Agilent / Keysight N8481A Thermocouple Power Sensors

The Agilent/Keysight N8481A is a thermocouple power sensor engineered for true average power measurement of CW and complex modulated signals across microwave frequencies. It delivers measurement uncertainty of ±0.35% (typical) from -1 dBm to +20 dBm at 25°C after zero and calibration, with power linearity better than 1% across its dynamic range. The sensor integrates EEPROM calibration factor storage, eliminating manual entry and associated errors while enabling fast setup and field recalibration.

Technical Specifications

• Frequency range: 10 MHz to 18 GHz


• Dynamic power range: -35 dBm to +20 dBm


• Power linearity: < 1%


• Measurement noise: < 80 nW typical at 50 MHz (normal mode, 1 average)


• Measurement uncertainty: ±0.35% (typical) from -1 dBm to +20 dBm at 25°C after zero and calibration


• SWR: Excellent for minimized mismatch uncertainty Physical


• Dimensions: 130 mm (length) × 38 mm (width) × 30 mm (height)


• Connector: Type-N male (standard); APC-7 available via Option 200 Environmental


• Operating temperature: 0 to 55 °C


• Built-in temperature compensation; recalibration recommended at significant temperature changes


• Frequent zeroing recommended below -1 dBm for temperature variations exceeding ±5 °C

Key Features

• Automatic EEPROM calibration factor storage and recall


• True average power measurement for modulated signals (TDMA, GSM, W-CDMA, WiMAX)


• Legacy 8480 Series replacement (excluding D-model sensors)


• Option CFT provides SCPI compatibility with 8480 Series power sensors and E7495A/B base station test set integration

Typical Applications

• Metrology and calibration labs


• Radar system characterization


• Mobile radio and cellular network testing


• TDMA, GSM, W-CDMA, WiMAX signal measurement


• Design and manufacturing test

Compatibility & Integration The N8481A operates with Keysight EPM Series (E4418B/19B, N1913A/14A), EPM-P Series (E4416A/17A), and P-Series (N1911A/12A, N8262A) power meters. Firmware upgrades may be required on some meters. Option CFT enables backward compatibility with legacy 8480 Series software environments and E7495A/B base station test sets.