High-Gain Millimeter-Wave Beam Scanning Transmitarray Antenna

Area of Science:

• Electromagnetics and Antennas
• Microwave Engineering
• Applied Physics

Background:

• Millimeter-wave (mmWave) frequencies offer large bandwidths but face challenges with antenna gain and beam steering.
• Transmitarray antennas (TAAs) are a promising solution for high-gain applications, but integrating scanning capabilities within limited apertures remains a challenge.

Purpose of the Study:

• To develop a high-gain millimeter-wave transmitarray antenna (TAA) with integrated scanning ability.
• To achieve beam scanning within a limited aperture area without modifying the primary array feed.
• To propose a beam-forming algorithm for enhancing scanning performance in array-fed TAAs.

Main Methods:

• Integration of an array feed as the primary emitter for the TAA.
• Addition of defocused phases to the monofocal lens phase distribution to enable beam dispersion.
• Design of a transmitarray using square waveguide elements with a focal-to-diameter ratio (F/D) of 0.6.
• Development of a beam-forming algorithm to determine array feed excitation coefficients.

Main Results:

• Achieved a 1-D scan with a scope of -5° to 5° through calculations.
• Measured a high gain of 37.95 dBi at 160 GHz.
• Observed a maximum 2.2 dB error between measured and calculated results in the 150-170 GHz operating band.

Conclusions:

• The developed transmitarray antenna successfully generates scannable high-gain beams in the millimeter-wave band.
• The proposed design and beam-forming algorithm demonstrate potential for future millimeter-wave communication and sensing applications.
• The compact aperture design avoids the need for array replacement or extension, offering practical advantages.