Chang Jiang You

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.

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.

Codesigned Wideband High-Efficiency Filtering SIW Slot Antenna with High Selectivity and Flat Gain Response

A substrate integrated waveguide (SIW) slot antenna with wideband bandpass filtering performance is proposed in this journal. It consists of a SIW cavity, a transverse slot, three metal posts, and a SMA connector. Three metal posts split the SIW cavity into two TE110-mode resonators. A long nonresonant transverse slot is utilized to realize a half TE110-mode resonator and generate radiation simultaneously so as to reduce the size and release the use of extra radiator. Three in-band resonance poles and a radiation null at both out-of-bands are obtained. A prototype is fabricated and measured. Measured results demonstrate the proposed antenna is with a center frequency of 4.26 GHz, a fractional bandwidth of 9.1%, a high efficiency of 93%, and flat gain response and good skirt selectivity of 270 dB/GHz and 330 dB/GHz for the lower and upper out-of-band, respectively.

Dual Orbital Angular Momentum Mode Antenna by Combination of Transmitarray and Reflectarray

A dual orbital angular momentum (OAM) mode antenna with l=0 and l=4 mode wave is presented. The proposed antenna employs a transmitarray and a reflectarray and uses a dual-polarization conical horn as the feed. By using two orthogonal linear polarization waves as excitations, the antenna can generate a pencil beam and an OAM beam, respectively.

Compact Bandpass Filter With High Selectivity Using Quarter-Mode Substrate Integrated Waveguide and Coplanar Waveguide

This letter presents a bandpass filter (BPF) based on a hybrid structure of quarter-mode substrate integrated waveguide (QMSIW) and coplanar waveguide (CPW). By incorporating two CPW resonators into two QMSIW resonators, the proposed filter obtains a high selectivity as the coupling between two CPW resonators is electric coupling, which helps to generate two transmission zeros. It also achieves compact layout as the embedded CPW resonators do not occupy extra area. In order to verify the design, a BPF with a center frequency of 8.7 GHz is fabricated and measured. The measured results show good agreement with the simulation results.

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.

Implementation of an X band leakage cancellation network for bandwidth improvement

In this paper, the implementation of an X band Tx-to-Rx leakage cancellation network to achieve bandwidth improvement and high isolation performance is presented. The circuit architecture and leakage cancellation theory are described in detail. The operation principle of leakage cancellation network is based on phase cancellation technique. This architecture is made up of three two-section Wilkinson power dividers and a hybrid-ring, which miniaturizes the leakage cancellation network, compared with conventional ferrite circulators. The proposed architecture has been completely implemented and measurements have been carried out for verification. The simulated bandwidth is presented with 83% fractional bandwidth above 30dB isolation, and the corresponding measured fractional bandwidth is 31.2%. Meanwhile, the simulated bandwidth is presented with 16% fractional bandwidth above 40dB isolation, and the corresponding measured fractional bandwidth is 6.4% The measured peak isolation is 46.2dB@9.361GHz. Although the measured fractional bandwidth is decreased, the high isolation bandwidth between Tx port and Rx port based on the circuit architecture proposed in this paper, is still enhanced, especially compared with other conventional high isolation networks.

A wideband bandpass filter based on stepped impedance stubs and substrate integrated coaxial line

In this paper, a novel wideband bandpass filter is proposed using a stepped impedance stubs resonator and substrate integrated coaxial line (SICL) technology. The resonator produces three resonant frequencies and two attenuation poles near the edges of the passband, so a wide bandwidth and a sharp rejection can be obtained. A filter prototype with compact size is simulated and the results indicate that the proposed filter centered at 13.16 GHz is realized with a bandwidth of 28.3%. The filter features low insertion loss, wide stopband, and low crosstalk.

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.

Design of planar narrow band millimetre-wave filter with wide stop-band

This paper presents a planar millimetre-wave (mmwave) band pass filter based on substrate integrated waveguide (SIW) and substrate integrated coaxial line (SICL) techniques. Four half wavelength mircrostrip resonators are imbedded in the SIW cavity to improve Q-factor. Due to the closed configuration which eliminates radiation loss, the filter presents a relatively low insertion loss. The proposed filter has a 3dB fractional bandwidth of 1.6% across frequencies from 29.8GHz to 30.3 GHz and 20dB rejection band from 30.7GHz to 58 GHz.