Radar device for detecting response signal

A radar device comprising:

• a signal producing unit for producing a question signal;
• an antenna for outputting the question signal produced in the signal producing unit and receiving both an echo of the question signal and a response signal sent from a search and rescue radar trans-ponder in response to the question signal;
• a filtering unit for receiving both the echo of the question signal and the response signal received in the antenna and suppressing intensity of components of both the echo of the question signal and the response signal placed in almost the same frequency band as that of the question signal to produce a filtered response signal;
• a circulator unit for sending the question signal produced in the signal producing unit to the antenna and sending both the echo of the question signal and the response signal received in the antenna to the filtering unit;
• and
• a signal receiving unit for receiving the filtered response signal produced in the filtering unit and extracting components of the filtered response signal placed in a receiving frequency band, which does not overlap with the frequency band of the question signal, from the filtered response signal to obtain an image signal.