A 4 GHz Near-Field Monitoring Planar Oscillator Sensor

Abstract

This work illustrates a negative resistance-based oscillator in microwave regime that is used as a non-contact sensing apparatus. The oscillator generates −0.28 dBm output power at 3.992 GHz that is used as a near-field monitoring device. A 4×6 mosaic pattern of dielectric slabs (2cm × 2cm each) is filled with various permittivity values ranging from 2.2 – 12.85. ±50 kHz resolution in recognizing the dielectric constant of the slabs in each row and column ensures a repeatable response when the sensor is 5mm away from the test surface.