MOL2000T – MOL3000

BALUNS

Small and well-shielded hardware modules designed to combine the signals received from both sensing elements of the free field derivative sensors to one single signal output

Very broadband flat response

Up to 10 GHZ bandwidth

Strong shielded modules

You may use Montena’s passive integrators are used to compensate the derivative behavior of B-dot, D-dot and V-dot sensors. They have 1 megohm output impedance and should be directly connected to the high impedance input of the oscilloscope.

The output electrical signal shall be integrated to recover the measured electromagnetic transient. This can be done by one of the passive integrators Montena has developed or by means of a mathematical integration.

To simplify your process, we recommend our PULSELab software application. It has been specifically designed to ease the measurement of electromagnetic transients with derivative sensors. We also strongly advise you to opt for our fiber-optic links to avoid interferences during measurements.

FAQ

What is a balun and what is its purpose in RF measurements?

A balun (short for balanced-to-unbalanced) is a passive device used to convert a differential signal into a single-ended signal, or the reverse. In practical terms, it allows measurement equipment with standard coaxial inputs to interface with differential sensors or circuits.

In high voltage measurement systems, a balun generates two signals with equal amplitude but opposite phase, creating a balanced pair from a single-ended input or combining differential signals into one output.

Baluns are widely used in RF testing, EMC experiments, and high-speed electronics where differential signals must be connected to oscilloscopes, digitizers, or RF instrumentation.

Why are baluns used with derivative field sensors?

Baluns are specifically used with free-field B-dot or D-dot probes because these sensors output differential signals.

A balun converts this differential output into a single-ended signal compatible with standard measurement equipment, typically 50-ohm coaxial systems. This conversion ensures proper signal transmission and preserves waveform fidelity.

Using a balun also improves measurement quality by maintaining signal symmetry and reducing unwanted common-mode noise. In pulsed electromagnetic environments—such as EMP testing or high-voltage experiments—this helps engineers capture fast transient signals more reliably.

What are the key parameters to consider when selecting a balun?

Several technical parameters determine whether a balun is suitable for a measurement setup:

Frequency bandwidth: the operating frequency range of the device
Insertion loss: signal attenuation introduced by the balun
Amplitude balance: how closely the two differential outputs match in magnitude
Phase balance: how close the phase shift is to the ideal 180° difference
Impedance matching: typically designed for 50-ohm RF systems

These parameters are critical for maintaining signal integrity, especially when measuring high-speed electromagnetic transients or wideband RF signals.

In which measurement setups are baluns typically used?

Baluns are commonly used in high-frequency and electromagnetic measurement environments where differential signals must be interfaced with standard RF instrumentation. Typical applications include:

Pulsed electromagnetic field measurements
EMP and HPM testing setups
High-voltage pulsed power experiments
EMC and immunity testing
Laboratory RF characterization of differential circuits

In these systems, a balun provides a simple and reliable way to connect differential sensors to oscilloscopes, digitizers, or fiber-optic measurement links while preserving signal fidelity.