A simple and compact microstrip-fed ultra wideband （UWB） printed monopole antenna is presented. The antenna is composed of a circular radiator and a finitely grounded plane. The antenna occupies about 16.62 GHz abso...A simple and compact microstrip-fed ultra wideband （UWB） printed monopole antenna is presented. The antenna is composed of a circular radiator and a finitely grounded plane. The antenna occupies about 16.62 GHz absolute bandwidth and 142.7% relative bandwidth covering from 3.38 GHz to 20 GHz with voltage standing wave ratio （VSWR） below two. A quasi-omnidirectional and quasi-symmetrical radiation pattern in H plane is obtained in the whole bandwidth. The high performance of the antenna is validated with measured and simulated results given. The antenna can be applied for the system design of UWB wireless communication.展开更多
A broadband microstrip patch antenna was analyzed and designed.Full wave analysis method(FWAM) was employed to show that a stacked microstrip dual patch antenna(SMDPA) might have a much wider bandwidth than that of ...A broadband microstrip patch antenna was analyzed and designed.Full wave analysis method(FWAM) was employed to show that a stacked microstrip dual patch antenna(SMDPA) might have a much wider bandwidth than that of the ordinanry uni patch one.By means of discrete complex image theory(DCIT),the Sommerfeld integrals (SI) involved were accurately calculated at a speed several hundred times faster than numerical integration method(NIM).The feeding structure of the SMDPA was then improved and the bandwidth was extended to about 22% or more for voltage standing wave ratio (VSWR)s≤2 Finally,a matching network was constructed to obtain a bandwidth of about 25% for s≤1.5.展开更多
According to the processing and interpretation of multichannel seismic reflection data in the area of Okinawa Trough, the BSR （bottom simulating reflector） was identified in 16 seismic profiles. By means of special ...According to the processing and interpretation of multichannel seismic reflection data in the area of Okinawa Trough, the BSR （bottom simulating reflector） was identified in 16 seismic profiles. By means of special processing technologies such as AVO and waveform inversion, the authors, for the first time, directly used the BSR to outline the distribution tendency of thickness of gas hydrate stability zone in the Trough and thought that the largest stability zone thickness was in the south and the smallest in the north. Then through calculation the authors got the thickness of hydrate stability zone and resource of the hydrate. This would be useful to the future hydrate exploration and resource evaluation in the Okinawa Trough.展开更多
A simple and compact microstrip-fed ultra wideband （UWB） printed monopole antenna with band-notched performance is proposed for wireless universal serial-bus （WUSB）. The antenna is composed of a U-shaped line radi...A simple and compact microstrip-fed ultra wideband （UWB） printed monopole antenna with band-notched performance is proposed for wireless universal serial-bus （WUSB）. The antenna is composed of a U-shaped line radiator and a small strip bar and is partially grounded, so that the measured impedance bandwidth of the antenna is about 7. 88 GHz covering 3. 12 to 11 GHz with VSWR below 2, and the expected band rejection of 5.06 to 5. 89 GHz is also obtained. The characteristics of the proposed antenna are analyzed, and the geometric parameters for optimal performance are investigated in detail. A relatively stable, quasi-omnidirectional and quasi-symmetrical radiation pattern is also found. The proposed band-notched UWB antenna requires no external filters to avoid interference with other systems, and thus, greatly simplifies the system design of an ultra wideband WUSB communication system.展开更多
The property of multi-band operation has been studied and investigated analytically through the design of a rectangular patch microstrip antenna having different numbers of wide slots arranged at both the radiating ed...The property of multi-band operation has been studied and investigated analytically through the design of a rectangular patch microstrip antenna having different numbers of wide slots arranged at both the radiating edges. The analyses were carried out using the method of moments simulation software. It is shown that a patch with three slots has a multi-band feature with four resonant frequencies at 1.6, 1.8, 2.65, and 4.83 GHz and adequate values of return loss and gain. It is also shown that a patch with two pairs of wide slots arranged at both the radiating edges has the dual band feature with resonant frequencies at 1.64 and 1.8 GHz and good values of return loss and gain.展开更多
