Designed wide-band microstrip line-fed T-shaped antenna on the Al ₂O₃ substrate

Recently, there have been rapid and great developments in wireless communication, the operation frequency increase and the size of the microwave devices reduces gradually. Substrates play an important role in the design and fabrication of the small-size microwave devices, especially the dielectric constant and quality factor. In this study, we are tried to design the wide-band microstrip line antenna on ceramic substrate in order to reduce the size of fabricated antenna. High quality factor A1₂O₃ ceramic is adopted as the substrate and the influences of the structure (the metal of covering and the length of ground) are also investigated in this thesis. Due to the larger dielectric constant of A1₂O₃ ceramic (£₁=9.8), the size of this antenna is small (25 mm 20 mm). For the designed antenna, the resonance frequency is near 4.2 GHz, the optimum bandwidth is 760 MHz (18.1%), and the return loss (S₁₁) is -36.77 dB. The gain of fabricated antenna is acceptable for the application in the communication.