Dielectric properties of new glass-ceramics for LTCC applied to microwave or millimeter-wave frequencies

A new glass-ceramics material called new-glass-ceramics (NGC) that consists of MgAl2O4 crystals (spinel) and highly crystallized Li–Mg–Zn–B–Si–O glass has been developed for microwave or millimeter-wave frequency applications. NGC can be sintered at temperatures below 1000 °C and co-fired with internal copper electrodes that have high electrical conductivity. Its dielectric constant is 7.4 and its Q value is higher than 2000 at 24 GHz. NGC specimens were investigated using X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry (EDX). NGC mainly consists of MgAl2O4, Mg3B2O6, and Li2MgSiO4 crystal phases, which have high Q values. Using NGC, we could make band pass filter (BPF) with the size 3.2 mm × 2.5 mm × 1.3 mm for fixed wireless access (F.W.A.) system at 26 GHz. This BPF can be mounted on circuit board by solder and shows good characteristics.