Patent ID: 7499036

Claim:
An antenna apparatus that controls the magnitude and gradient of a radiated electric field, including an antenna comprising: a) a voltage divider having at least two electrical contacts coupled to it; b) a plurality of spaced apart, low resistance, finger elements coupled to the voltage divider at intervals between the at least two contacts, such that the electrical potential along a long axis of each element is approximately uniform and each finger element radiates at an electric potential that is a function of the potential on the voltage divider where the element is coupled, wherein the voltage divider is a resistive divider; and c) a processor coupled to the voltage divider, wherein the processor sends commands to a drive signal transmitter, the commands causing the transmitter to send a sequence of three drive-signal states to the voltage divider, the three states comprising: i) zero voltage to the voltage divider, ii) a gradient voltage to the voltage divider, and iii) a constant voltage to the voltage divider.