DIODE LIMITER

PROBLEM TO BE SOLVED: To provide a compact diode limiter which a breakdown voltage. SOLUTION: A dielectric substrate 3 is held between two divided casings 1 and 2 which contain a waveguide 4, i.e., the substrate 3 crosses the waveguide 4. However, a through-hole is formed at the fringe of the waveguide 4 to secure the conduction between both sides of the substrate 3, so that the waveguide 4 becomes continuous at a part of the substrate 3 that is exposed to the waveguide 4 excluding a metallic pattern and a necessary transmission line. The metallic pattern is formed so as to make the transmission line formed on the substrate 3 function as a post of a waveguide type diode limiter at the opening face side and also function as a center conductor of a waveguide/ coaxial converter at the short-circuited face side. Two electrodes of a PIN diode 9 are connected to the transmission line and a ground pattern which function as the posts respectively. Then the reactance component of a control line is controlled via the stub cutting for the control of the reactance of the diode limiter that is done via a rotary screw.