JPS54146561A - Hermetic high-frequency window - Google Patents

Abstract

PURPOSE:To minimize the loss of the microwave transmission by setting the difference of the radiuses between the dielectric disk and the circular waveguide with flange to the 1/2 integer-fold electric length of the active wavelength. CONSTITUTION:Metalized layer 6 and 7 are formed on both surfaces of the edge part as well as the circumference part of dielectric disk 4, and circular waveguide 8 and 9 containing flange 8a and 9a are soldered to layer 6 to secure the airtightness between output waveguide 1 and external waveguide 3. In such constitution, impedance Z when the outsides of flange 8a and 9a are viewed from the insides is affected greatly by the difference R2-R1, where R2 is the outer radius of disk 4 and R1 is the inner radius of waveguide 8 each, and the impedance becomes zero in the case of R2-R1 = nlambda/2 (lambda: active wavelength; n: positive integer). In this case, no abnormal oscillation nor break of airtightness takes place at the area enclosed by layer 6 and 7 owing to so-called the choke effect and in the same state as the short- circuit in terms of the high frequency.