Agilent/Keysight 11941A

The Agilent/Keysight 11941A is a hand-held magnetic field probe designed for precise localized detection and analysis of electromagnetic emissions in electronic circuits and devices. It operates across 9 kHz to 30 MHz, enabling engineers to identify magnetic field radiation from surface currents, slots, cables, and integrated circuits during EMC pre-compliance testing and troubleshooting.

The probe measures magnetic field strength at the center of its sense loop rather than at the tip, making it ideal for close-proximity assessment of potential radiating points. Each unit is individually calibrated to ±2 dB antenna factor accuracy in a 377 Ω field impedance and supplies five antenna factors for converting dBµV spectrum analyzer readings to absolute magnetic-field strength in dBµA/m.

– Technical Specifications

• Frequency range: 9 kHz – 30 MHz
• Maximum input power: 0.5 W
• Dielectric breakdown: ±1 kV (typical)
• Connector: SMA with replaceable barrel
• VSWR: < 3:1
• Antenna factor accuracy: ±2 dB (individually calibrated, 377 Ω field impedance)
• Operating temperature: 0 °C to +40 °C
• Cable: 2-meter RG-223 coaxial
• Included adapters: SMA (f)-to-Type N (m) and SMA (f)-to-BNC (m)

– Key Features

• High electric field rejection minimizes measurement error and ensures calibrated, repeatable results
• Passive circuitry contributes only thermal noise to the measurement system
• Individual calibration with traceable antenna factors
• Compact, durable hand-held design

– Typical Applications

• EMC diagnostic and pre-compliance testing
• Signal tracing and electromagnetic interference source identification
• Circuit-board-level susceptibility testing when operated with an appropriate signal generator
• Localized magnetic field measurement from ICs, cables, and PCB structures

– Compatibility & Integration

The 11941A integrates with standard spectrum analyzers and RF measurement instruments via its SMA connector. Supplied adapters enable connection to Type N and BNC-equipped systems. The 2-meter cable supports both bench and field operations.