Patent ID: 7696948

Claim:
An antenna system comprising: a first monopole element; and a second monopole element; a phase shift element directly connected to a first end of the first monopole element and directly connected to a first end of the second monopole element, the phase shift element connecting first end of the first monopole element to the first end of the second monopole element; a first switch which controllably connects a radio signal to the first end of the first monopole element; a second switch which controllably connects the radio signal to the first end of the second monopole element; wherein when the first switch connects the radio signal to the first end of the first monopole element, the second switch disconnects the radio signal from the first end of the second monopole element, the radio signal directly drives the first monopole element and drives the second monopole element after passing through the phase shift element and radio signals radiated by the two monopole elements add constructively in a first direction; and wherein when the first switch is opened, disconnecting the radio signal from the first end of the first monopole element, the second switch is closed connecting the radio frequency signal to the first end of the second monopole element, the radio signal directly drives the second monopole element and drives the first monopole element after passing through the phase shift element; wherein an adaptive distance between the first and second monopole elements is selected such that the radio signals radiated by the two monopole elements add constructively in a second direction.