Unidirectional Antenna With Loaded Dielectric Substrate

A unidirectional antenna with loaded dielectric substrate composed of two shorted-circuited rectangular patches and a printed Gamma-shaped probe feed operated at 2.5 GHz is presented. The antenna is fully filled with dielectric substrate isin_r = 2.65. The height of the antenna is only 18 mm. A wide impedance bandwidth of 45.3% (SWR les 2) is achieved. The average gain is about 6.7 dBi. The antenna performance can be improved by introducing of a metallic wall. The backlobe is reduced from -11.1 to -20.1 dB at the lower frequency.