Wen-Sheng Zhao

Bio: Wen-Sheng Zhao is an academic researcher from Hangzhou Dianzi University. The author has contributed to research in topics: Equivalent circuit & Graphene. The author has an hindex of 18, co-authored 129 publications receiving 1212 citations. Previous affiliations of Wen-Sheng Zhao include Chinese Ministry of Education & Zhejiang University.

Signal Transmission Analysis of Multilayer Graphene Nano-Ribbon (MLGNR) Interconnects

Abstract: Signal transmission characteristics of some multilayer graphene nano-ribbon (MLGNR) interconnects are studied in this paper, with an equivalent single-conductor (ESC) model implemented for the analysis of their transient responses. In this model, both capacitive and inductive couplings between adjacent GNR layers are treated appropriately. According to the derived transfer function using the fourth-order approximation, the output voltage waveforms are predicted for both 14- and 22-nm technology nodes. In particular, the effects of Fermi level of MLGNR on the time delay of the transmitted rectangular pulse are examined and compared. Based on the decoupled partially differential equations (PDEs) for the common and differential modes of voltage wave propagation in the edge-coupled MLGNR interconnects, their output voltage responses are also predicted for different technology nodes, which are useful for the evaluation of on-chip signal integrity or EMC and EMI issues of MLGNR-built transmission lines for the future ICs.

Reconfigurable Terahertz Leaky-Wave Antenna Using Graphene-Based High-Impedance Surface

Abstract: The concept of graphene-based two-dimensional leaky-wave antenna (LWA), allowing both frequency tuning and beam steering in the terahertz band, is proposed in this paper. In its design, a graphene sheet is used as a tuning part of the high-impedance surface (HIS) that acts as the ground plane of such 2-D LWA. It is shown that, by adjusting the graphene conductivity, the reflection phase of the HIS can be altered effectively, thus controlling the resonant frequency of the 2-D LWA over a broad band. In addition, a flexible adjustment of its pointing direction can be achieved over a wide range, while keeping the operating frequency fixed. Transmission-line methods are used to accurately predict the antenna reconfigurable characteristics, which are further verified by means of commercial full-wave analysis tools.

Comparative Study on Multilayer Graphene Nanoribbon (MLGNR) Interconnects

Abstract: Based on an equivalent single-conductor (ESC) model of multilayer graphene nanoribbon (MLGNR) interconnects with side contacts, comparative study on their distributed parameters and transmission characteristics is performed in this paper. It is found that the number of conducting channels of a metallic MLGNR interconnect is the linear function of its width and Fermi energy, which can be described by an analytical equation. Its equivalent inductance and capacitance in the ESC model can also be characterized by a set of closed-form equations. Furthermore, according to the ITRS projection, transmission performance of the MLGNR interconnects with different contacts are predicted and compared with their Cu and carbon nanotube counterparts at different technology nodes. Also, some numerical results prove that MLGNR interconnects can provide better performance than Cu wires in particular at intermediate level. Even with the maximum crosstalk impacts considered, the advantage of MLGNR interconnects over Cu wires can still be kept.

Differential Microwave Microfluidic Sensor Based on Microstrip Complementary Split-Ring Resonator (MCSRR) Structure

Abstract: This paper presents a differential microwave microfluidic sensor based on the microstrip complementary split-ring resonator (MCSRR) structure for liquid characterization. At the resonance, the electric field concentrates along the slot, where the microfluidic channel is located. As the liquid sample is injected, the corresponding reflection coefficient is changed, while the reference response is unaffected. The relative permittivity and loss tangent of the liquid can be extracted from the variations in the resonant frequency and quality factor. A prototype of the proposed sensor is fabricated and measured for functionality validation. The proposed sensor exhibits a high sensitivity of 0.626% on average and is capable of suppressing unwanted environmental influences.

Electromagnetic Compatibility-Oriented Study on Through Silicon Single-Walled Carbon Nanotube Bundle Via (TS-SWCNTBV) Arrays

Abstract: Electromagnetic compatibility-oriented study is performed for accurately characterizing through silicon single-walled carbon nanotube bundle via (TS-SWCNTBV) array in this paper. Based on the modified equivalent lumped-element circuit model of a pair of TS-SWCNTBVs, its forward transmission coefficient, in comparison with copper- and tungsten-based TSVs, is investigated for different metallic fractions of the SWCNTs, with quantum effects treated appropriately. The 3-D transmission-line method (TLM) is further employed for studying mutual couplings in three, four, and nine TS-SWCNTBV arrays, respectively, where the effects of their geometrical and physical parameters on the effective capacitance and conductance are examined in detail. Also, transient coupling noises in different arrays excited by a clock signal, respectively, are predicted and compared, which are useful for the design of high density TS-SWCNTBV arrays with better signal transmission performance.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Rfid Handbook Fundamentals And Applications In Contactless Smart Cards And Identification

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Metasurfaces and their applications

Abstract: Metasurfaces are a topic of significant research and are used in various applications due to their unique ability to manipulate electromagnetic waves in microwave and optical frequencies. These artificial sheet materials, which are usually composed of metallic patches or dielectric etchings in planar or multi-layer configurations with subwavelength thickness, have the advantages of light weight, ease of fabrication, and ability to control wave propagation both on the surface and in the surrounding free space. Recent progress in the field has been classified by application and reviewed in this article. Starting with the development of frequency-selective surfaces and metamaterials, the unique capabilities of different kinds of metasurfaces have been highlighted. Surface impedance can be varied and manipulated by patterning the metasurface unit cells, which has broad applications in surface wave absorbers and surface waveguides. They also enable beam shaping in both transmission and reflection. Another important application is to radiate in a leaky wave mode as an antenna. Other applications of metasurfaces include cloaking, polarizers, and modulators. The controllable surface refractive index provided by metasurfaces can also be applied to lenses. When active and non-linear components are added to traditional metasurfaces, exceptional tunability and switching ability are enabled. Finally, metasurfaces allow applications in new forms of imaging.

A novel structure for tunable terahertz absorber based on graphene.

Abstract: Graphene can be used as a platform for tunable absorbers for its tunability of conductivity. In this paper, we proposed an “uneven dielectric slab structure” for the terahertz (THz) tunable absorber based on graphene. The absorber consists of graphene-dielectric stacks and an electric conductor layer, which is easy to fabricate in the manufacturing technique. Fine tuning of the absorption resonances can be conveniently achieved by adjusting the bias voltage. Both narrowband and broadband tunable absorbers made of this structure are demonstrated without using a patterned graphene. In addition, this type of graphene-based absorber exhibits stable resonances with a wide range angles of obliquely incident electromagnetic waves.