Over the past decades, with the rap

Over the past decades, with the rapid developments of wireless communications, microwave (MW) dielectric ceramics have been widely investigated as critical components of passive microwave devices such as substrates, resonators and filters, [1,2]. Furthermore, to satisfy the demands of miniaturization and multifunction of modern electronic devices, low temperature co-fired ceramic (LTCC) technology has attracted much attention from both scientific and industrial stakeholders. For LTCC applications, the densification temperature of the microwave dielectric ceramics should be lower than the melting temperatures of metallic electrodes such as Ag (~961 ◦C)[3–6].The sintering temperature of most ceramics (1200 ◦C) clearly exceeds the melting temperature of the electrodes, thereby precluding co-firing. The most common strategy to reduce the sintering temperature is the addition of a low melting point component [4,4,5,6]. Unfortunately, this leads to the formation of secondary phases with inferior dielectric performance. Hence the reduction of sintering temperature is accomplished at the expense of MW quality factor.