Microwave analysis of Ti-doped ZnAl2O4 and Mg-Co-doped variants

Abstract This study investigates zinc aluminate (ZnAl 2 O 4 , denoted as Z)-based microwave dielectric ceramics (MDCs) tailored for wireless communication applications, with an emphasis on microstrip patch antenna performance. Titanium doping (ZT) and co-doping with magnesium (ZTM) were employed to enhance essential dielectric parameters, including a near-zero temperature coefficient of resonant frequency (τ f ≈ 0), moderate relative permittivity (ε r < 20), and low dielectric loss. The synthesized ZT sample demonstrated a relative permittivity (ε r ) of 13.49 and dielectric loss (tanδ) of 0.39, while the ZTM composite exhibited ε r = 14.57 and tanδ = 0.158. Antenna prototypes fabricated using these materials showed excellent return losses of –25.96 dB (ZT) and –16.89 dB (ZTM) at an operating frequency of 2.19 GHz, with voltage standing wave ratios (VSWR) below 2, confirming efficient impedance matching. These results position ZnAl 2 O 4 -based MDCs as promising dielectric candidates for S-band microwave and wireless communication systems.