reflectarray, antenna, microstrip arrays
Reflectarrays are traditionally passive, planar microstrip antenna devices designed for reflected phase manipulation at each individual antenna element making up the array. By varying the phase response across the surface with the antenna elements, reflectarrays allows a planar surface to exhibit electromagnetically an arbitrary geometry, such as a spherical surface. Initially proposed as a low-cost replacement for bulky parabolic reflectors, reflectarrays have been successfully developed and utilized at both RF and millimeter-wave frequencies. From the standpoint of an optical systems designer, adapting low-frequency reflectarray technology to develop a sub-millimeter and infrared reflectarray (SMIR) would provide a highly desirable alternative to similarly behaved polished or diffractive optical devices. Compared to traditional optical reflectors, SMIRs should be cheaper to fabricate, have a smaller physical footprint, allow for utility stacking, and encourage direct integration of aberration correction. To demonstrate the feasibility of utilizing reflectarray technology at infrared (IR), a simple SMIR proof of concept has been successfully designed, fabricated, and tested. The SMIR is comprised of three independent arrays or "stripes" of a single size element on a coated optical flat. Actual reflectarray elements consist of variable size patches that exhibit higher operating bandwidths than reflectarrays utilizing other types of elements and are easier to fabricate at small dimensions. For testing, each stripe element has been chosen to exhibit a unique phase shift for measurement using an IR interferometer. Preliminary investigation of future reflectarray development is also discussed. Emphasis is placed on improving operating bandwidth, development of a planar focusing element, and aberration correction. With further development, SMIR technology should present a powerful tool for low cost, flexible optical system design.
Master of Science in Electrical Engineering (M.S.E.E.)
College of Engineering and Computer Science
Electrical and Computer Engineering
Length of Campus-only Access
Masters Thesis (Open Access)
Ginn, James, "Demonstrating Reflectarray Behavior At Infrared" (2006). Electronic Theses and Dissertations. 836.