<p>The booming evolution of 5G communications urgently necessitates the exploration and development of low-loss dielectric ceramics for microstrip antenna devices. This work focuses on the effect of Sr²⁺ doping on the microwave dielectric properties of Zn_1.8SiO_3.8 ceramics, aiming to explore their application potential in high-frequency communications. The Sr_xZn_1.8−xSiO_3.8 (<i>x</i> = 0–0.03) ceramics were characterized via XRD, SEM, Raman spectroscopy, and dielectric tests. Experimental results demonstrate that over the sintering temperature range of 1260–1290&#xa0;℃, the Sr_xZn_1.8−xSiO_3.8 ceramics exhibit a hexagonal phase belonging to the R3(148) space group. Sr²⁺ effectively lowers the optimal sintering temperature to 1260&#xa0;°C, facilitates more uniform grain growth, and improves the overall microwave dielectric performance within the investigated composition range. Among them, Sr_0.01Zn_1.79SiO_3.8 shows the optimal performance (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">\({\varepsilon}_{r}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>ε</mi> <mi>r</mi> </msub> </math></EquationSource> </InlineEquation>=6.305, <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(Q\times f\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>Q</mi> <mo>×</mo> <mi>f</mi> </mrow> </math></EquationSource> </InlineEquation>=103,695 GHz, <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\({\tau}_{f}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>τ</mi> <mi>f</mi> </msub> </math></EquationSource> </InlineEquation>= − 43.4&#xa0;ppm/°C).Based on this composition, a microstrip patch antenna was designed using CST simulation software, and its performance was assessed by return loss (S₁₁) and voltage standing wave ratio (VSWR). The simulation results reveal that the antenna exhibits S₁₁ characteristics in the 12.2–12.8&#xa0;GHz band, together with outstanding frequency selectivity. These results preliminarily indicate the potential of Sr_0.01Zn_1.79SiO_3.8 ceramics as dielectric substrates for high-frequency microwave devices at the simulation level.</p>