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 RF Bridges

Diode detectors for RF measurement

The pdf article by DWK given below gives a detailed discussion of the various possible diode detector configurations; but as pointed out by Dr Denis Jaisson, the formulae developed from p44 onwards are flawed because they rely on a turn-on angle and a forward voltage that cannot be determined rigorously. Instead, it is necessary to apply a transcendental equation for which the solution involves the W0 branch of the Lambert W function. A rigorous demonstration is given in Denis's paper (available from Researchgate) and leads to a set of closed formulae of sufficient simplicity to be entered directly into a spreadsheet.

ext link www.researchgate.net/publication/337921929_

Denis's theory supercedes the theory given below, but the general discussion of detector configurations and history might nevertheless be found informative.

Rectifier circuits, theory and calculation procedures (incomplete).
  + Spreadsheet calculations det_models.ods ,

Old worksheets IN5711.ods , det_Rin.ods .

Open document spreadsheets can be viewed and modified using Open Office.

Measurements using simple diode detectors:
See: RF Bridges, Background theory and experiment.
Current transformer efficiency factor.
Amplitude response of conventional and maximally-flat current transformers.

Diode data and application notes
Agilent Technologies www.agilent.com/
Agilent 1N5711, 1N5712, 5082-2303, 5082-28xx, 5082-2900. Schottky Barrier Diodes for General Purpose Applications.
AN923: Schottky Barrier Diode Video Detectors.
AN956-4: Schottky Diode Voltage Doubler.
AN956-5: Dynamic Range Extension of Schottky Detectors.
AN956-6: Temperature Dependence of Schottky Detector Voltage Sensitivity.
AN986: Square Law and Linear Detection.
AN987: Is Bias Current Necessary?
AN988: All Schottky Diodes are Zero Bias Detectors.
AN1156: Diode detector simulation using Agilent Technologies EEsof ADS software.

Avago HSMS-280x series High reverse breakdown (70 VRM ) surface-mount Schottky diodes and diode arrays.
Avago HSMS-282x series surface-mount Schottky diodes and diode arrays.
Avago Technologies www.avagotech.com/
Agilent HSMS-285x-series Low threshold surface-mount Schottky diodes and arrays

Pico-Amp diodes: Vishay Siliconix low reverse-leakage diodes - now discontinued by SIliconix but available from Linear systems.
PAD series: Linear systems low reverse leakage diodes.
Linear Systems www.linearsystems.com/

GEC GEX34, 1950s vintage germanium point-contact diode
(glass tube diameter is 4.7 mm. PVC outer sleeve has been removed).
Similar to the Sylvania 1N34A and Philips OA50 and OA60 series.

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