Phased array antennas and methods for controlling uniformity in processing a substrate

A system for directing a main beam towards a gap within a plasma chamber, comprising:

• a first power source configured to generate a first radio frequency (RF) signal;
• a plurality of attenuation elements coupled to the first power source via a connection point, wherein the plurality of attenuation elements include a first attenuation element and a second attenuation element, wherein the connection point is configured to split the first RF signal into a plurality of input signals, wherein the plurality of input signals include a first input signal and a second input signal, wherein the first attenuation element is configured to receive the first input signal to output a first attenuated signal and the second attenuation element is configured to receive the second input signal to output a second attenuated signal;
• a plurality of phase shift circuits coupled to the plurality of attenuation elements, wherein the plurality of phase shift circuits include a first phase shift circuit and a second phase shift circuit, wherein the first phase shift circuit is configured to receive the first attenuated signal to output the first attenuated signal, wherein the second phase shift circuit is configured to receive the second attenuated signal and modify a phase of the second attenuated signal to output a phase-shifted signal;
• a plurality of antenna elements coupled to the plurality of phase shift circuits, wherein the plurality of antenna elements include a first antenna element and a second antenna element, wherein the first antenna element is configured to receive the first attenuated signal from the first phase shift circuit and the second antenna element is configured to receive the phase-shifted signal from the second phase shift circuit to form the main beam that is directed at an angle towards the gap within the plasma chamber.