FSS-Based Band Pass Filter Design for C-Band Satellite Downlink Interference Mitigation

The increasing expansion of cellular networks into the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{C}$</tex>-band has led to increased interference challenges in satellite communication systems, particularly for downlinks operating in the frequency range of 3.6 GHz to 5.7 GHz. This issue threatens the reliability of critical satellite services like telecommunications, broadcasting, weather forecasting, and remote sensing. This paper presents the design and implementation of a Frequency Selective Surface (FSS)-based Band Pass Filter (BPF) to address C-band satellite downlink interference from cellular networks. The proposed filter allows satellite signals within the 3.6 GHz to 5.7 GHz range to pass through while blocking out-of-band interference from nearby cellular frequencies. By reducing adjacent channel interference, the filter improves signal quality and preserves the integrity of satellite communications. The paper involved two key phases: simulation and fabrication. Testing of the fabricated filter showed a strong correlation with simulation results, confirming the effectiveness of the FSS-based design in mitigating interference from cellular networks.