Controlled Reception Pattern Antennas for Global Navigation Satellite System (GNSS)

ABSTRACT: Toyon Research Corporation"s six-element GPS antenna rejects cross polarization over the entire hemisphere by no less than 15 dB when summed in the first fundamental mode of operation. The antenna was designed for a direction-finding application where high levels of multi-path were present. The antenna diameter is 5"and it was designed for operation in the L1 L2 GPS bands. Toyon proposes to modify the current design by replacing the six antenna elements with a thick patch design. The thick patches were designed for an OE-538 submarine mast, and they cover all of the GNSS bands. The thick patches are significantly larger in diameter than the original elements, so the total diameter of the array will go from 5"to no greater than 11.4". Toyon will also add one additional antenna element to the center of the array, bringing the total number of elements to seven. BENEFIT: Geodetic grade GPS antennas on the market today are expensive, need large ground-planes or choke rings, and can be somewhat heavy pieces of hardware. The GPS antenna that Toyon proposes to design for the GNSS solution is ideal in many ways. The antenna does not require a ground-plane and the antenna"s height profile will be less than 1.5". The cross polarization of the antenna is unmatched because of the orientation of the antenna elements. The nulling performance of the antenna is enhanced because of the vertical aperture of the array.