Agilent / Keysight N8481B Thermocouple Power Sensors 10 MHz to 18 GHz

The Agilent/Keysight N8481B is a thermocouple power sensor that measures average power across the 10 MHz to 18 GHz frequency band. It delivers accurate readings for continuous wave, modulated, and pulsed signals with power linearity better than 1%. The sensor accepts input power from 0 dBm to +44 dBm and features a precision Type-N connector for straightforward integration into RF and microwave test systems.

Its thermocouple element and excellent SWR characteristics minimize mismatch uncertainty, while NIST-traceable calibration ensures measurement integrity across demanding applications.

Technical Specifications

• Sensor Type: Thermocouple


• Measurement Type: Average Power


• Frequency Range: 10 MHz to 18 GHz


• Dynamic Range: 0 dBm to +44 dBm


• Power Linearity: Less than 1%


• Maximum Input Power: +44 dBm


• Minimum Input Power: 0 dBm


• Connector: Precision Type-N


• Dimensions: 283 mm (L) × 114 mm (H) × 83 mm (W)


• Calibration: NIST-traceable

Key Features

• Wide dynamic range with consistent linearity across the measurement span


• Excellent SWR performance reduces mismatch-related measurement errors


• Thermocouple-based design provides reliable long-term stability


• Handles CW, modulated, and pulsed waveforms without compromise


• EEPROM calibration storage eliminates manual factor entry (standard configuration)


• CFT option available for legacy 8480 Series replacement with manual calibration entry

Typical Applications

• Power measurement in microwave and RF test environments


• Signal characterization across S-band, C-band, X-band, and Ku-band frequencies


• Validation of transmitter output power and linearity


• Pulsed and modulated signal power assessment

Compatibility & Integration The N8481B pairs with Keysight EPM, EPM-P, and P-Series power meters. It is also compatible with E1416A VXI, 70100A, and 43x series power meters. SCPI command compatibility with the legacy 8480 series is supported through the CFT option, which enables manual calibration factor entry while maintaining backward compatibility. Standard units feature automatic EEPROM-based calibration storage; CFT variants disable EEPROM to support legacy workflows.