Agilent/Keysight Q347B

The Agilent/Keysight Q347B is a millimeter-wave noise source engineered for precise noise figure measurements across the Q-band frequency range. It generates stable broadband noise signals for characterization of devices and systems operating between 33 GHz and 50 GHz, enabling accurate gain and noise figure determination when paired with noise figure meters or compatible instrumentation. The Q347B produces two distinct noise states: powered-on noise output and powered-off thermal noise.

These dual states allow measurement systems to calculate the gain and added noise of a device under test, directly yielding noise figure results.

Technical Specifications

• Frequency Range: 33 GHz to 50 GHz


• Excess Noise Ratio (ENR): 6–13 dB; detailed specifications vary by frequency band (10–13 dB at 33–42 GHz, 6–12.5 dB at 42–50 GHz for one configuration; 14–17 dB at 33–42 GHz, 9–16 dB at 42–50 GHz for another)


• ENR Stability: < 0.005 dB/V with respect to voltage variation; < 0.009 dB/°C with respect to temperature variation


• VSWR: < 1.57 (source off, reflection coefficient 0.22); < 1.46 (source on, reflection coefficient 0.19)


• Power Requirements: +28 V ±1 V DC (automatically supplied by compatible noise figure meters)


• Switching Speed: < 10 μs


• Maximum Reverse Power: 100 mW


• Operating Temperature: 0 °C to 55 °C


• Dimensions: 53 mm × 108 mm × 62 mm


• Net Weight: 0.23 kg

Key Features

• Waveguide output with UG-383/U flange for direct integration into Q-band test systems


• Exceptional ENR stability enabling extended calibration intervals


• Low VSWR design minimizes reflections and measurement errors


• Compact form factor suited to integrated test benches


• Each unit supplied with calibration data documenting complex reflection coefficients in both ON and OFF states; annual recalibration recommended

Typical Applications

• Noise figure characterization of Q-band amplifiers, mixers, and transceivers


• System-level noise performance validation in 33–50 GHz applications


• Receiver noise figure verification in millimeter-wave communications systems

Compatibility & Integration The Q347B interfaces via BNC female connector for bias input and Q-band waveguide output. It integrates with Keysight NFA series and X-Series instruments (PXA, MXA) and any instrumentation supporting UG-383/U waveguide flanges.