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- Cheng, Shi, 1980-, et al.
(författare)
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Internal multiple-input, multiple-output antenna arrays for wireless wide area network and wireless local area network operation in seamless full metal cover laptops
- 2014
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Ingår i: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725 .- 1751-8733. ; 8:2, s. 73-79
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Tidskriftsartikel (refereegranskat)abstract
- A concept for multiple-input, multiple-output antenna arrays, integrated in an ultrathin full metal cover laptop computer, is proposed. The antennas are for octa-band wireless wide area network (WWAN) and triple-band wireless localarea network (WLAN) operation. The proposed solution makes use of the gap between the metallic display lid and keyboard chassis to form notch and slot antenna arrays, thereby removing the need for additional protrusions or openings. Simulated aswell as measured performance is presented. The notch antenna array for WWAN exhibits wide impedance bandwidth, with more than 24 dB isolation from 690 MHz to 3 GHz, and a total efficiency better than −2.5 dB. The slot antenna array forWLAN shows more than 12 dB isolation and a total efficiency of more than −3 dB. Both arrays exhibit a very-low envelope correlation coefficient of less than 0.1 within their respective frequency bands.
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| 5. |
- Lindberg, Peter, et al.
(författare)
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Technique of Ground Size Tuning for Isolation between Monopoles in Compact Wireless Terminals
- 2012
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 60:11, s. 5488-5491
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Tidskriftsartikel (refereegranskat)abstract
- Achieving good isolation between two antennas in a wireless terminal is a challenge, especially if it is small compared to the wavelength. This communication presents a technique useful for two monopoles. It is based on placing the monopoles collinearly and tuning the ground plane size to approximately λ/4. Simulations and measurements are presented to illustrate the technique. Different methods of tuning the ground plane size in small terminals are discussed.
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| 6. |
- Zazzi, Åsa, et al.
(författare)
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Structural investigations of natural and synthetic chlorite minerals by X-ray diffraction, Mossbauer spectroscopy and solid-state nuclear magnetic resonance
- 2006
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Ingår i: Clays and clay minerals. - 0009-8604 .- 1552-8367. ; 54:2, s. 252-265
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Tidskriftsartikel (refereegranskat)abstract
- The structures of one synthetic and two natural chlorites of the chlinochlore type were explored using X-ray diffraction, magic-angle spinning nuclear magnetic resonance (NMR) and Mossbauer spectroscopy. Rietveld refinements indicated that all structures are of the trioctahedral ordered IIb polytype. Mossbauer spectra provided the ratio Fe-II/Fe-III but gave no evidence for the presence of Fe-III in the brucite-like sheet. We also report unit-cell parameters, Mossbauer isomeric shifts, Si-29 NMR chemical shifts as well as Al-27 isotropic shifts and quadrupolar coupling parameters. Very broad Si-29 NMR peaks from the natural samples prevented us from obtaining accurate information on the Si-Al ordering in the tetrahedral sheets; the limitations of Si-29 NMR as applied to natural chlorites are discussed. High-resolution 3QMAS NMR resolved the Al-27 signal of the M4 octahedral site in the brucite-like sheet from the other three Al signals of crystallographically inequivalent octahedral positions.
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