Broadband flat absorber: clear absorption for variable scenarios

What is a broadband flat absorber – use & benefits

A broadband absorber is a lossy RF material (microwave absorber) that reduces reflected energy in the high-frequency range across a wide band. It shows its strengths when boundary conditions change – from frequency to angle of incidence – for example in EMC tests, antenna/OTA measurements and in the validation of radar and lidar sensor technology for autonomous driving. The result: clearer signals, fewer interfering reflections and reliable measurement conditions.

Specifications & Variants – ESorb MLA/OFA/EA2/EA5

ESorb broadband solutions are available based on polyurethane, urethane or silicone – with practical temperature windows and frequency covers (customer specifications):

• ESorb MLA (polyurethane): up to +90 °C, > 0.8 GHz
• ESorb OFA (polyurethane): up to +90 °C, > 5 GHz
• ESorb EA2 (urethane): up to +120 °C, 4-60 GHz
• ESorb EA2-S (silicone): up to +170 °C, 4-60 GHz
• ESorb EA5 (urethane): -40 °C to +120 °C, 1-12 GHz
• ESorb EA5-S (silicone): -40 °C to +170 °C, 1-12 GHz

This covers the UHF to EHF series and is customized as a drawing part according to your specifications. As microwave absorbers in the high-frequency range, they support stable measuring conditions and reproducible results.

Performance data & thickness – making a methodical selection

Thickness is crucial for effectiveness, especially in lower bands. For a well-founded decision, a clear process has proven its worth – or to put it another way: How thick do broadband flat absorbers need to be in order to reliably address your target band?

• Define target band & installation space: Define frequency window, check available installation depth.
• Compare variants: Test two to three material/thickness options in the real structure.
• Consider the environment: Select surface/substrate, cleaning, temperature and installation.

A brief comparison of the structure quickly shows which combination delivers the desired reflection reduction – without over-engineering.

Materials & principle – Dielectric Absorber Foam

Dielectric Absorber Foam uses a coordinated material structure for broadband impedance matching and damping. These variants combine dielectric and magnetic losses – advantageous when thinner layers are required or angles of incidence vary greatly. Which line is suitable depends on the band and installation space – matching the desired damping characteristics; the selection is made on an application-specific basis and without any blanket numerical promises.

Applications in practical setups – sensor technology in a variety of scenarios

Broadband flat absorbers stabilize measurement and operating conditions wherever reflections need to be reduced – in the laboratory and in the field:

• Free space/EMC setups: attenuate room reflections and create defined field conditions.
• Antenna & OTA measuring stations: Reduce multipath effects and increase repeatability.
• Sensor technology (radar/lidar): Reduce interfering reflections, stabilize detection – practical for automotive scenarios involving autonomous driving.

ESorb materials also calm internal reflections in test housings and measuring boxes. They improve the reflection behavior in the high-frequency range – a basis for reproducible tests of sensor technology, e.g. for Autonomous driving. You can find a classification of alternative solutions at Narrow-band flat absorbers and cavity absorbers.

Differentiation – broadband vs. narrowband vs. cavity

Broadband is the first choice when general conditions change – from the frequency component to the angle of incidence. For narrow bands with high attenuation in the target area, we recommend Narrowband flat absorbers. If standing waves occur in volumes, cavity cavity absorbers calm the internal field.

When narrowband provides the targeted attenuation

If the focus is on a specific band and the attenuation is to be maximized precisely there – for example in defined test setups – narrowband flat absorbers demonstrate their precision.

When cavity absorbers calm resonances

For standing waves in enclosures or measuring rooms, cavity absorbers minimize internal reflections and create more homogeneous conditions for reproducible results.

Procurement & assembly – Buy broadband absorbers according to specification

E.S. Electronic Service manufactures ESorb materials as panels, contours or sets. The microwave absorbers are tailored to the specific project – from carrier and surface to assembly. We recommend a short test with two thicknesses/materials in a real setup to quickly find the right solution. The specification and carrier are coordinated on a project-specific basis – as is the installation.

Get in touch with us

Contact us You will receive sound advice including samples and data sheets. On request, we can prepare a quotation and manufacture to specification.