Ltcc Coupled-Resonator Filters for Ka and V Band Applications

Project: National Science and Technology CouncilNational Science and Technology Council Academic Grants

Project Details


This project develops high performance filters with miniaturized size and excellent frequency selectivity for Ka-band and V-band applications. In modern wireless communication systems, Ka and V bands are attractive for providing wireless broadband transmission. However, since the operation frequency is very high, Ka-band and V-band filters require accurate circuit dimensions, which raises the difficulty in filter synthesis and fabrication. LTCC (Low Temperature Co-fired Ceramic) fabrication process is adopted to achieve circuit accuracy and compactness in terms of its multi-layer structure to stack resonators vertically. The coupled-resonator structure is applied in filter design to create a pair of transmission zeros located at the skirt of passband to improve frequency selectivity largely. Two different resonator types are utilized to design filters, one is the microstrip open-loop resonator and the other is the SIW (Substrate Integrated Waveguide) resonator. The design of half-wavelength open-loop resonators at high frequency is difficult due to their small size. Parasitic inductance induced by vertical interconnections will distort the high frequency component of circuits. Besides, quality factor of resonators may be reduced if the line width is too narrow or substrate is too thin. Recently, the new transmission line structure called SIW is presented and developed as an attractive technique for low loss, high quality, and planar structure. The control of resonant mode, negative coupling, and bandwidth enhancement of SIW is still an ongoing challenge. Coupling coefficients are the most of important parameters for coupled-type filter design. Conventional synthesis equations only realize the frequency response with specific mathematic functions. There are no existing formulas for extraction of coupling matrix when filters are required to have arbitrary frequency responses corresponding to specific spectrum masks for communication systems. Accordingly, this project proposes a novel method to extract coupling matrix for filters with arbitrary frequency responses. According to the aforementioned, this project develops 28-GHz and 60-GHz coupled-resonator filters by using the LTCC fabrication process, which is helpful for development of Ka-band and V-band circuits and promotion of LTCC technology at high frequency, especially in Taiwan. This research is divided to three subprojects: (1) Synthesis of miniaturized 28-GHz and 60-GHz open-loop cross-coupled bandpass filters with excellent vertical interconnection and vertically-stacked-resonator structures. (2) Synthesis of 28-GHz and 60-GHz SIW cross-coupled bandpass filters. Various negative coupling mechanism and feeding I/O structures will be studied to create zeros. (3) Extraction of coupling matrix for filters with arbitrary frequency responses. This project will also fabricate and measure five filters to demonstrate the capability of the proposed circuit structures and synthesis theorem.

Project IDs

Project ID:PB10108-2795
External Project ID:NSC101-2221-E182-052
Effective start/end date01/08/1231/07/13


  • Ka-band and V-band filters
  • 28-GHz and 60-GHz filters
  • cross-coupled filter
  • SIW filter
  • open-loop filter
  • synthesis with arbitrary frequency responses


Explore the research topics touched on by this project. These labels are generated based on the underlying awards/grants. Together they form a unique fingerprint.