Qinyin Xiang | Southwest Jiaotong University (original) (raw)

Papers by Qinyin Xiang

Journal of Electromagnetic Waves and Applications, 2011

—In this paper, novel bandpass filter and tunable bandpass filter are designed based on half-mode... more —In this paper, novel bandpass filter and tunable bandpass filter are designed based on half-mode substrate integrated waveguide (HMSIW) embedded with complementary resonators. Various passband characteristics are observed, and lumped equivalent circuit analysis models are developed. The configuration of the proposed bandpass filter is an open structure, and it is easy to load the active devices and build the bias/control networks on the signal plane. The tunable bandpass filter is presented based on the proposed novel bandpass filter loaded with semiconductor varactor diodes, and it has good spurious suppression characteristics and excellent out of band rejection. The prototype with overall size of 15.9 mm × 30.2 mm × 0.5 mm was designed and fabricated so as to validate the new structure. The measured central frequency is 1.538 GHz and 1.718 GHz, and the insertion loss is 5.1 dB and 3.3 dB, at 0 V and 30 V, respectively.

In this paper, two- and three-pole microstrip LC constant fractional bandwidth (CFBW) and constan... more In this paper, two- and three-pole microstrip LC constant fractional bandwidth (CFBW) and constant absolute bandwidth (CABW) tunable bandpass filters are proposed. The equivalent-circuit models are presented to study the tunable mechanism. The filter can be reconfigured by changing the capacitance of the LC resonators. Based on electric coupling coefficient compensation, second- and third-order tunable equivalent-circuit models with CFBW/CABW are presented. For demonstration, a semiconductor varactor diode loaded microstrip LC resonator is adopted in our work to design the second- and third-order tunable filters. The S-parameters, group delays, and third-order intercept points for different center frequencies of the filters are presented. Each resonator requires only one varactor diode for both central frequency and resonator coupling coefficient control.

IEEE Microwave and Wireless Components Letters, 2012

In this letter, a novel quadruple-mode resonator bandpass filter (BPF) with tunable bandwidth is ... more In this letter, a novel quadruple-mode resonator bandpass filter (BPF) with tunable bandwidth is proposed. By using two types of microwave varactors to tune the resonant frequencies and transmission zeros (TZs), the high-side edge of the passband and low-side edge of the passband can be separately varied. Therefore, the bandwidth could be tunable with reasonable adjust of the values of varactors. Theoretical expressions have been derived for the resonant frequencies and the TZs. The measured results of the BPF show that the fractional bandwidth can be tuned from 22% to 34% at a fixed centre frequency 2.0 GHz with a return loss better than 12 dB. The tested results show good agreement with simulated results.

Journal of Electromagnetic Waves and Applications, 2012

—In this paper, a compact and high selectivity broadband microstrip bandpass filter (BPF) using s... more —In this paper, a compact and high selectivity broadband microstrip bandpass filter (BPF) using stub-loaded resonator is proposed. The basic block of the proposed filter is a quadruple-mode resonator consisting of a stepped-impedance resonator and three shunt open stubs. The proposed resonator can provide two even-mode, two odd-mode frequencies and two transmission zeros. The even-mode resonant frequencies can be flexibly controlled by the centre stub, while the odd-mode frequencies are fixed. The two other symmetrical stubs can both affect even- and odd- mode frequencies. The proposed filter exhibits high selectivity profiting from the two transmission zeros (TZs) near the passband created by two types of stubs. The measured –3 dB bandwidth is 1.0 GHz at the centre frequency of 2.5 GHz, and the S 21 exhibits a wide spurious free response up to 6 GHz. Measured results show good agreements with EM simulation results.

