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- 2018
- compact modeling
- capacitive adiabatic logic
- MEMS
- full adder
- high-temperature electronics
- Microelectronics Science and Engineering
- Univ. Grenoble Alpes, CEA, LETI
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Classification of flat bands according to the band-crossing singularity of Bloch wave functions
摘要： We show that ?at bands can be categorized into two distinct classes, that is, singular and nonsingular ?at bands, by exploiting the singular behavior of their Bloch wave functions in momentum space. In the case of a singular ?at band, its Bloch wave function possesses immovable discontinuities generated by the band-crossing with other bands, and thus the vector bundle associated with the ?at band cannot be de?ned. This singularity precludes the compact localized states from forming a complete set spanning the ?at band. Once the degeneracy at the band crossing point is lifted, the singular ?at band becomes dispersive and can acquire a ?nite Chern number in general, suggesting a new route for obtaining a nearly ?at Chern band. On the other hand, the Bloch wave function of a nonsingular ?at band has no singularity, and thus forms a vector bundle. A nonsingular ?at band can be completely isolated from other bands while preserving the perfect ?atness. All one-dimensional ?at bands belong to the nonsingular class. We show that a singular ?at band displays a novel bulk-boundary correspondence such that the presence of the robust boundary mode is guaranteed by the singularity of the Bloch wave function. Moreover, we develop a general scheme to construct a ?at band model Hamiltonian in which one can freely design its singular or nonsingular nature. Finally, we propose a general formula for the compact localized state spanning the ?at band, which can be easily implemented in numerics and offer a basis set useful in analyzing correlation effects in ?at bands.
关键词： Chern number,singular band touching,flat bands,nonsingular band touching,bulk-boundary correspondence,compact localized states,Bloch wave functions
更新于2025-09-23 15:23:52
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System Design and Evaluation of a Compact and High Energy X-ray Talbot-Lau Grating Interferometer for Industrial Applications
摘要： X-ray grating interferometry has been an active area of research in recent years. In particular, various studies have been carried out for the practical use of the x-ray grating interferometer in medical and industrial fields. For the commercialization of the system, it needs to be optimized for its application. In this study, we have developed a prototype of the compact high energy x-ray grating interferometer of which the high effective energy and compactness is of our primary feature of design. We have designed the Talbot-Lau x-ray interferometer in a symmetrical geometry with an effective energy of 54.3 keV. The system has a source-to-analyzer grating distance of 788.4 mm, which is compact enough for a commercial product. In a normal operation, it took less than ten seconds to acquire a set of phase stepping images. The acquired images had a maximum visibility of about 15%, which is relatively high compared with the visibilities of the other high-energy grating interferometric systems reported so far.
关键词： X-ray phase contrast imaging,Dark-field imaging,Talbot-Lau interferometry,compact design,High energy phase contrast imaging
更新于2025-09-23 15:23:52
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A Novel Miniaturized Planar Ultra-Wideband Antenna
摘要： A novel miniaturized planar ultra-wideband antenna is proposed. The antenna design comprises an electromagnetically coupled structure and a tapered radiating slot, while a triangular slot is etched on the ground plane. The antenna miniaturization is realized by adopting an electromagnetically coupled structure formed by the notched half-ellipse patch and the strip attached to the ground. The proposed antenna can yield a large 10-dB impedance bandwidth ranging from 1.5 to 10.4 GHz with satisfactory radiation properties. It also features a physical size of 37.4 mm × 64 mm, equivalent to a compact electrical size of 0.19λ × 0.32λ at 1.5 GHz. The important design parameters are analyzed to comprehend the operating principle of the antenna. A good agreement between the simulated and measured results is achieved.
关键词： compact antenna,Ultra-wideband antenna,planar antenna,antenna miniaturization
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Design of Compact SIW Bandpass Filter for Millimeter-Wave Applications
摘要： this paper presents the design of two structures of substrate integrated waveguide (SIW) bandpass filter (BPF) for millimeter-wave application. By approaching the cruciform slot and ground vias, the numbers of resonance frequency was increased, and the filter structure can be miniaturized. Finally, the filter is designed to work at the center frequency of 22 GHz with the bandwidth of 1.4 GHz, and the numerical simulations shows good performance in the pass band and stopband.
关键词： Compact size,Bandpass,Millimeter wave,SIW
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Design of a Metamaterial Element in Deep Subwavelength Composed of Multilayer Meander Line (MML) Resonator Structures
摘要： An extremely compact metamaterial element is proposed with multilayer meander line (MML) resonator inclusions. The MML is featured with multiple single-planar meander line (SML) structures which are connected by via. The effective inductance in the new MML structure is thus multiplied leading to a reduced resonance frequency. A proof MML element is numerically demonstrated with period of 8mm. Very strong electric responses have been observed indicating the MML element is essentially a kind of electrically resonating structure. The proof MML element resonances at 237MHz in VHF band. The electrical period size is 1/158λ0 which is in deep subwavelength. By making the meander line thinner or incorporating more SML layers, the effective inductance can be further enhanced and the structure is more compact which is promising for radio frequency metamaterial designs in future.
