The HP/Agilent 11940A is a handheld close field probe designed for magnetic field detection and measurement across the 30 MHz to 1 GHz frequency range. It identifies and quantifies magnetic field radiation from electronic components, circuits, and cables—making it essential for EMC diagnostics, interference source identification, and signal leakage characterization. The probe delivers high electric field rejection for accurate, repeatable measurements in real-world environments. When paired with a signal generator, it functions as a localized magnetic field source for circuit-board-level susceptibility testing.
Technical Specifications
• Frequency range: 30 MHz to 1 GHz
• Maximum input power: 0.5 W
• Field impedance: Characterized for 377 Ω
• VSWR: <3:1 typical
• Antenna factor accuracy: ±2 dB (individually calibrated in 377 Ω field impedance)
• Dielectric breakdown: ±1 kV typical
• Operating temperature: 0 °C to +40 °C
• Storage temperature: -10 °C to +65 °C
– Key Features
• High electric field rejection minimizes measurement uncertainty in mixed-field environments
• Individually calibrated for traceable, repeatable measurements
• SMA connector with replaceable barrel
• Handheld form factor (net weight: 0.10 kg)
– Typical Applications
• Locating and quantifying magnetic field radiation from surface currents, slots, and cables
• IC emission characterization and circuit-level interference diagnosis
• Near-field susceptibility testing when driven by a signal generator
• Frequency-selective measurement and analysis with spectrum analyzers
– Compatibility & Integration
• Supplied with 2 m RG-223 coaxial cable
• Includes SMA(f)-to-Type-N(m) and SMA(f)-to-BNC(m) adapters for connection flexibility
• Functions with signal generators for localized field generation
• Works with spectrum analyzers to preserve frequency information during measurements
• Integrates into the HP/Agilent 11945A Close Field Probe Set for extended coverage (9 kHz to 1 GHz when paired with the 11941A probe)
