Sökning: "Ultra wideband signals"

Visar resultat 1 - 5 av 12 avhandlingar innehållade orden Ultra wideband signals.

1. 1. Ultra-Wideband Time Domain Measurement Systems for Microwave Tomography

   Författare :Xuezhi Zeng; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Time DomainMeasurement; Ultra-Wideband; EquivalentTime Sampling; Real Time Sampling; Microwave Tomography; Measurement Error; Frequency Domain Measurement;

   Sammanfattning : As a potential imaging modality for biomedical applications, microwave tomography has attracted a lot of interests in recent years. With microwave tomography, microwave signals are transmitted into the biological tissues and the scattered fields are recorded. LÄS MER

3. 2. Ultra-Wideband Wireless Channels - Estimation, Modeling and Material Characterization

   Författare :Telmo Santos; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ultra-wideband; channel modeling; channel parameter estimation; material characterization; microwave measurements;

   Sammanfattning : This licentiate thesis is focused on the characterization of ultra-wideband wireless channels. The thesis presents results on ultra-wideband communications as well as on the ultra-wideband characterization of materials. The communications related work consisted in the measurement and modeling of outdoor scenarios envisioned for infostation systems. LÄS MER

4. 3. Evaluation of Sigma-Delta-over-Fiber for High-Speed Wireless Applications

   Författare :Ibrahim Can Sezgin; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; energy harvesting; wireless power transfer; 1-bit communication; distributed-MIMO; Sigma-delta-over-fiber SDoF ; vertical-cavity surface-emitting-laser VCSEL ; radio frequency RF ; wideband; ultra-high speed communication;

   Sammanfattning : Future mobile communication networks aim to increase the communication speed, provide better reliability and improve the coverage. It needs to achieve all of these enhancements, while the number of users are increasing drastically. LÄS MER

5. 4. Impulse Radio UWB for the Internet-of-Things : A Study on UHF/UWB Hybrid Solution

   Författare :Zhuo Zou; Hannu Tenhunen; Tor Sverre Lande; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ultra-Wideband; impulse radio; IR-UWB; RFID; asymmetric links; UHF UWB hybrid; wireless sensing; energy detection; low power; radio receiver; positioning; Internet-of-Things;

   Sammanfattning : This dissertation investigates Ultra-Wideband (UWB) techniques for the next generation Radio Frequency Identification (RFID) towards the Internet-of-Things (IoT). In particular, an ultra-high frequency (UHF) wireless-powered UWB radio (UHF/UWB hybrid) with asymmetric links is explored from system architecture to circuit implementation. LÄS MER

7. 5. Sub-Nyquist Sampling Impulse Radio UWB Receivers for the Internet-of-Things

   Författare :Qin Zhou; Hannu Tenhunen; Li-Rong Zheng; Qiang Chen; Kari Halonen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ultra-Wideband; impulse radio; receiver; energy detection; compressed sensing; sub-Nyquist sampling; Internet-of-Things; Informations- och kommunikationsteknik; Information and Communication Technology;

   Sammanfattning : In the era of Internet-of-Things, the demand for short range wireless links featured by low-power and low-cost, robust communication and high-precision positioning is growing rapidly. Impulse Radio Ultra-Wideband (IR-UWB) technology characterized by the transmission of sub-nanosecond pulses spanning up to several GHz band with extremely low power spectral density emerges as a promising candidate. LÄS MER