Experimental verification of the effects of filler content on the quality factor of rubber antennas

Carbon black is a type of filler used in natural rubber to improve their mechanical and electronic properties. Previously, a preliminary study on the effects of filler content on the performance of flexible antennas through computer simulations has been reported by our group. In this paper, we continue the work by offering experimental data to support the simulations so that comprehensive understanding on the effects of filler content can be gained to meet practical requirements in the design of flexible antennas. Antennas of the same dimensions with carbon loadings varied from 10 % to 40 % were simulated and measured. CST Microwave Studio was used to simulate the antennas resonating at 2.45 GHz. Our study shows that the bandwidths for the antennas increased with filler content, while the resonance frequency can be tuned in the same manner. Since our measurement is in good agreement with the simulation, our studies proved that it is possible to control the antenna performance simply by adjusting the filler content of the substrate, without changing the antenna dimensions.