Single-pole multi-throw switch device having simple structure

A switch device comprising:

• an input point;
• a first output point;
• a second output point;
• a first transmission line connecting the input point to the first output point;
• a second transmission line connecting the input point to the second output point;
• a switch unit connected to the first output point;
• and
• a third transmission line of which one end is connected to the switch unit and the other end is connected to the second output point,
• wherein the third transmission line causes a 90-degree phase shift when a signal at an operating frequency is delivered therethrough,
• the switch unit is controlled to be in an ON or OFF state according to one control signal,
• opens each of the first output point and the one end of the third transmission line when in the OFF state, and
• grounds each of the first output point and the one end of the third transmission line when in the ON state.