A modified Koch fractal shape is used to decrease the dimensions of an antenna and resonates at more than one band for agricultural application. A new feeding technique of aperture coupled method called a non-uniform annular Photonic Band Gap is applied in order to integrate the designed antenna to the active elements. Subsequently, a transmission line transformer is designed using Genetic algorithm to achieve a perfect matching between the active element (amplifier) and the load (antenna). The proposed antenna is designed and fabricated. The results show that the proposed antenna has a high gain of 20.5 dB, 21 dB, and 22 dB at 0.915 GHz, 1.8 GHz and 2.45 GHz respectively with a compact size and low cost. The results predict its prospect as a promising alternative to the conventional one, which is compatibly applicable to agriculture applications especially when multiband function is required. © 2016 Electromagnetics Academy. All rights reserved.