本文提出一种基于圆台形吸收单元的超宽带、极化不敏感的超材料太赫兹吸收器.该超材料吸收器采用金属薄膜金和介质层二氧化硅交替叠加的多层结构.采用商业软件CST Studio Suite 2009时域求解器计算了其在0—10 THz波段内的吸收率A(ω),...本文提出一种基于圆台形吸收单元的超宽带、极化不敏感的超材料太赫兹吸收器.该超材料吸收器采用金属薄膜金和介质层二氧化硅交替叠加的多层结构.采用商业软件CST Studio Suite 2009时域求解器计算了其在0—10 THz波段内的吸收率A(ω),在2—10 THz之间实现了对入射太赫兹波的超宽频带强吸收.仿真结果表明,由于其圆台形单元结构,在器件垂直方向上形成一系列不同尺寸的微型吸收器,产生了吸收频点相连的多频吸收峰.利用不同吸收峰的耦合叠加效应,获得超过8 THz的超宽带太赫兹波吸收,吸收强度达到92.3%以上.这一结构具有超宽带强吸收,360极化不敏感以及易于加工等优越特性,因而在太赫兹波探测器、光谱成像以及隐身技术方面具有潜在的应用.展开更多
Electronic devices pervade everyday life,which has triggered severe electromagnetic(EM)wave pollution.To face this challenge,developing EM wave absorbers with ultra-broadband absorption capacity is critically required...Electronic devices pervade everyday life,which has triggered severe electromagnetic(EM)wave pollution.To face this challenge,developing EM wave absorbers with ultra-broadband absorption capacity is critically required.Currently,nano-composite construction has been widely utilized to realize impedance match and broadband absorption.However,complex experimental procedures,limited thermal stability,and interior oxidation resistance are still unneglectable issues.Therefore,it is appealing to realize ultra-broadband EM wave absorption in single-phase materials with good stability.Aiming at this target,two high-entropy transition metal carbides(HE TMCs)including(Zr,Hf,Nb,Ta)C(HE TMC-2)and(Cr,Zr,Hf,Nb,Ta)C(HE TMC-3)are designed and synthesized,of which the microwave absorption performance is investigated in comparison with previously reported(Ti,Zr,Hf,Nb,Ta)C(HE TMC-1).Due to the synergistic effects of dielectric and magnetic losses,HE TMC-2 and HE TMC-3 exhibit better impedance match and wider effective absorption bandwidth(EAB).In specific,the exclusion of Ti element in HE TMC-2 endows it optimal minimum reflection loss(RL_(min))and EAB of−41.7 dB(2.11 mm,10.52 GHz)and 3.5 GHz(at 3.0 mm),respectively.Remarkably,the incorporation of Cr element in HE TMC-3 significantly improves the impedance match,thus realizing EAB of 10.5,9.2,and 13.9 GHz at 2,3,and 4 mm,respectively.The significance of this study lays on realizing ultra-broadband capacity in HE TMC-3(Cr,Zr,Hf,Nb,Ta),demonstrating the effectiveness of high-entropy component design in tailoring the impedance match.展开更多
基于第三代半导体Ga N的高电子迁移率晶体管技术,利用Cree CGH4001O管芯大信号模型并结合ADS2009U1软件,结合商用Ga N管芯的自身特性,采用微带-电阻-微带-电容-微带的负反馈回路和整体负载牵引方法及宽带匹配网络,成功设计并实现了30-2 ...基于第三代半导体Ga N的高电子迁移率晶体管技术,利用Cree CGH4001O管芯大信号模型并结合ADS2009U1软件,结合商用Ga N管芯的自身特性,采用微带-电阻-微带-电容-微带的负反馈回路和整体负载牵引方法及宽带匹配网络,成功设计并实现了30-2 600 MHz超过6个倍频程的超宽带功率放大器。测试结果表明,该功率放大器的带内线性增益大于11.8 d B,线性增益平坦度小于±0.95 d B,输入回波小于-10.2 d B,1 d B压缩点输出功率大于36.5 d Bm,功率附加效率大于22%,饱和时输出功率大于39.1 d Bm,功率附加效率大于28%。该功率放大器在很宽的频带内有着平坦的增益,适用于对平坦度要求较高的超宽带系统中。展开更多
We numerically demonstrate a novel ultra-broadband polarization-independent metamaterial perfect absorber in the visible and near-infrared region involving the phase-change material Ge_2Sb_2Te_5(GST).The novel perfect...We numerically demonstrate a novel ultra-broadband polarization-independent metamaterial perfect absorber in the visible and near-infrared region involving the phase-change material Ge_2Sb_2Te_5(GST).The novel perfect absorber scheme consists of an array of high-index strong-absorbance GST square resonators separated from a continuous Au substrate by a low-index lossless dielectric layer(silica)and a high-index GST planar cavity.Three absorption peaks with the maximal absorbance up to 99.94% are achieved,owing to the excitation of plasmon-like dipolar or quadrupole resonances from the high-index GST resonators and cavity resonances generated by the GST planar cavity.The intensities and positions of the absorption peaks show strong dependence on structural parameters.A heat transfer model is used to investigate the temporal variation of temperature within the GST region.The results show that the temperature of amorphous GST can reach up to 433 K of the phase transition temperature from room temperature in just 0.37 ns with a relatively low incident light intensity of 1.11×10~8W∕m^2,due to the enhanced ultra-broadband light absorbance through strong plasmon resonances and cavity resonance in the absorber.The study suggests a feasible means to lower the power requirements for photonic devices based on a thermal phase change via engineering ultra-broadband light absorbers.展开更多
