Value chain · CLM-1098
In plain terms
The 1977 plan for a cheap rectenna was two flat planes, the front one doing all the work inside a metal shroud that is also the structure, wired in series to reach a thousand volts for the inverters; a five-element piece was built and worked, and the report says the next thing to build is a thousand-volt section.
The claim as recorded
Brown's 1977 design for a low-cost SPS rectenna returns to a two-plane construction: a reflecting plane of coarse mesh and a foreplane that collects, rectifies and busses, with a metallic shroud around the elements "which functions as both an environmental shield and as a main structural element of the rectenna"; the DC must be collected locally at 1,000 V or more because inverters to 60 Hz "become highly efficient only at voltage levels of 1000 volts or more", which is done by connecting in series sections of rectenna line in each of which the diodes are in parallel, reversing diode direction between sections; a five-element foreplane tested as part of the 199-element laboratory array showed no substantial difference in efficiency from the elements it replaced, but "the new two-plane design cannot be regarded as a completed development", and the recommended next step is a section that will "Provide 1000 volts of DC potential at the terminals" tested under a 5 kW gaussian illumination.
Evidence behind this: T3-contractor design description and recommendation; one five-element foreplane built and tested in a 199-element array.
Scope and limits
A DESIGN AND ONE FIVE-ELEMENT TEST PIECE; the shroud had holes cut for the dipoles with no weather seal, and the elements still used teflon machine screws (render reading, PDF 118). No cost is stated. The formula's inputs (n, w, r) are not evaluated for the SPS in the pages read.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
PDF 118 / printed 108, normalised: "which functions as both an environmental shield and as a main structural element of the rectenna"; "the new two-plane design cannot be regarded as a completed development"; the 199-element test and the "no substantial difference" conclusion are render readings of the same page. PDF 92 / printed 82, normalised: "become highly efficient only at voltage levels of 1000 volts or more"; the series-section scheme and the bus-length formula L = 10^3 (k / (n^2 w r))^(1/2), with k the I2R loss fraction, n elements per metre, w the DC power per element and r the DC resistance of one element's side rails, are on the same page (render reading; the layer garbles the formula). PDF 120 / printed 110, raw: "Provide 1000 volts of DC potential at the terminals"; the 5 kW generator and gaussian illumination recommendation on the same page. PDF 85 / printed 75: the four factors the design takes into account, weather protection, harmonic radiation, the front plane as structure, and 1,000 V output (render reading).
Basis: volts of DC bus; metres of string length against I2R loss fraction
Related records
- Answers question
- QST-007 not published in this release
Cite this
energyaperture.com/c/clm-1098
CLM-1098, Energy Aperture, as of 1977-08.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-558
- CLM-1095The three harmonic numbers the register has carried since the 1978 conference paper come from one rectenna element on a bench at five...CLM-1096In 1977 one rectenna element converted 90 per cent of eight watts of microwaves to DC but only 80 per cent of fifty milliwatts, and the...CLM-1097By 1976 a rectenna had delivered thirty kilowatts over a mile at 82 per cent, a certified bench system had turned DC into microwaves and...