Antenna Characterization – Optical RF-over-Fiber Link: OH4VNA | SPEAG

The OH4VNA is an advanced optical head system designed for precise S11 parameter measurements of electrically small antennas. By replacing traditional coaxial cables with a bi-directional RF-over-fiber link, OH4VNA eliminates cable-induced interference, enabling accurate and repeatable antenna characterization in the 500 MHz to 6 GHz frequency range.

Benefits

• Enables accurate S11 measurements without disturbing the antenna under test
• Eliminates the influence of RF cables on antenna impedance
• Fully passive system requiring no external or battery power
• Transparent to electromagnetic fields for true in-situ measurements
• Compatible with most modern vector network analyzers and simulation tools

Key Features

• Bi-directional RF-over-fiber link for minimal signal distortion
• Frequency range: 500 MHz – 6 GHz
• Based on SPEAG’s proven Time-Domain Sensor (TDS) technology
• Compact, lightweight, and easy to integrate into test setups
• Supports data import/export with Sim4Life and third-party design tools
• Ideal for mobile, body-worn, and implanted device antenna testing

Typical Applications

• Return loss (S11) characterization of electrically small antennas
• Antenna testing in mobile and wearable devices
• In-situ measurements in electromagnetically sensitive environments
• Research and development of compact RF systems
• Integration into automated antenna test platforms