Value chain · CLM-1143
In plain terms
Japan's flagship 2015 ground test: a solid-state GaN array of about one and a half square metres sent 1.8 kilowatts 55 metres and 335 watts of DC came out, under a fifth of the microwave power and about one-fifteenth of the DC that went in, with the beam self-steering onto the receiver.
The claim as recorded
On 8 March 2015 the METI SPS team's horizontal ground test at the Mitsubishi Electric facility in Hyogo used a phased array of "four 2.5 cm" x 60 x "60 cm panels each weighing 16.1 kg", each with "76 GaN class-F amplifiers, whose average amplifier efficiency was 60.3%, and total efficiency (DC" to "RF) was 35.1%", to "transmit 1.8 kW of 5.8-GHz microwave energy over a 55-m distance" to a 2.6 x 2.3 m rectenna of 36 modules; "The received rectified power was about 335-W DC"; the rectenna's RF to "DC conversion efficiency was 59% (diodes distributed from 59% to 62%)" and "The total receive efficiency, including the 96% efficiency of the power distribution unit" "was 42%"; retrodirective pointing at 2.45 GHz held the beam with the panels deliberately misaligned, which the review calls "directly applicable to an SPS which may experience subtle moment-generated deformations in space".
Evidence behind this: T2-review restatement of Mihara et al. IAC 2015 [99] and the retrodirective papers [114], [115], none held; the efficiency chain is stated but its denominators are not.
Scope and limits
59 PER CENT x 96 PER CENT = 56.6, NOT THE STATED 42 PER CENT "TOTAL RECEIVE EFFICIENCY" (0.42 / 0.566 = 0.74 would be the size of a beam collection term the paragraph never states; reader arithmetic); the review does not name the third factor or the denominators, and 335 W at 59 per cent implies 568 W at the diodes, 31.5 per cent of the 1.8 kW - recorded, not repaired. The 6.5 per cent DC-to-DC is this record's arithmetic, not the review's. Primaries not held; the retrodirective papers [114], [115] are separate. The date (8 March 2015), the 55 m distance and the METI SPS team attribution are the review's; its source, Mihara et al., IAC-2015-C3.2.1 ([99]), is not held, so these three details are unconfirmed at the primary.
What it assumes
The 1.8 kW is RF at the array face and the 35.1 per cent converts the array's DC input to it.
Where it comes from
PDF 11 / printed 239: "On March 8, 2015, the METI SPS team successfully carried out a horizontal ground microwave power beaming experiment at the Mitsubishi Electric Facility in Hyogo Prefecture" (normalised); "The phased array pictured in Fig. 21(a) took six years to complete and was equipped with state-of-the-art GaN amplifiers [99]" (R2); "Its four phased array panels combined to transmit 1.8 kW of 5.8-GHz microwave energy over a 55-m distance to the rectenna array shown in Fig. 21(b)" (normalised); "The received rectified power was about 335-W DC" (R2); "The system implemented retro-directivity at 2.45 GHz for each of the four individual phased arrays [114], [115]" (normalised); "The retrodirective subsystem was able to maintain beam pointing at the rectenna" (normalised); "This analysis is directly applicable to an SPS which may experience subtle moment-generated deformations in space" (normalised); "The phased array was composed of four 2.5 cm" (normalised); "60 cm panels each weighing 16.1 kg" (raw); "Each panel included 76 GaN class-F amplifiers, whose average amplifier efficiency was 60.3%, and total efficiency (DC" (R1); "RF) was 35.1%. Each amplifier connected to a 4-antenna subarray" (R1); "2.3 m rectenna array developed for the field experiment used 36 rectenna modules with the Schottky diode rectifiers" (R2); "DC conversion efficiency was 59% (diodes distributed from 59% to 62%)" (R1); "The total receive efficiency, including the 96% efficiency of the power distribution unit" (R1); "was 42%. The R&D project was conducted by J-Space System" (normalised); "The phased array and the rectenna array were developed by Mitsubishi Electric Corp. and IHI Aerospace Co., Ltd., respectively" (normalised). PDF 2, Fig. 2 (crop reading): point [18] at about 340 W and 55 m. Recomputed: 335 / 1,800 = 18.6 per cent RF-sent to DC-out; 1.8 / 0.351 = 5.13 kW DC in, 335 / 5,130 = 6.5 per cent DC-to-DC; 4 x 76 = 304 amplifiers, 1,216 antennas; 1.44 m2 transmit face, 1,250 W/m2; 5.98 m2 rectenna; 64.4 kg of panels, 28 W/kg; 0.59 x 0.96 = 0.566.
Basis: kW RF; W DC; GHz; m; per cent per stage; kg; cm
Cite this
energyaperture.com/c/clm-1143
CLM-1143, Energy Aperture, as of 2021-01.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-269
- CLM-1134The field's own 2021 scorecard: the two records were both set in 1975 (30-35 kW across about a mile, and 54 per cent DC in to DC out at...CLM-1135Modern power beaming, by the review's dating, starts in 1963 with a radar tube, a horn five and a half metres away and a single vacuum-tube...CLM-1136The famous 1964 helicopter hung fifteen metres up for ten hours on beamed microwaves, rectified by four and a half thousand diodes; then...CLM-1137In 1987 a Canadian model plane with a four-and-a-half-metre wingspan flew for twenty minutes at 150 metres on nothing but a microwave beam...CLM-1138A 1994 Japanese test sent five kilowatts from a three-metre dish to an eleven-square-metre rectenna 42 metres away and caught about...CLM-1139A 1995 Japanese blimp carrying a three-by-three-metre rectenna flew for four minutes at fifty metres on ten kilowatts of microwaves from...CLM-1141In 2002 a metre-wide rectenna moved along an exhibition floor in Houston, tracked by a self-steering 5.8 GHz beam, converting 82 per cent...CLM-1142In 2015 Mitsubishi Heavy sent ten kilowatts of microwaves half a kilometre along a Kobe pier to an eight-by-eight-metre receiver, enough to...More on the source page.