The paper presents a fully integrated ultra-wide band(UWB)low noise amplifier(LNA)for 3-10 GHz applications.It employs self-biased resistive-feedback and current-reused technique to achieve wide input matching and low...The paper presents a fully integrated ultra-wide band(UWB)low noise amplifier(LNA)for 3-10 GHz applications.It employs self-biased resistive-feedback and current-reused technique to achieve wide input matching and low power characteristics.An improved biased architecture is adopted in the second stage to attain a better gain-compensation performance.The design is verified with TSMC standard 1 P6 M 0.18μm RF CMOS process.The measurement results show that the parasitic problem of the transistors at high frequencies is solved.A high and flat S21 of 9.7±1.5 dB and the lowest NF 3.5 dB are achieved in the desired frequency band.The power consumption is only 7.5 mA under 1.6 V supply.The proposed LNA achieves broadband flat gain,low noise,and high linearity performance simultaneously,allowing it to be used in 3-10 GHz UWB applications.展开更多
The Peak to Average power Ratio (PAR) of a Multi-Band Orthogonal Frequency-Division Multiplexing (MB-OFDM) Ultra-Wide Band (UWB) signals can be substantially larger than that of single carrier or carrier-less ultra-wi...The Peak to Average power Ratio (PAR) of a Multi-Band Orthogonal Frequency-Division Multiplexing (MB-OFDM) Ultra-Wide Band (UWB) signals can be substantially larger than that of single carrier or carrier-less ultra-wideband signals. In this letter, a novel PAR reduction scheme for the MB-OFDM UWB system based on spreading and interleaving is proposed. By spreading the coded bits over each subcarrier in corresponding band and interleaving the spread symbols across all bands, the PAR statistics of the MB-OFDM signals can be improved and the PAR is reduced obviously. In the PAR reduction scheme, there is no loss in transmission data rate or Bit Error Rate (BER) performance decreasing. Since the spreading and interleaving operation are implemented by unitary Hadamard sequences and used for an approach to provide the robustness of the UWB system to narrowband interference, there is no additional implementation burden. Simulation results show that the investigated scheme gives the PAR reduction of 3dB compared with that of the original MB-OFDM signals.展开更多
In this paper, a compact coplanar epsilon.negative(ENG) antenna is proposed with ultra.wide operation band and small size of 18×11.5 mm2. The proposed antenna is designed based on a coplanar.waveguide(CPW) feedin...In this paper, a compact coplanar epsilon.negative(ENG) antenna is proposed with ultra.wide operation band and small size of 18×11.5 mm2. The proposed antenna is designed based on a coplanar.waveguide(CPW) feeding antenna, and thus the via.free structure is employed to realize the ENG unit cell, which is convenient to tune the frequency of zeroth.order resonance(ZOR) and extends the ZOR bandwidth. The high.order resonant frequencies are achieved and mainly determined by the separate slots that are located between the radiating patch and the ground plane. Adding the left.handed inductance between the radiating patch and ground has slight impact on the high.order resonant frequencies, and then the ultra.wide band is achieved by merging the ZOR bandwidth with the high.order resonant bandwidths. The ground plane primarily works as a matching network for the proposed antenna. Although it generates a low.frequency resonance, the performance is undesirable due to the impedance mismatching. The measured results show that the reflection coefficient, |S11| <.10 d B, is in a wide frequency range from 5.25 to 13 GHz, which covers the upper operation band of UWB communication. Also, the antenna contains relatively stable gains and omni.directional radiation patterns.展开更多
In this letter, a simple monopole antenna with variable band-notched characteristic for ultra wide band (UWB) function is proposed. Two L-shaped quarter-waveguide resonators coupled to the ground plane with two shorti...In this letter, a simple monopole antenna with variable band-notched characteristic for ultra wide band (UWB) function is proposed. Two L-shaped quarter-waveguide resonators coupled to the ground plane with two shorting tracks at the sides of the antenna are used to generate stop-band performance around 5.5 GHz (WLAN). The proposed antenna is fabricated on the substrate FR4 (relative permittivity of 4.7) and has a compact size of 16 × 28.5 × 1.6 mm. The designed antenna has a good impedance matching in 3.1 - 11.4 GHz frequency range with VSWR < 2, except the band 5 - 5.85 GHz.展开更多