为满足毫米波通信等应用领域对超宽带功率放大器的需求,文章采用南京电子器件研究所50 nm GaN HEMT工艺研制了一款覆盖W、F波段的超宽带功率放大器。首先,使用模型对实验数据进行拟合外推,得到宽带范围内管芯的功率阻抗;其次,采用LC结...为满足毫米波通信等应用领域对超宽带功率放大器的需求,文章采用南京电子器件研究所50 nm GaN HEMT工艺研制了一款覆盖W、F波段的超宽带功率放大器。首先,使用模型对实验数据进行拟合外推,得到宽带范围内管芯的功率阻抗;其次,采用LC结构加高低阻抗微带线方式进行宽带电路匹配,并设计了末级、级间和输入级的匹配电路拓扑结构;最后,对级间匹配电路进行综合优化调整,并采用兰格桥进行功率合成。最终,放大器在80GHz~140GHz范围内,典型线性增益达18dB,饱和输出功率达100mW,同时,在全频段范围内,芯片具有±1dB的功率平坦度和良好的回波损耗,在太赫兹领域具有广阔的应用前景。展开更多
The miniaturization and intelligence of near infrared(NIR)devices urgently require an excellent broadband NIR phosphor.However,emission spectra of most NIR phosphors cover less than 1200 nm with a full width at half m...The miniaturization and intelligence of near infrared(NIR)devices urgently require an excellent broadband NIR phosphor.However,emission spectra of most NIR phosphors cover less than 1200 nm with a full width at half maximum(FWHM)less than 200 nm and a peak wavelength less than 900 nm.Here,we successfully developed ultra-broadband NIR phosphors ScNbO_(4):Cr^(3+)which can overcome the above shortcomings based on a double-site occupancy strategy.The phosphors achieve ultra-broadband NIR emission from 800 to 1400 nm with a peak wavelength at 980 nm.Its FWHM is up to 217 nm.The valence state of Cr ions in phosphors was analyzed.The double-site occupancy of Cr^(3+)ions in the host and the relationship between host structure and optical properties are discussed in detail.NIR light transmission experiments show that phosphors have potential application value in non-destructive analysis.This work develops an excellent NIR luminescent material and provides an efficient method to obtain ultra-broadband NIR phosphors with longer peak wavelength.展开更多
文摘本文提出一种基于圆台形吸收单元的超宽带、极化不敏感的超材料太赫兹吸收器.该超材料吸收器采用金属薄膜金和介质层二氧化硅交替叠加的多层结构.采用商业软件CST Studio Suite 2009时域求解器计算了其在0—10 THz波段内的吸收率A(ω),在2—10 THz之间实现了对入射太赫兹波的超宽频带强吸收.仿真结果表明,由于其圆台形单元结构,在器件垂直方向上形成一系列不同尺寸的微型吸收器,产生了吸收频点相连的多频吸收峰.利用不同吸收峰的耦合叠加效应,获得超过8 THz的超宽带太赫兹波吸收,吸收强度达到92.3%以上.这一结构具有超宽带强吸收,360极化不敏感以及易于加工等优越特性,因而在太赫兹波探测器、光谱成像以及隐身技术方面具有潜在的应用.
基金We gratefully acknowledge the financial support from the National Natural Science Foundation of China(Nos.51972089,51672064,and U1435206).
文摘Electronic devices pervade everyday life,which has triggered severe electromagnetic(EM)wave pollution.To face this challenge,developing EM wave absorbers with ultra-broadband absorption capacity is critically required.Currently,nano-composite construction has been widely utilized to realize impedance match and broadband absorption.However,complex experimental procedures,limited thermal stability,and interior oxidation resistance are still unneglectable issues.Therefore,it is appealing to realize ultra-broadband EM wave absorption in single-phase materials with good stability.Aiming at this target,two high-entropy transition metal carbides(HE TMCs)including(Zr,Hf,Nb,Ta)C(HE TMC-2)and(Cr,Zr,Hf,Nb,Ta)C(HE TMC-3)are designed and synthesized,of which the microwave absorption performance is investigated in comparison with previously reported(Ti,Zr,Hf,Nb,Ta)C(HE TMC-1).Due to the synergistic effects of dielectric and magnetic losses,HE TMC-2 and HE TMC-3 exhibit better impedance match and wider effective absorption bandwidth(EAB).In specific,the exclusion of Ti element in HE TMC-2 endows it optimal minimum reflection loss(RL_(min))and EAB of−41.7 dB(2.11 mm,10.52 GHz)and 3.5 GHz(at 3.0 mm),respectively.Remarkably,the incorporation of Cr element in HE TMC-3 significantly improves the impedance match,thus realizing EAB of 10.5,9.2,and 13.9 GHz at 2,3,and 4 mm,respectively.The significance of this study lays on realizing ultra-broadband capacity in HE TMC-3(Cr,Zr,Hf,Nb,Ta),demonstrating the effectiveness of high-entropy component design in tailoring the impedance match.
