Open AccessMonolithic 3D‐printed slotted hemisphere resonator bandpass filter with extended spurious‐free stopband
Author(s) -
Li Jin,
Li Sheng,
Huang GuanLong,
Yuan Tao,
Attallah Moataz M.
Publication year - 2019
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
ISSN - 1350-911X
DOI - 10.1049/el.2018.7850
Subject(s) - stopband , resonator , passband , band pass filter , transition band , spurious relationship , materials science , helical resonator , filter (signal processing) , acoustics , optics , prototype filter , insertion loss , elliptic filter , optoelectronics , physics , electronic engineering , low pass filter , engineering , electrical engineering , computer science , machine learning
A method to effectively suppress the spurious modes in a hemispherical resonator is proposed and the suppression contributes to extension of the spurious‐free stopband for the hemispherical‐resonator‐based bandpass filters. The TM 2m1 and TE 101 modes in a hemispherical resonator are suppressed by interrupting the corresponding surface current via properly slotting the cavity shell, without significantly interfering with the fundamental TM 101 mode. Resonant modes in a slotted hemispherical (SH) resonator are analysed, and design and implementation of a proof‐of‐concept X ‐band fourth‐order SH‐resonator waveguide filter are presented. The filter is monolithically prototyped by employing metallic additive manufacturing technology. The filter demonstrates passband insertion and returns losses of averagely 0.9 dB and >20 dB, respectively, a small frequency shift of <0.9%, and a spurious‐free stopband frequency ratio of >1.8:1 with a stopband rejection over 34 dB at 10.5–16.4 GHz.