Nano-antennas are the optical equivalent of antennas that are used to transmit and receive information at radio frequencies. These antennas have been used in different applications in photonics such as optical imaging, particle manipulation, bio-sensing, and improvement of the performance of solar cells. In this article we study composite nano-antennas made of alternating layers of silica and gold. We show that a 50% filling factor leads to a 2.0 times increase in the electric-field enhancement factor when compared with a pure-gold antenna.