Sökning: "bandwidth efficiency"

Visar resultat 1 - 5 av 186 avhandlingar innehållade orden bandwidth efficiency.

  1. 1. Limitations on efficiency, size and bandwidth of small antennas

    Författare :Daniel Nyberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; log-periodic antennas; Small antennas; folded dipoles; radiation Q; fundamental limitations; bandwidth;

    Sammanfattning : The allocated space in a mobile phone for the antennas has become smaller and smaller following the size reduction of the mobile phones themselves and the integration of more functions in them. At the same time new communication systems are being planned where such small antennas also need to be wideband (UWB systems) or have multiple ports (MIMO systems). LÄS MER

  3. 2. Linearization of High Efficiency Transmitters for Wireless Communications

    Författare :Haiying Cao; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dynamic load modulation; Behavioral model; digital predistortion; I Q imbalance; Volterra series; efficiency; power amplifier; transmitter;

    Sammanfattning : In recent years, reducing energy consumption in wirelesscommunication systems has gained prominence. In order to achieve this energy saving, high power efficiency is necessary for the wireless transmitters used. LÄS MER

  4. 3. High-efficiency Power Amplification Techniques for Wireless Transmitters

    Författare :Hossein Mashad Nemati; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; load modulation; LDMOS; supply modulation; GaN HEMT; Power amplifier; wireless communications.; GaAs mHEMT; efficiency;

    Sammanfattning : The low efficiency of existing power amplifiers (PAs) is causing excessive energy consumption in wireless systems. Improving the PA efficiency is therefore of great environmental and economical importance. LÄS MER

  5. 4. Frequency Reconfigurable and Linear Power Amplifiers Based on Doherty and Varactor Load Modulation Techniques

    Författare :William Hallberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; gallium nitride GaN ; wideband; Class-J; linear; microwave; radio frequency RF ; Doherty; broadband; AM AM; silicon carbide SiC ; bandwidth; power amplifier PA ; AM PM; varactor; dynamic load modulation DLM ; fifth generation mobile networks 5G ; energy efficiency;

    Sammanfattning : In future mobile communication networks, there will be a shift towards higher carrier frequencies and highly integrated multiple antenna systems. The system performance will largely depend on the available RF hardware. As such, RF power amplifiers (PAs) with improved efficiency, linearity, and bandwidth are needed. LÄS MER

  7. 5. Advanced Transmitter Architectures Based on Switch Mode Power Amplifiers

    Författare :MUSTAFA ÖZEN; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; combiner; SMPA; Bandwidth; class-E; outphasing; energy efficiency;

    Sammanfattning : Nowadays the main driving parameters for the research in radio transmitters in wireless infrastructure are energy efficiency, frequency agility, and integration.This thesis presents new solutions at the device waveform-, circuit-, and transmitter level which exploit the inherent high efficiency potential of switch-mode power amplifiers (SMPAs) for realization of energy efficient, wide-band, highly integrated transmitters for wireless communication applications. LÄS MER