This paper proposes a new approach to further improving the bandwidth of a typical aperture-coupled stacked microstrip antenna by cutting triangular notches in the radiating sides of both radiating patches together wi...This paper proposes a new approach to further improving the bandwidth of a typical aperture-coupled stacked microstrip antenna by cutting triangular notches in the radiating sides of both radiating patches together with offsetting both patches. An antenna applying this new approach is designed,fabricated,and tested. The experimental antenna could achieve a measured impedance bandwidth of about 37.5% for the Voltage Standing Wave Ratio(VSWR) ≤ 2in X-band.展开更多
In order to broaden the bandwidth of a tapered slot- line antenna （TSA）, a bilateral tapered slot-line antenna （BTSA） with a new feeding structure of coplanar waveguide （CPW） is developed. Based on the fact that...In order to broaden the bandwidth of a tapered slot- line antenna （TSA）, a bilateral tapered slot-line antenna （BTSA） with a new feeding structure of coplanar waveguide （CPW） is developed. Based on the fact that the bandwidth limitation of TSA mainly depends on its feeding structure, an improved CPW-based feed structure etched on the backboard of the BTSA is adopted to perform traveling-wave transition. Both the simulation results and measurement data verify that the proposed feeding structure results in ＂high-pass＂ frequency response for antenna impedance matching. The voltage standing wave ratio （VSWR） is less than 2：1 when the frequency is higher than 3 GHz. The antenna gain exceeds 7 dBi with good radiation patterns when the bandwidth is from 4 to 16 GHz. This ultra wideband （UWB） antenna with a compact size is specially available for the electronic systems of counter-measure and microwave imaging.展开更多
U-slot patch antennas with П-shaped feed slot are studied, and numerical results based on the FDTD method are presented. The effects of varying physical parameters are investigated with a goal of understanding the co...U-slot patch antennas with П-shaped feed slot are studied, and numerical results based on the FDTD method are presented. The effects of varying physical parameters are investigated with a goal of understanding the coupling among different resonators. It is found that the U-slot patch antenna can be designed to attain 50% impedance bandwidth as well as 30-40% gain bandwidth. By altering the sizes of U-slot and feed slot, the wideband characteristic can be changed into a duai-frequency char- acteristic.展开更多
This paper proposes an estimation method of the directions of arrival(DOA) for the broadband signals received by a uniform planar antenna array including the mutual coupling effect. The process modeling of antenna arr...This paper proposes an estimation method of the directions of arrival(DOA) for the broadband signals received by a uniform planar antenna array including the mutual coupling effect. The process modeling of antenna array receiving dynamic signal is obtained accurately via building the array system electromagnetic space-time model, and the mutual coupling effect is included in the synthesis procedure automatically. The broadband signal is divided into several sub-bands, and the complex weight of these sub-bands frequencies is figured out using the least mean square iteration programming. In the proposed method, the mutual coupling effect is compensated at the different frequencies. The calculation results show that the method is suitable for the uniform linear and uniform circular array pattern integration, and it is commendably satisfied with the requirement of engineering design.展开更多
A kind of compact ultra wideband （UWB） monopole antenna with dual-band notched function is presented.The proposed antenna,using ＂C＂ and ＂L＂ apertures embedded in the annular ring patch and ground patch,gets two ...A kind of compact ultra wideband （UWB） monopole antenna with dual-band notched function is presented.The proposed antenna,using ＂C＂ and ＂L＂ apertures embedded in the annular ring patch and ground patch,gets two bandnotched characteristics in WiMAX3.5 GHz and WLAN 5.5 GHz.The size of antenna is 24 mm × 36 mm × 1.6 mm.The simulation results show that waveband range of the antenna is 2.7-10.6 GHz for S11 ＜-10 dB and the band-notched wavebands are 3.2-3.8 GHz and 5.1-6 GHz.So it has miniaturization,ultra-band and band-notched characteristics.Meanwhile,the radition pattern,directivety and gain are perfect,which meets the practical need.展开更多
