The Keysight 8490G is a precision coaxial fixed attenuator engineered for signal control across microwave and millimeter-wave frequencies. Operating from DC to 67 GHz with 50 Ω impedance and 1.85 mm connectors, it delivers the low SWR and insertion loss accuracy required for high-confidence measurements in RF and microwave systems.
Technical Specifications
Frequency Range: DC to 67 GHz
Impedance: 50 Ω nominal
Connectors: 1.85 mm coaxial
Attenuation Values: 3 dB, 6 dB, 10 dB, 20 dB, 30 dB, 40 dB
Maximum Input Power: 1 W average
DC Voltage Rating: ±7 Vdc maximum (blocking capacitor required above this level)
Operating Temperature: 0 °C to +55 °C
-# Insertion Loss & Accuracy
Example specifications for the 3 dB model:
• Insertion Loss (Maximum): 2.5 dB across 0 to 67 GHz
• Uncertainty (Maximum): ±0.3 dB across 0 to 67 GHz
Accuracy varies by attenuation value and frequency band; manufacturer documentation provides detailed performance data.
-# Standing Wave Ratio
Typical maximum SWR for standard attenuators:
• 1.15 up to 26.5 GHz
• 1.25 up to 40 GHz
• 1.45 up to 67 GHz
For 40 dB attenuators:
• 1.10 up to 26.5 GHz
• 1.15 up to 40 GHz
• 1.25 up to 67 GHz
– Key Features
• Low SWR minimizes signal reflections and preserves measurement integrity
• Swept-frequency testing on precision network analyzers confirms full specification compliance across entire operating range
• Compact, rugged construction for benchtop and integrated system deployments
• Multiple attenuation values support diverse dynamic range and power control requirements
– Typical Applications
• Power meter dynamic range extension for high-power signal measurement
• RF and microwave calibration standards
• RF substitution measurements
• Power reduction for sensitive components and instrument protection
• Radar and satellite system testing
• Wireless communications and microwave backhaul characterization
