A parabolic horn antenna designed for use as a high isolation antenna array in a wireless Internet access system where a high concentration of transceivers at one location is required. The rear, reflecting surface of the horn part of the antenna is a parabolic shape with the probe located at the focal point of the parabola. The sides of the antenna in the broad dimension are angled at an optimum degree increasing the opening aperture allowing the system to capture more RF energy. The length, therefore the aperture width is variable providing control over the gain of the system thus providing effective shielding and isolation for more dense antenna arrays.