This paper proposed a new flexible and wearable antennas design based on teragon pre-fractal geometry until the third level, for monitoring high-temperature in humans for wireless body area network operating band. The antennas were built in polyamide laminate dielectric material, which has suitable thermal and mechanical resistance characteristics for application in wearable antennas. The antenna’s structure was generated by teragon pre-fractal geometry using a MATLAB code and simulated with commercial software ANSYS. The application of teragon geometry allows controlling the resonance frequencies and radiation characteristics in comparison to simple square geometry. Teragon level 3 has provided maximum resonance frequency reduction, about 142.4%. In comparison of simulated and measured results on-body we noted that variation of resonance frequency is directly proportional to the fractal level, with the increase of fractal level there is greater variation in the difference between the simulated and measured resonance frequency, close results of gain, and higher simulated SAR value of 0.0653 mW/kg (K = 2), being within standard indicated by international institutions such as FCC and IEEE.