Abstract
In this paper, we apply the Double Negative Material in some basic applications, including waveguide, rectangular patch antenna and disc patch antenna. By analyzing theoretically we find that the sizes of these equipments can be greatly reduced by using multi-block (which may include both double positive and double negative material) dielectric materials. In addition, the sizes of patch antennas are no longer proportional to the working frequency but roughly to the ratio of the thicknesses of dielectric slabs. Still some new modes in both waveguide and patch antennas are found, and by working at the new modes the bandwidth of the patch antenna can be dramatically increased.