Value chain · CLM-1125
In plain terms
Four square metres of receiver turned 73 per cent of the microwave power arriving at it into 1.65 kW of DC, measured a kilometre from the transmitter; the main doubt is whether the probe antenna used to measure the arriving power sees the ground reflections the same way the receiver does.
The claim as recorded
The whole NRL 2022 array (about 4.45 m2, 19,488 elements, CLM-1122) under the defocused beam of CLM-1123 "achieves 1649 W output power delivered to a 30-" ohm resistor from "a total of 2265 W incident power" found by "Integrating this power density over the rectenna aperture", so "The corresponding RF-to-DC conversion efficiency is 73%", which the authors say "compares well with the state of the art reported to date at X band" and, in the abstract, "exceeds the current state of the art at X band"; with both ends turned to horizontal polarisation it "achieves 1581 W of output power at an illumination condition yielding 2229 W of incident RF power", 71 per cent; the stated error source is that the calibrated horn used to map the incident density "may respond differently to multipath scattering in comparison to the microstrip patch elements in the rectenna".
Evidence behind this: T1-peer-reviewed array-level measured efficiency with the method (calibrated-horn incident map integrated over the aperture) and the error source stated in words, without a numerical uncertainty.
Scope and limits
NO NUMERICAL UNCERTAINTY ("uncertainty" and "error bar" absent from the 16 pages); the error source is named in words only, and it bears on the denominator. Peak-of-pulse figures under 1 us pulses at 604 Hz (CLM-1123). The "state of the art at X band" claim is the authors' against their own review [1] (SRC-269). Area is stated three ways (4 m2, 4.49 m2, 4.45 m2 computed); the efficiency does not depend on it because the incident power was integrated, not multiplied.
What it assumes
The incident power is the integral of the horn-mapped density over the aperture (Fig. 21b), taken at the array's plane with the array absent.
Where it comes from
PDF 9 / printed 36: "achieves 1649 W output power delivered to a 30-" (raw) ohm resistor; integrating the mapped power density over the rectenna aperture gives, the paper states, a total of 2265 W incident power, and the corresponding RF-to-DC conversion efficiency is 73 per cent (R1); the authors say the result compares well with the state of the art reported to date at X band (normalised); 1581 W of output from 2229 W of incident RF power, an RF-to-DC efficiency of 71 per cent (R2); the paper says sources of experimental error in the efficiency calculation could include the use of a calibrated horn to map the received power density of Fig. 21b (R1), a horn which, continuing on PDF 10 / printed 37, may respond differently to multipath scattering than the microstrip patch elements in the rectenna (normalised). PDF 1: the abstract has a 4 m2 rectenna receiver producing the 1.6 kW of output power at a 73 per cent RF-to-DC conversion efficiency, which it says "exceeds the current state of the art at X band" (R1); PDF 13 (crop read): the conclusion restates it as a 4 m2 rectenna producing the 1.6 kW of output power at a 73 per cent RF-to-DC conversion efficiency (R2; the text layer drops the line-end hyphen of RF-to-DC, read at the zoom-5 crop). Recomputed: 1,649 / 2,265 = 0.728; 1,581 / 2,229 = 0.709; 1,649 / 19,488 = 84.6 mW per element; sqrt(1,649 x 30) = 222 V, 7.4 A; 2,265 / 4.45 = 509 W/m2 mean incident.
Basis: W DC out / W RF incident on the aperture, per cent; ohm
Related records
- Answers question
- QST-002 not published in this release
Cite this
energyaperture.com/c/clm-1125
CLM-1125, Energy Aperture, as of 2022-01.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-270
- CLM-1122About twenty thousand postage-stamp-sized antenna-plus-diode cells, each with an off-the-shelf microwave diode, wired into tiles, then...CLM-1123A five-metre dish and a 100 kW radar-type pulsed tube a kilometre away, bounced partly off the ground on purpose to get more power onto the...CLM-1124One panel the size of a sheet of paper turned about seven-tenths of the microwave power landing on it into DC, and did best at about three...CLM-1126They deliberately fried each of the four panels with ever-stronger pulses. A bare panel gave up at 672 watts out; clamping its voltage with...CLM-1127As flown, under two per cent of the microwave power fed to the dish came out of the receiver as electricity, because the beam had to be...CLM-1128A second test used a big radar dish in Massachusetts to light up a strip of LEDs on a tower over a kilometre away, with about a kilowatt...CLM-1129The authors say the 1975 record still stands at twenty times their power, that the custom diodes which set it no longer exist, and that...CLM-1130A quick way to size a ground-to-ground beam: at the distance where the dish stops focusing, the cone holding half the power is about twice...More on the source page.