This study designed a resistive film absorber (RFA) with > 90% absorptivity in the 16-27 GHz broadband to reduce electromagnetic radiation in on-board chip architectures. The size of the RFA unit is ...miniature, which is only 0.1λ L × 0.1λ L × 0.06λ L (where λ L is the lowest operating frequency cutoff wavelength). First, the impedance matching and loss principle of the RFA are analyzed based on the intrinsic parametric method and equivalent circuit theory. This explains the influences of each parameter on absorption performance and verifies that the designed RFA has good polarization insensitivity and angle stability. In addition, the measurements of a prototype RFA were obtained and found to be consistent with simulation results, which proves the feasibility of the RFA. Finally, the RFA was added to a chip architecture to verify its electromagnetic suppression effect with consideration of the influence of temperature on absorption performance. The combined simulation results indicate a significant reduction in the far-field radiation values of the chip architecture, with the maximum electromagnetic radiation suppression effect being 12 dB. These results demonstrate the reliability of the proposed electromagnetic suppression scheme and indicate that the RFA has wide application prospects for radiation suppression in chip systems and electronic packaging.
We present a single-layer, transmissive metalens for focusing the orthogonal polarization components of incident light to two independent focal spots without affecting the initial orthogonal ...polarization states. To produce the required phase profile, the cross-shaped nanorod, as the unit cell of the metalens, is developed to support arbitrary combinations of two independent phase shifts (0-<inline-formula> <tex-math notation="LaTeX">2\pi </tex-math></inline-formula>) of transverse electric and transverse magnetic polarized light. A deep neural network is trained to generate the design parameters of each unit cell efficiently and accurately. The metalens is simulated with finite-difference time-domain method and good agreements are observed comparing with theoretical prediction. This work provides a new solution to multi-foci metalens and polarization beam splitter and may find potential applications in deep sensing, holography, information encryption and display.
This article presents an efficient S‐parameter extraction method for memristor‐based crossbar array circuits. The proposed approach involves converting the array into an equivalent circuit and ...analytically solving the circuit to obtain the S‐parameters. Memristor‐based crossbar array circuit simulations and corresponding experimental measurements are conducted to verify the high accuracy and low computation complexity of the established method. These numerical results indicate that the authors’ S‐parameter extraction method has the potential for evaluating signal integrity performance in neuromorphic chips, thus aiding their design and optimization for diverse applications.
This article presents an efficient S‐parameter extraction method for memristor‐based crossbar array circuits. Memristor‐based crossbar array circuit simulations and corresponding experimental measurements are conducted to verify the high accuracy and low computation complexity of the established method. These numerical results indicate that the authors’ S‐parameter extraction method has the potential for evaluating signal integrity performance in neuromorphic chips, thus aiding their design and optimization for diverse applications.
Cinnamomi ramulus (CR) and Cinnamomi cortex (CC), both sourced from
Presl, are commonly used Chinese medicines in the Chinese Pharmacopeia. However, while CR functions to dissipate cold and to ...resolve external problems of the body, CC functions to warm the internal organs. To clarify the material basis of these different functions and clinical effects, a simple and reliable UPLC-Orbitrap-Exploris-120-MS/MS method combined with multivariate statistical analyses was established in this study with the aim of exploring the difference in chemical compositions of aqueous extracts of CR and CC. As the results indicated, a total of 58 compounds was identified, including nine flavonoids, 23 phenylpropanoids and phenolic acids, two coumarins, four lignans, four terpenoids, 11 organic acids and five other components. Of these compounds, 26 significant differential compounds were identified statistically including six unique components in CR and four unique components in CC. Additionally, a robust HPLC method combined with hierarchical clustering analysis (HCA) was developed to simultaneously determine the concentrations and differentiating capacities of five major active ingredients in CR and CC: coumarin, cinnamyl alcohol, cinnamic acid, 2-methoxycinnamic acid and cinnamaldehyde. The HCA results showed that these five components could be used as markers for successfully distinguishing CR and CC. Finally, molecular docking analyses were conducted to obtain the affinities between each of the abovementioned 26 differential components, focusing on targets involved in diabetes peripheral neuropathy (DPN). The results indicated that the special and high-concentration components in CR showed high docking scores of affinities with targets such as HbA1c and proteins in the AMPK-PGC1-SIRT3 signaling pathway, suggesting that CR has greater potential than CC for treating DPN.
