An Electromagnetic Band Gap (EBG) loaded square waveguide Band-Pass Filter (BPF) is proposed in this paper. It’s simply composed by symmetrically loading periodical metal diaphragms on each wall of a square waveguide...An Electromagnetic Band Gap (EBG) loaded square waveguide Band-Pass Filter (BPF) is proposed in this paper. It’s simply composed by symmetrically loading periodical metal diaphragms on each wall of a square waveguide. The influences of insert sizes and loading periods on the overall BPF performances are analyzed. Experimental results agree well with those predicted. 6 GHz pass-band with insert loss less than 1 dB, 2.5 GHz stop-band and larger than 25 dB polarization isolation can be obtained. The BPF can be applied in dual-polarized waveguide-based antenna-feed systems.展开更多
In this paper,an integrated substrate gap waveguide(ISGW)filtering antenna is proposed at millimeter wave band,whose surface wave and spurious modes are simultaneously suppressed.A secondorder filtering response is ob...In this paper,an integrated substrate gap waveguide(ISGW)filtering antenna is proposed at millimeter wave band,whose surface wave and spurious modes are simultaneously suppressed.A secondorder filtering response is obtained through a coupling feeding scheme using one uniform impedance resonator(UIR)and two stepped-impedance resonators(SIRs).To increase the stopband width of the antenna,the spurious modes are suppressed by selecting the appropriate sizes of the ISGW unit cell.Furthermore,the ISGW is implemented to improve the radiation performance of the antenna by alleviating the propagation of surface wave.And an equivalent circuit is investigated to reveal the working principle of ISGW.To demonstrate this methodology,an ISGW filtering antenna operating at a center frequency of 25 GHz is designed,fabricated,and measured.The results show that the antenna achieves a stopband width of 1.6f0(center frequency),an out-of-band suppression level of 21 dB,and a peak realized gain of 8.5 dBi.展开更多
采用基于第一性原理下的局域密度近似(LDA)方法对岩石矿物结构Ca硫族化合物CaX(X=S, Se, Te)的晶格常数和电子结构进行了研究.研究结果表明,使用LDA方法得到的晶格常数与实验值符合得很好,但带隙值却远低于实验值.为了获得可靠的带隙值...采用基于第一性原理下的局域密度近似(LDA)方法对岩石矿物结构Ca硫族化合物CaX(X=S, Se, Te)的晶格常数和电子结构进行了研究.研究结果表明,使用LDA方法得到的晶格常数与实验值符合得很好,但带隙值却远低于实验值.为了获得可靠的带隙值,使用了GW(G格林函数, W库伦屏蔽相互作用)近似方法对Ca硫族化合物的带隙进行修正.利用GW近似方法计算CaS和CaSe的带隙值比利用LDA计算的带隙值高,并且与实验值相吻合.同时也预测了CaTe的带隙值,尽管没有实验值作为参考,但GW近似计算的结果应该是合适的值.展开更多
集成基片间隙波导(Integrated Substrate Gap Waveguide,ISGW)采用3层介质基板实现了微带线的封装,降低了电路辐射损耗.作为多层非均匀介质传输线,ISGW的有效相对介电常数研究还未开展,严重制约了ISGW的应用电路研究.针对这一问题提出...集成基片间隙波导(Integrated Substrate Gap Waveguide,ISGW)采用3层介质基板实现了微带线的封装,降低了电路辐射损耗.作为多层非均匀介质传输线,ISGW的有效相对介电常数研究还未开展,严重制约了ISGW的应用电路研究.针对这一问题提出了一种ISGW有效相对介电常数的提取方法.首先,建立了一个毫米波ISGW模型,并仿真了模型的色散特性和传输特性;接着,提出一种基于阻抗匹配的半波长法提取ISGW的有效相对介电常数,推导了有效相对介电常数的提取公式;最后,对ISGW模型进行仿真,从ISGW模型的仿真S11结果中提取了有效相对介电常数,并与ANSYS软件中模型仿真结果中的有效相对介电常数数据比较,验证了提取方法的有效性.展开更多
In this paper, we investigate the optical transmission properties of perfect and defective two-segment-connected tri- angular waveguide networks （2SCTWNs） and find that after introducing defects in networks, many gr...In this paper, we investigate the optical transmission properties of perfect and defective two-segment-connected tri- angular waveguide networks （2SCTWNs） and find that after introducing defects in networks, many groups of transparent extreme narrow photonic passbands （ENPPs） will be created in the middle of the transmission spectra, the number for each group and the group number of ENPPs can he adjusted by the matching ratios of waveguide length （MRWLs）, the number of defects, and the number of unit cells of 2SCTWNs. The influences of MRWL, number of defects, and number of unit cells on the number, width, and position of these ENPPs are researched and a series of quantitative rules and prop- erties are obtained. It may be useful for the designing of high-sensitive optical switches, wavelength division multiplexers, extreme-narrowband filters, and other correlative waveguide network devices.展开更多
