Phase inversion type variable attenuator

Abstract

Abstract PURPOSE:To control the attenuation of a microwave input, by forming a variable attenuator through the connection of a PIN diode between both output terminals of the 1st and 2nd 3dB directional coupler and ground and inserting it between the 3rd and 4th directional couplers. CONSTITUTION:A signal incident to the terminal 1 is equally divided into two signals having a phase difference of 90 deg. with each other, at a 3dB directional coupler 3, and they reach a coupler 4 via a variable attenuator 78 and a synthesized signal appears at a terminal 2. If the bias to a terminal 23 is zero, diodes 9, 10 are turned off and the attenuation is zero. In this case, when a bias current applied to a terminal 24 is increased from 0 gradually, a signal appeared on a terminal 16 is gradually decreased into opposite phase, and the phase of the terminal 2 is inphase to the input to a terminal 15, and an output is obtained, where the two signals are summed. When a current to a bais terminal 24 is zero and the current to a terminal 23 is charged, an output with entirely opposite phase can be obtained. Thus, the attenuation of input microwave signal can be varied with electric control, the output phase can be inverted and electric performance which is excellent can be obtained with small size.

Inventors

• 👤 Shoji Takayama

Bibliographic Details