Value chain · CLM-1100
In plain terms
Boeing thought the receiving elements could be spaced almost twice as far apart as Raytheon's, halving their number, and that the receiver might lie flat on the ground rather than tilted at the satellite, but said the rectenna had had little attention and both ideas needed analysis.
The claim as recorded
Boeing's 1977 rectenna design considerations reach a tentative conclusion (the page's words, render reading) that square-grid dipole spacings up to 0.8 wavelengths could be used, "resulting in significant cost" savings, with a cell area of 96 cm2 against the 50 cm2 of the "Raytheon diamond grid configuration", the wider spacing also raising the power per diode and so its rectification efficiency; that a flat horizontal ground plane appears possible if the element density is reduced by the cosine of the beam's arrival angle from the vertical and the element gain is raised toward the beam; and that a line-fed cylindrical-parabola "Hogline" receiver could reduce diode count and raise diode power; and its recommendations say rectenna optimisation "received little attention in the current SPS study", calling for an analysis of efficiency against element spacing and a conceptual design of the collection, distribution, processing and grid interface.
Evidence behind this: T3-contractor design considerations, stated as tentative and recommended for further study.
Scope and limits
TENTATIVE, FROM A 7 x 9 ELEMENT ANALYSIS THE PAGE SAYS IS HIGHLY CONTAMINATED WITH EDGE EFFECTS (render reading; the layer garbles the phrase), WITH AN INFINITE-ARRAY ANALYSIS RECOMMENDED AND NOT DONE; no measurement. The Hogline is a concept sketch. Not the reference design in any later volume.
What it assumes
0.8 wavelengths at 2.45 GHz is 9.8 cm, so a 96 cm2 cell is (9.8 cm)^2; the 50 cm2 diamond grid is the RXCV element cell of SRC-558 ("very close to 50 square centimeters", render reading, PDF 59).
Where it comes from
PDF 75 / printed 55, raw: "dipole (square grid) spacings up to 0.8" wavelengths; raw: "resulting in significant cost" savings; raw: "Raytheon diamond grid configuration" of 50 cm2 against the square grid's 96 cm2 (render reading of the two areas; Figure 2-39 on PDF 76 labels them "CELL AREA = 50 CM2" over "OFFSET DIAMOND GRID", with DH = .64 and DE = 1.04 wavelengths, and "CELL AREA = 96 CM2" over "SQUARE GRID", with DH = DE = .8 wavelengths, render read; the layer garbles both labels); the cosine reduction, the "no fundamental reason" sentence and the three gain parameters (spacing, height above ground plane, passive reflector) are render readings of the same page; PDF 77 / printed 57: the required gain equation and Figure 2-41 "Horizontal Rectenna Configuration". PDF 78 / printed 58: the "Hogline" high-gain configuration with 97 per cent aperture efficiency at F/D = .15 and its claimed advantages (render reading). PDF 217 / printed 198, raw: "received little attention in the current SPS study"; the recommended tasks on the same page (render reading).
Basis: dipole grid spacing in wavelengths; cm2 of cell area per element
Related records
- Answers question
- QST-007 not published in this release
Cite this
energyaperture.com/c/clm-1100
CLM-1100, Energy Aperture, as of 1977-12.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-482
- CLM-1089The higher industrial band would have shrunk the receiving field to a fifth or a third of its size, at the price of a satellite that could...CLM-1099Boeing's 1977 sum gave the ground receiver 85 per cent, said it was probably a little low, and drew the trade that sets a rectenna's size...