Theoretical calculations predict transition frequencies in the terahertz range for the field-effect transistors based on carbon nanotubes, and this shows their suitability for being used in high frequency applications...Theoretical calculations predict transition frequencies in the terahertz range for the field-effect transistors based on carbon nanotubes, and this shows their suitability for being used in high frequency applications. In this paper, we have designed a field-effect transistor based on carbon nanotube with high transition frequency suitable for ultra-wide band applications. We did this by optimizing nanotube diameter, gate insulator thickness and dielectric constant. As a result, we achieved the transition frequency about 7.45 THz. The environment of open source software FETToy is used to simulate the device. Also a suitable model for calculating the transition frequency is presented.展开更多
The modern landmine's electronic fuse is susceptible to strong interference or can even be damaged by the ultra-wide band electromagnetic pulse(UWB-EMP). The finite-difference time-domain(FDTD) method in lossy me...The modern landmine's electronic fuse is susceptible to strong interference or can even be damaged by the ultra-wide band electromagnetic pulse(UWB-EMP). The finite-difference time-domain(FDTD) method in lossy media with cylindrical coordinates is used to study the interactions of the UWB-EMP with the landmine. First, the coupling of UWB-EMP into the landmine shielding shell through an aperture is numerically simulated. Second, the coupled electromagnetic field of mine shells made of different shielding materials and with apertures of different sizes is plotted. Third, the aperture coupling laws of UWB-EMP into shells are analyzed and categorized. Such an algorithm is capable of effectively preventing ladder similar errors, and consequently improving the calculation precision, and in addition to adopting the message passing interface(MPI) parallel method to divide the total calculating range into more sub-ranges, the overall calculating efficiency is greatly increased. These calculations are surely a constructive reference for modern landmine design against electromagnetic damage.展开更多
The evaluation of System Performance of UWB (ultra-wide band) jointing in MC (multi-carrier) signaling in correlated environments is presented in the report. The correlated Nakagami-m statistical distribution for the ...The evaluation of System Performance of UWB (ultra-wide band) jointing in MC (multi-carrier) signaling in correlated environments is presented in the report. The correlated Nakagami-m statistical distribution for the multipath fading model is assumed in this scenario. In fact to establish the model for analyzing in this article is using MC-CDMA (multi-carrier code-division multiple-access) system characterization combined with a UWB scheme. The average BER (bit error rate) is calculated and compared to a special case of previously published results. Studied results from this paper can be implied to approve the system performance for a UWB system combined with a MC-CDMA wireless communication system. It is worth noting that the Nakagami-m distributed fading parameter significantly dominates UWB system performance when it cooperates with MC signaling under a fading environment. Finally, it is worthy of noting that when the SNR (signal-to-noise ratio) at system’s receiver reaches a preset high threshold value, the parameter of power decay ratio effect could be not included.展开更多
To solve the precision self-positioning problem for mobile robot,a positioning program based on ultra-wideband technology was proposed. Ultra-wideband pulse has very high bandwidth; ranging accuracy can achieve centim...To solve the precision self-positioning problem for mobile robot,a positioning program based on ultra-wideband technology was proposed. Ultra-wideband pulse has very high bandwidth; ranging accuracy can achieve centimeter-level theoretically. The mobile robot obtained the distance to the reference node by sending ultra-wideband pulse. According to the geometric relations among the references and the robot,establish equations to calculate the position coordinates. Then Kalman filter algorithm was applied for mobile robot tracking. Simulation results show that robot positioning and tracking based on ultra-wideband technology can achieve indoor and outdoor seamless docking.展开更多
