The Keysight (Agilent) 11909A is a low-noise amplifier that extends measurement system sensitivity across 9 kHz to 1 GHz by delivering 32 dB gain with minimal noise contribution. Designed for precision detection of weak signals, it operates with a noise figure of 1.8 dB typical (5 MHz to 500 MHz) and maintains gain flatness of ±0.5 dB across most of its operating range. The amplifier handles up to +10 dBm output at 1 dB compression point and accepts maximum linear input of ±24 mV, making it suitable for applications where signal fidelity and system noise performance directly impact measurement accuracy.
Technical Specifications
Frequency & Gain
• Frequency range: 9 kHz to 1 GHz (–3 dB)
• Amplifier gain: 32 dB ± 1.5 dB @ 100 MHz
• Gain flatness: ±0.5 dB (25 kHz to 800 MHz)
Noise Performance
• Noise figure: 1.8 dB typical, 2.5 dB maximum (5 MHz to 500 MHz)
• Noise figure: 2.5 dB typical (1 GHz)
Power & Impedance
• Output power at 1 dB compression: +10 dBm
• Impedance: 50 ohms
• Input return loss: 8 dB
• Output return loss: 10 dB
• Reverse isolation: 35 dB
Input Protection
• Maximum input for linear operation: ±24 mV
• Input damage level: ±2 V DC
Environmental & Power
• Operating temperature: 0 °C to 55 °C
• Storage temperature: –25 °C to 75 °C
• Power supply: 100, 120, 220, or 240 V AC, 50/60 Hz, 20 VA
Physical
• Dimensions: 91 mm (H) × 109 mm (W) × 183 mm (D)
• Weight: 3.3 lbs (1.5 kg)
• Connectors: Type N input/output
– Key Features
• Low-noise design optimized for weak signal detection
• Stable gain across 9 kHz to 1 GHz bandwidth
• 50 ohm matched input and output
• Direct integration with spectrum analyzers and receiver systems
– Typical Applications
• Enhancing receiver and spectrum analyzer sensitivity
• Close-field probe measurements for device emissions
• Radiated emissions testing with antenna-based systems
– Compatibility & Integration
The 11909A pairs with Keysight (Agilent) 11940A and 11941A close-field probes for low-level emission detection.
