The Effect of Boundary Support and Refl ector Dimensions on Infl atable Parabolic Antenna Performance
نویسندگان
چکیده
Nomenclature A Aperture area of the antenna (square meters) D Diameter of antenna aperture (meters) Ef Gravitational potential energy due to film (Joules) Ep Hydrostatic pressure potential energy (Joules) ET Total energy of the inflatable reflector system (Joules) F Focal length of antenna (meters) G Effective antenna gain GI Ideal antenna gain g Acceleration due to gravity (meters per square second) Kt,m Tendon stiffness constant in the m th supporting tendon (Newtons) S f Relaxed film strain energy (Joules) S t Relaxed tendon strain energy (Joules) N Number of triangular elements in the upper and lower shells Nf Number of triangular elements in the lower shell Nt Number of supporting tendons p0 Constant differential pressure (Pascals) W ∗ f Relaxed film strain energy density (Joules per square meter) W ∗ t,m Relaxed tendon strain energy density in the m th supporting tendon (Joules per square meter) E Young’s modulus of film (Pascals) ν Poisson’s ratio of film material ΩR Reference configuration Ω Deformed configuration α Rim modification factor γ Tendon length adjustment factor εm Strain in the m th supporting tendon (meters per meter) λ Radiation wavelength (meters) f Radiation frequency (Hertz) IR k-dimensional Euclidean space r̂ Unit direction vector from the antenna to a point in the far field (unit meter) ĵ Unit direction vector (0, 1, 0) (unit meter) k̂ Unit direction vector (0, 0, 1) (unit meter) NASA/TM—2011-217110 2
منابع مشابه
Numerical Modeling and Experimental Study of Probe-Fed Rectangular Dielectric Resonator Antenna (RDRA) Supported by Finite Circular Ground Plane
Dielectric Resonator Antennas (DRAs) have received increased interest in recent years for their potential applications in microwave and millimeter wave communication systems. DRAs are normally used with the support of a ground plane. The radiation and impedance properties therefore depend not only on their physical dimensions and dielectric properties, but also on the size of the ground plane. ...
متن کاملParameter determination in a parabolic inverse problem in general dimensions
It is well known that the parabolic partial differential equations in two or more space dimensions with overspecified boundary data, feature in the mathematical modeling of many phenomena. In this article, an inverse problem of determining an unknown time-dependent source term of a parabolic equation in general dimensions is considered. Employing some transformations, we change the inverse prob...
متن کاملParabolic Re ector Array Signal Processing for Improved Rural Area Coverage in Personal Satellite Communications
A b s t r a c t
متن کاملAn Optical Re ector System for the CANGAROO-II Telescope
We have developed light and durable mirrors made of CFRP (Carbon Fiber Reinforced Plastics) laminates for the re ector of the new CANGAROO-II 7 m telescope. The re ector has a parabolic shape (F/1.1) with a 30 m 2 e ective area which consists of 60 small spherical mirrors. The attitude of each mirror can be remotely adjusted by stepping motors. After the rst adjustment work, the re ector o ers ...
متن کاملCoupling Effects and Performance of Loran Transmitter Antennas
It is known that if a conductor resides in the neighboring of an antenna with a small distance relative to the wavelength, it induces a reverse current on the conductor. This paper involves the unavoidable coupling effects on some common types of LF antennas, due to the large wavelength in this frequency band. In particular, after some discussions about top-loaded antennas, the coupling effect ...
متن کامل