Journal of Electromagnetic Waves and Applications, 2012

In this paper, a novel bandstop filter based on microstrip LC resonators and 1-bit frequency reco... more In this paper, a novel bandstop filter based on microstrip LC resonators and 1-bit frequency reconfigurable bandstop filter are presented. The configuration of the proposed LC resonators has open structure and is suitable to load with reconfigurable capacitors. Lumped elements models have been developed, and the frequency tuning capability of the bandstop filter is studied, and it is shown that the filter stopband can be reconfigured by the loading capacitance. A 1-bit reconfigurable bandstop filter is designed based on the proposed novel bandstop filter loaded with two switchable 3.5mm × 6.5mm × 0.508mm Rogers 5880 single metal plane PCB capacitors. The prototype with compact overall size of 22mm × 39mm was designed and fabricated to validate the new structure. The measured stop-band central frequency is 3.04GHz and 2.513 GHz in cutoff state and connected state, respectively. 500 MHz central frequency reconfigurable capability is obtained.

Journal of Electromagnetic Waves and Applications, 2012

In this paper, novel evanescent mode substrate integrated waveguide (SIW) and half-mode substrate... more In this paper, novel evanescent mode substrate integrated waveguide (SIW) and half-mode substrate integrated waveguide (HMSIW) filters are proposed, and their applications to mechanical and electrical reconfigurable bandpass filters (BPFs) are studied. SIW and HMSIW loaded with coupled complementary split-ring resonators achieve forward electromagnetic wave transmission below the waveguide cutoff frequency due to evanescent wave amplification. The half-mode configuration of the proposed SIW BPF is an opening structure, and the proposed HMSIW BPF is suitable to load with control elements. The electric/magnetic coupling effects and frequency responses reconfigurable mechanics of the proposed HMSIW structure are studied based on lumped equivalent circuit model. By using floating capacitors with mechanical switches and PIN diodes loaded on the HMSIW resonators, two one-bit HMSIW 500 MHz mechanical and 300 MHz electrical reconfigurable BPFs are demonstrated.

Journal of Electromagnetic Waves and Applications, 2011

Novel bandstop filters based on the defected microstrip structure with complementary split-ring r... more Novel bandstop filters based on the defected microstrip structure with complementary split-ring resonators (CSRRs)/half-CSRRs etched on the microstrip surface are presented in this paper. By changing the configurations of the CSRRs, varied stop-band and pass-band characteristics are observed, and half-CSRRs is proposed to build a novel bandstop filter. A detailed explanation for the generation and variations of the stop-band and pass-band has been given. Lumped equivalent circuit analysis model is developed as well. The proposed filters exhibit compact size due to the employment of sub-wavelength resonators, and the overall size of the prototype is 12.2 mm × 28.95 mm × 0.8 mm. The measured −20 dB bandwidth of S 21 is from 2.51 GHz to 3 GHz, and the S 21 exhibits a wide spurious free response up to 10 GHz.

In this paper a metamaterial-inspired antenna with high gain and good directivity is designed. Ba... more In this paper a metamaterial-inspired antenna with high gain and good directivity is designed. Based on the concept of composite right/left-handed transmission line (CRLH-TL), the proposed antenna is realized based on three leakage wave unit cell and a left handed circular ring slot incorporated on the surface. The maximum achievable gain at the resonant frequency of 5.6 GHz is 6.933 dBi, and the return loss at 5.6 GHz can be 18 db. This proposed design has a simple structure and a compact dimension of 35 mm*40 mm*1 mm, which is suitable for particular wireless communication application such as WiFi and WLAN.

A CMOS capacitor-free low-dropout (LDO) voltage regulator with 0.65-1.8 V power supply is present... more A CMOS capacitor-free low-dropout (LDO) voltage regulator with 0.65-1.8 V power supply is presented. Positive feedback is used to build the differential computation of the error amplifier and the positive feedback gain is less than unity to ensure the stability. The LDO is designed in TSMC 0.18 μm CMOS processes. The maximum output current of the LDO is 50 mA at an output of 0.5 V. The simulation results show the average settling time of 9.9 μs can be achieved with 0.5% error for load current change between 5 mA and 50 mA, and the line and load regulations are 0.847%/V and 22.8 ppm/mA, respectively.

