In this paper, a novel Radio Frequency Identification chipless tag for permittivity sensing characterized by a reduced size, an original shape and a low manufacturing cost is presented. The tag consists of a linear shape taken with multiple linear slots etched on the metal patch, ensuring a multi-frequency response. It enables the development of a robust tag with 8 bits as data capacity within a reduced surface is of 17.5×23 mm². Hence, using the frequency Domain Approach, the chipless tag is able to obtain more than 64 different binary states, by the utilization of the frequency shifting technique and the bandwidth distribution. Also, the operating frequency band ranges from 3.5 to 6.5 GHz. The new design is simulated, realized and experimentally validated by a bi-static measurement in the anechoic chamber. Then, preliminary tests are used for defining the Radio Frequency sensing chipless tag for permittivity monitoring, and proving its feasibility to control the evolution of a material over time or after use.