A critical stage in the development of an antenna, the hardware design is completed using various software and research. The antenna designs being developed in this case includes four antenna patches on a PCB board. The four patches will be arranged in a 2 x 2 layout on the PCB as this is the most efficient layout for beam steering with Butler Matrix. Before the design of the 2 x 2 antenna array can begin however, a single patch design on an infinite ground plane must first be completed. This is done to more efficiently simulate the base parameters needed for the four patches.
Single Patch Design with Radiation Beam at 2.4GHz
Once the design of the single patch on a finite ground plane is complete as shown above, the full array design can begin. In this case, a 2 x 2 was chosen for the purpose of efficiently steering the beam in many directions using Butler Matrix. In order to do this beam steering with Butler Matrix, a directional coupler is connected to the ports of the antenna patches. It then shifts the phase of two ports by 90 degrees to achieve the outputting radiation beam. When none of the ports are being shifted at all, the antenna array outputs a beam straight upward.
2 x 2 Antenna Array with upward Beam Form at 2.4 GHz
2 x 2 Antenna Array with rotational Beam Form at 2.4 GHz
Branchline Coupler response at 2.4 GHz