Agilent/Keysight 8474B

The Agilent/Keysight 8474B is a precision RF detector engineered for accurate power measurements across microwave and RF systems from 0.01 GHz to 18 GHz. Built around a gallium arsenide planar-doped barrier (PDB) detecting element, it delivers superior linearity and thermal stability compared to point-contact and Schottky diode alternatives.

Technical Specifications

Frequency Range: 0.01 GHz to 18 GHz Frequency Response: ±0.35 dB across the full frequency range Maximum SWR: 1.3 Low-Level Sensitivity: >0.4 mV/µW Maximum Operating Input Power: 200 mW; typical short-term maximum 1 W (<1 minute) Output Polarity: Negative (standard); positive available (Option 103) Square Law Response: PDB detectors exhibit ≤3% response variation from 2 to 18 GHz. Option 102 (External Square Law Load) achieves ±0.5 dB deviation from ideal square-law response Noise: <50 µV peak-to-peak (CW power at 100 mV output, 400 kHz bandwidth) Operating Temperature: −65 °C to 100 °C Connectors: Type-N male input; BNC female output Dimensions: 59.86 mm × 41.15 mm × 37.36 mm Weight: 85.3 grams

Key Features

• PDB technology reduces square-law nonlinearity to 3% versus 9.5% for Schottky devices


• Exceptionally flat frequency response ensures accurate measurements across the 0.01–18 GHz band


• ESD hardening rated to 10 hits at 25 kV (body contact)


• Requires no DC bias; integrates directly with standard oscilloscopes


• Environmental qualification to MIL-STD 883 including vibration (20–200 Hz, 20g), shock (500g, 0.5 ms), salt atmosphere, and moisture resistance

Typical Applications

• CW and pulsed RF power measurement


• Power leveling in swept microwave systems


• Frequency response characterization of microwave components


• Closed-loop power leveling circuits in microwave instruments

Compatibility & Integration The detector integrates a GaAs diode matched to 50 Ω transmission line with a miniature thin-film circuit. Type-N male input and BNC female output enable direct connection to standard RF measurement systems without external biasing.