An inkjet biocompatible, flexible, and compact Radio-Frequency Identification (RFID) tag antenna is proposed and numerically analyzed. The proposed antenna operates into a UHF band, uses paper as a dielectric substrate, and conductive ink. This alternative offers a low-cost and battery-free RFID tag antenna, that is based on a combination of meander microstrip lines and capacitive elements, which help to obtain a compact size and match the impedance. The performance of the proposed tag was analyzed as a function of the conductive ink type and the curvature, and the results evidence that the RFID tag with copper ink offers better electrical behavior. The simulation results reveal that the antenna with copper ink operates at 915 MHz with a gain of 1.81 dBi, an omnidirectional pattern, and bandwidth of 23.47 MHz. Likewise, the flexibility test established that the electrical properties are preserved when the antenna is bent at different radii. Based on these results, the tag can be used in tracking, identification applications, and wireless sensors.