The results of an analysis of the temporal and spatial distribution of typhoon precipitation influencing Fujian from 1960 to 2005 show that typhoon precipitation in Fujian province occurs from May to November, with th...The results of an analysis of the temporal and spatial distribution of typhoon precipitation influencing Fujian from 1960 to 2005 show that typhoon precipitation in Fujian province occurs from May to November, with the most in August. There has been a decreasing trend since 1960. Typhoon precipitation gradually decreases from the coastal region to the northwestern mainland of Fujian and the maximum typhoon precipitation occurs in the northeast and the south of Fujian. Typhoon torrential rain is one of the extreme rainfall events in Fujian. High frequencies of typhoon torrential rain occur in the coastal and southwest regions of the province. With the impact of Fujian＇s terrain, typhoon precipitation occurs more easily to the east of the mountains than to the west. Atmospheric circulation at 500 hPa over Asia and sea surface temperature anomalies of the equatorial eastern Pacific are analyzed, with the finding that they are closely connected with the anomaly of typhoon precipitation influencing Fujian, possibly mainly by modulating the northbound track of typhoons via changing the atmosphere circulation to lead to the anomaly of typhoon precipitation over the province展开更多
Based on the framework of the geo-info spectra of montane altitudinal belts, this paper firstly reviews six classification systems for the spectra of mountain altitudinal belts in China and considers that detailed reg...Based on the framework of the geo-info spectra of montane altitudinal belts, this paper firstly reviews six classification systems for the spectra of mountain altitudinal belts in China and considers that detailed regional study of altitudinal belts is the key for reaching standardization and systemization of mountain altitudinal belts. Only can this further identify and resolve problems with the study of altitudinal belts. The factors forming the spectra of altitudinal belts are analyzed in the Tianshan Mountains of China, and a digital altitudinal belt system is constructed for the northern flank, southern flank, the heartland, and Ili valley in the west. The characteristics of each belt are revealed with a summarization of the pattern of areal differentiation of altitudinal belts.展开更多
With high-resolution conductivity-temperature-depth （CTD） observations conducted in Oct.-Nov. 2005, this study provides a detailed quasi-synoptic description of the North Pacific Tropic Water （NPTW）, North Pacific...With high-resolution conductivity-temperature-depth （CTD） observations conducted in Oct.-Nov. 2005, this study provides a detailed quasi-synoptic description of the North Pacific Tropic Water （NPTW）, North Pacific Intermediate Water （NPIW） and Antarctic Intermediate Water （AAIW） in the western North Pacific. Some novel features are found. NPTW enters the western ocean with highest-salinity core off shore at 15°-18°N, and then splits to flow northward and southward along the western boundary. Its salinity decreases and density increases outside the core region. NPIW spreads westward north of 15°N with lowest salinity off shore at 21°N, but mainly hugs the Mindanao coast south of 12°N. It shoals and thins toward the south, with salinity increasing and density decreasing. AAIW extends to higher latitude off shore than that in shore, and it is traced as a salinity minimum to only 10°N at 130°E. Most of the South Pacific waters turn northeastward rather than directly flow northward upon reaching to the Mindanao coast, indicating the eastward shift of the Mindanao Undercurrent （MUC）.展开更多
文摘A simple and compact microstrip-fed ultra wideband （UWB） printed monopole antenna is presented. The antenna is composed of a circular radiator and a finitely grounded plane. The antenna occupies about 16.62 GHz absolute bandwidth and 142.7% relative bandwidth covering from 3.38 GHz to 20 GHz with voltage standing wave ratio （VSWR） below two. A quasi-omnidirectional and quasi-symmetrical radiation pattern in H plane is obtained in the whole bandwidth. The high performance of the antenna is validated with measured and simulated results given. The antenna can be applied for the system design of UWB wireless communication.
文摘A broadband microstrip patch antenna was analyzed and designed.Full wave analysis method(FWAM) was employed to show that a stacked microstrip dual patch antenna(SMDPA) might have a much wider bandwidth than that of the ordinanry uni patch one.By means of discrete complex image theory(DCIT),the Sommerfeld integrals (SI) involved were accurately calculated at a speed several hundred times faster than numerical integration method(NIM).The feeding structure of the SMDPA was then improved and the bandwidth was extended to about 22% or more for voltage standing wave ratio (VSWR)s≤2 Finally,a matching network was constructed to obtain a bandwidth of about 25% for s≤1.5.
