System and method of system

A system comprising:

• a first coupler having one end portion terminated and configured to receive a first signal input from another end portion;
• a second coupler configured to move in a direction in which the first coupler extends while maintaining a certain distance from the first coupler;
• a third coupler having one end portion terminated and configured to receive a second signal input from another end portion;
• a fourth coupler configured to move in a direction in which the third coupler extends while maintaining a certain distance from the third coupler;
• a detection unit configured to detect a phase difference between a signal output from the second coupler via the first coupler based on the first signal and a signal output from the fourth coupler via the third coupler based on the second signal;
• and
• a calculation unit configured to calculate a position based on information of the phase difference output from the detection unit.

A method of a system,

• the system including:
• a first coupler having one end portion terminated and configured to receive a first signal input from another end portion;
• and a second coupler configured to move in a direction in which the first coupler extends while maintaining a certain distance from the first coupler,
• the method comprising:
• receiving a second signal having a frequency same as a frequency of the first signal and transmitting a signal;
• receiving the transmitted signal;
• detecting a phase difference between a signal output from the second coupler and the signal received and output by the receiving;
• and
• calculating a position based on information of the detected phase difference.