Design of a Feasible Miniaturized Bandgap Structure in the HF Band

Bandgap structures are applicable for High-Frequency (HF) radars to improve the propagationcharacteristics. The present paper demonstrates a stepwiseprocess to design a feasible bandgap structure at HFfrequencies. At these frequencies, Printed Circuit Board (PCB)materials are impractical for substrate due to large dimensionsof the structures. Thus, soil is replaced as it is the mostavailable dielectric material. The process begins with designinga mushroom-like structure at 10 MHz. Next, the effect ofremoving via on the resonance frequency and bandgap isinvestigated. Subsequently, the metallic patch is replaced by ametallic grid to ease implementation, relieve expenses andreduce RCS. Unfortunately, the metallic grid exhibits a higherresonance frequency and needs to be miniaturized to operate at10 MHz. Miniaturization reduces the width of grid to 75% andkeeps more than 70% of the bandgap. Compared with theconventional mushroom-like structure, the miniaturized gridstructure eases implementation, lowers expenses, downsizesdimensions, significantly reduces RCS and preserves 67% ofbandgap.

Design of a Feasible Miniaturized Bandgap Structure in the HF Band Keywords:

HF radars , bandgap structure , miniaturization , EBG