An investigation on the tuning of a microstrip patch antenna using carbon nanotube thin films

Carbon nanotubes (CNTs) have been considered for designing antennas, but their losses result in poor radiation efficiency, especially at microwave frequencies. However, their outstanding carrier mobility, large surface area per unit mass and adjustable surface chemistry make them ideal for functions such as reconfigurability and tuning. In this paper, we investigate the tunability of a patch antenna using a CNT thin film placed across a set of electrodes connected to the non-radiating edge. In a passive implementation, the surface impedance of the CNT film can be changed by altering its thickness. Through simulations, the effect of varying the surface impedance is parametrically examined to demonstrate about 500 MHz tunability in a patch antenna resonant at 6.6 GHz. Antenna losses are minimized by confining the CNT film to a small area outside the radiator.