Value chain · CLM-1126
In plain terms
They deliberately fried each of the four panels with ever-stronger pulses. A bare panel gave up at 672 watts out; clamping its voltage with a Zener let it take about 30 per cent more incoming power before failing, and shorting it outright about 50 per cent more, which is the best any clamp could do.
The claim as recorded
NRL's 2022 test to destruction of the four rectenna quadrants, each mounted alone at the target centre and hit with "Individual 1" us "pulses of incrementally increasing power" until degradation showed on an oscilloscope: the unprotected quadrant reached 672 W of output before it was damaged, from which the paper infers that the full array could have gone well past 1.6 kW, to about 2.7 kW, before destruction; a quadrant with "four 53-V TVS diodes (STMicroelectronics 1.5KE62A) to protect 4 groups of 6 rectenna tiles" got "little improvement"; one with "four 56-V Zener diodes (ON Semiconductor 1N5370BG)" "fails at 1.1 dB higher input power density"; and a shorted output gave "The 1.7 dB increase in power handling" that "establishes an upper bound on the performance of overvoltage protection devices"; the authors call ">1 dB" a "substantial improvement in survivability" and argue the single-specimen results are significant because "each quadrant contains 4872 diodes" and Schottky arrays "fail safe", "degrading gracefully as an ensemble until severe failure is reached".
Evidence behind this: T1-peer-reviewed destructive test on four specimens of 4,872 diodes each, one per protection scheme, the significance argued by the authors rather than by repetition.
Scope and limits
ONE QUADRANT PER SCHEME, NO REPEATS; the protected quadrants survive higher incident density by clamping their output at 410-480 W, below the unprotected quadrant's 672 W, so "power handling" here is survival, not deliverable output (a crop reading the text does not put in words). Single 1 us pulses, not sustained power or heat. The "2.7 kW" is the authors' extrapolation of one quadrant's limit to four. The Zener and TVS clamp voltages (212 V, 224 V) sit at the array's operating voltage, which is why the clamps engage at all.
What it assumes
Failure is what the oscilloscope showed as degradation of the quadrant's output; the paper gives no post-mortem of which diodes failed.
Where it comes from
PDF 10 / printed 37: the paper says no information is available on whether such protection devices also enhance the survivability of large rectenna arrays (normalised); the manufacturer, the paper says, cannot provide reliability information beyond the "20 dBm maximum RF input power specification" (R2); "Individual 1" (raw) us pulses of incrementally increasing power are transmitted at each quadrant, the paper says, until damage/degradation is observed (normalised); "four 53-V TVS diodes (STMicroelectronics 1.5KE62A)" protecting 4 groups of 6 rectenna tiles within the quadrant (normalised); "four 56-V Zener diodes (ON Semiconductor 1N5370BG)" (normalised); the unprotected quadrant reached 672 W of output before it was damaged, which the paper takes to mean the full array could have gone well past 1.6 kW, to about 2.7 kW, before destruction (R1); the paper reports that the TVS diode gave little improvement over the unprotected array and that the Zener-protected array failed at 1.1 dB higher incident density (normalised); the paper reads the 1.7 dB gain of the short-circuit-protected array as the upper bound on what an overvoltage protection device can give (normalised); "each quadrant contains 4872 diodes" (raw); the Schottky diodes in large rectenna arrays tend, the paper says, to "fail safe" (raw), "degrading gracefully as an ensemble" until severe failure is reached (normalised); a >1 dB increase in RF power handling can be understood, the authors say, as a "substantial improvement in survivability" (normalised). PDF 1: the paper presents the destruction test of four large arrays as showing that overvoltage protection circuits can raise an array's RF power handling by more than 1 dB (normalised). Fig. 24 at the zoom-5 crop (render readings): unprotected fails at about 670 W near 1,130 W/m2 peak density; TVS clamps near 450 W and fails near 1,220 W/m2; Zener clamps near 480 W and fails near 1,470 W/m2; short holds near 410 W and fails near 1,650 W/m2. Recomputed: 672 x 4 = 2,688 W; 10^0.11 = 1.29, 1,130 x 1.29 = 1,460; 10^0.17 = 1.48, 1,130 x 1.48 = 1,670, both matching the crop; 4 x 53 = 212 V and 4 x 56 = 224 V of clamp against the 222 V the array runs at for 1,649 W into 30 ohm.
Basis: W DC per quadrant; dB of incident power density; V
Cite this
energyaperture.com/c/clm-1126
CLM-1126, 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-1125Four 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...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.