Value chain · CLM-1177
In plain terms
The flat layers that carry the antennas must be stacked at least a quarter of a wavelength apart, but not so far apart that neighbouring antennas are more than about six-tenths of a wavelength away, or the beam grows unwanted side beams. The layers are very thin, less than a twentieth of the gap between them.
The claim as recorded
CASSIOPeiA's layers must be more than a quarter wavelength apart, with no element further than lambda/sqrt(3) from its four nearest neighbours; the patent's smallest worked example spaces its layers 0.393 wavelengths apart; and the paper describes the layers as less than a twentieth as thick as their spacing. SRC-026: "The layer spacing must exceed [1/4 lambda], such that each monopole is clear of adjacent layers, but is restricted such that no element is spaced further than [lambda/sqrt3] from its four nearest neighbours across the virtual helical surface (to prevent grating lobes)." The patent's 3 x 5 example is offset row to row by "(at most) 0.393 [lambda], giving a separation of [lambda/2] between end elements on adjacent rows", with "height, E, of 1.572 [lambda] (measured between element centres)". SRC-026 also says "the substrate layers are very thin in relation to their spacing (< 1:20)".
Evidence behind this: Inventor's T2 paper and T3 patent; the weaker sets the tier. A layout rule and one worked example, not a built structure.
Scope and limits
THE lambda/2 ON SRC-088 PDF 20 IS THE ELEMENT SPACING, NOT THE LAYER PITCH; reading it as the pitch is the error this record corrects (3d-02, recheck section 3, DISAGREE). THE 1:20 IS A THERMAL REMARK, NOT A STATED DESIGN RULE: it appears in a sentence explaining why direct heating is negligible. At a lambda/2 pitch it bounds thickness to about 3.1 mm at 2.45 GHz and 1.3 mm at 5.8 GHz; at the patent's 0.393 lambda, 2.4 mm and 1.0 mm (own arithmetic). The patent example is one embodiment, 3 x 5 elements with D = lambda; its H/D of 1.572 must not be carried to a kilometre-scale helix. The 2022 thesis (CLM-1182) builds the same rule differently, with a 14 mm vertical rise at 5.8 GHz.
What it assumes
That the patent's "0.393 [lambda]" is the axial layer spacing; the page gives it as the row-to-row offset and the arithmetic above is what makes it the spacing.
Where it comes from
PDF 4 [173], raw, transliterated: "The layer spacing must exceed [1/4 lambda], such that each monopole is clear of adjacent layers, but is restricted such that no element is spaced further than [lambda/sqrt3] from its four nearest neighbours across the virtual helical surface (to prevent grating lobes)." SRC-088 PDF 20 [8], raw, transliterated: "The minimum practical array may comprise a 3 x 5 array of elements, i.e. 5 planes or layers of 3 elements spaced [lambda/2] apart"; "may be offset angularly from the adjacent row by between 36[deg] (where 5 x 36[deg] = 180[deg]) and (at most) 0.393 [lambda], giving a separation of [lambda/2] between end elements on adjacent rows"; "Having maximum diameter, D, of [lambda] and height, E, of 1.572 [lambda] (measured between element centres)". SRC-026 PDF 7 [176], raw: "Additional 1-sun direct heating is assumed negligible in comparison, since the substrate layers are very thin in relation to their spacing (< 1:20) and oriented edge-on to the Sun." ARITHMETIC PERFORMED HERE, NOT QUOTED: 1.572 lambda over 4 gaps between 5 layers is 0.393 lambda per gap; end elements at radius lambda/2 turned 36 degrees are 0.309 lambda apart in plan, and sqrt(0.309^2 + 0.393^2) = 0.500 lambda, matching the page's lambda/2 (3d-02, recheck section 3).
Basis: layer spacing and element spacing in wavelengths; thickness-to-spacing ratio
Cite this
energyaperture.com/c/clm-1177
CLM-1177, Energy Aperture, as of 2019.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-026
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- Also from SRC-088
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