Complementary Periodic Structures for Miniaturization of Planar Antennas

In this paper various layered planar periodic structures which provide miniaturization of planar antennas are proposed and discussed. The proposed designs are based on two concepts, reactive impedance surfaces and complementary periodic structures. In the proposed structures, complementary periodic rings and slots are patterned on the intermediate boundaries of the dielectric layers. A patch antenna is patterned on top of the first layer and the whole structure is grounded. The dielectric layers can be either similar or may have different dielectric constants and thicknesses. The dielectric constants and thicknesses of the layers can be chosen in a wide range of values. Two distinct configurations are studied simultaneously, namely, complementary circular rings and complementary square rings. The proposed designs provide a miniaturization factor in the range of 2.1-4.5 for planar antennas working in the frequency range of 2-22GHz. Parametric studies are provided to demonstrate high flexibility of the structures.