Measurement of dielectric and mechanical properties of LTCC for MMW-band application

In this study, the dielectric and mechanical properties of an alumina-glass based low temperature co-fired ceramic (LTCC) have been investigated. The dielectric properties at millimeter-wave (MMW) band (especially 60 GHz) of commercially available LTCC substrate were measured using cavity resonance method and the mechanical properties were measured by three point bending method. RNE XB substrates manufactured by RN2 technologies have appropriate dielectric properties at MMW band. CBCPW (Conductor backed coplanar waveguide) lines for MMW were designed and also measured. The transmission losses of CBCPW lines on LTCC substrate with tan¿ less than 0.0025 were 0.1 dB/mm. As the tan¿ increased to 0.0032, the losses of CBCPW lines at 60 GHz showed to 0.15 dB/mm wherein this loss value was sufficiently low in the application of LTCC as a packaging technology for MMW band. As expected, the transmission losses of lines critically depended on the dielectric characteristics of the LTCC substrate.