Print a small size U-shape-modified broadband slot antenna on ceramic substrate

A microstrip-line-fed U-shaped modified slot antenna is designed and fabricated on AI₂O₃ ceramic substrate using the printing method. The influences of the length of microstrip-fed line and the thickness of AI₂O₃ ceramic on the characteristics of designed antennas are well defined in this study. As compared to other available current designs, the proposed structure of the fabricated antennas would offer the advantages of large bandwidth, large return loss, low profile and easy fabrication. Due to the larger dielectric constant of AI₂O₃ ceramic, the fabricated antenna has a small ground plane size of 30 mm x 30mm, and that is smaller than the slot antennas fabricated on a FR4 substrate. The fabricated slot antenna has a broad bandwidth of 275 MHz/8.9%, a high return loss of -28.0 dB and a maximum gain of 2.77 dBi at 3.12 GHz.