Which 85027 model covers the highest frequency?

The 85027D covers the highest frequency band; its frequency range is 10 MHz to 50 GHz.

Which model has the lowest published insertion loss?

85027B specifies the lowest maximum insertion loss in the mid band: maximum insertion loss 6.5 dB from 0.01 to 18 GHz (and 8.0 dB from 18 to 26.5 GHz).

Do these bridges support AC and DC detection?

Several 85027 models support AC and DC detection, but behaviour is analyzer dependent. 85027B and 85027D explicitly note integrated detection for both AC and DC. Other models state detection modes are dependent on the connected scalar network analyzer.

What connector types are used across the series?

Connector types vary by model: 85027A uses Type‑N (female); 85027B and 85027E use 3.5 mm (female); 85027D uses 2.4 mm (female). Several models also include an integrated multi‑pin analyzer cable.

Keysight Technologies (Agilent HP) 85027 Directional Bridges

6 models with full specifications in Bridges.

This page describes the Keysight (Agilent HP) 85027 series of directional bridges and how that series is organized for reflection measurements in coaxial test setups. It is written for test engineers and procurement specialists who need to pick an accessory for scalar or vector network analysis. The text explains the product split by frequency and capabilities, highlights the measurement trade‑offs (port match, directivity, insertion loss and detection mode), and lists the practical integration points you must check against your analyzer and cabling before specifying or ordering.

Nominal impedance: 50 Ω
Common operating temperature: 0 to 55 °C
Maximum continuous RF input power: +23 dBm
Highest frequency model: 85027D: 10 MHz – 50 GHz
Mid/high frequency band: 85027B / 85027E: 10 MHz – 26.5 GHz

All models

Model	Type	Frequency Range	Nominal Impedance	Operating Temperature
85027D	Directional	10 MHz - 50 GHz	50 Ω	0 to 55
85027E	Directional	10 MHz to 26.5 GHz	50 Ω	0 to +55 °C
85027A	Directional	10 MHz - 18 GHz	50 Ω	0 to 55 °C
85027B	Directional	10 MHz to 26.5 GHz	50 Ω	0 to +55 °C
85027C	Directional	10 MHz - 18 GHz	50 Ω	0 to 55 °C
86205A	*misc	300 kHz to 6 GHz	50 Ω	0 to 55 °C

How the 85027 lineup is structured

The 85027 series is offered in multiple frequency bands and mechanical interfaces so you can match a bridge to the frequency range and connectors of your test setup. Models 85027A and 85027C cover the lower microwave band; they are positioned for up to 18 GHz. Models 85027B and 85027E extend that range to 26.5 GHz and give lower insertion loss options for measurements through the mid gigahertz band. The 85027D extends the family to millimeter‑wave coaxial work with coverage out to 50 GHz. Choose the model whose rated frequency range and connector type match your device-under-test and analyzer front end.

Performance differentiators to compare

Directivity, test‑port match (return loss / SWR) and insertion loss are the primary performance tradeoffs.

Directivity: 85027A has ≥40 dB (0.01–8 GHz), ≥37 dB (8–12.4 GHz) and ≥35 dB (12.4–18 GHz). 85027C lists minimum directivity ≥36 dB (0.01–12.4 GHz) and ≥34 dB (12.4–18 GHz). 85027E specifies ≥40 dB (0.01–20 GHz) and ≥36 dB (20–26.5 GHz). 85027B specifies ≥40 dB (0.01–20 GHz). Higher directivity reduces measurement uncertainty on small reflections.
Test‑port match and insertion loss: 85027A publishes test‑port return loss figures (for example ≥30 dB from 0.01–8 GHz) and a typical insertion loss at 18 GHz of 8.0 dB. 85027C gives SWR bands (for example SWR ≤1.15 to 8.4 GHz) and a typical insertion loss at 18 GHz of 8.0 dB. 85027B quotes maximum insertion loss 6.5 dB (0.01–18 GHz) and 8.0 dB (18–26.5 GHz). Use the insertion loss spec when the available signal level is limited.

Integration and analyzer compatibility

Connector type, cable/interface and analyzer detection mode determine practical compatibility.

Connectors and cabling: 85027A uses a Type‑N (female) RF input. 85027B and 85027E use 3.5 mm (female) RF inputs; 85027D uses 2.4 mm (female). Several models include an integrated 1.5 m multi‑pin cable for direct connection to HP/Agilent scalar network analyzers; 85027C uses a custom multi‑pin analog interface.
Power and detection: These bridges are host powered through the analyzer connection. 85027B and 85027D list integrated detection capabilities for both AC and DC modes (with analyzer dependency noted for some models). Where detection mode matters, verify that the bridge is supported by the scalar network analyzer model you plan to use: the Agilent/Keysight 8757 is explicitly listed for AC and DC detection with several 85027 variants, and some models reference operation with the 8756 and 8755 in AC mode.