This paper presents a planar ultra-wideband (UWB) bandpass filter with sharp out-of-band rejection performance. The filter is formed by a folded multiple-mode resonator to realize high performance in an operation band...This paper presents a planar ultra-wideband (UWB) bandpass filter with sharp out-of-band rejection performance. The filter is formed by a folded multiple-mode resonator to realize high performance in an operation band from 3.3 to 10 GHz with a very compact size of 20 mm × 20 mm × 0.5 mm. An extra notched band centered at 5.8 GHz is further accomplished by etching a Hilbert fractal curve slit on the filter without the necessity of readjusting the geometrical parameters. The simulated and measured results are in good agreement.展开更多
This paper presents the design and analysis of a miniaturized and novel wearable ultra-wideband(UWB)band-notch textile antenna for Body Area Networks(BANs).The major goal of building the antenna for wearable applicati...This paper presents the design and analysis of a miniaturized and novel wearable ultra-wideband(UWB)band-notch textile antenna for Body Area Networks(BANs).The major goal of building the antenna for wearable applications with band notch in X-band is to reject the downlink band(7.25 to 7.75 GHz)of satellite communication in the UWB frequency ranges of 3.1–10.6 GHz to keep away from interference.Computer Simulation Technology(CST)TM Microwave Studio,which is user-friendly and reliable,was used to model and simulate the antenna.The radiating element of the antenna is designed on Jeans’textile substrate,which has a relative permittivity of 1.7.The thickness of the jeans’fabric substrate has been considered to be 1 mm.Return loss,gain,bandwidth,impedance,radiation,and total efficiency,and radiation patterns are presented and investigated.The antenna is simulated placed on the three layers of the human body model,and the on-body results are summarized in comparison with free space.Results and analysis indicate that this antenna has good band-notch characteristics in the frequency range of 7.25 GHz to 7.75 GHz.The parametric study varying the relative permittivity of Jeans’fabric substrate of this antenna is also evaluated.In addition,effects on the antenna parameters of variation of ground plane size have been reported.The antenna is 25 mm×16 mm×1.07 mm in total volume.Results reveal that this antenna achieves the design goal and performs well both in free space and on the body.展开更多
The C-band is allocated for commercial telecommunications via satellites. Amateur satellite operations in the frequency range 5.830 to 5.850 GHz for down-links and 5.650 to 5.670 GHz for up-links are allowed by Intern...The C-band is allocated for commercial telecommunications via satellites. Amateur satellite operations in the frequency range 5.830 to 5.850 GHz for down-links and 5.650 to 5.670 GHz for up-links are allowed by International Telecommunication Union. The X-band is used for terrestrial broadband communication, radar applications, and portions of the X-band are assigned for deep space telecommunications. In this paper, a design of 4 × 1 Ultra Wide Band (UWB) antenna array for C-band and X-band applications is introduced. Metamaterial sixteen-unit cells are incorporated into each antenna element for radiation characteristics enhancement purposes. Permeability and permittivity of metamaterial unit cells are obtained all over the operating bandwidth. UWB unequal power divider is used to feed the proposed four elements antenna array based on Chebyshev excitation method. The proposed antenna has a suitable 3 dB beam width and gains all over the operating bandwidth which extends from 5.6 GHz to 10.9 GHz. The proposed antenna covers 60% and 72.5% of the C-band and X-band, respectively. The proposed antenna is fabricated, measured, and good agreement is obtained between simulated and measured results. The obtained performance ensures the suitability of the proposed antenna array for C-band and X-band applications.展开更多