文摘According to the processing and interpretation of multichannel seismic reflection data in the area of Okinawa Trough, the BSR （bottom simulating reflector） was identified in 16 seismic profiles. By means of special processing technologies such as AVO and waveform inversion, the authors, for the first time, directly used the BSR to outline the distribution tendency of thickness of gas hydrate stability zone in the Trough and thought that the largest stability zone thickness was in the south and the smallest in the north. Then through calculation the authors got the thickness of hydrate stability zone and resource of the hydrate. This would be useful to the future hydrate exploration and resource evaluation in the Okinawa Trough.
文摘A simple and compact microstrip-fed ultra wideband （UWB） printed monopole antenna with band-notched performance is proposed for wireless universal serial-bus （WUSB）. The antenna is composed of a U-shaped line radiator and a small strip bar and is partially grounded, so that the measured impedance bandwidth of the antenna is about 7. 88 GHz covering 3. 12 to 11 GHz with VSWR below 2, and the expected band rejection of 5.06 to 5. 89 GHz is also obtained. The characteristics of the proposed antenna are analyzed, and the geometric parameters for optimal performance are investigated in detail. A relatively stable, quasi-omnidirectional and quasi-symmetrical radiation pattern is also found. The proposed band-notched UWB antenna requires no external filters to avoid interference with other systems, and thus, greatly simplifies the system design of an ultra wideband WUSB communication system.
文摘The property of multi-band operation has been studied and investigated analytically through the design of a rectangular patch microstrip antenna having different numbers of wide slots arranged at both the radiating edges. The analyses were carried out using the method of moments simulation software. It is shown that a patch with three slots has a multi-band feature with four resonant frequencies at 1.6, 1.8, 2.65, and 4.83 GHz and adequate values of return loss and gain. It is also shown that a patch with two pairs of wide slots arranged at both the radiating edges has the dual band feature with resonant frequencies at 1.64 and 1.8 GHz and good values of return loss and gain.
文摘This paper proposes a new approach to further improving the bandwidth of a typical aperture-coupled stacked microstrip antenna by cutting triangular notches in the radiating sides of both radiating patches together with offsetting both patches. An antenna applying this new approach is designed,fabricated,and tested. The experimental antenna could achieve a measured impedance bandwidth of about 37.5% for the Voltage Standing Wave Ratio(VSWR) ≤ 2in X-band.
基金The National High Technology Research and Development Program of China(863 Program)(No.2007AA01Z264)
文摘In order to broaden the bandwidth of a tapered slot- line antenna （TSA）, a bilateral tapered slot-line antenna （BTSA） with a new feeding structure of coplanar waveguide （CPW） is developed. Based on the fact that the bandwidth limitation of TSA mainly depends on its feeding structure, an improved CPW-based feed structure etched on the backboard of the BTSA is adopted to perform traveling-wave transition. Both the simulation results and measurement data verify that the proposed feeding structure results in ＂high-pass＂ frequency response for antenna impedance matching. The voltage standing wave ratio （VSWR） is less than 2：1 when the frequency is higher than 3 GHz. The antenna gain exceeds 7 dBi with good radiation patterns when the bandwidth is from 4 to 16 GHz. This ultra wideband （UWB） antenna with a compact size is specially available for the electronic systems of counter-measure and microwave imaging.
文摘U-slot patch antennas with П-shaped feed slot are studied, and numerical results based on the FDTD method are presented. The effects of varying physical parameters are investigated with a goal of understanding the coupling among different resonators. It is found that the U-slot patch antenna can be designed to attain 50% impedance bandwidth as well as 30-40% gain bandwidth. By altering the sizes of U-slot and feed slot, the wideband characteristic can be changed into a duai-frequency char- acteristic.
