Wideband 23.5-29.5-GHz Phased Arrays for Multistandard 5G Applications and Carrier Aggregation

• Published in: IEEE transactions on microwave theory and techniques Vol. 69; no. 1; pp. 235 - 247
• Main Authors: Yin, Yusheng, Ustundag, Berktug, Kibaroglu, Kerim, Sayginer, Mustafa, Rebeiz, Gabriel M.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 5G mobile communication; 64-QAM; Antenna measurements; Bandwidths; Broadband; Carrier aggregation (CA); Effective isotropic radiated power (EIRP); Error analysis; error vector magnitude (EVM); fifth-generation (5G) phased array; Impedance matching; Phase control; Phased arrays; stacked-patch antenna; Waveforms; Wideband
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2020.3024217

This article presents a 23.5-29.5-GHz <inline-formula> <tex-math notation="LaTeX">8\times 8 </tex-math></inline-formula> phased array for wideband multistandard applications. The array is based on wideband high-performance <inline-formula> <tex-math notation="LaTeX">2\times 2 </tex-math></inline-formula> transmit/receive (TRX) quad-beamformer chips with 6 bit of phase control and 8 bit of gain control. The antenna is designed using a stacked-patch structure combined with a two-stage impedance matching network to enhance its bandwidth. The <inline-formula> <tex-math notation="LaTeX">8\times 8 </tex-math></inline-formula> phased array achieves an effective isotropic radiated power (EIRP) of 54.8 dBm at P1dB with a 3-dB bandwidth of 23.5-30.5 GHz and can scan to ±60° in the azimuth plane and +/40° in the elevation plane with excellent patterns with a single-point calibration at 27 GHz. Measured error vector magnitude (EVM) for a 64-QAM 200 and 800-Mbaud waveforms result in a system EVM of 5% (−26 dB) in the TX mode at an average EIRP of 46-47 dBm at 24.5-29.5 GHz. Also, the wideband array is capable of 16-QAM 24-Gb/s links with an EVM <16% over all scan angles. An interband carrier aggregation (CA) system is also demonstrated with the wideband array using 200-Mbaud 64-QAM waveforms with 25- and 29-GHz carriers. The phased-array phase and amplitude settings are chosen such that the 25- and 29-GHz waveforms are radiating simultaneously at the same angle with low scan loss, resulting in an efficient system. Also, the out-of-band third-order intermodulation products generated by the power amplifier on each element are filtered out by the antenna. CA measurements with up to 50° scan angles are demonstrated with low EVM. To the best of our knowledge, this is the first demonstration of CA in millimeter-wave fifth-generation (5G) systems.