Abstract: The present invention offers significant improvements in the performance of a radio receiver operating in an environment with high desired band interference. The present invention comprises a high selectivity RF circuit that is located between the antenna and the radio receiver, and utilizes superheterodyne technology to filter adjacent channel interference in the desired band frequency spectrum. This type of interference is problematic for IEEE 802.11 radio receivers that are implemented with the popular direct conversion radio receiver architectures. The present invention may be utilized in many types of radio receivers. The high selectivity RF circuit comprises channel select filters, a down-converter, an up-converter and a programmable local oscillator.

Abstract: A conical radiator coupled to an antenna patch disposed along a first end of the radiator, said patch disposed on an insulator. A ground plane is connected to the insulator and a radome is disposed opposite a second end of the radiator. The radome has a first region presenting a convex surface towards the radiator, and the radome has a second region presenting a concave surface towards the radiator. The first end of the conical radiator is the apex of the cone. A ground plane is included and a portion of the ground plane is a planar surface and another portion extends away from the planar portion towards the radome. Also disclosed is a method for forming a radiation pattern by shaping the radome to effectuate a predetermined radiation pattern using localized convex and concave surfaces positioned on the radome at different points in relation to the conical radiator.