An Archimedean spiral antenna with dielectric loading providing directional radiation patterns using a novel shape 3D printed ground structure

A spiral antenna is a radiation element that radiates a circularly polarized wave over a wide frequency bandwidth. It is commonly used in receiving application, where wideband antennas and circular polarization are needed, such as onboard a military platform. To avoid environmental hazards that may deteriorate an externally mounted antenna, this investigation evaluates the design and performance of an Archimedean spiral antenna intended for seamless integration into the armor of an existing platform. The effect of loading different materials on top of the radiating surface of the antenna and the effect of applying different conducting ground structures of various geometric configurations to the back of the antenna are modeled, determining the optimum performance for use in this application. The superstrate loading is necessary to protect the structure of the antenna and also to achieve miniaturization of the spiral antenna. Lack of a ground plane with a spiral antenna necessitates the use of a conducting grounding structure to minimize the back lobe and increase the gain of the spiral antenna on the main lobe. This study identifies an antenna design, superstrate material, and a 3D ground structure combination acceptable for potential military application.;The significance of light weight design for communication has increased tremendously, and hence weight reduction of antennas is a major consideration for seamless integration to existing systems. A novel 3D printed ground structure is designed to enhance the Right-Hand Circular Polarization (RHCP) gains and minimize the undesired radiation in the lower hemisphere of the spiral antenna without the loss of the antenna's broadband characteristics. Due to the high resolution and accuracy of the 3D printer, the printed design is able to achieve 90% weight reduction in comparison to the traditional Computerized Numerical Control (CNC) machining method.;The design and prototyping of a spiral antenna that can seamlessly integrate with current military platforms and Defense communication systems conducted under this research is a success. Based on simulated and measured results, the protective dielectric material loaded spiral antenna, backed by a conducting ground structure, is verified and validated as a capable antenna for use with this unique application.