Advantest U4941 – RF Field Analyzer, 9 kHz to 2.2 GHz, 1 kHz to 3 MHz resolution

The Advantest U4941 is a portable RF field analyzer designed for field strength measurements and EMI analysis from 9 kHz to 2.2 GHz. This lightweight instrument combines wide frequency coverage with selectable resolution bandwidths ranging from 1 kHz to 3 MHz, enabling precise signal characterization in both laboratory and field environments.

Technical Specifications

• Frequency range: 9 kHz to 2.2 GHz


• Resolution bandwidth: 1 kHz to 3 MHz (selectable)


• Display dynamic range: 100 dB


• Input impedance: 50 Ω nominal (U4941/U4941N); 75 Ω nominal (U4941N variant) Signal Integrity


• VSWR (preamplifier OFF): ≤1.5:1 from 100 kHz to 2 GHz; ≤2:1 from 9 kHz to 2.2 GHz


• VSWR (preamplifier ON, 10 MHz to 2.0 GHz): <2:1


• Internal preamplifier gain: 20 dB


• Single-sideband noise floor: -105 dBc/Hz to -100 dBc/Hz


• IF gain uncertainty (post-calibration): <+0.5 dB


• Scale fidelity (post-calibration): +1.5 dB/90 dB logarithmic; <+1 dB/10 dB; <+0.2 dB/1 dB Power & Portability


• AC mains, external DC (+10 to +16 V), or optional battery pack (≈2 hours operation; 1-hour rapid charge)


• Weight: 6.5 kg


• Dimensions: 5.8 × 11.5 × 13 inches

Key Features

• Built-in quasi-peak detector and EMC filters for EMI/RFI measurements


• Reduced dB measurement function


• N-type RF input connector


• Video output (BNC, 75 Ω, 1 Vp-p); phone output (0.2 W into 8 Ω)


• External trigger (BNC) and gate inputs (10 kΩ nominal impedance)


• Two PCMCIA slots for data storage and instrument configuration recall

Interfaces & Control

• IEEE-488 bus connector for spectrum analyzer integration


• RS-232 serial interface (D-SUB 9-pin)


• TTL-compatible external trigger input

Typical Applications Field strength surveys, broadband EMI/RFI characterization, on-site maintenance diagnostics, and frequency spectrum assessments in telecommunications, broadcast, and industrial RF environments.