1D Beam Switching Four Element Microstrip Patch Array Antenna with Planar 90° Hybrid Coupler

This paper designs and simulates a $2 \times 2$ microstrip patch array antenna for one-dimensional beam switching applications in the sub-6 GHz 5G frequency band. It incorporates a planar 90° hybrid coupler to generate a signal with phase difference between two parallel microstrip lines. A vertically flipped “T”-shaped slot line, measuring 0.1 mm in width, has been cut in the ground plane to create a “Magic-T” junction in the middle of the design. This allows the in-phase and out-of-phase signals to propagate separately along the slot line of the ground plane, while the hybrid circuit and patch are positioned on top of the Teflon Glass Fiber substrate. At the Magic-T junction, the $\Sigma$ and $\Delta$ signals from the coupled parallel microstrip lines are split apart and sent to the patches that have a phase difference. According to the simulated findings, the antenna can switch its beam up to a maximum of ±17° throughout the frequency range of 3.44 GHz to 3.60 GHz while maintaining a main lobe gain of more than 20 dB and a side lobe level differential with a main lobe gain of more than 10 dB.