Polyyne,an sp~1-hybridized linear allotrope of carbon,has a tunable quasiparticle energy gap,which depends on the terminated chemical ending groups as well as the chain length.Previously,nitrogen doping was utilized t...Polyyne,an sp~1-hybridized linear allotrope of carbon,has a tunable quasiparticle energy gap,which depends on the terminated chemical ending groups as well as the chain length.Previously,nitrogen doping was utilized to tailor the properties of different kinds of allotrope of carbon.However,how the nitrogen doping tailors the properties of the polyyne remains unexplored.Here,we applied the GW method to study the quasiparticle energy gaps of the N-doped polyynes with different lengths.When a C atom is substituted by an N atom in a polyyne,the quasiparticle energy gap varies with the substituted position in the polyyne.The modification is particularly pronounced when the second-nearest-neighboring carbon atom of a hydrogen atom is substituted.In addition,the nitrogen doping makes the Fermi level closer to the lowest unoccupied molecular orbital,resulting in an n-type semiconductor.Our results suggest another route to tailor the electronic properties of polyyne in addition to the length of polyyne and the terminated chemical ending groups.展开更多
Three dual-mode band-pass filters are presented in the present paper. The first filter is realized by dual-mode substrate integrated waveguide (SIW) cavity;the second is based on the integration of SIW cavity with ele...Three dual-mode band-pass filters are presented in the present paper. The first filter is realized by dual-mode substrate integrated waveguide (SIW) cavity;the second is based on the integration of SIW cavity with electromagnetic band gap (EBG);and the third is based on the integration of SIW cavity with complementary split ring resonator (CSRR). The dual-mode SIW cavity is designed to have a fractional bandwidth of 4.95% at the midband frequency of 9.08 GHz;the proposed EBG-SIW resonator operates at 9.12 GHz with a bandwidth of 4.38% and the CSRR-SIW resonator operates at 8.66 GHz with a bandwidth of 2.54%. The proposed filters have the high Q-factors and generate a transmission zero in upper stopband, and these by the use of Rogers RT/duriod 5880 (tm).展开更多
A rectangular waveguide band-stop filter using electromagnetic crystals (EMXT) surface as the top and bottom walls is presented in this letter. The EMXT surface has a band gap that can prevent electromagnetic wave fro...A rectangular waveguide band-stop filter using electromagnetic crystals (EMXT) surface as the top and bottom walls is presented in this letter. The EMXT surface has a band gap that can prevent electromagnetic wave from propagating along the waveguide. Dispersion properties of the waveguide filter are analyzed using an approximated lumped-element circuit model. A W-band prototype based on the proposed waveguide filter is designed and characterized. The experimental results show a rejection band centered at 97 GHz and a rejection level of 16 dB.展开更多
文摘An Electromagnetic Band Gap (EBG) loaded square waveguide Band-Pass Filter (BPF) is proposed in this paper. It’s simply composed by symmetrically loading periodical metal diaphragms on each wall of a square waveguide. The influences of insert sizes and loading periods on the overall BPF performances are analyzed. Experimental results agree well with those predicted. 6 GHz pass-band with insert loss less than 1 dB, 2.5 GHz stop-band and larger than 25 dB polarization isolation can be obtained. The BPF can be applied in dual-polarized waveguide-based antenna-feed systems.
基金This work was supported by the National Key research and development program of China(No.2021YFB 2900401)the national natural science foundation of China(No.62361057,No.61861046)+1 种基金the key natural science foundation of Shenzhen(No.JCYJ20220818102209020)the key research and development program of Shenzhen(No.ZDSYS20210623091807023).
文摘In this paper,an integrated substrate gap waveguide(ISGW)filtering antenna is proposed at millimeter wave band,whose surface wave and spurious modes are simultaneously suppressed.A secondorder filtering response is obtained through a coupling feeding scheme using one uniform impedance resonator(UIR)and two stepped-impedance resonators(SIRs).To increase the stopband width of the antenna,the spurious modes are suppressed by selecting the appropriate sizes of the ISGW unit cell.Furthermore,the ISGW is implemented to improve the radiation performance of the antenna by alleviating the propagation of surface wave.And an equivalent circuit is investigated to reveal the working principle of ISGW.To demonstrate this methodology,an ISGW filtering antenna operating at a center frequency of 25 GHz is designed,fabricated,and measured.The results show that the antenna achieves a stopband width of 1.6f0(center frequency),an out-of-band suppression level of 21 dB,and a peak realized gain of 8.5 dBi.
