Research on bandwidth-reconfigurable Fabry−Pérot antennas for shipboard communication

Objective To address the core contradiction in naval communication systems where a single antenna struggles to balance wide-band channel capacity with high-gain frequency selectivity, this study investigates a bandwidth-reconfigurable high-gain antenna suitable for complex electromagnetic environments.

Method Based on the fundamental spatial resonant filtering theory of Fabry–Pérot (FP) resonant cavities, an overall architecture of FP antenna with continuously tunable cavity height equipped with a movable ground plane is designed. A novel mechanically self-tunable bandwidth reconfiguration mechanism integrating electromagnetic multimode excitation theory and resonant filtering theory is innovatively proposed. By thoroughly analyzing the near-field electromagnetic coupling behavior between the U-shaped probe feed and the partially reflective surface (PRS) metasurface, as well as the excitation evolution law of multi-order resonant modes inside the cavity, a reconfigurable theoretical framework of "cavity height–coupling–bandwidth" is established. Relying on the HFSS full-wave finite element simulation platform, multi-dimensional modeling and simulation including electromagnetic field distribution, Smith impedance chart and radiation pattern of the antenna are carried out for iterative performance optimization. Finally, a physical prototype is fabricated and comparative measurements are implemented in an anechoic chamber to fully verify the theoretical correctness and engineering feasibility of the mechanical tuning reconfiguration mechanism.

Results Simulation and experimental results demonstrate that this antenna achieves excellent impedance matching with S₁₁ < −15 dB in both shielded and radiated states. In shielded mode, the relative bandwidth is 2.6% (impedance bandwidth 150 MHz), with symmetrical E−plane and H-plane patterns and side lobe levels below −15 dB. In radiated mode, the relative bandwidth increases to 6.7% (impedance bandwidth 400 MHz), with side lobe levels around −12 dB. By adjusting the cavity height via a movable ground plane, stable switching between narrowband high-reliability and wideband high-throughput operating modes is achieved.

Conclusion The proposed mechanically tuned FP antenna structure achieves dynamic bandwidth reconfiguration without additional active components. It clarifies the regulatory relationship between cavity height and coupling mechanisms with bandwidth characteristics. Simulation and experimental results demonstrate excellent agreement, providing effective theoretical foundations and technical approaches for the application of adaptive antennas in complex electromagnetic environments aboard naval vessels.