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Brushable Iron Epoxy Surface Wave Coating


C-RAM 369 and 369-RT (340-2)
C-RAM 369 is a high loss coating which can be brushed or sprayed on metal surfaces to attenuate surface waves. C-RAM 369 is a two component epoxy resin filled with particles having a high magnetic loss tangent in the microwave frequency range.

When an object is illuminated by radar, surface currents are induced to flow on the object, causing it to radiate energy in all directions. Radiation occurs primarily at discontinuities in the skin. These are joints, trailing edges and places where there is a change in contour. Application of C-RAM 369 to these areas will suppress the surface currents and significantly reduce the radiation. The edge of the coating is usually serrated or saw toothed to provide a transition.

C-RAM 369 can be applied to selected parts of antennas to adjust patterns and reduce side lobes. For example, the edge of a parabola can be coated for this purpose. Here again serration of the edge of the coating pointed toward the center is useful. The coating can also be used in transmission line systems as an attenuator.

The coating thickness is applied approx 0.1 – 0.2 mm at a time, and can be built up with multiple coats. Performance depends on wavelength as well as on thickness tapers across the surface. Surfaces should be prepared in accordance with standard procedures. Cuming Microwave can supply information for specific applications.

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