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Lu Gao,
Jin Guo,
YueHui Wang, Tao Yu,
Qiang Zhang,
ChunGuang Li,
XueQiang Zhang,
Hong Li,
JunJie Li,
WuXia Li,
ChangZhi Gu,
JiBao Meng,
Ji Feng,
YuSheng He
[show abstract]
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ABSTRACT: This paper reports a 6-pole high-temperature superconducting (HTS) microstrip bandpass filter for radio astronomy applications.
The filter has a center frequency of 23 GHz and a bandwidth the 2 GHz. We have made many efforts, such as adopting 0.25-mm-thick
substrate, carefully designing the housing box and filter layout, to solve the problems in realizing a K-band planar filter.
A special straight-line half-wavelength resonator (center-widen resonator) was also designed to reduce the insertion loss
of the filter. The measured results showed a midband insertion loss of 0.11 dB with a ripple of 0.4 dB, and a return loss
better than 11.5 dB. Good agreement was obtained between simulated and measured results.
Chinese Science Bulletin 04/2012; 54(19):3485-3488. · 1.32 Impact Factor
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Qiang Zhang,
Yongbo Bian,
Jin Guo,
Bin Cui,
Jia Wang, Tao Yu,
Lu Gao,
Yuehui Wang,
Chunguang Li,
Xueqiang Zhang,
Hong Li,
Changzheng Gao,
Yusheng He
[show abstract]
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ABSTRACT: A compact L-band high temperature superconducting (HTS) microstrip input duplexer for satellite communication application has been developed. The duplexer has two output channels with center frequencies at 1200 and 1250 MHz, respectively. It was fabricated on a single piece of 2-in double-sided YBCO thin film on LaAlO<sub>3</sub> substrate with a dimension of 26 ?? 42 mm. The duplexer consists of a T-junction and two bandpass filters, i.e., a ten-pole filter and an eight-pole filter for the two transmission channels, respectively. Both of the two HTS bandpass filters were specially designed to suppress the second-harmonic spurious passband. Moreover, an HTS bandstop filter is added to the duplexer to improve the out-of-band rejection at a special frequency band. As a result of the preceding special designs, in addition to a very low insertion loss (0.2 dB), considerably sharp band edge (21 dB/MHz), and good voltage standing wave ratio (better than 1.4:1), much deeper out-of-band rejection (more than 75 dB) can be realized in a much wider frequency range, i.e., up to 3 GHz, which is almost three times above the center frequency of the passbands. Although all the elements of the duplexer are integrated within a single-piece YBCO film and the layout is compact, excellent isolation (higher than 80 dB) between the two channels has still been achieved.
IEEE Transactions on Appiled Superconductivity 03/2010; · 1.04 Impact Factor
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Yuehui Wang,
Xueqiang Zhang,
Xiaofeng He,
Lu Gao, Tao Yu,
Qiang Zhang,
Jin Guo,
Jia Wang,
Bin Cui,
Yongbo Bian,
Hong Li,
Qiang Luo,
Changzhi Gu,
Yusheng He
[show abstract]
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ABSTRACT: A novel structure is presented to optimize the design of narrow band dual mode patch filters. Using this method, a narrow band dual mode high power HTS filter with center frequency 2.015 GHz, fractional bandwidth less than 0.35%, return loss greater than 20 dB, near band-edge rejection close to -45 dB, and insertion loss less than 0.2 dB has been designed and fabricated. The filter can work at a power of 11.7 W without obvious deterioration of its transmission response.
IEEE Microwave and Wireless Components Letters 08/2009; · 1.72 Impact Factor
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Tao Yu,
Chunguang Li,
Fei Li,
Qiang Zhang,
Liang Sun,
Lu Gao,
Yuehui Wang,
Xueqiang Zhang,
Hong Li,
Chengjin Jin,
Jianbin Li,
Hongfei Liu,
Changzheng Gao,
Jibao Meng,
Yusheng He
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ABSTRACT: A 12-pole wideband superconducting microstrip bandpass filter, which has a fractional bandwidth of 38% and a center frequency of 1455 MHz, is presented for the Miyun 50-m radio astronomy telescope, Beijing, China. A novel resonator, which can not only generate very large coupling, but also push its first spurious resonant peak away from the passband, is introduced. A new style interleaved coupling structure is proposed and successfully used in this study to realize the remarkably required strong coupling. To achieve high edge slope on the high side of the passband, as required, a single transmission zero was introduced. The filter was fabricated on a 36 mm times 30 mm times 0.5 mm double-sided YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7</sub> film deposited on an MgO substrate. The measured results showed that the filter had 0.05-dB minimum insertion loss, 0.08-dB passband ripple, and 23-dB return loss at a temperature of 40 K. The first spurious peak did not appear until 2632 MHz. The overall measured performance showed good agreement with the simulation.
