A Free-formed EBG resonator antenna at millimeter wave frequencies

Abstract

Electromagnetic bandgap structures (EBG) finds increasing number of applications in antennas and microwave devices. In this paper, we present an EBG resonator antenna based on woodpile structure at millimeter frequency. The dispersion characteristics of the woodpile structures have been analyzed using 3D FDTD codes with a periodic boundary condition (PBC). An annular slot antenna is used as the radiating element at 93GHz. For the construction of the woodpile structure, we use alumina rods (ε r = 9.6) with 0.4mm diameter. A new method is employed for the fabrication of the woodpile using extrusion freeforming technique. The freeforming technique is very useful to construct complicated 3D structures. The designed EBG antenna shows improved directivities. At 93GHz, directivity of 18dBi has been achieved, which is approximately 11dB improvement for the original antenna.