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.

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]}