IEEE Transactions on Microwave Theory and Techniques 08/2009; · 1.85 Impact Factor
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Lu Gao,
Liang Sun,
Fei Li,
Qiang Zhang,
Yuehui Wang, Tao Yu,
Jin Guo,
Yongbo Bian,
Chunguang Li,
Xueqiang Zhang,
Hong Li,
Jibao Meng,
Yusheng He
[show abstract]
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ABSTRACT: This paper reports a development of a narrowband high-temperature superconducting filter with both high selectivity and flat group delay. The filter has a center frequency of 8.625 GHz and a 3-dB bandwidth of 42 MHz (a fractional bandwidth of 0.49%). In order to achieve both high band-edge steepness and excellent group-delay flatness, we introduce a 14-resonator quasi-elliptic function response with three pairs of transmission zeros (one pair for high selectivity and two pairs for flat group delay) in the cascaded quadruplet coupling structure. We also develop a novel low radiation resonator (double-folded resonator) to reduce the parasitic coupling and meet other requirements for the 8-GHz filter. The filter was fabricated on a 2-in-diameter 0.5-mm-thick MgO wafer with double-sided YBCO films. The measured results show a midband insertion loss of 1.6 dB and a return loss better than 15.5 dB. Band-edge steepness reaches over 11.7 dB/MHz at both the high- and low-frequency edges. The 60-dB rectangle ratio is less than 1.25. The out-of-band rejection is over 70 dB at 5.98 MHz from the 3-dB band edge. The variation of group delay is less than 23 ns over 33 MHz (78.5% of 3-dB bandwidth), and less than 30 ns over 34.5 MHz (82% of 3-dB bandwidth).
IEEE Transactions on Microwave Theory and Techniques 08/2009; · 1.85 Impact Factor
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Tao Yu,
Chunguang Li,
Fei Li,
Qiang Zhang,
Liang Sun,
Xueqiang Zhang,
Aisheng He,
Hong Li,
Qiang Luo,
Changzhi Gu,
Haiyan Tian,
Dongning Zheng,
Changzheng Gao,
Yusheng He
[show abstract]
[hide abstract]
ABSTRACT: To produce a filter small enough to fit a 2-in wafer in the very high frequency (VHF) band while avoiding parasitic cross coupling among nonadjacent resonators, a novel quasi-lumped element resonator with interdigital capacitor, double-spiral inductor, and pad capacitor have been introduced. This resonator has not only a highly miniature structure but also a very weak far-field radiation. A ten-pole quasi-elliptic filter with group-delay equalization, which has a 7.1-MHz 1-dB passband and a center frequency of 257.5 MHz, is designed and fabricated on a 37.3 x mm x 30.1 x mm x 0.5 x mm LaAlO<sub>3</sub> substrate. The measured results showed a 0.24-dB insertion loss, a 15-dB return loss, and a 70-dB out-of-band rejection. Moreover, the group delay variation is less than 50 ns over 70% of the 1-dB passband and the band where the phase error ripple is within plusmn5<sup>deg</sup> is more than 80% of the 1-dB passband. The overall experimental performance showed excellent agreement with the theory and simulation, which is a good proof of the advantage of our weak far-field radiation resonator. The result showed that the novel resonator is very suitable to fabricate narrowband ultrahigh frequency, VHF, or even lower frequency high-temperature superconductor filters on a 2-in wafer.
IEEE Transactions on Appiled Superconductivity 05/2009; · 1.04 Impact Factor
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ABSTRACT: A recent development of a twelve-pole high-temperature-superconducting (HTS) bandpass filter with group delay self-equalization for 3G wireless applications is reported. The filter is designed to have a 5.425MHz pass-band at a centre frequency of 2121.5MHz. The filter exhibits a quasi-elliptic function response implemented with a cascaded quadruplet (CQ) coupling structure. Two pair of complex frequency transmission zeros have been introduced to implement linear phase for group delay self-equalization. The filter was fabricated on a 0.5mm-thick MgO wafer with double-sided YBCO films. The filter displayed a minimum insertion loss of 0.2 dB in the passband and a return loss better than 14 dB over the pass-band. Out-of-band rejection at both sides is higher than 57dB with the skirt-slope as high as 100dB/MHz. The filter shows a 60ns fluctuation of group delay within 78% pass-band which matches the requirement of TD-SCDMA standard of 3G mobile telecommunication.
Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves and Workshop on Terahertz Technologies, 2007. MSMW '07. The Sixth International Kharkov Symposium on; 07/2007
