Efficient Luneberg Lens for Multi-frequency SATCOM Anttenna

A Luneberg lens is a sphere of low-loss dielectric material whose index of refraction varies along any radius in accord with Luneberg's equation. The lens is inherently wideband and is a candidate for multi-frequency aircraft SATCOM antennas. Thecontinuously varying index of refraction is often approximated by a series of concentric spherical shells of constant refractive indices. Difficulty has been encountered in achieving maximum gain performance at high microwave frequencies, believed due todifficulties with current multi-shell fabrication technology. Current fabrication material possesses a relatively low melting point, limiting transmitting power due to RF heating. Low dielectric, low loss syntactic foam composite materials and fabricationtechnology have been invented for multi-shell lens manufacture that overcome problems of lens non-homogeneity, between shell gaps, and low material melting point. Lens designs that maximize gain for an 8-inch diameter lens illuminated at 44GHz have beendeveloped utilizing lens modeling software using spherical wave functions and boundary value matching. A cost/benefit analysis was performed on these designs. Utilizing these designs, lenses will be fabricated, performance will be measured at 20, 30 and44GHz, and RF source power heating effects will be determined. Fabrication repeatability will be documented.