Agilent/Keysight 4191A

The Keysight 4191A RF Impedance Analyzer measures impedance and related parameters across 1 MHz to 1 GHz with 1% basic accuracy. It delivers spot and swept measurements of impedance, admittance, resistance, reactance, inductance, capacitance, quality factor, and phase angle. The instrument combines fast measurement speed - 250 ms in high-speed mode, 800 ms in normal mode - with flexible bias control and direct engineering parameter display.

Technical Specifications

• Operating range: 1 MHz to 1 GHz


• Frequency resolution: 100 Hz to 500 MHz or 200 Hz to 1000 MHz (Option 002)


• Frequency accuracy: 3 ppm (Option 002)


• Display resolution: 4 ½ digits maximum Measurement Parameters and Ranges


• Impedance |Z| and Resistance R: 100 mΩ to 20 kΩ


• Admittance |Y|: 100 µS to 10 S


• Conductance G: 20 µS to 10 S


• Inductance L: 0.1 nH to 5 mH


• Capacitance C: 0.1 pF to 1 µF


• Reactance X: 100 mΩ to 20 kΩ


• Dissipation Factor D and Quality Factor Q: 0.001 to 1000


• Reflection Coefficient: 0.0000 to ±1.0000


• Phase Angle: ±0.01° to 180.00° Measurement Speed


• Normal mode (running average): ~800 ms


• High-speed mode (instantaneous): ~250 ms DC Bias


• Internal: ±40 V in 10 mV steps with auto-sweep function


• External: ±40 V maximum, 100 mA maximum input current

Key Features

• Basic accuracy of 1% across many impedance elements


• Dual measurement modes for flexibility between speed and averaging


• Internal and external bias capability for component characterization under load


• IEEE-STD-488 (HP-IB) control and data transfer


• Optional analog voltage outputs for X-Y recorder interface (Option 004)

Typical Applications

• RF component characterization and quality assurance


• Electronic material impedance profiling


• R&D circuit validation across MHz to GHz frequencies


• Systems integration validation

Compatibility & Integration HP-IB interface enables remote control and automated measurement sequences. Optional analog output channels support direct graphical recording. Operating temperature range 0°C to 55°C; power requirement 100/120/220/240 VAC, 48–66 Hz, 150 VA maximum. Dimensions: 425.5 mm × 230 mm × 574 mm; weight approximately 24 kg.