Millimeter-wave pseudo-vector power density probes

OH4VNA - Optical Head for Vector Network Analyzers

OH4VNA is a bi-directional radiofrequency (RF-) over-fiber link that offers the most reliable means to measure the S11 of electrically small antennas in the 500 MHz – 6 GHz frequency range. Previously, in mobile, body-worn, or implanted devices, the exact measurement of the antenna performance was often seriously hindered due to the presence of RF cables connected to antenna, which change the electrical size of the device and, thus, also the impedance of the antenna to be measured. With OH4VNA, we present a new system, one that is based on our proven time domain sensor (TDS) technology, in which the RF cable to the antenna port is replaced by a non-disturbing fiber-optic system that requires no external or battery power. This is a major breakthrough, as this system is transparent to the RF electromagnetic (EM) fields created by the antenna and, therefore, allows the device to be characterized under fully isolated conditions.

OH4VNA Features

EM Transparent


Fiber-optic technology brings the VNA signals to the antenna port, meaning that there is:

  • no perturbance of the measurement result by a connected cable
  • no disturbance by surface currents from a cable
  • no extension of the ground plane by a cable
  • no need to include chokes, baluns, or ferrites
Wideband 500 MHz – 6 GHz
Miniature and Durable Usage of standard mini SMP connectors for minimized electrical size, highest performance, and durability


The OH4VNA system comes with a calibration kit compatible with mini SMP connectors

Versatile PC-based control software with interfaces compatible with a wide range of VNAs on the market
Design Validation Import of simulation results allows direct comparison of measurement results with design goals
Support High-level support available directly from SPEAG's R&D and advanced application teams in Zurich, with day-to-day support available directly from your nearest SPEAG representative.
LASER Safety Classification IEC60825-1 2007 Class 1
US FDA CDRH registration