3D conformal bandpass millimeter-wave frequency selective surface with improved fields of view

Area of Science:

• Electromagnetics and Applied Physics
• Microwave Engineering
• Materials Science

Background:

• Conventional planar frequency selective surfaces (FSSs) exhibit sensitivity to incidence angles and are typically characterized in the far-field.
• Near-field applications require FSS designs with enhanced angular stability and compact form factors.

Purpose of the Study:

• To present a novel spherical dome frequency selective surface (FSS) for improved angularly stable bandpass filtering in near-field antenna applications.
• To demonstrate the advantages of conformal FSS over planar FSS in the near-field region.
• To report on the design, manufacturing, and measurement challenges and provide guidelines for 3D-printed, electroplated FSS.

Main Methods:

• Simulations comparing a conformal FSS with a finite planar FSS in the 26–40 GHz frequency range.
• 3D printing and copper electroplating techniques for fabricating the conformal FSS.
• Experimental validation comparing simulated and measured results for the conformal FSS.

Main Results:

• The conformal FSS demonstrates improved angularly stable bandpass filtering performance in the near-field compared to planar FSS.
• Simulated and measured results for the 3D-printed conformal FSS show good agreement.
• The developed conformal FSS is low-cost, lightweight, and suitable for compact mm-wave systems.

Conclusions:

• Spherical dome FSS offers significant advantages for near-field applications, particularly as radomes for compact mm-wave systems.
• 3D printing and electroplating provide a viable, cost-effective method for fabricating conformal FSS.
• Guidelines are provided to address design, manufacturing, and measurement challenges for conformal FSS.