Journal of Electromagnetic Waves and Applications, 2011

—In this paper, novel bandpass filter and tunable bandpass filter are designed based on half-mode... more —In this paper, novel bandpass filter and tunable bandpass filter are designed based on half-mode substrate integrated waveguide (HMSIW) embedded with complementary resonators. Various passband characteristics are observed, and lumped equivalent circuit analysis models are developed. The configuration of the proposed bandpass filter is an open structure, and it is easy to load the active devices and build the bias/control networks on the signal plane. The tunable bandpass filter is presented based on the proposed novel bandpass filter loaded with semiconductor varactor diodes, and it has good spurious suppression characteristics and excellent out of band rejection. The prototype with overall size of 15.9 mm × 30.2 mm × 0.5 mm was designed and fabricated so as to validate the new structure. The measured central frequency is 1.538 GHz and 1.718 GHz, and the insertion loss is 5.1 dB and 3.3 dB, at 0 V and 30 V, respectively.

In this paper, two- and three-pole microstrip LC constant fractional bandwidth (CFBW) and constan... more In this paper, two- and three-pole microstrip LC constant fractional bandwidth (CFBW) and constant absolute bandwidth (CABW) tunable bandpass filters are proposed. The equivalent-circuit models are presented to study the tunable mechanism. The filter can be reconfigured by changing the capacitance of the LC resonators. Based on electric coupling coefficient compensation, second- and third-order tunable equivalent-circuit models with CFBW/CABW are presented. For demonstration, a semiconductor varactor diode loaded microstrip LC resonator is adopted in our work to design the second- and third-order tunable filters. The S-parameters, group delays, and third-order intercept points for different center frequencies of the filters are presented. Each resonator requires only one varactor diode for both central frequency and resonator coupling coefficient control.

IEEE Microwave and Wireless Components Letters, 2012

In this letter, a novel quadruple-mode resonator bandpass filter (BPF) with tunable bandwidth is ... more In this letter, a novel quadruple-mode resonator bandpass filter (BPF) with tunable bandwidth is proposed. By using two types of microwave varactors to tune the resonant frequencies and transmission zeros (TZs), the high-side edge of the passband and low-side edge of the passband can be separately varied. Therefore, the bandwidth could be tunable with reasonable adjust of the values of varactors. Theoretical expressions have been derived for the resonant frequencies and the TZs. The measured results of the BPF show that the fractional bandwidth can be tuned from 22% to 34% at a fixed centre frequency 2.0 GHz with a return loss better than 12 dB. The tested results show good agreement with simulated results.

Journal of Electromagnetic Waves and Applications, 2012

—In this paper, a compact and high selectivity broadband microstrip bandpass filter (BPF) using s... more —In this paper, a compact and high selectivity broadband microstrip bandpass filter (BPF) using stub-loaded resonator is proposed. The basic block of the proposed filter is a quadruple-mode resonator consisting of a stepped-impedance resonator and three shunt open stubs. The proposed resonator can provide two even-mode, two odd-mode frequencies and two transmission zeros. The even-mode resonant frequencies can be flexibly controlled by the centre stub, while the odd-mode frequencies are fixed. The two other symmetrical stubs can both affect even- and odd- mode frequencies. The proposed filter exhibits high selectivity profiting from the two transmission zeros (TZs) near the passband created by two types of stubs. The measured –3 dB bandwidth is 1.0 GHz at the centre frequency of 2.5 GHz, and the S 21 exhibits a wide spurious free response up to 6 GHz. Measured results show good agreements with EM simulation results.

