A Study of Proximity Sensor Circuit Focusing on Variations in Antenna Impedance

We are developing a radio wave sensing technology focusing on antenna impedance. Since this sensing method uses physical phenomena different from conventional sensing technology, it may be able to complement conventional sensors. In the studies, we investigated a sensing method that covers a range of less than several tens of centimeters by measuring the complex voltage reflectance and confirmed its validity by FDTD analysis. However, the sensor circuit for this method had not yet been developed. In this paper, a prototype sensing circuit corresponding to the proposed sensing method was fabricated and evaluated.