Agilent/Keysight U1818A

The Agilent/Keysight U1818A is an active differential probe engineered for RF and microwave in-circuit measurements from 100 kHz to 7 GHz. It routes signals between network, spectrum, and signal source analyzers and the device under test, enabling precise component-level troubleshooting and design validation without component removal. Built for R&D and quality assurance teams in wireline, wireless communications, and aerospace/defense sectors, the U1818A delivers low-noise RF probing with high input impedance and minimal loading effects.

– Technical Specifications

Frequency Performance
• Bandwidth: 100 kHz to 7 GHz
• Frequency response flatness: ±1.5 dB
• Noise floor: Less than -130 dBm/Hz (10 MHz to 7 GHz)
• Noise spectral density: <-120 dBm/Hz (100 kHz to 10 MHz); <-130 dBm/Hz (10 MHz to 1 GHz)

Input Characteristics
• Maximum CW input power: 16 dBm
• Maximum DC input voltage: ±10 V
• Single-ended impedance (1 MHz): 25 kΩ
• Differential impedance (1 MHz): 50 kΩ
• Capacitance between tips: 0.09 pF
• Capacitance between tip and ground: 0.26 pF

Output Characteristics
• Nominal probe attenuation: -10 dB
• Output return loss: ≤-13 dB (100 kHz to 7 GHz); ≤-8 dB (7 GHz to 12 GHz)

– Key Features

• Compact, lightweight design for field and bench applications
• Powered via probe power port from compatible instruments or benchtop supply
• Interchangeable probe heads (ordered separately) from InfiniiMax II series
• Compatible with extension cables, attenuator kits, DC blocking capacitors, and probe positioners

– Typical Applications

• RF trace measurement without component removal
• Phase noise and jitter characterization in high-speed digital PCB design
• Network analyzer response calibration
• In-circuit signal validation across RF/microwave circuits

– Compatibility & Integration

Designed for direct integration with Keysight network, spectrum, and signal source analyzers. Supports InfiniiMax II probe heads including N5380B, N5381A, N5382A, and N5425A models.