Based on the high positioning accuracy,low cost and low-power consumption,the ultra-wide-band(UWB)is an ideal solution for indoor unmanned aerial vehicle(UAV)localization and navigation.However,the UWB signals are eas...Based on the high positioning accuracy,low cost and low-power consumption,the ultra-wide-band(UWB)is an ideal solution for indoor unmanned aerial vehicle(UAV)localization and navigation.However,the UWB signals are easy to be blocked or reflected by obstacles such as walls and furniture.A resilient tightly-coupled inertial navigation system(INS)/UWB integration is proposed and implemented for indoor UAV navigation in this paper.A factor graph optimization(FGO)method enhanced by resilient stochastic model is established to cope with the indoor challenging scenarios.To deal with the impact of UWB non-line-of-sight(NLOS)signals and noise uncertainty,the conventional neural net-works(CNNs)are introduced into the stochastic modelling to improve the resilience and reliability of the integration.Based on the status that the UWB features are limited,a‘two-phase'CNNs structure was designed and implemented:one for signal classification and the other one for measurement noise prediction.The proposed resilient FGO method is tested on flighting UAV platform under actual indoor challenging scenario.Compared to classical FGO method,the overall positioning errors can be decreased from about 0.60 m to centimeter-level under signal block and reflection scenarios.The superiority of resilient FGO which effectively verified in constrained environment is pretty important for positioning accuracy and integrity for indoor navigation task.展开更多
This paper presents a compact Multiple Input Multiple Output(MIMO)antenna with WLAN band notch for Ultra-Wideband(UWB)applications.The antenna is designed on 0.8mmthick low-cost FR-4 substrate having a compact size of...This paper presents a compact Multiple Input Multiple Output(MIMO)antenna with WLAN band notch for Ultra-Wideband(UWB)applications.The antenna is designed on 0.8mmthick low-cost FR-4 substrate having a compact size of 22mm×30 mm.The proposed antenna comprises of two monopole patches on the top layer of substrate while having a shared ground on its bottom layer.The mutual coupling between adjacent patches has been reduced by using a novel stub with shared ground structure.The stub consists of complementary rectangular slots that disturb the surface current direction and thus result in reducing mutual coupling between two ports.A slot is etched in the radiating patch for WLAN band notch.The slot is used to suppress frequencies ranging from 5.1 to 5.9 GHz.The results show that the proposed antenna has a very good impedance bandwidth of|S11|<−10 dB within the frequency band from 3.1–14 GHz.A low mutual coupling of less than−23 dB is achieved within the entire UWB band.Furthermore,the antenna has a peak gain of 5.8 dB,low ECC<0.002 and high Diversity Gain(DG>9.98).展开更多
A small-sized, low-profile, and planar dual band antenna for Bluetooth (2.4 - 2.484 GHz) and ultra-wideband (UWB) (3.1 - 10.6 GHz) with multi-band notched antennas is presented. Two antennas A and B with different typ...A small-sized, low-profile, and planar dual band antenna for Bluetooth (2.4 - 2.484 GHz) and ultra-wideband (UWB) (3.1 - 10.6 GHz) with multi-band notched antennas is presented. Two antennas A and B with different types of slots are used to obtain tri-band notched characteristic. In antenna A notched bands, 5 - 6 GHz for WLAN, and 3.3 - 4 GHz for WiMAX, are achieved using a U-slot in ground structure and in the radiating patch. In antenna B two notched bands at 3.3 - 4 GHz, for WiMAX and 7.2 GHz for C-band satellite communication systems are achieved by using a U-slot in ground structure and a H-shaped slot in the radiating patch. The radiation characteristics of the two antennas are calculated using a commercial EM simulator based on Finite Element Method (FEM) and the Finite Integration Technique (FIT). The two antennas show acceptable gain flatness with stable omnidirectional radiation patterns across the integrated Bluetooth and UWB bands.展开更多
基金Supported by the National Natural Science Foundation of China(No.61534003,61874024,61871116)
文摘The paper presents a fully integrated ultra-wide band(UWB)low noise amplifier(LNA)for 3-10 GHz applications.It employs self-biased resistive-feedback and current-reused technique to achieve wide input matching and low power characteristics.An improved biased architecture is adopted in the second stage to attain a better gain-compensation performance.The design is verified with TSMC standard 1 P6 M 0.18μm RF CMOS process.The measurement results show that the parasitic problem of the transistors at high frequencies is solved.A high and flat S21 of 9.7±1.5 dB and the lowest NF 3.5 dB are achieved in the desired frequency band.The power consumption is only 7.5 mA under 1.6 V supply.The proposed LNA achieves broadband flat gain,low noise,and high linearity performance simultaneously,allowing it to be used in 3-10 GHz UWB applications.
基金Supported by the National 863 High Technology Research Program of China (N0.2005AA123320)Universities Natural Science Research Project of Jiangsu Province (No.05KJB510101).
