Sub-THz Fully Inline Dual-band Filter Based on High-Order Mode Resonators

This article delves into the design and development of a compact W-band dual-band waveguide filter based on high-order mode resonators, specifically the TE 301 and TE 102 modes. The filter is designed to operate in the critical sub-THz band, which is essential for scientific applications such as radio astronomy, imaging radar, and wireless communication. The article explores the advantages of using rectangular waveguides, which offer low loss, high Q-factor, and ease of manufacture. It also discusses the challenges and solutions associated with developing dual-band waveguide filters, including the parallel-connecting method, the splitting method, and the dual-mode hybrid scheme. The proposed filter design features a rotational symmetric structure, which simplifies the design and fabrication process. The article provides detailed information on the filter's geometry, magnetic field distributions, and coupling matrix method. It also includes a thorough analysis of the filter's performance, including its insertion loss, return loss, and bandwidth. The article concludes with a comparison of the proposed filter with state-of-the-art dual-band filters, demonstrating its competitive performance in terms of bandwidth, low loss, and isolation. Additionally, the article discusses the potential for scaling up the filter design method to THz applications for future transceiver systems.