HP / Agilent 8491A Coaxial Fixed Attenuator, DC to 12.4 GHz

The HP/Agilent 8491A is a coaxial fixed attenuator engineered for RF and microwave signal conditioning across DC to 12.4 GHz. This 50 ohm device delivers precise attenuation values from 3 dB to 60 dB with accuracy tolerances ranging from ±0.3 dB (3–6 dB) to ±2.0 dB (60 dB), supported by exceptional temperature stability of 0.0001 dB/dB/°C. Rated for 2 W average input power (100 W peak, derated to 1.3 W at 55 °C), it maintains SWR of 1.2 across 1–8 GHz and 1.3 to 12.4 GHz, making it suitable for measurement accuracy, signal level control, and impedance matching in test laboratories and production environments.

## Technical Specifications

• **Frequency Range:** DC to 12.4 GHz
• **Attenuation Values:** 3, 6, 10, 20, 30, 40, 50, 60 dB (nominal)
• **Impedance:** 50 ohms
• **Attenuation Accuracy:**
– 3–6 dB: ±0.3 dB
– 10–20 dB: ±0.5 dB
– 30 dB: ±1.0 dB
– 40–50 dB: ±1.5 dB
– 60 dB: ±2.0 dB
• **Maximum Input Power:** 2 W average, 100 W peak (derated to 1.3 W at 55 °C)
• **SWR:** 1.2 (1–8 GHz), 1.3 (8–12.4 GHz)
• **Temperature Stability:** 0.0001 dB/dB/°C
• **Power Sensitivity:** 0.001 dB/dB/W
• **Operating Temperature:** 0 °C to +55 °C
• **Non-Operating Temperature:** -55 °C to +85 °C

## Key Features

• Type-N connectors (male and female) compatible with MIL-C-71B and MIL-C-39012
• Compact form factor: 67 mm × 21 mm, 110 g
• EMC compliance: MIL STD 461 method RE02, VDE 0871 EN55011, FCC part 18
• Low frequency-dependent variation and minimal power-induced drift

## Typical Applications

• Signal path attenuation in test and measurement systems
• Impedance matching and SWR optimization
• Power level conditioning for sensitive equipment
• Laboratory and production RF/microwave testing

## Compatibility & Integration

Type-N connectors provide direct integration with standard 50 ohm RF systems. Avoid mating with HP 0.071″ pin male connectors to prevent connector damage.