Wireless Passive Ultrahigh Sensitivity LC Pressure Sensor Based on Ionic Dielectric Layer for Wearable Electronics

This study presents a highly sensitive wireless passive flexible pressure sensor. The sensor employs an ionic film as the dielectric layer, utilizes a spiral coil as the antenna for transmitting and receiving signals of the sensor, and adopts a sandwich process to complete the fabrication of the sensor. This study validates through circuit analysis and simulation that the sensor can be used for wireless passive detection of pressure information. First, the performance of the ionic film is examined. The sensor fabricated with the ionic film has high sensitivity (38.74 N-1), fast response time (100 ms), and high stability. This study also tests the wireless transmission performance between the sensor and the antenna. The test results indicate that the sensor can achieve wireless signal detection within a range of 13 mm. The pressure sensitivity of the sensor in the range of 0–0.5 N is 394.94 MHz/N. When the applied pressure increases from 0.5 to 10 N, the resonant frequency of the sensor decreases from 210 to 160 MHz, and the pressure sensitivity is 4.15 MHz/N. The sensor can realize palm bending detection, breathing, and voice recognition, and has extensive application prospects in the fields of human-computer interaction and wearables.