A Wideband Water-Based 3D-Printed Reflect-Transmit Antenna Array Toward mmWave Positioning Applications

Area of Science:

• Electromagnetics and Antenna Engineering
• Materials Science for RF Applications

Background:

• Millimeter-wave (mm-wave) systems require advanced antenna solutions for efficient beam manipulation.
• Existing antenna designs often face limitations in achieving simultaneous reflection and transmission functionalities with wide bandwidths.

Purpose of the Study:

• To propose and characterize a novel water-based reflect-transmit antenna (WBRTA) array for mm-wave applications.
• To demonstrate the capability of the WBRTA for simultaneous beam splitting and tilting in both reflection and transmission modes.

Main Methods:

• The WBRTA array utilizes a hybrid design combining low-permittivity polylactic acid (PLA) and high-permittivity water-based unit cells.
• The distinct dielectric properties of PLA and water enable tailored transmission and reflection characteristics.
• Simulations and analysis were performed to evaluate beam splitting, beam tilting, gain, sidelobe levels, and cross-polarization.

Main Results:

• The WBRTA achieved simultaneous beam splitting in reflection and transmission over a wide bandwidth.
• Beam tilting up to 45° was demonstrated in both reflection and transmission modes.
• Peak gains of 25.2 dBi (transmission) and 24 dBi (reflection) were recorded, with low sidelobe levels (-22 dB and -17 dB, respectively) and high polarization purity (x-pol < -81 dB).

Conclusions:

• The proposed WBRTA is a promising antenna structure for mm-wave applications requiring versatile beam control.
• Its wide bandwidth, low sidelobe levels, and high polarization purity make it suitable for positioning-oriented sensing functions in future wireless systems.