On the Use of Dielectric Honeycomb as Microwave Substrate for 3D Long Range Radar Antennas

Dielectric honeycomb structures are a suitable substrate for microwave applications since their dielectric constant and losses are low and when laminated they offer excellent mechanical properties and light weight. This paper studies the electrical properties of dielectric honeycomb structures composed of various materials for large antenna distribution networks. Glass fiber honeycomb with polyimide resin is shown to have very low losses although they are higher than that of a closed cell polyethylene foam material. Additionally, the honeycomb material is shown to be anisotropic in the two axes containing the honeycomb cells, which can complicate the distribution network design and manufacturing. Finally, the adhesive placed near the Cu track needed to build the laminated structure is shown to increase the losses, while the adhesive near the ground is not critical in this regard.