Yong Mao Huang

Size-reduced bandpass filters using quarter-mode substrate integrated waveguide loaded with different defected ground structure patterns

In this paper, three different defected ground structure (DGS) patterns are proposed and loaded into quarter-mode substrate integrated waveguide (QMSIW) to implement three size-reduced bandpass filters. Using QMSIW can achieve a size reduction nearly 75% with respect to its substrate integrated waveguide (SIW) counterpart. Furthermore, the utilization of DGS can further reduce size over 40% compared with its corresponding conventional QMSIW circuits. Measured results of these filters are in good agreement with the simulated ones, with size reductions, compared with some reported QMSIW filters, about 26%, 34% and 42%, respectively.

Compact Dual-Band Filter Using Open/Short Stub Loaded Stepped Impedance Resonators (OSLSIRs/SSLSIRs)

A novel microstrip dual-band filter with high frequency selectivity and extended rejection band is reported in this letter. The proposed filter employs one pair of open stub loaded stepped impedance resonators (OSLSIRs) functioning at two frequencies of interest. Two short stub loaded stepped impedance resonators (SSLSIRs) are embedded between the coupled OSLSIRs to generate quasi-elliptic response at two diverse frequencies. Contributed by the 0° feed structure, extra transmission zeros are produced to enhance the out-of-band rejection. OSLSIRs/SSLSIRs are chosen to achieve desired in-band performance and misaligned harmonic frequencies simultaneously. To demonstrate the efficacy of the design concept, a dual-band filter centering at 1.63 and 2.73 GHz is implemented. The design methodology and measured results are presented.

A Bandpass Filter Based on Half Mode Substrate Integrated Waveguide-to-Defected Ground Structure Cells

A half mode substrate integrated waveguide-to-defected ground structure (HMSIW-DGS) cell and its embedded form are proposed to miniaturize a bandpass filter. Both cells can purchase wideband frequency response and low insertion loss, as well as simple and easy fabrication. By cascading two of them according to design requirement, an X-band bandpass filter is designed and measured to meet compact size, low insertion loss, good return loss, second harmonic suppression, and linear phase.

Small-reflected substrate integrated waveguide termination with multi-step shape and absorbing material

A planar wideband substrate integrated waveguide (SIW) termination with multi-step shape and absorbing material is reported. Early reported absorbing material based SIW terminations exhibit fractional bandwidth (FBW) less than 45%. To broaden bandwidth, the multi-section stepped-impedance transformation is introduced into the design of SIW termination based on the theory of small reflection. The multi-step shape such as trident is used to mold the absorbing material, so that the impedance matching between the substrate and absorbing material can be improved and achieve a wider bandwidth. Measurement of the fabricated prototype exhibits a FBW over 70% with return loss better than 17dB, as well as system integration capability and low structure complexity.

Miniaturized dual-band filters based on quarter-mode substrate integrated waveguide loaded with double-sided stepped-impedance complementary split-ring resonators

This paper presents two miniaturized dual-band filters based on quarter-mode substrate integrated waveguide (QMSIW) loaded with double-sided stepped-impedance complementary split-ring resonator (DS-SICSRR). The modified SICSRRs, realized by employing the stepped-impedance concept into the conventional CSRR, are with longer electrical lengths and thus exhibit more compact size as compared with its corresponding conventional CSRR counterpart. Subsequently, by loading the SICSRRs with different sizes into the two sides of the QmSIW cavity, two cavity resonators with dual-band response are realized. Since sizes of the SICSRRs on the two sides are tuned independently, the two passbands of the proposed resonator can be controlled flexibly. Based on the proposed QMSIW-DS-SICSRR cavity resonators, two dual-band bandpass filters are implemented, with their measured results in good agreement with the simulated ones. Compared with some related works, the two proposed dual-band filters exhibit size-reduction about 52% and 64%, as well as more controlling flexibility of the two passbands.

Bandpass power dividers using quarter-mode substrate integrated waveguide and defected ground structure

In this paper, two bandpass power dividers (BPD), one using conventional quarter-mode substrate integrated waveguide (QMSIW) and the other using both QMSIW and defected ground structure (DGS), are presented. Compared with conventional substrate integrated waveguide (SIW) circuitry, QMSIW can contribute to a size reduction of nearly 75%. And DGS-loaded QMSIW can further improve the size miniaturization with a size reduction over 45%, as well as lower insertion loss and wider stopband. Measured results of the two implemented BPDs are in good agreement with the simulations.

Design of compact bandpass filter based on quarter-mode substrate integrated waveguide with mixed coupling

In this paper, a compact bandpass filter using quarter-mode substrate integrated waveguide (QMSIW) cavities with mixed coupling is presented. The mixed coupling is realized by etching a coplanar waveguide(CPW) at the magnetic coupled neighborhood section of two cascaded QMSIW resonators, which introduces two transmission zeros at the lower and higher rejection band. The filter enjoys merits of good selectivity, miniaturized size and wide stop band. In order to verify the design concept, a bandpass filter with center frequency of 8.625GHz is fabricated and measured. The measured results show good agreement with the simulated results.