Value chain · CLM-0946
In plain terms
A rectenna under test emitted a spurious signal. The cause was the resistor they hung on its output, not the rectenna itself, and swapping the resistor made it stop. The diode's own harmonics were measured separately and plotted.
The claim as recorded
A spurious emission measured during rectenna testing came from the DC load hung on the rectenna's output, not from the rectifying junction, and changing the load removed it. A 5 W wire-wound resistor, whose capacitive and inductive elements interact with the microwave beam, produced a spurious signal at 320 MHz; substituting a carbon resistive load and shorting the lead wires between rectenna and load made it disappear. Diode harmonics were separately measured across 2 kHz to 10 GHz. So part of what a rectenna radiates is an installation property rather than an intrinsic one, and that part is fixable by changing a component.
Evidence behind this: T3-primary-report, and this is the only instrumented measurement of rectenna emission the register holds. The other two sources for the same property are a characteristics table and a flight observation; this one put a spectrum analyser on the hardware.
Scope and limits
A BENCH TEST AT 89 cm, NOT A FIELD MEASUREMENT, and on the deliberately mismatched three-element test article described at CLM-0943. NO EMISSION LEVEL IS QUOTED IN THIS RECORD. The spectra are figures, and their captions in the text layer are corrupted to the point of illegibility - one visible set of analyser settings reads "CENTER 1.450GHz SPAN 2.900GHz" - so the numbers would have to be read off the plots by eye and nobody here has done that. The 320 MHz signal is identified by its cause, not quantified; this record says a spurious emission existed and what removed it, and says nothing about how strong it was or whether it would matter at power. NOTHING HERE ESTABLISHES THAT A DEPLOYED RECTENNA'S EMISSION IS MOSTLY LOAD-DRIVEN - one spurious signal in one test article had that cause, and the diode harmonics are a separate phenomenon that changing the resistor did not touch.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
PDF p.21, transcribed with the raw rendering shown because the text layer carries letter-for-digit and letter-for-letter corruption in this passage and a scan is not repaired and then called verbatim. Raw: "A 5 W wire wound resistor was first used. This type of resistor has capacitive and inductive elements which interact with the microwave power beam. A spurious signal a 320 MHz was generated during the rectenna testing. Atter switching to a carbon resistive load and shorting of the wire leads between the rectenna and the load, the spurious signal disappeared." "a 320 MHz" is "at 320 MHz" and "Atter" is "After"; both are shown unrepaired above and read in the render. Also raw, same page: "Figures 22, 23, and 24 show the 2 kHz to 10 GHz spectrum when the METS rectenna was operating. The harmonics produced by the rectenna diode are shown in figures 23 and 24." Load sizing context on the same page: the choice was "based on the breakdown voltage (55 V) of the rectenna diodes".
Related records
- Answers question
- QST-001 not published in this release
Cite this
energyaperture.com/c/clm-0946
CLM-0946, Energy Aperture, as of 1993.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-340
- CLM-0948The "space ready" rectenna was tested for surviving the rocket launch and fitting into its container. Its report describes no vacuum or...CLM-0953The rectenna was squashed to fit its container, which spoiled the impedance match between it and the incoming beam. The report accepts this...