JPS56106402A - Variable attenuator - Google Patents

Abstract

PURPOSE:To obtain a variable attenuator that requires no special parts and can be produced through a simple working technique, by providing several fixed conductors or resistors plus a resistor whose degree of insertion can be varied from outside into a waveguide. CONSTITUTION:Several fixed conductors or resistors 3 plus the resistor 2 whose degree of insertion can be varied from outside are installed into the waveguide 1. For instance, two pieces of conductor bars (or resistors bars) 3 are fixed on the face E of the rectangular waveguide 1 with a space L of about 1/2 wavelength within the waveguide. The length and diameter (d) of the bar 3 are decided by the using frequency band and the band characteristics. At the same time, the screw 4 with the bar 2 attached at the tip is put into the face H at the center position of the two bars 3. The diameter D is decided by the using frequency band and the necessary maximum amount of attenuation. Then the amount of attenuation is controlled by varying the degree of insertion of the bar 2 into the waveguide, and the screw 4 is fixed at the necessary position with the lock nut 7.