Design and implementation of a patch-fractal antenna with phase control using Butler matrix

Abstract

The study presents the successful design and implementation of a phase-controlled patch-fractal antenna using the Butler array. This work focuses on developing a laboratory prototype of a 4x4 array using microstrip technology. Theoretical conditions are established, and the theoretical basis of the microwave circuits that make up the matrix is described. Each element is individually designed, optimized, and simulated using specialized software (Ansoft Designer and Advanced Design System), and then its performance is verified by evaluating functional parameters. The tested designs are integrated into a single circuit to form the Butler matrix and are subjected to simulation and optimization before manufacturing. The functionality of the components is verified using a vector network analyzer. An analysis of the discrepancy between the measured values and the theoretical target parameters is performed, providing a comprehensive evaluation of the prototype's performance. Implementing the 4x4 Butler matrix together with the design of patch-fractal microstrip antennas has allowed practical phase control, demonstrating its viability in various applications. Results from both simulation and laboratory tests support the ability to direct the radiation lobe in various areas without the need for additional mechanical structures. The applicability of this antenna in short-range radar systems is highlighted, offering flexibility in addressing without compromising essential electromagnetic properties. For future applications requiring more precise control with a more significant number of radiation lobes, a Butler array with more ports is suggested.

Keywords

• butler matrix
• patch-fractal antenna
• micro-strip
• microwave