RF interference choke device and RF testing apparatus incorporating the same

A radio frequency (RF) testing apparatus for an electronic device under test (DUT) that includes an antenna element unit, said RF testing apparatus comprising:

• a platform used to support the electronic DUT thereon;
• an impedance matching circuit board mounted to said platform and used to be electrically connected to the antenna element unit of the electronic DUT when the electronic DUT is disposed on said platform for providing impedance matching between the antenna element unit and at least one coaxial cable, which is electrically connected to said impedance matching circuit board to serve as a transmission line for signals transmitted to or outputted from the antenna element unit of the electronic DUT;
• and
• at least one RF interference choke device mounted to said at least one coaxial cable for reducing transmission of RF interference signals originating from outside of said at least one coaxial cable, each of the RF interference signals having a frequency within one of a first frequency band and a second frequency band that are different from each other, each of said at least one RF interference choke device including a planar dielectric board having a first board portion, a second board portion that is opposite to said first board portion in a lengthwise direction of said dielectric board, and a third board portion that interconnects said first and second board portions, said first board portion being formed with two elongate first slots that extend in the lengthwise direction, that are arranged symmetrically about a central line of said dielectric board parallel to the lengthwise direction and that have a first length associated with the first frequency band, said second board portion being formed with two elongate second slots that extend in the lengthwise direction, that are arranged symmetrically about the central line and that have a second length associated with the second frequency band, said third board portion being defined between said first and second slots, and
• a metal layer that is attached to said dielectric board and that connects with a respective one of said at least one coaxial cable, said metal layer having a U-shaped first pattern that is disposed on said first board portion and that surrounds said first slots, a U-shaped second pattern that is disposed on said second board portion and that surrounds said second slots, and a strip-shaped third pattern that extends along the central line and that interconnects integrally said first and second patterns.