Phase shifter assembly, feeder panel, cavity phase shifter, and base station antenna

A phase shifter assembly comprising:

• a mounting surface for mounting the feeder panel;
• an offset cavity pair comprising a first cavity and a second cavity arranged side by side with each other and separated by a common separation wall, the first cavity having a first hollow channel protruding forward from the mounting surface, and the second cavity having a second hollow channel protruding forward from the mounting surface, wherein a first transmission line is mounted within the first cavity and a second transmission line is mounted within the second cavity;
• and
• a feeder panel for feeding a radiation element, wherein the feeder panel has a feed section extending across the first and second hollow channels, wherein the coupling between a ground surface of the feed section and the offset cavity pair is changed such that the resonance caused by the coupling is at least partially shifted out from a predetermined operating frequency range.