Variable attenuator

A variable attenuator comprising:

• a first transmission line and a second transmission line having an electrical length of λ/4 corresponding to a wavelength λ of an input signal and coupled to each other;
• an input terminal provided at one end of the first transmission line;
• a through terminal provided at the other end of the first transmission line;
• a coupling terminal provided at one end of the second transmission line;
• an output terminal provided at the other end of the second transmission line;
• a first resistance element connected between the input terminal and a ground, includes a first transistor having a first control terminal,
• a second resistance element connected between the output terminal and the ground, includes a second transistor having a second control terminal,
• a third resistance element connected between the through terminal and the ground, includes a third transistor having a third control terminal, and
• a fourth resistance element connected between the coupling terminal and the ground, includes a fourth transistor having a fourth control terminal, wherein
• the first control terminal receives a first control signal,
• the second control terminal receives a second control signal,
• the third control terminal receives a third control signal, and
• the fourth control terminal receives a fourth control signal.