The Keysight (Agilent HP) 11940A is a passive, close-field magnetic (H-field) probe designed for EMI/EMC troubleshooting and diagnostic measurements over the frequency range of 30 MHz to 1 GHz. Featuring a unique dual-loop design, it provides exceptional rejection of electric (E-field) fields, ensuring highly localized and accurate magnetic field measurements. Each probe is individually calibrated, with its unique antenna factor calibration curve printed directly on the probe body for convenient and precise measurement conversion.

Specifications

Physical

ParameterValue
Power SupplyPassive (none required)
Operating Temperature0 °C to 55 °C
Dimensions (W×H×D)46 mm × 140 mm × 19 mm
Weight0.11 kg

Electrical Performance

ParameterValue
Frequency Range30 MHz to 1 GHz
Probe TypeH-Field (Magnetic Field)
Sensor DesignDual-loop (for common-mode E-field rejection)
Nominal Impedance50 ohms
Maximum Continuous Input RF Power0.5 W (+27 dBm)
Output Connector TypeSMA female

Calibration & Traceability

ParameterValue
Calibration TypeIndividually calibrated; antenna factors plotted on probe handle
Calibration Accuracy±2 dB (typical)

System Compatibility & Accessories

ParameterValue
Compatible EquipmentSpectrum Analyzers, EMI Receivers, Oscilloscopes
Related Probe SetHP 11945A Close-Field Probe Set

Environmental

ParameterValue
Storage Temperature-40 °C to +75 °C
Operating Humidity95% RH @ 40 °C

Electrical

ParameterValue
Maximum Safe DC Current0.5 A
Maximum Safe Electric Field1000 V/m

Technology

Passive Near-Field Probing

Applications

EMI/EMC Diagnostic and Pre-compliance Testing