Researchers from Southeast University in China have developed a compact, dual-band, dual-polarized, duplex (D³) phased array architecture that integrates four independent beamforming systems on a single printed circuit board (PCB). This innovative design supports concurrent, dual-band, and dual-polarized four-beam operations at 28 GHz and 38 GHz, making it a promising solution for beyond fifth-generation (B5G) and sixth-generation (6G) millimeter-wave multistandard systems.

The proposed phased array leverages a brick-type architecture, enabling two-dimensional scalability. This means it can function as a standalone small-scale phased array or serve as a sub-block for larger-scale arrays. A novel dual-polarized end-fire magnetoelectric dipole antenna was developed as the radiating element, achieving an impedance bandwidth with a return loss below －10 dB across the frequency range of 24.8–40.3 GHz, which is one of the broadest operating bands reported for PCB-based, co-apertured, and dual-polarized end-fire antennas.

In terms of performance, the fabricated phased array demonstrated beam-scanning ranges exceeding 90° and 60° at 28 GHz and 38 GHz, respectively. The effective isotropic radiated power (EIRP) values exhibited distinct frequency selectivities between the two bands. For instance, within the 26.5–29.5 GHz band, the EIRP peaks reached 30.6 dBm (H-pol) and 31.4 dBm (V-pol), with spectral fluctuations below 1.5 dB. In the 37–40 GHz band, the maximum EIRP values were 27.6 dBm (H-pol) and 27.5 dBm (V-pol), with fluctuations limited to 2.4 dB. The array also achieved out-of-band attenuation greater than 37 dB for the H-pol 28 GHz beam and more than 28 dB for the V-pol 28 GHz beam in the 37–40 GHz band.

The D³ phased array’s ability to support both time-division duplex (TDD) and frequency-division duplex (FDD) operations is a notable feature. This capability ensures high spectral efficiency and communication flexibility, which are essential for future B5G/6G wireless communication systems. The array’s architecture allows it to transmit or receive signals simultaneously in both frequency bands, supporting concurrent dual-band operation through frequency-domain isolation rather than time-domain switching.

The researchers validated the phased array’s performance through extensive experiments. The beam-scanning performance was evaluated in an anechoic chamber, and calibration was performed to compensate for channel inconsistencies. The results showed satisfactory agreement between simulated and measured beam-scanning patterns, confirming the successful implementation of the D³ phased array system. Additionally, wireless transmission experiments using a 64-quadrature amplitude modulation (QAM) signal with an 80 MHz bandwidth demonstrated reliable performance across multiple beams with distinct polarizations.

The scalability of the phased array was also demonstrated through electromagnetic simulations of an upscaled 8×8 planar configuration. The results indicated that the beam scanning ranges could fully cover the angular range of －45° to 45° at 28 GHz and －30° to 30° at 38 GHz, with scanning losses below 3 dB for both polarizations.

This research, published in Engineering, highlights the potential of the D³ phased array to meet the increasing demands of high-bandwidth and low-latency communications in B5G/6G applications such as telemedicine, virtual reality, and autonomous driving.

The paper “Compact Millimeter-Wave, Dual-Band, Dual-Polarized, Duplex, and Scalable Phased Array Enabling B5G/6G Multistandard Systems,” is authored by Kai Chen, Jun Xu, Renrong Zhao, Lei Xiang, Debin Hou, Zhiqiang Yu, Jianyi Zhou, Jixin Chen, Zhang-Cheng Hao, Wei Hong. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.06.017. For more information about Engineering, visit the website at https://www.sciencedirect.com/journal/engineering.