Sökning: "electronics and photonics Electrical engineering"

Visar resultat 11 - 15 av 100 avhandlingar innehållade orden electronics and photonics Electrical engineering.

  1. 11. Active and Passive Unequally Spaced Reflect-Arrays and Elements of RF Integration Techniques

    Författare :Dhanesh G. Kurup; Anders Rydberg; Mohamed Himdi; Peter S Hall; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Active Antenna; Reflect-arrays; NRD guide; RF integration; Elektroteknik; elektronik och fotonik; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning : Using an array synthesis tool based on a modified differential evolution algorithm, it is shown that the position-phase synthesis exhibits improved pattern characteristics compared to both the phase only and position only synthesis of uniform amplitude antenna arrays. The design of an unequally spaced planar reflect-array and an active power combining reflect-array are presented. LÄS MER

  3. 12. Generation, Modulation, and Detection of Signals in Microwave Photonic Systems

    Författare :Andreas Wiberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Microwave photonics; radio over fiber; mm-wave generation; PSK; QAM; subcarrier modulation; photonic frequency multiplication; spurious free dynamic range third-order intercept point; millimeter-wave photonics; uni-travelling-carrier photodiode; millimeter-wave communication system;

    Sammanfattning : This thesis deals with the use of photonic technology in microwave and millimeter-wave applications. The two major parts of this work have been techniques for transmission and signal generation. LÄS MER

  4. 13. Optical spectroscopy of InGaAs quantum dots

    Författare :Arvid Larsson; Per Olof Holtz; Artur Zrenner; Linköpings universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; quantum dot; semiconductor; optical properties; spin; transport; wetting layer; polarization; kvantprick; halvledare; optiska egenskaper; spin; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik; Materials science; Teknisk materialvetenskap; Condensed matter physics; Kondenserade materiens fysik; Semiconductor physics; Halvledarfysik;

    Sammanfattning : The work presented in this thesis deals with optical studies of semiconductor quantum dots (QDs) in the InGaAs material system. It is shown that for self-assembled InAs QDs, the interaction with the surrounding GaAs barrier and the InAs wetting layer (WL) in particular, has a very large impact on their optical properties. LÄS MER

  5. 14. Characterization of electrical properties in 4H-SiC by imaging techniques

    Författare :John Österman; Anders Hallén; Vito Raineri; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Elektroteknik; elektronik och fotonik; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning : 4H-SiC has physical properties supremely suited for a variety of high power, high frequency and high temperature electronic device applications. To fully take advantage of the material's potential, several problems remain to be solved. LÄS MER

  7. 15. Permanent-Magnet Synchronous Machines with Non-Overlapping Concentrated Windings for Low-Speed Direct-Drive Applications

    Författare :Florence Meier; Juliette Soulard; Zi-Qiang Zhu; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electronic engineering; electrical engineering; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning :  Many geared electric drives can benefit from removing the gearbox and driving directly the load at low speed using a permanent-magnet synchronous machine (PMSM). PMSMs with non-overlapping concentrated windings are particularly attractive in low-speed direct drives since they allow, among other advantages, a high number of poles with a limited number of slots. LÄS MER