Bandwidth Enhancement for 1bit Reconfigurable Reflection Element by Modifying Microstrip Patch Structures

With the continuous evolution of wireless communication technologies, especially in the current context of the booming development of intelligent reflecting surface (IRS) technology, the 1-bit reconfigurable reflective antenna (1-bit RRA) unit element has become a key component of the IRS array due to its simple structure, low cost, and easy integration. Aiming at the stringent requirements for high-efficiency and stable reflective elements in Ku - band satellite communication scenarios, this paper meticulously designs a 1-bit RRA unit element based on PIN diodes. This design innovatively slots the traditional rectangular patch and adds a ring-shaped rectangular patch. By doing so, it successfully broadens the operating bandwidth of the unit element without changing its original size. The bandwidth of the original unit element is only 12.25-12.75 GHz, while that of the optimized unit element is expanded to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$12.55-13.45\ \text{GHz}$</tex>, representing a significant increase. This improvement is of great significance. A wider bandwidth means that the satellite communication system can flexibly allocate resources across a broader frequency range, effectively coping with complex and variable communication environments. In addition to the expanded bandwidth, the optimized unit element can maintain a stable phase difference of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$180^{\circ} \pm 20^{\circ}$</tex> within the frequency band of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$12.55-13.45\ \text{GHz}$</tex>. Compared with the original rectangular microstrip patch structure, the phase difference of the optimized patch changes more smoothly, and the reflection loss is less than 0.5 dB across the entire frequency band. These performance optimizations effectively overcome the problem of high losses of traditional 1-bit unit elements at operating frequencies, providing a practical solution for achieving precise beam control and enhancing communication quality in complex satellite communication environments.