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[IEEE 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Paris, France (2019.9.1-2019.9.6)] 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Unit-cell design for antenna arrays efficiently matched to uni-travelling-carrier photodiodes
摘要： We present an antenna array with a backing reflector that allows one to obtain efficient matching to integrated sources or loads with low input resistance. In the infinite array limit, it is possible to describe the proposed unit-cell as an equivalent network with closed-form expressions for its different constituents. This analytic approach enables the preliminary design of arrays with improved matching efficiency for optimum power transmission/reception. The proposed solution has enabled an improved matching to a uni-travelling-carrier photodiode with a maximum improvement of 3 dB in the radiated power with respect to a 72-(cid:2) antenna, and featuring a 50% bandwidth.
关键词： uni-travelling-carrier photodiodes,radiated power,unit-cell design,impedance matching,antenna array
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems (COMCAS) - Tel-Aviv, Israel (2019.11.4-2019.11.6)] 2019 IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems (COMCAS) - Terahertz Range Elementary Dipole Excitation of a Thin Dielectric Disk Sandwiched between Two Graphene Covers: Integral Equation Analysis
摘要： We study, using the integral equation technique, the scattering of the field radiated by an elementary dipole, by a thin dielectric disk sandwiched between two conformal graphene covers, on the top and bottom faces. To build a mathematical model of such scatterer, we use the generalized boundary condition in the form first obtained by Mitzner and Bleszynski et al. and generalized by Karlsson. This enables us to derive dual integral equations in the disk plane for the Hankel transforms of the tangential electric and magnetic field components, and cast it to a set of two coupled Fredholm second-kind integral equations. The latter equations are discretized and solved numerically with the guaranteed convergence. We compute and plot the power radiated by an elementary magnetic dipole placed above such a composite disk, in the THz range. This reveals that the studied scatterer is a complicated open resonator supporting the low-frequency plasmon modes and the high-frequency dielectric-disk modes.
关键词： generalized boundary condition,radiated power,thin disk,graphene,plasmon resonances
更新于2025-09-16 10:30:52
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Using CCDF statistics for characterizing the radiated power dynamics in the near field of a mobile phone operating in 3G+ and 4G+ communication standards
摘要： In this article, an original method to assess the radiated power density of the near field in the immediate vicinity of mobile terminals using both electric and magnetic field strengths determination is proposed. The complementary cumulative distribution function (CCDF) is used for the first time to assess exposure. A demonstration of the CCDF’s capabilities for providing a realistic representation of different wireless communication usage profiles is provided. Following the methodology description, an experimental setup was designed and a measurement campaign was conducted on a mobile terminal. The exposure assessment was performed for real life operating situations by selecting seven common application services used by mobile subscribers. For 4G+ communication technologies the near field power density is the highest during file upload, followed by VoIP, video call, file download, streaming services and browsing. For 3G+ networks the higher to lower power density values were associated with: file upload, file download, streaming, VoIP, video call and browsing services. The total near field radiated power density was found to be on average 34 times higher for the tested applications running in the 4G+ as compared to the 3G+, with values ranging from 180 times - during file upload, down to 1.2 times - during video streaming. Significantly higher radiated power densities were emitted while using VoIP and video call on 4G+ network as compared to 3G+ network. Present results strongly suggest that higher exposure is expected for the same application running under 4G+ rather than under 3G+. By applying an original procedure, it has been experimentally highlighted that different generations of communication technologies will lead to different exposure shapes in amplitude and in time, suggesting a future need for introducing the dose rate quantification.
关键词： 3G+,radiated power,4G+,realistic exposure,application services,CCDF,near field
更新于2025-09-09 09:28:46