The Journal of China Universities of Posts and Telecommunications ›› 2024, Vol. 31 ›› Issue (3): 87-94.doi: 10.19682/j.cnki.1005-8885.2024.1008

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W-band millimeter wave vialess microstrip-to-microstrip vertical transition in multilayer LCP substrate

Liu Weihong, Zhang Xu, Guan Dongyang   

  1. School of Electronic Engineering, Xian University of Posts and Telecommunications, Xi'an 710121, China
  • Received:2022-12-27 Revised:2024-01-02 Online:2024-06-30 Published:2024-06-30
  • Contact: Liu Weihong E-mail:liuweihong@xupt.edu.cn
  • Supported by:
    the Shaanxi Provincial Innovation Team Project (2020TD-019) and Xi'an Sciences Plan Project (21XJZZ0075).

Abstract: In this paper, a W-band broadband vialess microstrip (MS)-to-MS vertical transition in multilayer liquid crystal
polymer (LCP) substrate is presented, which consists of two MS lines in the top layer, a common ground plane and
slotline resonators in the second layer, and a close-loop transmission-line in the third layer. To increase the
passband of the vialess vertical transition, an H-shaped slotline resonator is introduced, which greatly improves the
impedance performance of the slotline resonator, and the full-wave simulated results indicate that insertion loss
(IL) is less than 2 dB and return loss (RL) is better than 10 dB at W-band. To verify this design, the broadband
vertical transition is fabricated and measured. The measured results indicate that a broadband vertical transition
with RL better than 10 dB and IL less than 5.67 dB can be obtained in the frequency range from 70.00 GHz to
104.09 GHz. Due to the fabrication error in the preparation process, the measured results are deteriorated
compared to the simulated results, and the investigation indicates that the deviation is caused by the thickness error
of the LCP substrate.

Key words: W-band, broadband, microstrip (MS)-to-MS, vialess vertical transition, liquid crystal polymer (LCP)