Monolithic 3D printed waveguide filters with wide spurious-free stopbands using dimpled spherical resonators

Cheng Guo, Yang Yu*, Sheng Li, Xiaozhu Wen, Anxue Zhang, Yi Wang, Moataz Attallah

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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Employing a family of dimpled and slotted spherical resonators, and a set of X-band waveguide bandpass filters (BPFs) is presented in this study. The resonators originated from spherical resonators with depression (hence, dimples are formed) and cutting slots into the resonator shell. With a large number of experiments, the combination of using the twisted coupling topology, depression and slotting on the resonators results in filters with simultaneous low insertion loss (IL), good out-of-band rejection and wide spurious-free stopband. Several BPFs are designed and 3D printed using the selective laser melting (SLM) technique where they are made in one piece. The monolithic implementation of these filters is allowed by the compatibility of the microwave and the mechanical design, which minimises the required supporting structures inside the filters. The measurement results show ILs of 0.2–0.3 dB and are better than 15 dB return loss. There is a small frequency shift of less than 0.9%, and a measured spurious-free stopband covering the entire X–Ku bands (8.2–18 GHz) with rejection over 34 dB. Additionally, for the SLM printed devices, the influences of temperature to the S-parameter responses, as well as polishing, which lowers the losses, are included in this study.

Original languageEnglish
Pages (from-to)1657-1670
Number of pages14
JournalIET Microwaves, Antennas and Propagation
Issue number12
Early online date9 Jul 2021
Publication statusPublished - 7 Oct 2021

Bibliographical note

Funding Information:
The work was supported by the National Natural Science Foundation of China under Grant 62001367.

Publisher Copyright:
© 2021 The Authors. IET Microwaves, Antennas & Propagation published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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