Sökning: "active antennas"

Visar resultat 16 - 20 av 41 avhandlingar innehållade orden active antennas.

1. 16. Characterization of MIMO Antennas and Terminals: Measurements in Reverberation Chambers

   Författare :Chen Xiaoming; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; channel characterization; Reverberation chamber; measurement uncertainty.; maximum ratio combining MRC diversity gain; multiple-input multiple-output MIMO capacity;

   Sammanfattning : The reverberation chamber (RC) has drawn attention as a multipath emulator over the past decade for both passive and active over-the-air (OTA) tests. The overview of this thesis is given in Chapter 1. LÄS MER

3. 17. Development of the Eleven Antenna - A Decade Bandwidth Feed for Reflector Antennas

   Författare :Rikard Olsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Recently there has been a growing interest in reducing the number of antennas on different platforms by combining several functions in the same antenna. To achieve this, the multifunction antenna needs to be either very broadband or multi band to cover the frequencies of all functions. LÄS MER

4. 18. Characterization of Small Antennas & Wireless Devices for MIMO Systems in Multipath & Line-of-Sight

   Författare :Ahmed Hussain; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; USRP; OTA; SDR; RIMP; TRP; TIS; Reverberation chamber; Rayleigh; MIMO; LOS; LTE; Throughput;

   Sammanfattning : The current thesis investigates over-the-air (OTA) performance characterization of small antennas and wireless terminals in rich isotropic multipath (RIMP) environment, as well as in pure line-of-sight (LOS) environment when taking into account the random positions and orientations of the mobile terminals caused by the realistic user behavior. The latest mobile wireless terminals such as smart phones and tablets can be used in any random orientation thereby making even a received LOS-component appear as a random voltage at the antenna ports over time. LÄS MER

5. 19. Characterization of Small Antennas & Wireless Devices for MIMO Systems in Rich Isotropic Multipath & Random Line-of-Sight

   Författare :Ahmed Hussain; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; MIMO; Rayleigh; reverberation chamber; random LOS; RIMP; LTE; OTA;

   Sammanfattning : The current thesis is about over-the-air (OTA) performance characterization of wireless terminals in rich isotropic multipath (RIMP) environment as well as in pure line-of-sight (LOS) environment while not ignoring the random positions and orientations of the mobile terminals due to randomness of the user. The latest mobile wireless terminals such as iPhone and iPad can be used in any random position and orientation thereby making the received LOS-component toappear as a random voltage at the antenna ports. LÄS MER

7. 20. Compact RF Integration and Packaging Solutions Based on Metasurfaces for Millimeter-Wave Applications

   Författare :Abbas Vosoogh; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : The millimeter-wave frequency range has got a lot of attention over the past few years because it contains unused frequency spectrum resources that are suitable for delivering Gbit/s end-user access in areas with high user density. Due to the limited output power that the current RF active components can deliver in millimeter-wave frequencies, antennas with the features of low profile, high gain, high efficiency and low cost are needed to compensate free space path loss and increase the communication distance for the emerging high data rate wireless systems. LÄS MER