mm-Wave Complex Permittivity Extraction of LTCC Substrate Under the Influence of Surface Roughness

As many emerging technologies require the use of high-speed signals, understanding dielectric properties materials used in manufacturing printed circuit boards (PCBs) is an essential aspect for accurate designs, especially at millimeter-wave (mm-wave) frequencies. This work demonstrates a methodology extracting complex relative permittivity substrates covering mm-wave For this purpose, low-temperature cofired ceramic (LTCC) substrate was measured up to 85 GHz and its extracted. The approach based on multiline thru–reflect–line (TRL) calibration measuring propagation constant electromagnetic (EM) simulations estimate losses contributed by conductor while accounting surface roughness. An effective obtained, from which actual loss tangent LTCC are estimated values show excellent agreement compared with results obtained via split cavity resonator measurements.