文摘采用基于第一性原理下的局域密度近似(LDA)方法对岩石矿物结构Ca硫族化合物CaX(X=S, Se, Te)的晶格常数和电子结构进行了研究.研究结果表明,使用LDA方法得到的晶格常数与实验值符合得很好,但带隙值却远低于实验值.为了获得可靠的带隙值,使用了GW(G格林函数, W库伦屏蔽相互作用)近似方法对Ca硫族化合物的带隙进行修正.利用GW近似方法计算CaS和CaSe的带隙值比利用LDA计算的带隙值高,并且与实验值相吻合.同时也预测了CaTe的带隙值,尽管没有实验值作为参考,但GW近似计算的结果应该是合适的值.
文摘集成基片间隙波导(Integrated Substrate Gap Waveguide,ISGW)采用3层介质基板实现了微带线的封装,降低了电路辐射损耗.作为多层非均匀介质传输线,ISGW的有效相对介电常数研究还未开展,严重制约了ISGW的应用电路研究.针对这一问题提出了一种ISGW有效相对介电常数的提取方法.首先,建立了一个毫米波ISGW模型,并仿真了模型的色散特性和传输特性;接着,提出一种基于阻抗匹配的半波长法提取ISGW的有效相对介电常数,推导了有效相对介电常数的提取公式;最后,对ISGW模型进行仿真,从ISGW模型的仿真S11结果中提取了有效相对介电常数,并与ANSYS软件中模型仿真结果中的有效相对介电常数数据比较,验证了提取方法的有效性.
基金Project supported by the National Natural Science Foundations of China(Grant Nos.11374107 and 10974061)
文摘In this paper, we investigate the optical transmission properties of perfect and defective two-segment-connected tri- angular waveguide networks （2SCTWNs） and find that after introducing defects in networks, many groups of transparent extreme narrow photonic passbands （ENPPs） will be created in the middle of the transmission spectra, the number for each group and the group number of ENPPs can he adjusted by the matching ratios of waveguide length （MRWLs）, the number of defects, and the number of unit cells of 2SCTWNs. The influences of MRWL, number of defects, and number of unit cells on the number, width, and position of these ENPPs are researched and a series of quantitative rules and prop- erties are obtained. It may be useful for the designing of high-sensitive optical switches, wavelength division multiplexers, extreme-narrowband filters, and other correlative waveguide network devices.
基金Project supported by Guangdong Basic and Applied Basic Research Foundation(Grant No.2019A1515011227)the National Natural Science Foundation of China(Grant No.51902353)+1 种基金the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(Grant No.22lgqb03)the Fund from the State Key Laboratory of Optoelectronic Materials and Technologies(Grant No.OEMT-2022-ZRC-01)
文摘Polyyne,an sp~1-hybridized linear allotrope of carbon,has a tunable quasiparticle energy gap,which depends on the terminated chemical ending groups as well as the chain length.Previously,nitrogen doping was utilized to tailor the properties of different kinds of allotrope of carbon.However,how the nitrogen doping tailors the properties of the polyyne remains unexplored.Here,we applied the GW method to study the quasiparticle energy gaps of the N-doped polyynes with different lengths.When a C atom is substituted by an N atom in a polyyne,the quasiparticle energy gap varies with the substituted position in the polyyne.The modification is particularly pronounced when the second-nearest-neighboring carbon atom of a hydrogen atom is substituted.In addition,the nitrogen doping makes the Fermi level closer to the lowest unoccupied molecular orbital,resulting in an n-type semiconductor.Our results suggest another route to tailor the electronic properties of polyyne in addition to the length of polyyne and the terminated chemical ending groups.
文摘Three dual-mode band-pass filters are presented in the present paper. The first filter is realized by dual-mode substrate integrated waveguide (SIW) cavity;the second is based on the integration of SIW cavity with electromagnetic band gap (EBG);and the third is based on the integration of SIW cavity with complementary split ring resonator (CSRR). The dual-mode SIW cavity is designed to have a fractional bandwidth of 4.95% at the midband frequency of 9.08 GHz;the proposed EBG-SIW resonator operates at 9.12 GHz with a bandwidth of 4.38% and the CSRR-SIW resonator operates at 8.66 GHz with a bandwidth of 2.54%. The proposed filters have the high Q-factors and generate a transmission zero in upper stopband, and these by the use of Rogers RT/duriod 5880 (tm).
文摘A rectangular waveguide band-stop filter using electromagnetic crystals (EMXT) surface as the top and bottom walls is presented in this letter. The EMXT surface has a band gap that can prevent electromagnetic wave from propagating along the waveguide. Dispersion properties of the waveguide filter are analyzed using an approximated lumped-element circuit model. A W-band prototype based on the proposed waveguide filter is designed and characterized. The experimental results show a rejection band centered at 97 GHz and a rejection level of 16 dB.