文摘The Peak to Average power Ratio (PAR) of a Multi-Band Orthogonal Frequency-Division Multiplexing (MB-OFDM) Ultra-Wide Band (UWB) signals can be substantially larger than that of single carrier or carrier-less ultra-wideband signals. In this letter, a novel PAR reduction scheme for the MB-OFDM UWB system based on spreading and interleaving is proposed. By spreading the coded bits over each subcarrier in corresponding band and interleaving the spread symbols across all bands, the PAR statistics of the MB-OFDM signals can be improved and the PAR is reduced obviously. In the PAR reduction scheme, there is no loss in transmission data rate or Bit Error Rate (BER) performance decreasing. Since the spreading and interleaving operation are implemented by unitary Hadamard sequences and used for an approach to provide the robustness of the UWB system to narrowband interference, there is no additional implementation burden. Simulation results show that the investigated scheme gives the PAR reduction of 3dB compared with that of the original MB-OFDM signals.
基金supported by the National Natural Science Foundation of China (NNSF) under Grant 61531016National Natural Science Foundation of China (NNSF) under Grant 61271090+1 种基金Sichuan province science and technology support project under Grant 2016GZ0059Sichuan province science and technology support project under Grant 2017GZ0110
文摘In this paper, a compact coplanar epsilon.negative(ENG) antenna is proposed with ultra.wide operation band and small size of 18×11.5 mm2. The proposed antenna is designed based on a coplanar.waveguide(CPW) feeding antenna, and thus the via.free structure is employed to realize the ENG unit cell, which is convenient to tune the frequency of zeroth.order resonance(ZOR) and extends the ZOR bandwidth. The high.order resonant frequencies are achieved and mainly determined by the separate slots that are located between the radiating patch and the ground plane. Adding the left.handed inductance between the radiating patch and ground has slight impact on the high.order resonant frequencies, and then the ultra.wide band is achieved by merging the ZOR bandwidth with the high.order resonant bandwidths. The ground plane primarily works as a matching network for the proposed antenna. Although it generates a low.frequency resonance, the performance is undesirable due to the impedance mismatching. The measured results show that the reflection coefficient, |S11| <.10 d B, is in a wide frequency range from 5.25 to 13 GHz, which covers the upper operation band of UWB communication. Also, the antenna contains relatively stable gains and omni.directional radiation patterns.
文摘In this letter, a simple monopole antenna with variable band-notched characteristic for ultra wide band (UWB) function is proposed. Two L-shaped quarter-waveguide resonators coupled to the ground plane with two shorting tracks at the sides of the antenna are used to generate stop-band performance around 5.5 GHz (WLAN). The proposed antenna is fabricated on the substrate FR4 (relative permittivity of 4.7) and has a compact size of 16 × 28.5 × 1.6 mm. The designed antenna has a good impedance matching in 3.1 - 11.4 GHz frequency range with VSWR < 2, except the band 5 - 5.85 GHz.
文摘Theoretical calculations predict transition frequencies in the terahertz range for the field-effect transistors based on carbon nanotubes, and this shows their suitability for being used in high frequency applications. In this paper, we have designed a field-effect transistor based on carbon nanotube with high transition frequency suitable for ultra-wide band applications. We did this by optimizing nanotube diameter, gate insulator thickness and dielectric constant. As a result, we achieved the transition frequency about 7.45 THz. The environment of open source software FETToy is used to simulate the device. Also a suitable model for calculating the transition frequency is presented.
基金Project supported by the Postdoctoral Science Foundation of China(Grant No.2014M552610)
文摘The modern landmine's electronic fuse is susceptible to strong interference or can even be damaged by the ultra-wide band electromagnetic pulse(UWB-EMP). The finite-difference time-domain(FDTD) method in lossy media with cylindrical coordinates is used to study the interactions of the UWB-EMP with the landmine. First, the coupling of UWB-EMP into the landmine shielding shell through an aperture is numerically simulated. Second, the coupled electromagnetic field of mine shells made of different shielding materials and with apertures of different sizes is plotted. Third, the aperture coupling laws of UWB-EMP into shells are analyzed and categorized. Such an algorithm is capable of effectively preventing ladder similar errors, and consequently improving the calculation precision, and in addition to adopting the message passing interface(MPI) parallel method to divide the total calculating range into more sub-ranges, the overall calculating efficiency is greatly increased. These calculations are surely a constructive reference for modern landmine design against electromagnetic damage.
