Agilent/Keysight 85027C

The Agilent/Keysight 85027C is a precision directional bridge for scalar reflection measurements across 10 MHz to 18 GHz. It couples incident and reflected signals from a device under test, enabling return loss characterization with high directivity and minimal test port loading. The bridge operates in AC or DC detection modes depending on the connected scalar network analyzer

AC mode for noise-immune measurements, DC mode for modulation-sensitive devices.

Technical Specifications

• Frequency Range: 10 MHz to 18 GHz


• Characteristic Impedance: 50 Ohms


• Connectors: Type N (female) at input and test port


• Directivity: 36 dB (10 MHz–12.4 GHz), 34 dB (12.4–18 GHz)


• Test Port Match (SWR): <1.15 (10 MHz–8.4 GHz), <1.25 (8.4–12.4 GHz), <1.43 (12.4–18 GHz)


• Typical Insertion Loss: 6.5 dB @ 10 MHz, 8.0 dB @ 18 GHz


• Minimum Input Power (40 dB Return Loss): +2 dBm @ 18 GHz


• Maximum Input Power: +23 dBm or +10 Volts


• Detection Modes: AC and DC (configurable)


• Dimensions: 26 mm (H) × 124 mm (W) × 118 mm (D)


• Weight: 0.5 kg net, 2.3 kg shipping

Key Features

• High directivity ensures accurate reflection measurements across the full frequency range


• Low test port SWR minimizes DUT loading errors


• Dual detection capability accommodates both noise-sensitive and DC-coupled measurement scenarios


• Compact package integrates into existing test benches


• Includes Type N shielded short, open, and m–m adapter

Typical Applications

• Return loss and reflection coefficient measurement


• Device impedance characterization


• Transmission measurements (with external power splitter and detectors)


• Component and filter validation at microwave frequencies

Compatibility & Integration Designed for Keysight 8757 series scalar network analyzers (AC/DC detection) and Keysight 8756/8755 series analyzers (AC detection mode). Ratio and transmission measurements require additional HP 85025 series (AC/DC) or HP 11664 series (AC only) detectors and a power splitter.