A finite 3D field simulation method for permittivity gradient implementation of a novel porosification process in LTCC

High frequency substrates show a manifold variety of complex permittivities for different applications. Recent research results demonstrated the possibility of local decrease of the permittivity on LTCC by chemical etching processes, which enables the design of high quality antennas on LTCC. This paper shows a novel approach on the determination of the quantitative reduction of the effective permittivity by scanning electron microscope analyses in combination with finite 3D field simulations of the resulting inhomogeneous material. By the characterization of two different porosified LTCCs it could be shown that this process is suitable for direct antenna integration on glass-ceramic substrates with enhanced values of relative permittivities.