Journal of Electromagnetic Engineering and Science (Jan 2024)

Packaging and Antenna-Assembled Hybrid Stacked PCB with Novel Vertical Transition for 39 GHz 5G Base Stations

  • Youngju Lee,
  • Dohyuk Ha,
  • Kwanghyun Baek,
  • Juneseok Lee,
  • Sanghoon Park,
  • Jung-Ho Park,
  • Jinsu Heo,
  • Jae Hee Kim

DOI
https://doi.org/10.26866/jees.2024.1.r.201
Journal volume & issue
Vol. 24, no. 1
pp. 26 – 33

Abstract

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This paper proposes a novel packaging and large-scale antenna-assembled structure for a printed circuit board (PCB) that reinforces productivity, facilitates cost reduction, and maintains reliability. This was achieved by splitting the antenna from the main board and packaging it into a radio-frequency integrated circuit. In addition, two innovative solutions—an externally attachable flexible PCB antenna and a PCB-embedded coaxial line—are introduced to overcome the degradation in antenna performance and vertical RF transition loss in the proposed low-cost hybrid PCB. First, the proposed externally attachable flexible PCB antenna and a parasitic air-coupled antenna, which were easily assembled on the PCB, achieved an antenna efficiency of 95% and an impedance bandwidth of 7 GHz. Second, the fabricated coaxial line exhibited enhanced impedance matching over a wide frequency range of 30–40 GHz and improved insertion loss of approximately 1.4 dB. Furthermore, the packaged antenna, composed of 256 dual-polarized antenna elements per stream, incorporated a 39 GHz CMOS-based 16-channel phased-array transceiver IC. The set-level beam-forming measurements were verified considering an effective isotropic radiated power of 55 dBm at boresight and a steering range >±60°. In addition to being suitable for mass production in terms of cost and reliability, the proposed structures and solutions met the required antenna and beam-forming performance for commercial 39 GHz base stations without sacrificing performance.

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