High frequency limiter

Abstract

In order to provide a high-frequency limiter capable of absorbing variation in characteristic parameters of a PIN diode to acquire a desired limiting characteristic, an external re-entrant coaxial cavity is constituted by an external pedestaland a cavityinside a lower conductor partand an upper conductor part, and an internal re-entrant coaxial cavity is constituted by an inner wall of the external pedestaland by an internal pedestaland a post. A PIN diodeis joined between the postand the internal pedestal. Resonance windowsandare provided between the resonator part and a waveguide connected thereto. A projected amount x of the external pedestalwith respect to the cavityand an insertion amount y of the postinto the external pedestalare adjustable independently. Further, a partitionis provided between each of the resonance partsandto form a coupling hole, and electromagnetic fields of the adjacent resonance partsandare made to be an even mode coupling, and thereby, the coupling holehas a low-pass characteristic. Thus, generation of unnecessary resonance mode can be suppressed and a band expansion of a cutoff characteristic can be realized.