Variabel dämpare, sammansatt variabel dämpare samt en mobil kommunikationsapparat innefattande en variabel dämpare eller en sammansatt variabel dämpare

摘要

A compact variable attenuator, composite variable attenuator, and mobile communication apparatus capable of variably controlling attenuation continuously. The variable attenuator includes a first comb line comprising first and second lines which are electromagnetically coupled with a coupling coefficient M, a second comb line comprising third and fourth lines which are electromagnetically coupled with a coupling coefficient M, and first and second diodes connected to the third and fourth lines of the second comb line. A first terminal is connected to one end of the first line and a second terminal is connected to one end of the second line. The first and second diodes are connected between one end of each of the third and fourth lines and a ground with their anodes connected to one end of each of the third and fourth lines, respectively. First and second control terminals for turning the first and second diodes on and off are connected at the junction of other end of the first line and the other end of the third line and at the junction of the other end of the second line and the other end of the fourth line via resistors.