关键词： compact element,multilayer meander line (MML) structure,Metamaterials
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - A Compact Omnidirectional Circularly Polarized Antenna for 5G Communication System
摘要： In this paper, a compact omnidirectional circularly polarized antenna for 5G communication system is proposed. The design concept is the combination of vertical currents and a surrounding loop current. A center disk-loaded feeding pin and four plated vias are utilized to generate the vertical component of the electric field. While a square loop is employed to produce the horizontal component. Simulation results indicates that the overlapped impedance and AR bandwidth ranges from 27.3 to 28.6 GHz, which covers the 27.5-28.35 GHz band for 5G cellular communication systems. Good omnidirectional radiation patterns can be obtained in azimuthal plane.
关键词： compact antenna,Circularly polarized (CP),5G communication
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE CPMT Symposium Japan (ICSJ) - Kyoto, Japan (2018.11.19-2018.11.21)] 2018 IEEE CPMT Symposium Japan (ICSJ) - A 53-Gbit/s VCSEL-Based High Density Optical Assembly for Large Capacity Optical Interconnection
摘要： A 53-Gbit/s VCSEL-based compact optical module is proposed. In order to realize 50-Gbit/s-class optical transmission, high-bandwidth optical devices are important. Accordingly, the feasibilities of a high speed optical circuit applying high-bandwidth (> 20 GHz) optical devices were studied by simulation. Moreover, an optical module at the receiver (Rx) side was fabricated on the basis of simulation results by applying our developed high density optical assembly techniques, and it successfully demonstrated 53.125-Gbit/s PAM4 multimode optical transmission.
关键词： compact optical module,High-density optical assembly,Optical interconnect,4-level pulse amplitude modulation (PAM4)
更新于2025-09-23 15:22:29
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Compact Wideband Reflective/Absorptive Bandstop Filter With Multitransmission Zeros
摘要： Novel wideband re?ective bandstop ?lters (RBSFs) and absorptive bandstop ?lters (ABSFs) with high stopband rejection (SR) and good frequency selectivity are proposed. Based on a coupled line (CL) with an open-circuited stub, a broad stopband response with three transmission zeros (TZs) is implemented in a compact circuit con?guration. Two modi?ed CL structures are loaded at the ports resulting in two additional TZs. In addition, a grounded resistor is introduced to absorb unwanted signals in the stopband. For demonstration, the ?ve-zero RBSFs and three-zero ABSFs operating at 2 GHz are designed and built. The re?ective ?lter shows a 35-dB SR with 79.5% relative bandwidth (RB). The absorptive ?lter with 69.5% RB of 24-dB SR achieves an all-passband 12.2-dB return loss. Good agreements between simulated and measured results are observed.
关键词： Compact,transmission zeros (TZs),wideband,re?ective bandstop ?lters (RBSFs) and absorptive bandstop ?lters (ABSFs),coupled line (CL)
更新于2025-09-23 15:22:29
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[IEEE 2018 XXIIIrd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - Tbilisi (2018.9.24-2018.9.27)] 2018 XXIIIrd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - Dual – Band Microtrip Quasi – Yagi Antenna Design for Free Band and 5G Mobile Communication
摘要： In this work, numerical and experimental analyses of a dual-band microstrip patch dipole-loop antenna are done. This design operates at amateur radio, amateur satellite (2.3-2.4 GHz) band and planned 5G mobile communication band; 3.4-3.8 GHz frequencies. There are two different radiating structures and regions in this antenna. One of the radiating structure is a rectangle shaped loop which is responsible for operation at lower frequency (2.3-2.4 GHz) and the other structure is a printed dipole which is responsible for operation of the upper (3.4-3.6 Hz) frequency. Apart from different operation frequencies, these structures also illustrates different radiation characteristics. The loop shaped region radiates bi-directional broadside radiation while the dipole part radiates with higher gain (peak gain 5 dBi). Proposed design is validated by High Frequency Structure Simulator (HFSS) and also measurements are carried out on fabricated prototype.
关键词： compact low cost and profile antennas,dual band,microstrip antenna,free band,5G
更新于2025-09-23 15:22:29
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[IEEE 2018 Dynamics of Systems, Mechanisms and Machines (Dynamics) - Omsk, Russia (2018.11.13-2018.11.15)] 2018 Dynamics of Systems, Mechanisms and Machines (Dynamics) - Automatic Nonlinear Modeling Technique for Gaas HEMT
摘要： A new technique for nonlinear transistor modeling is suggested. The technique includes an analytical extraction and a multistage optimization, providing fully automated modeling. An extraction algorithm for the parameters of an internal voltage-controlled current source Ids is shown. A fully automated workflow of small-signal model extraction is presented. An approach for obtaining parameters of nonlinear capacitances is described. A 0.15um GaAs pHEMT nonlinear model was built and verified with measured IV-curve, multi-bias S-parameters and power characteristics.
关键词： compact nonlinear model,microwave transistor,large-signal model,GaAs HEMT
更新于2025-09-23 15:22:29