Preparation and characterization of doped LiZn0.92Cu0.08PO4 ceramic for microwave and millimeter-wave substrates

Purpose This paper aims to report on fabrication procedure and presents microstructure and dielectric behaviour of LiZn 0.92 Cu 0.08 PO 4 ceramic material with Li 2 CO 3 as a sintering aid. Design/methodology/approach Substrates based on LiZn 0.92 Cu 0.08 PO 4 with Li 2 CO 3 addition were prepared via solid-state synthesis, doping, milling, pressing and sintering. Characterization of the composition, microstructure and dielectric properties was performed using X-ray diffractometry, energy dispersive spectroscopy, scanning electron microscopy, impedance spectroscopy in the 100 Hz to 2 MHz range and time-domain spectroscopy in the 0.1–3 THz range. Findings Doped LiZnPO 4 ceramic, which exhibits a low dielectric constant of 5.9 at 1 THz and low sintering temperature of 800 °C, suitable for low temperature co-fired ceramics (LTCC) technology, was successfully prepared. However, further studies are needed to lower dielectric losses by optimising the doping level, synthesis and sintering conditions. Originality/value Search for new low dielectric constant materials applicable in LTCC technology and optimization of processing are essential tasks for developing modern microwave circuits. The dielectric characterization of doped LiZnPO 4 ceramic in the terahertz range, which was performed for the first time, is crucial for potential millimetre-wave applications of this substrate material.