Optically transparent on-glass frequency selective surface for 5G millimeter-wave dual-band manipulation with sub-6G...

Area of Science:

• Electromagnetics and Metamaterials
• Wireless Communication Engineering
• Materials Science

Background:

• Fifth-generation (5G) wireless communication systems require advanced solutions for efficient signal transmission across diverse frequency bands, including millimeter-wave (mm-wave) and sub-6 GHz.
• Existing frequency selective surfaces (FSS) often compromise optical transparency or performance, limiting their integration into practical communication infrastructure.
• The need for spectrally efficient and optically compatible components is crucial for enhancing 5G network capabilities, such as outdoor-to-indoor communication.

Purpose of the Study:

• To propose and demonstrate an optically transparent on-glass frequency selective surface (FSS) with tailored transmittivity for 5G millimeter-wave (mm-wave) and sub-6G signals.
• To design a multi-resonant FSS structure capable of selectively transmitting desired frequency bands while maintaining high optical transparency.
• To validate the performance of the proposed FSS through fabrication and experimental measurements for 5G applications.

Main Methods:

• Design of a multi-resonant FSS structure integrated onto a double-layer glass substrate, incorporating two metallic square loops and a hollowed patch.
• Fabrication of a proof-of-concept prototype to experimentally verify the designed FSS characteristics.
• Measurement of transmission amplitudes and insertion losses across relevant 5G frequency bands (sub-6G, n257/n258, and n260) to assess performance.

Main Results:

• The fabricated FSS achieved an optical transparency of 62.1%.
• Dual passbands were successfully constructed, covering 5G mm-wave bands (n257/n258 and n260) and demonstrating sub-6G compatibility with an average in-band transmission of -2.42 dB.
• Experimental validation showed transmission amplitudes above -3.2 dB in the 1.5-6 GHz, 23.5-30.7 GHz, and 36.1-40 GHz ranges, with minimum insertion losses of 0.71 dB, 0.35 dB, and 0.97 dB, respectively.

Conclusions:

• The proposed optically transparent on-glass FSS effectively filters and transmits multiple 5G frequency bands with high out-of-band rejection and low insertion loss.
• The design offers a promising solution for integrating advanced filtering capabilities into transparent surfaces, facilitating applications like outdoor-to-indoor 5G communication.
• The FSS exhibits excellent potential for enhancing spectrum compatibility and enabling new functionalities in 5G wireless systems.