Microstrip reflectarrays with multi-layer grounded substrates and superstrates
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Presented is a description of the single stacked element, and measured and calculated results at 2.56 GHz. Also included are measured results for the array, and calculated results of a stacked element for the required frequency-scaled version at 32 GHz.
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Several factors that govern the bandwidth performance of the.
The development of a compact, lightweight, dual-frequency antenna feed for future soil moisture and sea surface salinity (SSS) missions is described.
In order to meet the increasingly stringent budget constraints for space missions, NASA is currently developing lightweight spacecrafts with reduced stowed volume but with increased capabilities.
The development of a compact, lightweight, dual-frequency antenna feed for future soil moistur and sea surface salinity missions is described.
A network was derived that accurately accounts for large gap discontinuties (with respect to a wavelength) without sufering from the limitations of available numeric techniques.
Inflatable technology has been identified as a potential solution to the problem of achieving small mass, high packaging efficiency, and reliable deployment for future NASA spaceborne synthetic aperture radar (SAR) antennas.
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A compact four-element multiple-input multiple-output (MIMO) antenna array based on the miniaturized mi-crostrip patch is presented. The reduction in array form factor is realized by partially populating the ground plane with elec-tromagnetic band gap (EBG) cells constructed from cross slots, in combination with reactively loading each patch with a slot. The resultant 2 × 2 array system demonstrates excellent inter-element isolation and can be easily fabricated using traditional milling and printing techniques, as it exploits a 2D layout that can be conveniently implemented on two sides of a single-layer substrate, without the need for any via structures. The operation of the array near the 2.5 GHz band is verified with full-wave simulations. The size of the new design is approximately 42% of that employing conventional patch elements.
It is possible to design and construct simple, efficient microwave antenna, either linearly or circularly polarized, which should be useful in phased arrays. Mounted on thin dielectric substrate, it extends slightly above ground plane. Space behind ground plane is required for feed line and mounting hardware.
Low profile, engineering model EMU antennas were constructed. Final data for these antennas meet most of the electrical requirements in a 6 in. x 18 in. x 1.4 in. package which weighs under 2.0 lbs. Coverage data calculated at the design frequencies very nearly meets the design goal of providing a gain greater than or equal to -10 dBi over 80% of a sphere. Recommendations are made for future work directed toward producing an efficient quality design capable of operating in a space environment.
Flush-mountable assembly composed of disk radiator sandwiched between planes of metal-clad dielectric board has greater bandwidths and beamwidths than simple disk antenna. Conducting planes connect so that disk is enclosed in cavity with Y-shaped slot in top plane. Cavity is excited by microwave energy from disk and radiates from trislot aperature.
A multiple antenna assembly for communicating electromagnetic radiation is disclosed. An antenna element stack is constructed of a plurality of elliptical lamina antenna elements mutally separated by layers of dielectric material, and separated from a ground plane by dielectric material. The antenna assembly is coupled through a feed line in contact with the top antenna element. A conductor joins the remaining antenna elements to the ground plane. Each individual antenna element is operable for communication reception and transmission within a frequency band determined by the size of the particular antenna element. The sizes of the antenna elements may be selected to provide electromagnetic radiation communication over several distinct frequency bands, or to connect the individual bands into a broad band.