Abstract: An antenna structure has a radiating element and a ground plane. The ground plane has a central region relatively closely spaced apart from the radiating element and a peripheral region extending away from the central region. The peripheral region comprises at least one conductive layer that extends radially beyond the radiating element and provides a sheet resistivity higher than that of the radiating element. Though physically small, the ground plane simulates an infinite ground plane, and the antenna structure reduces multipath signals caused by reflection from the earth.

Abstract: An antenna structure has a radiating element and a ground plane. The ground plane has a central region relatively closely spaced apart from the radiating element and a peripheral region extending away from the central region. The peripheral region comprises at least the conductive layer that extends radially beyond the radiating element and provides a sheet resistivity higher than that of the radiating element. Though physically small, the ground plane simulates an infinite ground plane, and the antenna structure reduces multipath signals caused by reflection from the earth.

Abstract: An antenna structure has a radiating element and a ground plane. The ground plane has a central region relatively closely spaced apart from the radiating element and a peripheral region extending away from the central region. At least the peripheral region of the ground plane has a sheet resistivity that increases as radial distance from the central region increases. Though physically small, the ground plane simulates an infinite ground plane, and the antenna structure reduces multipath signals caused by reflection from the earth.

Abstract: An antenna system comprises a stack of elements that include a GPS patch antenna on a groundplane with an associated low-noise amplifier (LNA), a first Faraday shield of flat ribbon cable covering a first ferrite rod magnetic field antenna, a second ferrite rod magnetic field antenna separated from and orthogonal to the first ferrite rod magnetic field antenna, a second Faraday shield of flat ribbon cable covering the second ferrite rod magnetic field antenna and having a LNA for each of the ferrite rod magnetic field antennas. A third Faraday shield is positioned between the first and second ferrite rod magnetic field antennas. All the Faraday shields are connected to ground such that there are no loops that may act as shorted turns to avoid desensitizing the ferrite rod magnetic field antennas.