文摘The evaluation of System Performance of UWB (ultra-wide band) jointing in MC (multi-carrier) signaling in correlated environments is presented in the report. The correlated Nakagami-m statistical distribution for the multipath fading model is assumed in this scenario. In fact to establish the model for analyzing in this article is using MC-CDMA (multi-carrier code-division multiple-access) system characterization combined with a UWB scheme. The average BER (bit error rate) is calculated and compared to a special case of previously published results. Studied results from this paper can be implied to approve the system performance for a UWB system combined with a MC-CDMA wireless communication system. It is worth noting that the Nakagami-m distributed fading parameter significantly dominates UWB system performance when it cooperates with MC signaling under a fading environment. Finally, it is worthy of noting that when the SNR (signal-to-noise ratio) at system’s receiver reaches a preset high threshold value, the parameter of power decay ratio effect could be not included.
基金High Technology Research and Development Program(863program) of China (No.2007AA041604)
文摘To solve the precision self-positioning problem for mobile robot,a positioning program based on ultra-wideband technology was proposed. Ultra-wideband pulse has very high bandwidth; ranging accuracy can achieve centimeter-level theoretically. The mobile robot obtained the distance to the reference node by sending ultra-wideband pulse. According to the geometric relations among the references and the robot,establish equations to calculate the position coordinates. Then Kalman filter algorithm was applied for mobile robot tracking. Simulation results show that robot positioning and tracking based on ultra-wideband technology can achieve indoor and outdoor seamless docking.
文摘This paper presents a planar ultra-wideband (UWB) bandpass filter with sharp out-of-band rejection performance. The filter is formed by a folded multiple-mode resonator to realize high performance in an operation band from 3.3 to 10 GHz with a very compact size of 20 mm × 20 mm × 0.5 mm. An extra notched band centered at 5.8 GHz is further accomplished by etching a Hilbert fractal curve slit on the filter without the necessity of readjusting the geometrical parameters. The simulated and measured results are in good agreement.
基金Taif University Researchers are supporting project number(TURSP-2020/216),Taif University,Taif,Saudi Arabia.
文摘This paper presents the design and analysis of a miniaturized and novel wearable ultra-wideband(UWB)band-notch textile antenna for Body Area Networks(BANs).The major goal of building the antenna for wearable applications with band notch in X-band is to reject the downlink band(7.25 to 7.75 GHz)of satellite communication in the UWB frequency ranges of 3.1–10.6 GHz to keep away from interference.Computer Simulation Technology(CST)TM Microwave Studio,which is user-friendly and reliable,was used to model and simulate the antenna.The radiating element of the antenna is designed on Jeans’textile substrate,which has a relative permittivity of 1.7.The thickness of the jeans’fabric substrate has been considered to be 1 mm.Return loss,gain,bandwidth,impedance,radiation,and total efficiency,and radiation patterns are presented and investigated.The antenna is simulated placed on the three layers of the human body model,and the on-body results are summarized in comparison with free space.Results and analysis indicate that this antenna has good band-notch characteristics in the frequency range of 7.25 GHz to 7.75 GHz.The parametric study varying the relative permittivity of Jeans’fabric substrate of this antenna is also evaluated.In addition,effects on the antenna parameters of variation of ground plane size have been reported.The antenna is 25 mm×16 mm×1.07 mm in total volume.Results reveal that this antenna achieves the design goal and performs well both in free space and on the body.
文摘The C-band is allocated for commercial telecommunications via satellites. Amateur satellite operations in the frequency range 5.830 to 5.850 GHz for down-links and 5.650 to 5.670 GHz for up-links are allowed by International Telecommunication Union. The X-band is used for terrestrial broadband communication, radar applications, and portions of the X-band are assigned for deep space telecommunications. In this paper, a design of 4 × 1 Ultra Wide Band (UWB) antenna array for C-band and X-band applications is introduced. Metamaterial sixteen-unit cells are incorporated into each antenna element for radiation characteristics enhancement purposes. Permeability and permittivity of metamaterial unit cells are obtained all over the operating bandwidth. UWB unequal power divider is used to feed the proposed four elements antenna array based on Chebyshev excitation method. The proposed antenna has a suitable 3 dB beam width and gains all over the operating bandwidth which extends from 5.6 GHz to 10.9 GHz. The proposed antenna covers 60% and 72.5% of the C-band and X-band, respectively. The proposed antenna is fabricated, measured, and good agreement is obtained between simulated and measured results. The obtained performance ensures the suitability of the proposed antenna array for C-band and X-band applications.
