This work addresses the pedagogical disconnect between digital circuit design and electromagnetic theory in engineering education by presenting a cross-disciplinary teaching case that integrates digital control based on a field-programmable gate array (FPGA) with a smart reflectarray antenna system. The objective is to establish a unified “theory–simulation–design” learning framework that enables students to comprehend both the hardware description language (HDL) programming of FPGAs and the physical principles governing antenna array beamforming, thereby bridging the knowledge gap between digital systems and applied electromagnetics.

The methodology focuses on the co-design of a 1-bit electronically reconfigurable reflectarray unit cell and its FPGA control architecture, implemented across four key stages. First, we selected a reflectarray architecture, rather than phased arrays or transmitarrays, due to its favorable balance of system cost, pedagogical clarity, and fabrication feasibility. The system consists of a feed horn antenna that illuminates an 8 × 8 planar aperture. Second, we designed the unit cell of the reflectarray as a multi-layer microstrip patch structure, with the dimensions 29 mm × 29 mm, operating at a center frequency of 5.2 GHz. The stack of the cell employs two F4B substrates and an RO4450F bonding layer, with a total thickness of 2.6 mm. Each unit cell integrates a PIN diode with DC-biasing circuitry, enabling binary control of the reflected phase. Full-wave simulations under periodic boundary conditions confirm that within the 5.15–5.26 GHz band, the phase difference of the reflection between the ON and OFF states of the diode is approximately 180°, achieving robust 1-bit phase quantization with a reflection loss below −1.5 dB. Third, the FPGA serves as the central controller. The target beam directions are calculated using array theory to derive the required phase compensation map across the aperture. This map is quantized into a binary matrix, where logical “0” corresponds to the OFF state of the diode, while logical “1” corresponds to the ON state. Fourth, the FPGA distributes these binary signals to individual array elements via a shift register architecture, enabling parallel and real-time reconfiguration of the phase gradient of the aperture. This design allows rapid beam switching simply by updating the phase encoding matrix stored in the FPGA memory.

Simulation results for the 8 × 8 reflectarray with a feed distance of 183 mm demonstrate effective beam steering within a ±30° scanning range in both the xz and yz planes. The synthesized radiation patterns exhibit well-defined main lobes aligned with the specified steering angles. Sidelobe levels and cross-polarization components remain consistently low across the entire scanning range, confirming that the 1-bit phase quantization controlled by the FPGA does not introduce significant pattern degradation. The reflectarray achieves a realized gain of approximately 15 dBi, which is primarily limited by the relatively small number of unit cells and feed blockage effects. Nevertheless, the simulation outcomes successfully validate the core concept of the teaching case: direct manipulation of electromagnetic wavefronts through FPGA-driven digital logic.

This teaching case effectively integrates antenna array theory with FPGA-based digital control technology, providing an integrated learning pathway from theoretical analysis and hardware-oriented design to simulation validation. The approach dismantles traditional disciplinary barriers, enabling students to develop practical skills in Verilog HDL programming and antenna simulation while cultivating systems thinking essential for addressing complex engineering challenges. This case provides a replicable pedagogical model for developing engineering professionals with interdisciplinary expertise in digital control and applied electromagnetics.