Agilent/Keysight 85138B

The Agilent/Keysight 85138B is a precision 50-ohm coaxial termination load for DC to 50 GHz applications. This calibration standard terminates coaxial systems in their characteristic impedance, enabling accurate and repeatable RF and microwave measurements across demanding test environments.

Technical Specifications

• Frequency Range: DC to 50 GHz


• Impedance: 50 ohms


• Connector: 2.4 mm female


• Maximum SWR: 1.07 (DC–26.5 GHz) | 1.12 (26.5–40 GHz) | 1.22 (40–50 GHz)


• Maximum Power: 0.5 W average, 100 W peak


• Physical Length: 20.95 mm (0.82 in)


• Physical Diameter: 8.25 mm (0.32 in)


• Connector Face Depth: 0.3 mm (0.6 in)

Key Features

• Low-reflection design ensures minimal signal distortion across the full frequency band


• SWR specifications tighten at lower frequencies, reaching 1.07 below 26.5 GHz for high-precision calibration


• Compact 2.4 mm form factor integrates directly into modern network analyzer ports


• Peak power handling of 100 W accommodates both CW and pulsed measurement applications


• DC-rated performance enables characterization of low-frequency and broadband systems

Typical Applications

• Network analyzer calibration and verification


• RF and microwave test port termination


• S-parameter measurement reference standards


• High-frequency component characterization


• System impedance matching validation

Compatibility & Integration The 85138B interfaces with network analyzers and RF/microwave test instruments equipped with 2.4 mm female ports. Its impedance and SWR specifications position it as a calibration standard across the DC to 50 GHz band, with performance optimized for precision measurements in sub-26.5 GHz applications.