Agilent/Keysight N4421B

The Agilent/Keysight N4421B is a multiport S-parameter test set that extends Vector Network Analyzer capabilities for complex multi-port measurements. Integrated with PNA and PNA-L series VNAs, it delivers 4-port error-corrected measurements using electronic calibration (ECal) for fast, accurate, and repeatable characterization. The test set eliminates mechanical calibration procedures, reducing setup time and operator-induced measurement errors.

Technical Specifications

Frequency Range: 10 MHz to 50 GHz (Option H67 extends range to 67 GHz when paired with E8361A). Port Configuration: Supports 2-port VNAs for 4-port measurements. Multiport family extends to 16-port capability. Calibration: Electronic calibration via single-connection process. USB-controlled ECal modules operate directly from the network analyzer without external PC. Transmission Loss (Typical):

• 20–30 GHz: −31 dB


• 30–40 GHz: −36 dB


• 40–50 GHz: −41 dB


• 50–60 GHz: −47 dB


• 60–67 GHz: −48 dB


• 67 GHz: −50 dB Switching: Solid-state switches for reliable, high-speed operation.

Key Features

• Direct VNA control via PNA/PNA-L Option 550 or compatible models (E8364B with Option 014)


• Balanced measurement architecture for differential device testing


• Time-domain reflectometry (TDR) enhancements


• Single USB cable integration

Typical Applications

• Wireless infrastructure components and integrated modules


• High-speed digital interconnect characterization


• Signal integrity analysis including eye diagram measurements at elevated bit rates


• RLCG extraction for differential transmission line modeling


• Broadband device modeling with extended calibration range capability

Compatibility & Integration Designed for Agilent/Keysight PNA and PNA-L series network analyzers. ECal modules integrate via USB with no external software or controllers required.