5G microstrip patch antenna and microwave dielectric properties of cold sintered LiWVO₆–K₂MoO₄ composite ceramics

In this paper, (1-x)LiWVO₆-xK₂MoO₄ (LWVO-KMO, x = 60, 65, 70, 75, 80, 90 wt%) composite ceramics with >92% relative density were prepared by cold sintering at 160 °C under a uniaxial pressure of 300 MPa for 1 h. X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Raman spectroscopy demonstrate that LWVO and KMO coexist without other impurities. (1-x)LWVO-xKMO composite ceramics exhibit relative permittivity (ε_r) ranging from 6.8 to 8.5, microwave quality factor (Q × f) ranging from 2050 to 7182 GHz, and temperature coefficient of resonant frequency (τ_f) ranging from −49 to +25 ppm/°C. Based on cold sintered 30 wt%LWVO-70 wt%KMO composite ceramic with ε_r ~7.8, Q × f ~4514 GHz, and near zero τ_f ~1.3 ppm/°C, a prototype microstrip patch antenna was designed and manufactured. Through testing, it shows excellent antenna performance with a center frequency of 6.58 GHz, a bandwidth of 170 MHz (−10 dB) and a total efficiency of up to 89.5%.