Agilent / Keysight 85521A 4-in-1 OSLT Mechanical Calibration Kit, DC to 26.5 GHz, Type-3.5 mm (f) 50 ohm

The Keysight 85521A is a 4-in-1 OSLT mechanical calibration kit engineered to characterize and correct systematic errors in vector network analyzers and RF measurement systems. Operating across DC to 26.5 GHz with Type-3.5 mm female connectors and 50-ohm impedance, this kit delivers the four essential calibration standards

Open, Short, Load, and Thru - in a single, portable assembly. The integrated Thru standard enables direct calibration of non-insertable devices such as filters and female-female connector cables, eliminating the need for external reference standards during those measurement phases.

Technical Specifications

• Calibration Standards: Open, Short, Load, Thru (OSLT)


• Connector Type: 3.5 mm (female)


• Impedance: 50 ohm


• Frequency Range: DC to 26.5 GHz


• Physical Dimensions: 68 × 37 × 14 mm

Performance Characteristics Open Phase Error:

• DC to 5 GHz: ≤ 1.5°


• 5 to 15 GHz: ≤ 3.0°


• 15 to 26.5 GHz: ≤ 4.5° Short Phase Error:


• DC to 5 GHz: ≤ 1.0°


• 5 to 15 GHz: ≤ 2.5°


• 15 to 26.5 GHz: ≤ 4.0° Load Return Loss:


• DC to 5 GHz: ≥ 42 dB


• 5 to 15 GHz: ≥ 36 dB


• 15 to 26.5 GHz: ≥ 32 dB

Key Features

• Compact, lightweight design optimized for field and lab use


• Tight phase error specifications across the full frequency range ensure accurate de-embedding


• Integrated Thru standard streamlines calibration workflows for female-female mated components


• 50-ohm impedance standard for broadband RF applications

Typical Applications

• Vector network analyzer calibration and error correction


• Systematic error characterization in RF test setups


• Calibration of passive components with female connector interfaces


• Broadband impedance and reflection measurements

Compatibility & Integration The 85521A integrates with the 8522xA Series and all instruments featuring 3.5 mm female connectors. Its compact form factor supports both benchtop and portable measurement configurations.