A tunable third-order bandpass filter based on combining dual-mode square-shaped substrate integrated waveguide resonator with triangular-shaped resonator

作者：Li, Lei; Zhao, Dehao^*; Bai, Junkai; Wang, Qing; Lei, Zhenya

来源：International Journal of RF and Microwave Computer-Aided Engineering, 2019, 29(1): e21454.

DOI：10.1002/mmce.21454

• dual-mode square-shaped resonator
• triangular-shaped resonator
• tunable SIW filter

A frequency reconfigurable third-order bandpass filter based on two substrate integrated waveguide (SIW) cavities is presented in this article. The purposed filter consists of a dual-mode square-shaped resonator and a triangular-shaped resonator. In the square-shaped cavity, four lumped capacitors are loaded as electrical tuning elements in the area where the electric fields of diagonal TE201 and TE102 modes are strongest. And an another capacitor is loaded at the suitable region of the triangular-shaped cavity. Square-shaped cavity introduces two transmission zeros and the triangular-shaped cavity can suppress out-of-band spurious modes. The method that combines the resonators with different shapes and multiple modes into an organic whole cannot only achieve synchronous tuning but also have complementary advantages and improve out-of-band rejection. To verify its practicality, a SIW reconfigurable bandpass filter is simulated when the capacitance value varies from 0 to 1.4 pF and measured at 0.7, 0.8, and 0.9 pF, respectively. Measured results show that when the center frequency is tuned from 3.42 to 3.52GHz, the proposed filter exhibits good tuning performance with insertion loss of less than 2.5 dB and return loss of better than 10 dB, which is suitable for fifth-generation communication system.

• 出版日期2019-1
• 单位西安电子科技大学