Agilent / Keysight R8486A Thermocouple Waveguide Power Sensor

The Agilent/Keysight R8486A is a thermocouple power sensor engineered for precision power measurement in waveguide systems operating from 26.5 GHz to 40 GHz. The sensor employs a thermocouple-based measurement architecture with two junctions fabricated on a silicon chip: a hot junction positioned at the resistive element and a cold junction at the chip perimeter. This dual-junction design delivers stable, accurate readings with minimal SWR to reduce mismatch uncertainty.

Technical Specifications

• Frequency Range: 26.5 GHz to 40 GHz


• Power Measurement Range: -30 dBm to +20 dBm (1 µW to 100 mW)


• Waveguide Flange: UG-599/U


• Measurement Mechanism: Thermocouple sensor on silicon chip


• Calibration Port: 50 MHz calibration port for traceability to NIST millimeter-wave sensor calibration standards


• SWR: Low, for reduced mismatch uncertainty


• Weight: Approximately 5 lbs

Key Features

• Two-junction thermocouple configuration on monolithic silicon substrate


• Excellent low SWR minimizes measurement error from source mismatch


• NIST-traceable calibration provides metrological validity


• Calibration port at 50 MHz enables simplified periodic verification


• Standard UG-599/U waveguide interface for direct integration into test setups

Typical Applications

• Millimeter-wave power measurement in the Ka band (26.5–40 GHz)


• Waveguide-based RF system characterization and validation


• High-frequency power monitoring in laboratory and production environments

Compatibility & Integration The R8486A mates with Keysight EPM series power meters (E4418A/B, E4419A/B, N1913A/14A), EPM-P series (E4416A/17A), P-series (N1911A/12A), 70100A, and E1416A VXI instrumentation. Legacy support includes discontinued Agilent/HP 435A/B, 436A, 437A, and 438A series meters. This sensor is obsolete.