Integration of Millimeter-Wave Air Filled Cavities and Filters Using Vertically Aligned Carbon Nanotubes

This work is a step towards the 3D integration of millimeter-wave and THz circuits and subsystems with a nano-packaging technology using vertically aligned carbon nanotubes (VACNTs). In doing so, we have developed and optimized a fabrication process based on a low temperature transfer of VACNT, allowing to successfully implement millimeter-wave air filled cavities and filters towards 75 GHz. The circuits were designed and optimized using a finite element modeling tool. We particularly studied the impact of the VACNT density, which allowed to bridge the gap between device design and fabrication. The measured insertion loss values for the cavity and the filter are 3.78 dB and 4.38 dB, respectively. These experimental values obtained are in excellent agreement with the calculated ones, which paves the way for the 3D integration of more complex and higher frequency functions using this vertically aligned carbon nanotube technology.