The HP/Agilent 11941A is a handheld close field probe for magnetic field measurements spanning 9 kHz to 30 MHz. Designed for EMC diagnostics and EMI troubleshooting, it isolates and characterizes magnetic field radiation from surface currents, slots, cables, and integrated circuits with high electric field rejection. The probe delivers repeatable, calibrated amplitude and frequency measurements suitable for spectrum analyzer integration. Its passive circuitry introduces only thermal noise, while individual antenna factor calibration ensures ±2 dB accuracy in 377 Ω field impedance. Beyond diagnostic measurements, the 11941A functions as a localized magnetic field source for susceptibility testing when paired with a signal generator.
Technical Specifications
• Frequency Range: 9 kHz to 30 MHz
• Maximum Input Power: 0.5 W
• Antenna Factor Accuracy: ±2 dB (individually calibrated in 377 Ω field impedance)
• VSWR: < 3:1, typical
• Dielectric Breakdown: ±1 kV, typical
• Operating Temperature Range: 0 °C to +40 °C
• Connector: SMA, replaceable barrel
– Key Features
• High electric field rejection for reduced measurement errors
• Passive circuitry—minimal thermal noise contribution
• Individually calibrated for field measurements
• Handheld form factor for localized field assessment
• Dual-mode operation: diagnostic probe or susceptibility test source
– Typical Applications
• EMC compliance testing and diagnostic surveys
• Identification of EMI sources in circuit board layouts
• Magnetic field characterization of cables and interconnects
• Susceptibility testing with paired signal generators
• Design-phase troubleshooting of radiated emissions
– Compatibility & Integration
The probe connects via SMA (replaceable) and is optimized for spectrum analyzer workflows. Standard accessories include a two-meter RG-223 coaxial cable, SMA (f) to Type-N (m) adapter, and SMA (f) to BNC (m) adapter. The 11941A integrates into the broader HP/Agilent 11945A Close Field Probe Set alongside the 11940A (30 MHz – 1 GHz) for extended frequency coverage.
