A One-bit Transmit Phased Array with Spatial Excitation for Sub-6 GHz Wireless Systems

Introduction. Due to the increasing number of users, growing rates of data transmission, and rapid advancement of the Internet of Things, the parameter of channel capacity is acquiring greater importance in modern communication systems. In wireless communication systems, capacity limitation occurs due to a low signal-to-noise ratio, one reason for which consists in high losses associated with the propagation of electromagnetic waves. These losses can be compensated using high-gain antenna systems, such as metasurfaces, transmitarrays, or reflectarrays.

Aim. Development and research of a one-bit transmit phased antenna array with spatial excitation for use in wireless communication networks across sub-6 GHz frequencies. The issues of reducing the insertion losses associated with the cell geometry and control components are discussed. Account is taken of the parasitic parameters of p–i–ndiodes used as control elements for phase adjustment in a unit cell. Methods for suppressing cross-polarization in a unit cell with the purpose of reducing insertion losses are studied.

Materials and methods. The characteristics of unit cells in a transmit antenna array were studied by numerical electrodynamic modeling in the CST Microwave Studio computer-aided design system. The obtained results were confirmed by an experimental study of samples.

Results. A unique design of a unit cell comprising the main element of a transmitarray was proposed. On its basis, a transmitarray was designed and manufactured, whose measurements proved the level of insertion losses to be lower than 1.5 dB in the operating frequency band of 210 MHz (3.6 %). The level of cross-polarization was found to be lower than 24 dB, and the gain attenuation did not exceed 2.5 dB in the range of beam deflection from 45° to -45°.

Conclusion. The design simplicity, low losses, and acceptable cross-polarization levels of the developed one-bit transmit phased antenna array with spatial excitation confirm its feasibility for modern communication systems.

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