Moving the Golden Standard from the ideal, virtual world to the real world presents a more complex set of problems. Any manufacturing process introduces dimensional tolerances which must be considered and quantified. The standard device must be constructed from real world materials as opposed to ideal mathematical representations. This introduces the significant challenge of characterizing the electrical properties of the materials and establishing tolerances for those properties.
For example, with the Samtec Golden Standard structure, some critical physical dimensions are conductor thickness, dielectric thickness uniformity, trace widths, trace pitch, ground plane spacings, overall flatness, and length.
A similar challenge is faced in accurately characterizing the electrical properties of the
dielectric material such as loss tangent and dielectric constant. Nominal values are usually attainable, but batch to batch variations can be much more difficult to quantify.
To establish correlation at frequencies above the 10 GHz range, PCB Assembly Golden Standard boards have been precision milled from tight tolerance substrate materials. Golden Standard boards which are included in the free kit are manufactured using high end commercial etch and laminating processes and tight tolerance materials. While tolerances are not as tight as those obtained with a milling process, they have been found to be acceptable for many correlation studies up to several GHz.
Golden Standard boards are constructed from FR4 laminate dielectric. FR4 is used in a
wide variety of applications and is readily available. Variability in the dielectric properties of FR4 is not as well controlled as in some more expensive substrate materials. Variation in dielectric properties can become an important factor in differences between board samples at higher frequencies. Samtec Golden Standard boards are constructed from substrate materials which are carefully ed to ensure acceptable physical and electrical consistency from batch to batch.
One of the greatest challenges in constructing a physical board is in devising a means to connect it to test instrumentation. pcb assembly For the Golden Standard boards, SMA connectors are used as they are PCB Assembly nearly universal. The transition between the circular coaxial structure of the connector to the planar PCB microstrip structure can introduce effects not predicted by the analytical solutions in some parameters at higher frequencies.