Low-Profile and High-Passband Roll-Off Frequency-Selective Structure Using Bent Waveguides

• Published in: IEEE antennas and wireless propagation letters Vol. 19; no. 12; pp. 2117 - 2121
• Main Authors: Chen, Guo-Wen, Wong, Sai-Wai, Li, Yin, Guo, Zai-Cheng, Zhang, Long, Rashid, Amir Khurrum, Xie, Ning, Zhu, Lei
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Bent cavity resonator; Cavity resonators; Couplings; Filtering theory; Frequency response; Frequency selective surfaces; frequency-selective structure; high roll-off selectivity; Magnetic fields; Passband; Rectangular waveguides; Resonant frequency; Selectivity; Skirts; substrate integrated waveguide; Substrate integrated waveguides; TE polarization; Unit cell
• ISSN: 1536-1225; 1548-5757
• DOI: 10.1109/LAWP.2020.3024532

This letter applies bent cavity resonators to realize a low-profile frequency selective structure exhibiting high selectivity of filtering response. The structure is realized through substrate integrated waveguide technology. Its unit cell includes three cavities that support TE 101 and TE 102 modes of rectangular waveguides. Couplings of these cavities with air is adjusted in such a way that two transmission zeros are produced near the skirts of a narrow passband. The concept of bent waveguides is proposed to reduce the overall thickness by 38%. A prototype is designed and fabricated with its frequency centered at 10.4 GHz. A relatively stable frequency response is exhibited for TE polarization, under a moderate variation (<30°) of incident angle. Measured results are in good agreement with those obtained through simulations.