Uncooled radio frequency bolometer based on carbon nanotube thin films

Carbon nanotube thin films deposited on sapphire substrates have been used to realize a microwave power sensor that operates at and above room temperature. The detector includes a power-sensitive resistor that has been incorporated into a voltage divider circuit. Using lock-in detection, experiments were performed with 915 MHz test signals that showed detection down to -45 dBm. A sensitivity of 0.36mV/mW was achieved with the device held at a temperature of 15°C. Additional experiments (which included static and pulsed current versus voltage measurements) indicate that the primary physical mechanism responsible for power detection near room temperature is Joule heating.