HP / Agilent 8491B Coaxial Fixed Attenuator, DC to 18 GHz

The HP/Agilent 8491B is a coaxial fixed attenuator engineered for precision signal level reduction across DC to 18 GHz. Built with thin-film tantalum nitride resistive elements on sapphire or alumina substrates, it delivers flat attenuation response and low VSWR across its operating range. Type-N stainless steel connectors ensure high repeatability and mechanical durability in laboratory, field, and production environments.

## Technical Specifications

**Frequency Range:** DC to 18 GHz

**Attenuation Values:** Available in 3 dB, 6 dB, and 10 dB increments from 10 dB to 60 dB, with frequency-dependent accuracy specifications ranging from ±0.3 dB to ±2.0 dB depending on attenuation level and frequency band.

**Voltage Standing Wave Ratio (VSWR):**
• 1.25:1 (DC to 8 GHz)
• 1.35:1 (8 GHz to 12.4 GHz)
• 1.5:1 (12.4 GHz to 18 GHz)

**Power Handling:** 2 W average, 100 W peak; derated to 1.3 W average at 55 °C.

**Impedance:** 50 Ohms

**Connectors:** Type-N male and female (MIL-C-71 / MIL-C-39012 compatible)

**Dimensions:** 67 mm × 21 mm; Net weight 110 g

**Operating Temperature:** 0 °C to +55 °C

## Key Features

• Swept-frequency tested across entire DC to 18 GHz band on precision analyzers
• Actual attenuation values stamped on attenuator body
• Optional NIST-traceable calibration data available (Option 849xx-UK6) with tabulated attenuation and SWR at specified frequencies
• Stainless steel connectors for extended wear life

## Typical Applications

Signal level adjustment, impedance matching, and component isolation in RF and microwave test systems.

## Compatibility & Integration

Type-N connectors compatible with standard 50 Ohm RF infrastructure. Compliance with MIL STD 461 RE02, VDE 0871, and FCC radiated interference standards.