Temperature‐Compensated LiMgPO₄: A New Glass‐Free Low‐Temperature Cofired Ceramic

Abstract

The feasibility of LiMgPO4 (LMP) ceramic for low‐temperature cofired ceramic (LTCC) application was investigated. The ceramic was prepared by the conventional solid‐state ceramic method. The ceramic sintered at 950°C showed a relative permittivity (ɛr) of 6.6 and high quality factor (Qu×f) of 79 100 GHz with a τf of −55 ppm/°C. The relatively large negative τf value was lowered by preparing LMP–TiO2 composite. The composite with 0.12 volume fraction TiO2 showed good microwave dielectric properties: ɛr=10, Qu×f=26 900 GHz, and τf=+1.2 ppm/°C. LMP–TiO2 composite did not react with the commonly used electrode material silver.

Casting and characterization of LiMgPO4 glass free LTCC tape for microwave applications

“…14 The LiMgPO 4 ceramic has good microwave dielectric properties: ε r = 6.6, Q u × f = 79,100 GHz and τ f = −55 ppm/ • C. The ceramic is also chemically compatible with Ag. 14 In the present work we report the dispersion and tape casting of LiMgPO 4 ceramic with an objective to develop a low loss glass free LTCC tape for microwave applications.…”

“…6 Some glass free ceramics have also been reported for LTCC applications. [7][8][9][10][11][12][13][14][15] In our previous work we reported the microwave dielectric properties of LiMgPO 4 ceramic which can be sintered at 950 • C without any glass addition. 14 The LiMgPO 4 ceramic has good microwave dielectric properties: ε r = 6.6, Q u × f = 79,100 GHz and τ f = −55 ppm/ • C. The ceramic is also chemically compatible with Ag.…”

Effects of P2O5/TiO2 ratio on the sintering behavior and microwave dielectric properties of TiP2O7

“…Both pyrophosphates and orthophosphates have good microwave dielectric properties coupled with a relatively low sintering temperature below 1200 1C. Recently, a forsterite type phosphate LiMgPO 4 was reported to have low sintering temperature and excellent microwave dielectric properties among the phosphates [8]. However, to the best of our knowledge, no work about the microwave dielectric properties of pyrophosphates with tetravalent cations has been reported.…”

B2O3-modified fused silica microwave dielectric materials with ultra-low dielectric constant

“…[1][2][3] The microwave substrate material should have a low dielectric constant (ε r ) to shorten the phase delay, high Qf value to reduce the power dissipation, and low temperature coefficient of resonant frequency (τ f ) to maintain the temperature stability of microwave circuits. Low-dielectric-constant ceramics are the most important microwave substrate materials, [4][5][6][7][8][9][10][11][12] for which the dielectric constant is usually between 5 polymer-ceramic composites and glass ceramics, the Qf value is usually relatively low. 3,13 On the other hand, SiO 2 polymorphs are important insulating materials with very low dielectric constant around 4 and low dielectric loss, indicating their possible applications as microwave substrates.…”