In-Situ Free-Space Dielectric Testing of Unclad Substrates
Non-destructive free-space characterization evaluates bulk dielectric properties of raw unclad laminates without etched coupon waste or copper interface errors.
Spot Focusing Horn
Concentrating Aperture
Focusing of microwave energy into a small spot allows for the localized measurement of material properties without the interference of edges or mounting fixtures. The spot focusing horn incorporates a plano-convex or biconvex lens at the mouth of the antenna to converge the radiated energy. This configuration creates a small region of high power density at a specific distance from the device.
Inspection Utility
Characterizing small samples or scanning large panels for uniformity requires a beam that does not spread over a large area. By using a spot focusing horn, an inspection system can resolve variations in dielectric constant or thickness with high spatial resolution. The lens corrects the spherical phase front emerging from the horn into a planar or converging front.
This focal point is where the material is placed to achieve the highest sensitivity to transmission losses. Careful calibration removes the effects of the lens and the internal reflections within the horn structure. Manufacturers use this setup to map the quality of radomes or high-frequency substrates before assembly.
Focal Depth
The distance over which the beam remains focused is limited by the laws of diffraction. Beyond this range, the spot focusing horn loses its ability to isolate small features, and the measurement becomes an average of a larger surface area.