文摘基于第三代半导体Ga N的高电子迁移率晶体管技术,利用Cree CGH4001O管芯大信号模型并结合ADS2009U1软件,结合商用Ga N管芯的自身特性,采用微带-电阻-微带-电容-微带的负反馈回路和整体负载牵引方法及宽带匹配网络,成功设计并实现了30-2 600 MHz超过6个倍频程的超宽带功率放大器。测试结果表明,该功率放大器的带内线性增益大于11.8 d B,线性增益平坦度小于±0.95 d B,输入回波小于-10.2 d B,1 d B压缩点输出功率大于36.5 d Bm,功率附加效率大于22%,饱和时输出功率大于39.1 d Bm,功率附加效率大于28%。该功率放大器在很宽的频带内有着平坦的增益,适用于对平坦度要求较高的超宽带系统中。
基金973 Program of China(2013CB632704)National Natural Science Foundation of China(NSFC)(11374357,11434017)
文摘We numerically demonstrate a novel ultra-broadband polarization-independent metamaterial perfect absorber in the visible and near-infrared region involving the phase-change material Ge_2Sb_2Te_5(GST).The novel perfect absorber scheme consists of an array of high-index strong-absorbance GST square resonators separated from a continuous Au substrate by a low-index lossless dielectric layer(silica)and a high-index GST planar cavity.Three absorption peaks with the maximal absorbance up to 99.94% are achieved,owing to the excitation of plasmon-like dipolar or quadrupole resonances from the high-index GST resonators and cavity resonances generated by the GST planar cavity.The intensities and positions of the absorption peaks show strong dependence on structural parameters.A heat transfer model is used to investigate the temporal variation of temperature within the GST region.The results show that the temperature of amorphous GST can reach up to 433 K of the phase transition temperature from room temperature in just 0.37 ns with a relatively low incident light intensity of 1.11×10~8W∕m^2,due to the enhanced ultra-broadband light absorbance through strong plasmon resonances and cavity resonance in the absorber.The study suggests a feasible means to lower the power requirements for photonic devices based on a thermal phase change via engineering ultra-broadband light absorbers.
文摘为满足毫米波通信等应用领域对超宽带功率放大器的需求,文章采用南京电子器件研究所50 nm GaN HEMT工艺研制了一款覆盖W、F波段的超宽带功率放大器。首先,使用模型对实验数据进行拟合外推,得到宽带范围内管芯的功率阻抗;其次,采用LC结构加高低阻抗微带线方式进行宽带电路匹配,并设计了末级、级间和输入级的匹配电路拓扑结构;最后,对级间匹配电路进行综合优化调整,并采用兰格桥进行功率合成。最终,放大器在80GHz~140GHz范围内,典型线性增益达18dB,饱和输出功率达100mW,同时,在全频段范围内,芯片具有±1dB的功率平坦度和良好的回波损耗,在太赫兹领域具有广阔的应用前景。
基金Project supported by the National Natural Science Foundation of China (62127816)the Guangdong Introducing Innovative and Entrepreneurial Teams of"The Pearl River Talent Recruitment Program" (2019ZT08X340)。
文摘The miniaturization and intelligence of near infrared(NIR)devices urgently require an excellent broadband NIR phosphor.However,emission spectra of most NIR phosphors cover less than 1200 nm with a full width at half maximum(FWHM)less than 200 nm and a peak wavelength less than 900 nm.Here,we successfully developed ultra-broadband NIR phosphors ScNbO_(4):Cr^(3+)which can overcome the above shortcomings based on a double-site occupancy strategy.The phosphors achieve ultra-broadband NIR emission from 800 to 1400 nm with a peak wavelength at 980 nm.Its FWHM is up to 217 nm.The valence state of Cr ions in phosphors was analyzed.The double-site occupancy of Cr^(3+)ions in the host and the relationship between host structure and optical properties are discussed in detail.NIR light transmission experiments show that phosphors have potential application value in non-destructive analysis.This work develops an excellent NIR luminescent material and provides an efficient method to obtain ultra-broadband NIR phosphors with longer peak wavelength.