In this paper, an improved algorithm for extracting the effective constitutive parameters of a metamaterial is derived. The procedure invokes the Kramers-Kronig relations to ensure the uniqueness of ...the solution. The accuracy of the method is demonstrated by retrieving the effective material parameters of a homogeneous slab. This study reveals under which conditions the calculation of the refractive index involves more than one branch of the complex logarithmic function. A metamaterial built up from wires and split-ring resonators is then investigated. The applicability and limits of the presented algorithm are explored by observing how the effective parameters of a metamaterial slab converge as its thickness is increased.
This article proposes a broadband inverse analysis method for the higher order modes inside the resistively loaded monocone transverse electromagnetic (TEM) cell. The analytic solutions of the field ...pattern for each higher order mode are derived in the frequency domain. The deep learning technique is employed to effectively predict coefficients of these modes over a wide frequency range (1.885-300 MHz) only given the <inline-formula> <tex-math notation="LaTeX">E </tex-math></inline-formula>-field amplitude distribution. The predicted results agree well with measurement ones, which validates the accuracy of the deep neural network method, and furthermore, it is analyzed in the time domain with fast Fourier transform (FFT). This work reveals the mechanism of higher order mode-induced field distortion in both the frequency domain of broadband and the time domain, provides guidance for elimination of higher order modes in monocone TEM cells, and can be extended to mode analysis for other kinds of wideband antennas.
A low-profile broadband bandpass frequency selective surface (FSS) with two rapid band edges is proposed in this paper for 5G near-field applications. The overall structure consists of three metallic ...layers, separated by two thin substrates with a thickness of 0.07λ. In addition, some centro-symmetric miniaturized slots are introduced in the middle metallic layer to further improve its stability and reduce its physical dimensions. A corresponding equivalent circuit model (ECM) is also proposed to better analyze the principles of the proposed FSS. Finally, an FSS prototype working at the center frequency of 27.5 GHz with a relative -3 dB bandwidth of 20.5% is fabricated and measured. More than 25 dB shielding effectiveness can be obtained out of the passband for a bandwidth of 1.46 GHz in this experiment. Both 3-D full-wave simulations and ECM results are in good agreement with the experimental results, having a maximum deviation of only 2.257% in the transmission zeros and poles. These results demonstrate that the proposed FSS is a good candidate for 5G near-field EMI shielding.
This article presents a novel extraction method for parasitic parameters of on-wafer calibration standards using an optimization strategy. Based on the physical models of the calibration standards, ...the parasitic parameters of all calibration standards can be extracted using the Bayesian optimization method with a fast calculation speed and high accuracy. Compared with the conventional thru-reflect-line (TRL) extraction method, the proposed approach can work well in systems with high crosstalk. The methodology is validated through on-wafer measurements using a ground-signal-ground (GSG) probe with low crosstalk and a ground-signal (GS) probe with high crosstalk. The proposed method shows a comparable accuracy with the TRL method in the low-crosstalk case, while it has higher accuracy in the high-crosstalk scenario.
Inspired by the dispersion engineering of spoof surface plasmon polaritons, in this paper, a comprehensive scheme is proposed, which firstly develops a plasmonic absorbing structure (PAS) with wide ...absorption band and high angular stability. The PAS unit cell is composed of a graded metallic strip array printed on a dielectric grid and backed with a metal ground. It realizes wideband absorption in the frequency range of 18–37 GHz. Moreover, a commercial absorbing film is further integrated with the proposed PAS to expand the overall absorption bandwidth covering around 5.5–55 GHz without increasing the thickness of the whole structure excessively. Simulated and experimental results show that the proposed hybrid metamaterial absorber can provide ultra‐broadband absorption with simple design procedure and light weight, allowing potential applications such as RCS reduction of antennas, electromagnetic shielding, and so on.
An ultrawideband dual-polarized frequency selective absorber with a tunable reflective notch is proposed in this paper. The structure is constructed by combining a broadband frequency-selective ...absorber (FSA) as well as a tunable lossless frequency-selective surface (FSS). The FSA consists of a lossy layer, an air spacer, which is backed with a metal plane. Varactors are employed in the lossless FSS and a DC bias is applied to adjust the frequency of the reflective notch. An equivalent circuit model of the notch-tunable FSA is established to explain the operating principle, and the impedance condition of the ultrawide absorptive band is discussed. The equivalent circuit model results agree well with the frequency-domain simulation results. The absorption band with a reflection coefficient below -10 dB extends from 2 GHz to 8 GHz. It's worth mentioning that the reflective notch with nearly perfect reflection is demonstrated to be tuned from 2.24 GHz to 4.56 GHz. A prototype of the structure is fabricated and measured to validate the design concept. Its measured absorption band from 2.5 GHz to 8 GHz is in favorable agreement with the simulated results. These findings will be useful for designing intelligent antenna reflector systems with out-of-band radar cross section reduction.
