Search

The principle of the distributed magnetic sensor by magneto-impedance effect with time domain reflectometry was demonstrated, and the position and strength of the magnetic field were detected simultaneously with a magnetic coaxial cable. This paper presents a distributed magnetic sensor using the forward and reverse reflection coefficients S11 and S22 from both ends of a single magnetic coaxial cable. The method using reflection coefficients includes novel features such as: (1) improvement of the signal-noise ratio for equivalent measurement time and (2) cancellation of the time fluctuation by jitter. It is confirmed that the SNR of a reflected wave with a vector network analyzer is improved by 21.3 dB compared to that of an oscilloscope. Furthermore, the attenuation of a signal wave can be compensated by synthesizing the reflected waves from both ends. As a result, the signal wave is less affected by the attenuation along the length of the cable and is improved by 19.0 dB at the position of 180 mm.