Clogging determination device

A clogging determination device comprising:

• a first antenna disposed at one of a side of a first end and a side of a second end of a filter disposed internally of a case which serves as a flow path for an exhaust gas;
• a second antenna disposed at the other of the side of the first end and the side of the second end of the filter;
• a multi-tone signal generator that has an output terminal coupled to the first antenna, outputs from the output terminal a multi-tone signal obtained by compositing a plurality of signals having different frequencies, and moves a position of an envelope of the multi-tone signal emitted to the filter from the first antenna, in a direction of the flow path in the filter by changing a phase or a frequency of at least one of the plurality of signals;
• a detector that is coupled to the second antenna, and detects an intensity of the multi-tone signal received by the second antenna;
• and
• a determinator that determines a degree of clogging of the filter based on an intensity of the multi-tone signal outputted from the first antenna and the intensity of the multi-tone signal detected by the detector.