Agilent/Keysight 11904A

The Agilent/Keysight 11940A is a handheld close-field probe engineered for detection and measurement of magnetic field radiation from surface currents, slots, cables, and integrated circuits. Optimized for electromagnetic compatibility (EMC) diagnostic and troubleshooting, this probe delivers high electric field rejection to enable accurate, calibrated, and repeatable field measurements across PCBs and electronic assemblies.

Technical Specifications

Frequency Range: 30 MHz to 1 GHz Antenna Factor Accuracy: ±2 dB in 377 ohm field impedance (individually calibrated at 30, 100, 500, 850, and 1000 MHz) VSWR: < 3:1 (typical) Maximum Input Power: 0.5 watts Dielectric Breakdown: ±1 kV (typical) Connector: SMA, replaceable barrel Operating Temperature Range: 0°C to +40°C Storage Temperature Range: -10°C to +65°C Weight: 0.10 kg (0.22 lbs)

Key Features

• High-level electric field rejection for isolated magnetic field detection


• Individually calibrated antenna factor traceable to 377 ohm field impedance


• VSWR controlled to typical < 3:1 across the operating band


• solid dielectric isolation rated to ±1 kV


• Field-replaceable SMA connector assembly


• Compact handheld form factor

Typical Applications

• EMC diagnostic and root-cause analysis


• Near-field radiation profiling on PCBs and ICs


• Slot and cable radiation assessment


• Electromagnetic interference localization


• In-circuit troubleshooting of RF and mixed-signal designs

Compatibility & Integration Supplied with a 2-meter RG-223 coaxial cable, SMA (f) to Type-N (m) adapter, and SMA (f) to BNC (m) adapter, enabling direct connection to spectrum analyzers, network analyzers, and EMC test receivers with standard 50 ohm connectors.