

Abstract

PURPOSE:To secure such a fundamental mode oscillation that is stable in high output and low strain all the time by installing a Q-switch in a specific position of a transmission passage which should make the phase at the load side looking from a magnetron a reverse sink phase when it is in a band blocking state. CONSTITUTION:A transmission line 2 is connected to an interval between an output terminal 1a of a magnetron 1 and a terminal 3a of a circulator 3. A movable parallel stub 10 with a limiter diode 10a as a Q-switch is connected to a position 2a in a distance l from the terminal 1a in this line 2. The stub 10 consists of a T-type branch circuit 10b constituted of a branch path a 1/4 wavelength of guide wave length at a terminal short circuit and the liminter diode 10a parallelly connected to the position 2a. According to suchlike constitution, at the time of build-up in the oscillating initial stage of the magnetron, the Q switch is in an unconductive state, and since load looking from the magnetron is infinity, a fundamental mode becomes predominant over an unnecessary mode and thereby it oscillates first. Consequently, unnecessary mode oscillation at the build-up of the oscillating initial stage is checkable.