Journal of Electromagnetic Waves and Applications, 2012

In this paper, a novel bandstop filter based on microstrip LC resonators and 1-bit frequency reco... more In this paper, a novel bandstop filter based on microstrip LC resonators and 1-bit frequency reconfigurable bandstop filter are presented. The configuration of the proposed LC resonators has open structure and is suitable to load with reconfigurable capacitors. Lumped elements models have been developed, and the frequency tuning capability of the bandstop filter is studied, and it is shown that the filter stopband can be reconfigured by the loading capacitance. A 1-bit reconfigurable bandstop filter is designed based on the proposed novel bandstop filter loaded with two switchable 3.5mm × 6.5mm × 0.508mm Rogers 5880 single metal plane PCB capacitors. The prototype with compact overall size of 22mm × 39mm was designed and fabricated to validate the new structure. The measured stop-band central frequency is 3.04GHz and 2.513 GHz in cutoff state and connected state, respectively. 500 MHz central frequency reconfigurable capability is obtained.

Journal of Electromagnetic Waves and Applications, 2012

In this paper, novel evanescent mode substrate integrated waveguide (SIW) and half-mode substrate... more In this paper, novel evanescent mode substrate integrated waveguide (SIW) and half-mode substrate integrated waveguide (HMSIW) filters are proposed, and their applications to mechanical and electrical reconfigurable bandpass filters (BPFs) are studied. SIW and HMSIW loaded with coupled complementary split-ring resonators achieve forward electromagnetic wave transmission below the waveguide cutoff frequency due to evanescent wave amplification. The half-mode configuration of the proposed SIW BPF is an opening structure, and the proposed HMSIW BPF is suitable to load with control elements. The electric/magnetic coupling effects and frequency responses reconfigurable mechanics of the proposed HMSIW structure are studied based on lumped equivalent circuit model. By using floating capacitors with mechanical switches and PIN diodes loaded on the HMSIW resonators, two one-bit HMSIW 500 MHz mechanical and 300 MHz electrical reconfigurable BPFs are demonstrated.

Journal of Electromagnetic Waves and Applications, 2011

Novel bandstop filters based on the defected microstrip structure with complementary split-ring r... more Novel bandstop filters based on the defected microstrip structure with complementary split-ring resonators (CSRRs)/half-CSRRs etched on the microstrip surface are presented in this paper. By changing the configurations of the CSRRs, varied stop-band and pass-band characteristics are observed, and half-CSRRs is proposed to build a novel bandstop filter. A detailed explanation for the generation and variations of the stop-band and pass-band has been given. Lumped equivalent circuit analysis model is developed as well. The proposed filters exhibit compact size due to the employment of sub-wavelength resonators, and the overall size of the prototype is 12.2 mm × 28.95 mm × 0.8 mm. The measured −20 dB bandwidth of S 21 is from 2.51 GHz to 3 GHz, and the S 21 exhibits a wide spurious free response up to 10 GHz.

In this paper a metamaterial-inspired antenna with high gain and good directivity is designed. Ba... more In this paper a metamaterial-inspired antenna with high gain and good directivity is designed. Based on the concept of composite right/left-handed transmission line (CRLH-TL), the proposed antenna is realized based on three leakage wave unit cell and a left handed circular ring slot incorporated on the surface. The maximum achievable gain at the resonant frequency of 5.6 GHz is 6.933 dBi, and the return loss at 5.6 GHz can be 18 db. This proposed design has a simple structure and a compact dimension of 35 mm*40 mm*1 mm, which is suitable for particular wireless communication application such as WiFi and WLAN.

A CMOS capacitor-free low-dropout (LDO) voltage regulator with 0.65-1.8 V power supply is present... more A CMOS capacitor-free low-dropout (LDO) voltage regulator with 0.65-1.8 V power supply is presented. Positive feedback is used to build the differential computation of the error amplifier and the positive feedback gain is less than unity to ensure the stability. The LDO is designed in TSMC 0.18 μm CMOS processes. The maximum output current of the LDO is 50 mA at an output of 0.5 V. The simulation results show the average settling time of 9.9 μs can be achieved with 0.5% error for load current change between 5 mA and 50 mA, and the line and load regulations are 0.847%/V and 22.8 ppm/mA, respectively.