mmWave Zero Order Resonant Antenna with Patch-Like Radiation Fed by a Butler Matrix for Passive Beamforming

Area of Science:

• Electromagnetics
• Antenna Theory
• Metamaterials

Background:

• Composite right-left-handed (CRLH) structures offer unique electromagnetic properties.
• Traditional antenna designs often rely on metallic vias, which can complicate fabrication and limit performance.
• Via-less antenna designs are desirable for miniaturization and improved integration.

Purpose of the Study:

• To design and fabricate a compact, via-less zero-order resonant antenna at 30 GHz using the CRLH principle.
• To analyze the antenna's characteristics through equivalent circuit modeling and dispersion diagrams.
• To demonstrate a passive beamforming array utilizing the proposed CRLH antenna and a Butler matrix.

Main Methods:

• A novel CRLH antenna was designed by connecting mirror images of CRLH unit cells, eliminating the need for metallic vias.
• Equivalent circuit analysis, parameter extraction, and dispersion diagram studies were performed.
• A 4x4 Butler matrix implemented using substrate integrated waveguides fed the CRLH antennas to create a beamforming array.

Main Results:

• The fabricated CRLH antenna exhibited patch-like radiation at 30 GHz with a measured realized gain of 5.35 dBi.
• The antenna demonstrated a wide operational bandwidth of 10 GHz, free from spurious resonances.
• The passive beamforming array achieved distinct scanning angles of 12°, -68°, 64°, and -11° for different excitations.

Conclusions:

• The developed via-less CRLH antenna is a promising solution for high-frequency applications requiring compact and efficient radiating elements.
• The integration of CRLH antennas with Butler matrices enables effective passive beamforming.
• This work contributes to advancements in metamaterial-based antennas and phased array systems.