Abstarct: Abstract This thesis aims to monitor human temperature using wearable sensors as a non-invasive and real-time method. Our purpose is baxsed on the use of textile sensors that can be integrated with the person’s clothes. The origin of antenna sensor measurement presented here is baxsed on changes in fabric relative permittivity related to variations in body temperature in the range from 35℃ to 41℃. The structures are such that a microstrip patch antenna and an aperture coupled antenna are implemented on the textile in the X frequency band. In the first step of designing the sensor, the measurement setup is designed to extract ε_r and tanδ characteristics of various commercial fabrics using a Keysight N1501A-101 high temperature dielectric probe. After examining a few samples of different fabrics in the setup, the commercial cashmere fabric with the highest changes in relative permittivity is selected to design the microstrip patch antenna. The rate of change in relative permittivity of this fabric is about 0.02 for a temperature step of 2℃. The antenna sensor provides a frequency shift of 60-80 MHz per temperature step in the X frequency band. The frequency shift per 1℃ is found to be about 35 MHz, which is acceptable and can provide good temperature detection. On the other hand, an aperture coupling structure baxsed on the properties of glass wool was also investigated separately. The rate of change in relative permittivity of glass wool is about 0.1 for a temperature step of 2℃. The measured frequency shift rate is about 60 MHz per 1℃, resulting from this structure. Given that fever is one of the main symptoms of many diseases and that its early detection can prevent endangering people’s lives, the proposed wearable sensor may find important applications in fever monitoring.