SIW‐based interdigital bandpass filter with harmonic suppression

A novel configuration for substrate integrated waveguide (SIW) based bandpass filter with interdigital type resonators is presented. In the proposed structure, interdigital type resonators consisting of vias and circular caps at top of them are combined into a bowtie SIW structure. SIW is fed by a tapered microstrip line transition providing low loss and good matching. In order to improve harmonic suppression performance of the filter, the dumbbell shaped defected ground structure (DGS) is etched to the ground side of the microstrip line feeding section. The proposed filter structure is put in a conducting box in order to improve attenuation levels at the band edges and prevent radiation to the outside. The prototype is designed at 9 GHz center frequency with 500 MHz bandwidth, analyzed and fabricated for verification. The measurement results are in good agreement with the simulations, and the filter exhibits more than 30 dB harmonic suppression.

[1]  Ke Wu,et al.  Substrate Integrated Waveguide Cross-Coupled Filter With Negative Coupling Structure , 2008, IEEE Transactions on Microwave Theory and Techniques.

[2]  R. J. Wenzel,et al.  Synthesis of Combline and Capacitively Loaded Interdigital Bandpass Filters of Arbitrary Bandwidth , 1971 .

[3]  Ke Wu,et al.  Novel substrate integrated waveguide cavity filter with defected ground structure , 2005, IEEE Transactions on Microwave Theory and Techniques.

[4]  Jose Ernesto Rayas-Sanchez,et al.  An Improved EM-Based Design Procedure for Single-Layer Substrate Integrated Waveguide Interconnects with Microstrip Transitions , 2009, 2009 IEEE MTT-S International Microwave Workshop Series on Signal Integrity and High-Speed Interconnects.

[5]  Ke Wu,et al.  Review of substrate-integrated waveguide circuits and antennas , 2011 .

[6]  S. Sanyal,et al.  A novel defected ground structure for planar circuits , 2006, IEEE Microwave and Wireless Components Letters.

[7]  Tao Yang,et al.  Substrate Integrated Waveguide Loaded by Complementary Split-Ring Resonators and Its Applications to Miniaturized Waveguide Filters , 2009, IEEE Transactions on Microwave Theory and Techniques.

[8]  D. Deslandes.  Design equations for tapered microstrip-to-Substrate Integrated Waveguide transitions , 2010, 2010 IEEE MTT-S International Microwave Symposium.

[9]  V. E. Boria,et al.  Compact CPW-Fed Combline Filter in Substrate Integrated Waveguide Technology , 2012, IEEE Microwave and Wireless Components Letters.

[10]  R. Stephenson.  A and V , 1962, The British journal of ophthalmology.

[11]  Jong-Chul Lee,et al.  Iris waveguide bandpass filter using substrate integrated waveguide (SIW) for satellite communication , 2005, 2005 Asia-Pacific Microwave Conference Proceedings.

[12]  C. Quendo,et al.  Reconfigurable Planar SIW Cavity Resonator and Filter , 2006, 2006 IEEE MTT-S International Microwave Symposium Digest.

[13]  Vicente E. Boria,et al.  Capacitively loaded resonator for compact substrate integrated waveguide filters , 2010, The 40th European Microwave Conference.

[14]  Jr. R. Wyndrum.  Microwave filters, impedance-matching networks, and coupling structures , 1965 .

[15]  C. Quendo,et al.  Design of a Substrate Integrated Waveguide (SIW) Filter Using a Novel Topology of Coupling , 2008, IEEE Microwave and Wireless Components Letters.

[16]  Chao Li,et al.  A compact planar bandpass filter with wide out‐of‐band rejection implemented by substrate‐integrated waveguide and complementary split‐ring resonator , 2011 .