Affordable Thin Lens Using Single Polarized Disparate Filter Arrays for Beyond 5G toward 6G

Area of Science:

• Electrical Engineering
• Electromagnetics
• Materials Science

Background:

• Commercial millimeter wave (mmWave) printed circuit board (PCB) manufacturing faces limitations in fabricating fine metallic patterns (<100 μm gap/width).
• These limitations hinder the adoption of thin lens technology for high-frequency 5G applications (60 GHz and above), which demand finer trace geometries.
• Existing thin lens designs are constrained by the precision capabilities of standard PCB fabrication processes.

Purpose of the Study:

• To propose a novel thin lens design approach that circumvents the fineness limitations of commercial PCB manufacturing.
• To enable the fabrication of thin lenses for high-frequency mmWave applications, specifically targeting 60 GHz and beyond.
• To demonstrate a design methodology that allows for wider metallic trace dimensions while maintaining desired electromagnetic performance.

Main Methods:

• The proposed design utilizes single-polarized lumped element models for lens unit cells.
• This approach allows for achieving larger capacitance and inductance values within the same physical footprint compared to conventional designs.
• The design strategy focuses on mitigating process constraints by enabling wider trace widths and gaps.

Main Results:

• The single-polarized unit cell design significantly widens the required gap/width of metallic traces for equivalent in-plane capacitance/inductance.
• This enables thin lens operation at higher frequencies within the process limits of fabricable fine traces.
• A fabricated 60 GHz thin lens demonstrated a gain enhancement of 16 dB for a 4x4 patch antenna array (16.5 dBi initial gain).

Conclusions:

• The proposed design approach effectively overcomes the fineness limitations of commercial PCB manufacturing for thin lens applications.
• This technique facilitates the development of high-frequency mmWave lenses, crucial for advancing 5G and future wireless systems.
• The successful fabrication and testing of the 60 GHz lens validate the design methodology and its practical applicability.