Design of multi-beam phased array antennas for coastal disaster preventing radar system

The proposed antenna was designed with a multilayer feeding structure that combines microstrip line and slot elements in order to control the phase characteristics of the antenna. The simulated reflection coefficients of the antenna fed by port #1 and port #2 obtained approximately -28 dB and below -35 dB at the center frequency, respectively. The isolation between two ports obtained excellent characteristics of -20 dB. The phase control method was utilized by the control of the lengths of the transmission lines connected to the ports. The phases of 4 patches fed at port #1 were appeared in the same ones. In case of port #2 feeding phase of two patches was shown in the same one while phase of the other two patches was obtained in the out-of phase.