基金National Natural Science Foundation of China(Grant No.62203111)the Open Research Fund of State Key Laboratory of Information Engineering in Surveying,Mapping and Remote Sensing,Wuhan University(Grant No.21P01)the Foundation of Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology,Ministry of Education,China(Grant No.SEU-MIAN-202101)to provide fund for conducting experiments。
文摘Based on the high positioning accuracy,low cost and low-power consumption,the ultra-wide-band(UWB)is an ideal solution for indoor unmanned aerial vehicle(UAV)localization and navigation.However,the UWB signals are easy to be blocked or reflected by obstacles such as walls and furniture.A resilient tightly-coupled inertial navigation system(INS)/UWB integration is proposed and implemented for indoor UAV navigation in this paper.A factor graph optimization(FGO)method enhanced by resilient stochastic model is established to cope with the indoor challenging scenarios.To deal with the impact of UWB non-line-of-sight(NLOS)signals and noise uncertainty,the conventional neural net-works(CNNs)are introduced into the stochastic modelling to improve the resilience and reliability of the integration.Based on the status that the UWB features are limited,a‘two-phase'CNNs structure was designed and implemented:one for signal classification and the other one for measurement noise prediction.The proposed resilient FGO method is tested on flighting UAV platform under actual indoor challenging scenario.Compared to classical FGO method,the overall positioning errors can be decreased from about 0.60 m to centimeter-level under signal block and reflection scenarios.The superiority of resilient FGO which effectively verified in constrained environment is pretty important for positioning accuracy and integrity for indoor navigation task.
基金The authors would like to acknowledge the support from Taif University Researchers Supporting Project Number (TURSP-2020/264),Taif University,。
文摘This paper presents a compact Multiple Input Multiple Output(MIMO)antenna with WLAN band notch for Ultra-Wideband(UWB)applications.The antenna is designed on 0.8mmthick low-cost FR-4 substrate having a compact size of 22mm×30 mm.The proposed antenna comprises of two monopole patches on the top layer of substrate while having a shared ground on its bottom layer.The mutual coupling between adjacent patches has been reduced by using a novel stub with shared ground structure.The stub consists of complementary rectangular slots that disturb the surface current direction and thus result in reducing mutual coupling between two ports.A slot is etched in the radiating patch for WLAN band notch.The slot is used to suppress frequencies ranging from 5.1 to 5.9 GHz.The results show that the proposed antenna has a very good impedance bandwidth of|S11|<−10 dB within the frequency band from 3.1–14 GHz.A low mutual coupling of less than−23 dB is achieved within the entire UWB band.Furthermore,the antenna has a peak gain of 5.8 dB,low ECC<0.002 and high Diversity Gain(DG>9.98).
文摘A small-sized, low-profile, and planar dual band antenna for Bluetooth (2.4 - 2.484 GHz) and ultra-wideband (UWB) (3.1 - 10.6 GHz) with multi-band notched antennas is presented. Two antennas A and B with different types of slots are used to obtain tri-band notched characteristic. In antenna A notched bands, 5 - 6 GHz for WLAN, and 3.3 - 4 GHz for WiMAX, are achieved using a U-slot in ground structure and in the radiating patch. In antenna B two notched bands at 3.3 - 4 GHz, for WiMAX and 7.2 GHz for C-band satellite communication systems are achieved by using a U-slot in ground structure and a H-shaped slot in the radiating patch. The radiation characteristics of the two antennas are calculated using a commercial EM simulator based on Finite Element Method (FEM) and the Finite Integration Technique (FIT). The two antennas show acceptable gain flatness with stable omnidirectional radiation patterns across the integrated Bluetooth and UWB bands.