Frequently asked questions on the eoSense opto-electronic converter

The purpose of these Frequently Asked Questions (FAQs) is to answer most of questions in order to help you to better understand the measuring performances and advantages of using Kapteos technologies inside the applications.

FAQS on eoSense instrument

General frequently asked technical questions

The main question to ask yourself is the frequency bandwidth of the electric field to be measured.
To date, 7 choices of converters are available:

  • 40 Hz to 30 MHz (eoSense LF-30S)
  • 1 kHz to 1 GHz (eoSense MF-01U)
  • 100 MHz to 10 GHz (eoSense HF-10)
  • 100 MHz to 20 GHz (eoSense HF-20)
  • 20 kHz to 40 GHz (eoSense HF-40)

Which ever version of the chosen converter, the probe will work on any of the converter (after calibration at Kapteos).

Above 40 GHz, systems are proposed on requirement.

Before an eventual purchase, Kapteos offers 3 possibilities of service:

  • A theoretical approach based on an online simulation software available at the following address:
  • The rental of an equipment
  • The measurements made by Kapteos in your application (in your premises or in an already installed application)

If the required document is not available on our website, please contact your local supplier or Kapteos by email at, or by telephone at +33 (0)4 79 62 88 34 from Monday to Friday from 9:00 to 12:00 a.m. and 2:00 p.m. to 5:00 p.m.

The converter is routinely calibrated at delivery. A calibration certificate is supplied with the unit. This calibration is valid for 2 years. It is strongly recommended that a calibration renewal request is applied at least 2 months before the expiry date as the renewal procedure requires the return of the equipment at Kapteos and involves a complex tooling.
In no event, the calibration is done by Kapteos at the customer’s plant.

At maximum, the eoSense converter can measure 3 channels, so 3 probes (one channel = one probe). If you need to connect more than 3 probes, Kapteos proposes an accessory called eoSwitch. This accessory (under development) enables up to 48 probes to be connected to a single eoSense converter.

No because of the calibration procedure. A probe must be always connected to the same input channel. On top of that, the real-time antenna factor correction involves to have always the same probe at the same input channel.

A user guide shows all the conditions of use of the converter and particularly thermal conditions which must be between 15 and 30 °C. The maximum and minimum temperatures must be respected because they strongly affect the correct functioning of the system.

This is a very important point in the operation of the eoSense converter.
As a matter of fact, the antenna factor enables:

  • To calculate in real time the absolute value of the electric field
  • To measure in real time all the errors due to the measurement chain (from the probe to the converter output) due to the environment of the measurement (temperature, humidity …). This correction also takes into account almost all the frequency band to be measured and not a single frequency.

With this performing system, the eoSense converter allows the electric field measurement outside a laboratory temperature-regulated room and thus make extremely repetitive field measurements.
This antenna factor is available through an analogue electrical signal for each channel of the device.

To be more precise on the antenna factor/normalisation factor

The E-field is calculated as follows: E (V/m) = E ref / NF * V out with

  • E (V/m) = measured electric field in volts per meter (V/m)
  • E ref = the calibration value of the eoSense converter related to the concerned channel (one E ref per channel)
  • V out = voltage available on the bottom channel connector of eoSense which is connected to your instrument (oscilloscope, VNA, spectrum analyser…). This voltage is an analog value always present and is a proportional value to the measured electric field.
  • NF out = voltage available on the upper channel BNC connector of eoSense. This voltage is an analog value always present and is related (for each channel) of the losses, drifts, frequencies….

So, to measure an electric field in V/m, you have to:

  • Connect V out (bottom output connector of eoSense converter) to your instrument to channel 1 for exemple
  • Connect NF out (upper output BNC connector of eoSense converter) to your instrument to channel 2 for exemple
  • Apply the above formula

If you do not have enough inputs on your instrument (oscilloscope for exemple), you may follow the following steps:

  • Connect V out (bottom output connector of eoSense) to your instrument to channel 1 for exemple
  • Perform the measurement
  • Export the antenna factor (AF) values (values shown on the main software window) of eoSense
  • Synchronise (with the time) the file from the measured values V out with the exported file from eoSense
  • Apply the following formula E (V/m) = AF * V out

The following elements are available for sale:

  • eoSwitch to connect from 4 up to 48 probes onto an eoSense converter
  • eoLink to extend the fibre optic length between the converter and the probe

For further information on these items, please contact Kapteos by email at, or by telephone at +33 (0)4 79 62 88 34 from Monday to Friday from 9:00 to 12:00 a.m. and 2:00 p.m. to 5:00 p.m.

When Kapteos develops a new software version of the converter, this one is sent by email to the customer.
A PDF installation guide is provided to help you in the few installation steps.

Yes. Kapteos offers trainings at the customer’s plant in order to understand all the possibilities offered by the many features of the eoSense converter. This training is compulsory and performed by Kapteos experts.

For further information on these trainings, please contact Kapteos by email at, or by telephone at +33 (0)4 79 62 88 34 from Monday to Friday from 9:00 to 12:00 a.m. and 2:00 p.m. to 5:00 p.m.