Multifrequency-Coded RFID Microstrip Photosensor Based on ZnOAgCuS Nanocomposites

Radio frequency identification (RFID) is widely used in indoor lighting systems due to advantages, such as programmability, stability, and high detection accuracy. Herein, a multifrequency-coded RFID microstrip photosensor based on zinc oxide (ZnO)/silver (Ag)/copper sulfide (CuS) nanocomposites is designed; at the same time, it has the excellent photoelectric performance of ZnO and CuS, which enhances the response of the sensor to the light signal, and the high photoconductivity of Ag, enhances the RFID radio frequency signal, improves the reading distance and accuracy, and can be used to detect the light of four frequencies. A complementary open-loop resonator (CSRR) patch microstrip antenna was designed using high-frequency structure simulator (HFSS) software, and the structure of the photosensor was optimized. Three coding rings are designed by adjusting the length and width of the patch, so that the sensor can realize three-digit coding, and the actual antenna is prepared by sculpting technology. The nanorod-like ZnO, nanolinear Ag, and spherical CuS are prepared by a hydrothermal method, and their structures and morphologies are characterized by SEM, energy-dispersive X-ray spectrometry (EDS), XRD, TEM, and XPS. The amplitude of the antenna under the code “111” is −26.49 dB, and the detection performance is the best. The sensor made by drip coating can detect ambient light in the range of 2.833–2.928 GHz. For a light intensity of 0–53.9 klx, the response time of the photosensor is 17 s, the recovery time is 15 s, the response time of the resistance is 16 s, and the recovery time is 11 s, indicating that the ZnO/Ag/CuS nanocomposites have good responsiveness and recovery.