The Experimental Comparison of Under-Panel-Sensing (UPS) Using FMCW Radar Sensor

Abstract

According to the trend of full displays on phones and TVs. The camera and fingerprints are shifted from the trimmed display panel or wider edges to the underside of the display. However, no attempt has been made to use radar for interaction sensing under the panel. In this paper, we present a comparison of the under-panel-sensing (UPS) and normal sensing (without panel) using frequency modulation continuous wave (FMCW) radar. In our experiments, we compare the range estimation, Doppler, and direction of arrival (DOA) distortion due to refraction and diffraction as the radio frequency (RF) signal penetrates the liquid crystal panel and glass. The signal-to-noise ratio shows no significant difference in the range estimation for the five different colors of liquid crystal display (LCD). However, the amplitude is reduced by about 6 dB compared to the measurement without LCD. The Doppler frequency is almost same even the LCD is installed. The DOA results show that there is a noise component in range-azimuth map at the specific angle along the distance, and by removing the DC component, the DOA information of the moving target can be extracted.