基金supported by the Chinese Natural Science Foundation (61401075)
文摘This paper proposes an estimation method of the directions of arrival(DOA) for the broadband signals received by a uniform planar antenna array including the mutual coupling effect. The process modeling of antenna array receiving dynamic signal is obtained accurately via building the array system electromagnetic space-time model, and the mutual coupling effect is included in the synthesis procedure automatically. The broadband signal is divided into several sub-bands, and the complex weight of these sub-bands frequencies is figured out using the least mean square iteration programming. In the proposed method, the mutual coupling effect is compensated at the different frequencies. The calculation results show that the method is suitable for the uniform linear and uniform circular array pattern integration, and it is commendably satisfied with the requirement of engineering design.
文摘A kind of compact ultra wideband （UWB） monopole antenna with dual-band notched function is presented.The proposed antenna,using ＂C＂ and ＂L＂ apertures embedded in the annular ring patch and ground patch,gets two bandnotched characteristics in WiMAX3.5 GHz and WLAN 5.5 GHz.The size of antenna is 24 mm × 36 mm × 1.6 mm.The simulation results show that waveband range of the antenna is 2.7-10.6 GHz for S11 ＜-10 dB and the band-notched wavebands are 3.2-3.8 GHz and 5.1-6 GHz.So it has miniaturization,ultra-band and band-notched characteristics.Meanwhile,the radition pattern,directivety and gain are perfect,which meets the practical need.
基金Project from Natural Science Foundation of China (40775046)Project from Research Plan "973" (2006CB403601)
文摘The results of an analysis of the temporal and spatial distribution of typhoon precipitation influencing Fujian from 1960 to 2005 show that typhoon precipitation in Fujian province occurs from May to November, with the most in August. There has been a decreasing trend since 1960. Typhoon precipitation gradually decreases from the coastal region to the northwestern mainland of Fujian and the maximum typhoon precipitation occurs in the northeast and the south of Fujian. Typhoon torrential rain is one of the extreme rainfall events in Fujian. High frequencies of typhoon torrential rain occur in the coastal and southwest regions of the province. With the impact of Fujian＇s terrain, typhoon precipitation occurs more easily to the east of the mountains than to the west. Atmospheric circulation at 500 hPa over Asia and sea surface temperature anomalies of the equatorial eastern Pacific are analyzed, with the finding that they are closely connected with the anomaly of typhoon precipitation influencing Fujian, possibly mainly by modulating the northbound track of typhoons via changing the atmosphere circulation to lead to the anomaly of typhoon precipitation over the province
文摘Based on the framework of the geo-info spectra of montane altitudinal belts, this paper firstly reviews six classification systems for the spectra of mountain altitudinal belts in China and considers that detailed regional study of altitudinal belts is the key for reaching standardization and systemization of mountain altitudinal belts. Only can this further identify and resolve problems with the study of altitudinal belts. The factors forming the spectra of altitudinal belts are analyzed in the Tianshan Mountains of China, and a digital altitudinal belt system is constructed for the northern flank, southern flank, the heartland, and Ili valley in the west. The characteristics of each belt are revealed with a summarization of the pattern of areal differentiation of altitudinal belts.
基金Supported by the National Natural Science Foundation of China (Nos 40890153 and 40576016)
文摘With high-resolution conductivity-temperature-depth （CTD） observations conducted in Oct.-Nov. 2005, this study provides a detailed quasi-synoptic description of the North Pacific Tropic Water （NPTW）, North Pacific Intermediate Water （NPIW） and Antarctic Intermediate Water （AAIW） in the western North Pacific. Some novel features are found. NPTW enters the western ocean with highest-salinity core off shore at 15°-18°N, and then splits to flow northward and southward along the western boundary. Its salinity decreases and density increases outside the core region. NPIW spreads westward north of 15°N with lowest salinity off shore at 21°N, but mainly hugs the Mindanao coast south of 12°N. It shoals and thins toward the south, with salinity increasing and density decreasing. AAIW extends to higher latitude off shore than that in shore, and it is traced as a salinity minimum to only 10°N at 130°E. Most of the South Pacific waters turn northeastward rather than directly flow northward upon reaching to the Mindanao coast, indicating the eastward shift of the Mindanao Undercurrent （MUC）.
