Choke ring antenna

A choke ring antenna is a directional antenna designed for reception of GNSS signals from satellites. It consists of a number of concentric conductive cylinders around a central antenna.

Patent diagram of a choke ring antenna^[1]

Choke ring antenna at a DGPS Reference Station

The first choke ring antennas were invented at JPL;^[2] since 1989 they have been improved and extended by many companies.^{[citation needed]}

Due to its intricate construction, it is often enclosed in a protective cover or radome when placed outside and exposed to the elements.^{[citation needed]}

Benefits

Choke ring antennas have excellent phase center stability, polarization purity, suppression of radiation below the horizon and multipath rejection.^[3] This makes them highly suited for satellite navigation. In a GNSS ground-based receiver, a choke ring antenna can provide millimeter precision measurements for use in surveying and geological measurements.^[4]

See also

• Trimble Inc. - one manufacturer of this product.
• Patch antenna - a DIRECTIONAL type of antenna.
• Magellan Navigation - another manufacturer of this product.