Abstract-In this paper, we present the design, simulation, and measurement of a dual-band metamaterial absorber in the microwave region. Simulated and experimental results show that the absorber has two perfect absorption points near 11.15 GHz and 16.01 GHz. Absorptions under different polarizations of incident EM waves are measured with magnitude of over 97% at low-frequency peak and 99% at high-frequency peak respectively. Current distribution at the dual absorptive peaks is also given to study the physical mechanism of power loss. Moreover, it is verified by experiment that the absorptions of this kind of metamaterial absorber remain over 90% at the low-frequency peak and 92% at the high-frequency peak with wide incident angles ranging from 0 • to 60 • for both transverse electric wave and transverse magnetic wave.

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Electric toroidal dipolar response has been achieved by metamaterial based on sun-like aperture element at microwave frequency. It is confirmed numerically by scattered powers that the electric toroidal dipolar moment dominates over other moments at the corresponding resonance. This proposed metamaterial exhibits resonant transparency under linearly polarized incidence caused by destructive interference between magnetic dipole and electric toroidal dipole. Notably, it also provides circular cross-polarization conversions between left-handed circularly polarized wave and right-handed circularly polarized wave at the same frequency. These properties associated with elusive electric toroidal dipolar moment offer an avenue for various potential applications in microwave devices.

PurposePrimary low-grade thyroid-like papillary adenocarcinomas are extremely rare neoplasms that generally originate in the nasopharynx. Here, we describe a novel case of a 15-year-old Chinese girl who was diagnosed with low-grade thyroid-like papillary adenocarcinoma, including a brief review of the literature to reveal the clinicopathological features of low-grade thyroid-like nasopharyngeal papillary adenocarcinoma.Materials and MethodsImmunohistochemistry was used to evaluate the expression of pan-cytokeratin (CKpan), cytokeratin (CK) 7, thyroid transcription factor 1 (TTF-1), vimentin, epithelial membrane antigen (EMA), thyroglobulin, CD15, S100, P40, CK20, CDX-2, glial fibrillary acidic protein (GFAP), and Ki-67. Additionally, in situ hybridization investigation was utilized to identify the presence of small Epstein-Barr virus (EBV)–encoded RNA.ResultsHistopathological analysis revealed florid proliferation of papillary structures lined by columnar epithelial cells with fibrovascular cores. Immunohistochemically, the neoplastic cells were positive for CKpan, CK7, TTF-1, vimentin, and EMA, but negative for thyroglobulin, CD15, S100, P40, CK20, CDX-2, and GFAP. The Ki-67–labeling index reached 5% in the most concentrated spot. In situ hybridization for EBV was negative.ConclusionDue to the distinct rarity of low-grade thyroid-like papillary adenocarcinomaswith a favorable clinical outcome, a nationwide effort to raise public awareness of this neoplasm is required.

In this paper, a broadband metamaterial absorber (MA) based on a multi-layer structure is presented. The advantages of this MA are the small periodic unit size, they are thin, have excellent polarization characteristics and are adaptive for wide angles of oblique incident electromagnetic waves. The unit cell of the broadband MA is composed of three dual-band sub-cells; each presents two resonant frequencies so as to form a wide absorptive spectrum when stacked. The sandwiched dual-band sub-cell is composed of one metallic annular patch and one metallic circular patch each etched on a lossy substrate. The radii of the metallic patches forming each sub-cell are different so as to appear to have different resonant frequencies. In the design of the unit cell there are metallic circular patches and an air layer at the bottom of each sub-cell to form magnetic coupling and avoid coupling between sub-cells. The broadband MA presents good absorptivity above 80% between 8.8 and 10.8 GHz, with a full width at half maximum (FWHM) absorption bandwidth of 2.3 GHz and a relative FWHM absorption bandwidth of 23%.