This article presents a wide-range soft anisotropic thermistor with a direct wireless radio frequency (RF) interface. The thermistor is based on a flexible and stretchable composite of short carbon fiber (CF) incorporated into polydimethylsiloxane (PDMS), enabling a large-area processing. The RF sensing interface overcomes the decades-old sensing range limitation of traditional thermistors. The composite exhibits a high resistance sensitivity over 1000°C⁻¹, with stability against bending (20,000 cycles) and stretching (1000 cycles). The anisotropic composite is used as a substrate for sub-6 GHz RF components, where the thermistor-based microwave resonators achieve a wide temperature sensing range (30–205°C) and high sensitivity (3.2 MHz/°C) compared to other flexible and RF temperature sensors. Wireless sensing is demonstrated using a microstrip patch antenna based on the thermistor substrate and a battery-less RF identification tag. The RF-based sensor readout technique enables direct integration of functional materials in wireless sensing applications. The thermistor composite is designed for RF sensing, with a temperature-modulated absorption of RF waves. The PTC thermistor acts as a temperature-modulated dielectric loss term, reducing the radiated power. The composite's resistance changes with temperature, allowing for a wide temperature sensing range and high sensitivity. The thermistor's response is measured using a microstrip patch antenna and a RF identification tag, demonstrating a wide dynamic range and high sensitivity. The thermistor's resistance is also measured using a DC readout, showing a high TCR (Temperature Coefficient of Resistance) and stability against bending and stretching. The RF sensing approach enables a direct wireless readout, with the thermistor-based resonators achieving a high sensitivity and wide dynamic range. The thermistor is also used in a wireless RFID tag, demonstrating a battery-less wireless readout. The thermistor's performance is compared to other flexible and RF temperature sensors, showing a significant improvement in sensitivity and dynamic range. The article concludes that the proposed thermistor composite enables a direct wireless interface with the sensor, demonstrating a significant improvement in RF sensing capabilities.This article presents a wide-range soft anisotropic thermistor with a direct wireless radio frequency (RF) interface. The thermistor is based on a flexible and stretchable composite of short carbon fiber (CF) incorporated into polydimethylsiloxane (PDMS), enabling a large-area processing. The RF sensing interface overcomes the decades-old sensing range limitation of traditional thermistors. The composite exhibits a high resistance sensitivity over 1000°C⁻¹, with stability against bending (20,000 cycles) and stretching (1000 cycles). The anisotropic composite is used as a substrate for sub-6 GHz RF components, where the thermistor-based microwave resonators achieve a wide temperature sensing range (30–205°C) and high sensitivity (3.2 MHz/°C) compared to other flexible and RF temperature sensors. Wireless sensing is demonstrated using a microstrip patch antenna based on the thermistor substrate and a battery-less RF identification tag. The RF-based sensor readout technique enables direct integration of functional materials in wireless sensing applications. The thermistor composite is designed for RF sensing, with a temperature-modulated absorption of RF waves. The PTC thermistor acts as a temperature-modulated dielectric loss term, reducing the radiated power. The composite's resistance changes with temperature, allowing for a wide temperature sensing range and high sensitivity. The thermistor's response is measured using a microstrip patch antenna and a RF identification tag, demonstrating a wide dynamic range and high sensitivity. The thermistor's resistance is also measured using a DC readout, showing a high TCR (Temperature Coefficient of Resistance) and stability against bending and stretching. The RF sensing approach enables a direct wireless readout, with the thermistor-based resonators achieving a high sensitivity and wide dynamic range. The thermistor is also used in a wireless RFID tag, demonstrating a battery-less wireless readout. The thermistor's performance is compared to other flexible and RF temperature sensors, showing a significant improvement in sensitivity and dynamic range. The article concludes that the proposed thermistor composite enables a direct wireless interface with the sensor, demonstrating a significant improvement in RF sensing capabilities.