Agilent / Keysight N8485A Thermocouple Power Sensors 10 MHz to 26.5 GHz

The Keysight N8485A is a thermocouple power sensor engineered for precise RF and microwave power measurements across 10 MHz to 26.5 GHz. Delivering <1% power linearity and dynamic range from -35 dBm to +20 dBm, this sensor combines high accuracy with repeatability for demanding test environments. An onboard EEPROM automatically stores and downloads calibration factors, linearity corrections, and temperature compensation data—eliminating manual entry and streamlining measurement workflows.

– Technical Specifications

Frequency & Power Range
• Frequency: 10 MHz to 26.5 GHz (33 GHz with Option 033)
• Dynamic Range: -35 dBm to +20 dBm
• Average Power Measurement: -30 dBm to +20 dBm
• Dual-range power capability for enhanced sensitivity

Accuracy & Performance
• Power Linearity: <1%
• Temperature Compensation: 0 to 55 °C (re-zero recommended above ±5 °C variation for measurements below -25 dBm)
• Impedance: 50 Ohms
• NIST-traceable calibration

Damage Levels & Limits
• Average Power: +25 dBm maximum
• Peak Power: 15 W / 2 µs
• Maximum Energy Per Pulse: 30 W·µs

Physical & Interface
• Connector: 3.5 mm (m)
• Dimensions: 60 mm length × 20 mm diameter
• Includes 3.5 mm (f) to Type-N (m) calibration adapter

– Key Features

• EEPROM calibration storage eliminates manual factor entry and reduces setup errors
• Built-in temperature compensation maintains accuracy across operating range
• Low SWR minimizes mismatch uncertainty
• Excellent repeatability and linearity for stable, reliable measurements
• Compact 60 mm probe design

– Typical Applications

• RF and microwave power measurement in laboratory and field environments
• Power linearity and dynamic range testing
• Calibration and verification of RF systems
• Temperature-compensated power analysis

– Compatibility & Integration

The N8485A interfaces with Keysight power meters including EPM, EPM-P, and P-Series families. Compatibility may require firmware upgrade. The sensor's standard 3.5 mm connector and included calibration adapter support direct integration into existing test setups.