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Honeycomb Waveguide – An Attenuation Performance Explanation of a MAJR Products Honeycomb Waveguide Panel due to the Effect of a Waveguide Beyond Cuttoff Principle
What is a honeycomb Waveguide panel?
A shielding honeycomb waveguide panel is a product that lets air flow into and out of an EMI/RFI shielded enclosure. The entering fresh air may be either cooled, heated, or at ambient temperature depending on the shielded enclosure environment and contents. For electronic equipment, the primary reason for airflow is usually to cool electronics; if a manned military shelter the reason is to circulate fresh air and to either cool or heat the air depending on the external environment.
How a shielded honeycomb waveguide panel attenuates
Depending on the wavelength of the electromagnetic wave entering the honeycomb waveguide panel, every cell of the metal honeycomb core provides attenuation (shielding) to that electromagnetic wave and is described as a waveguide below cutoff.
Each individual honeycomb cell acts as a waveguide and because the honeycomb cell aperture (height and width) is much smaller than a half wavelength of the electromagnetic wave entering the honeycomb, the honeycomb cell attenuates the wave.
Attenuation is accomplished by increased wave impedance and reflection cancellation as the electromagnetic wave propagates through the honeycomb waveguide thickness and number of cells. The thicker the honeycomb cell, the more attenuation the honeycomb panel will provide, therefore an approximation is Attenuation (dB) = 28 x Thickness / width.
Depending on the polarization of the electromagnetic wave, the only frequencies of the electromagnetic wave that pass without attenuation through the honeycomb cells are those that have a half wavelength dimensionally smaller than the diagonal dimension of the cell.
Applications of a Shielded Honeycomb Waveguide Panel
- Custom honeycomb panels designed to meet specific shielding, airflow, and mounting requirements.
- Honeycomb is available in aluminum or steel with tin, nickel, or chromate(aluminum) to meet specific attenuation and environmental requirements of MIL-STD-461 and MIL-STD 810.
- High permeability steel honeycomb available for magnetic (H-Field) shielding to 60 dB attenuation levels. (>80 dB attenuation using 1 in. thick tin plated steel honeycomb).
- Standard and custom sizes and mounting configurations available.
- An EMI/RFI gasket is always supplied as an integral part of the honeycomb vent panel assembly.
- Honeycomb panel mounting is accomplished with either frame thru-holes or captive fasteners located and installed to standard or custom dimensions.
To learn more about MAJR’s Honeycomb Waveguide Panels or other products, like: EMI/RFI Shielded Ventilation Panels, EMI/RFI Shielded Fan Ventilation Panels, EMI/RFI Shielded Air Filtration Panels, or EMI/RFI Shielded Honeycomb Ventilation Panels, visit our website and fill out the form or call us at 877-625-6033.