Patent ID: 8670720
Filing Date: 2014-03-11
Classification: H01P,H01Q

Abstract:
1. A device for phase shifting a radio frequency (RF) signal for a base station antenna, the device comprising: a substrate having a top planar surface and a bottom planar surface; a stationary ground plane coupled to the top planar surface of the substrate; a signal line on the bottom planar surface of the substrate, wherein the signal line comprises an input port, an output port, and conducting material, wherein the input port receives the RF signal having a first phase and the conducting material transmits the RF signal across the bottom planar surface of the substrate to the output port, and wherein the RF signal has a second phase at the output port; a plurality of types of defected ground structures on the top planar surface, wherein a first type of defected ground structure is a short stem dumbbell structure and a second type of defected ground structure is a long stem dumbbell structure, wherein the first type of defected ground structure is nested within the second type of defected ground structure, wherein the defected ground structures are operable to shift a phase of the RF signal from the first phase at the input port to the second phase at the output port, and wherein a difference between the second phase and the first phase is a phase shift of the RF signal; and a movable ground plane operable to cover a portion of the plurality of types of defected ground structures, the top planar surface of the substrate, and the stationary ground plane, thereby adjusting the phase shift of the RF signal.