High-Q microwave resonator based on millions of nanotube cantilevers

When microwave signal frequencies are tuned close to the mechanical resonant frequency of an array of metallic cantilevered carbon nanotubes, the array sandwiched between two coplanar waveguide lines shows a notch in the transmission coefficient of the microwave signal due to a metal-lossy dielectric transition of the carbon nanotube array at the mechanical resonant frequency of the cantilever. As a result, the nanotube acts like a resonator. We have demonstrated that the quality factor of such an array of millions of nanotube cantilevers displays a quality factor of 800 at room temperature at the fundamental resonance frequency of 1.4 GHz.