The HP/Agilent 4291B RF Impedance/Material Analyzer measures impedance and material properties from 1 MHz to 1.8 GHz using direct voltage-current measurement techniques. This approach delivers superior accuracy across a wide impedance range—0.1 Ω to 50 kΩ—compared to reflection-based methods, enabling precise characterization of low-inductance components (nH range), low-capacitance devices (1 pF), and dielectric/magnetic materials. Basic impedance accuracy reaches ±0.8% with 1 mHz frequency resolution.
## Technical Specifications
**Measurement Range & Accuracy**
• Operating Frequency: 1 MHz to 1.8 GHz
• Frequency Resolution: 1 mHz
• Impedance Measurement Range: 0.1 Ω to 50 kΩ
• Basic Impedance Accuracy: ±0.8%
• Q Accuracy: Enables low-loss component analysis
**Measurement Parameters**
• Impedance: |Z|, |Y|, θz, θy, R, X, G, B, Cp, Cs, Lp, Ls, Rp, Rs, D, Q, |Γ|, Γx, Γy
• Material Parameters (Optional): Permittivity (|ε’|, ε”), Permeability (|µ’|, µ”)
• Converted Parameters: |G|, U, Gx, Gy
**Stimulus Characteristics**
• AC Voltage Range: 0.2 mVrms to 1 Vrms (1 MHz ≤ f ≤ 1 GHz); 0.2 mVrms to 0.5 Vrms (1 GHz < f ≤ 1.8 GHz)
• AC Current Range: 4 µArms to 20 mArms (shorted terminal); 4 µArms to 10 mArms (50 Ω termination)
• AC Voltage Resolution: 2 mV @ 110 mVrms < VOSC ≤ 500 mVrms
• AC Current Resolution: 50 µA @ 2.75 mArms < IOSC ≤ 12.5 mArms
• Output Impedance: 50 Ω (nominal)
• Basic OSC Level Accuracy: ±2 dB + 6 dB × f[MHz]/1800 @ 23 ±5°C (terminated with 50 Ω, V ≤ 250 mV)
**DC Bias (Option 001)**
• DC Voltage: 0 to ±40 V with 0.1% + 4 mV accuracy
• DC Current: 0 to ±100 mA with 0.5% + 30 µA accuracy
**Frequency Reference**
• Standard Accuracy: < ±10 ppm/year @ ±5°C
• Precision Reference (Option 1D5): < ±1 ppm/year @ 0°C to 55°C (referenced to 23°C)
**Calibration & Compensation**
• Calibration Types: Open/Short/50 Ω, Low Loss CAL
• Compensation: Open/Short/Load, Port Extension, Fixture Electrical Length
## Key Features
• Direct voltage-current measurement eliminates systematic errors inherent in reflection techniques
• Wide impedance measurement span accommodates passive components and material samples
• Optional DC bias for parametric analysis under operating conditions
• Advanced calibration and error compensation improves fixture-related accuracy
• Precision frequency reference option available for temperature-stable applications
## Typical Applications
• R&D characterization of inductors, capacitors, and passive RF components
• Quality control testing of surface-mount and integrated circuit packages
• Thin-film device evaluation
• Dielectric and magnetic material property measurement
## Compatibility & Integration
The instrument operates with standard 50 Ω measurement fixtures and supports fixture electrical length compensation for improved repeatability across different test configurations.
