SBIR-STTR Award

In order to obtain increased bandwidth, airborne satellite communication systems are planned for V/W band. The sufficiency of the half-wave solid designs, thin skin A-sandwich designs, and C-sandwich designs fails at V/W band, where the wave length decreases to nearly 0.125². The object of the Phase I effort for a V/W band airborne radome is twofold: first to determine wall designs that provide acceptable: transmission, cross polarization, stiffness, toughness, weight, and cost and second to fabricate sample coupons that demonstrate such wall designs are realizable with available materials . The thickness, stiffness, and bird strike resistance of the designs for V/W band radomes must be the maximum possible with an electrical thickness that is consistent with good transmission and low cross polarization. Flat panel model calculations are presented that improve the electrical performance of the half wave, quartz laminate skin A-sandwich which is hare defined to be the base line. The improved designs are denoted Multi-Layer #1, #2, and #3. These are described by flat panel transmission and cross polarization calculations, total thickness, areal weight ( PSF), and modulus-moment product (E×I) which characterizes stiffness. The objective is to provide an acceptable combination of electrical performance, stiffness, and weight.

Benefit:
The design strategy and the materials proposed for the V/W band radome design are applicable to all radomes that must operate at millimeter wave frequencies. Low dielectric, light weight, low cost materials become particularly important for the emerging millimeter wave, commercial aircraft and the more mature, military millimeter wave market. Formal acceptance of new materials for airborne applications (commercial and now probably military) for FAA structural certification requires extensive data, time, and cost. The structural data acquired by the proposed effort is directed toward that goal.

Keywords:
Airborne Radomes, V/W Band, Transmission, Cross Polarization, Stiffness.

The sufficiency of the half-wave solid designs, thin skin A-sandwich designs, and C-sandwich designs fails at V/W band, where the wave length decreases to 0.15². Wall designs suitable with acceptable transmission and cross polarization have been fabricated as flat panel construction sample panels and have been evaluated for 0° and 60° CP incidence for the Phase I effort. The best of these flat panel designs will be chosen for the radome fabrication effort of Phase II. The thickness, stiffness, and bird strike resistance of these designs must be the maximum possible while providing good circular polarization (CP) transmission and low cross polarization over the relatively wide range of incidence angles (0° to 65°) required for the streamlined shape typical of dorsal airborne radomes. The object of the Phase II effort is to design, fabricate, and measure a V/W band airborne radome in order to verify the electrical and structural performance predictions that will be completed as part of the design effort. Extension of the resin Vacuum Infusion Process (VIP) to fabricating the laminate portion of construction sample panels to radome laminate fabrication is also a significant feature of the proposed Phase II effort.

Benefit:
FAA certification (acceptance) of new materials for airborne applications (commercial and now probably military ) focuses on reliability and safety of flight, requiring either reference to or the creation of an extensive data base for structural coupons. The qualification of new materials for radomes which have no established FAA data base becomes time consuming and costly. Improved electrical performance is not an element of the FAA certification for safety of flight. The proposed Phase II effort provides an opportunity to acquire structural data for new materials that offer improved electrical performance. Innegra laminates also offer improved resistance to bird strike damag

Keywords:
Airborne Radomes, V/W Band, Transmission, Cross Polarization, Stiffness.