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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

On-chip antenna element and array design for short range millimeter-wave communications

Emrick, Rudy M. January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 102-106).
42

Silicon-based millimeter-wave front-end development for multi-gigabit wireless applications

Sarkar, Saikat. January 2007 (has links)
Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Laskar, Joy; Committee Member: Chang, Jae Joon; Committee Member: Cressler, John D.; Committee Member: Kornegay, Kevin T.; Committee Member: Lee, Chang-Ho; Committee Member: Tentzeris, Manos M.. Part of the SMARTech Electronic Thesis and Dissertation Collection.
43

Low-power, high-efficiency, and high-linearity CMOS millimeter-wave circuits and transceivers for wireless communications

Juntunen, Eric A. 26 April 2012 (has links)
This dissertation presents the design and implementation of circuits and transceivers in CMOS technology to enable many new millimeter-wave applications. A simple approach is presented for accurately modeling the millimeter-wave characteristics of transistors that are not fully captured by contemporary parasitic extraction techniques. Next, the integration of a low-power 60-GHz CMOS on-off keying (OOK) receiver in 90-nm CMOS for use in multi-gigabit per second wireless communications is demonstrated. The use of non-coherent OOK demodulation by a novel demodulator enabled a data throughput of 3.5 Gbps and resulted in the lowest power budget (31pJ/bit) for integrated 60-GHz CMOS OOK receivers at the time of publication. Also presented is the design of a high-power, high-efficiency 45-GHz VCO in 45-nm SOI CMOS. The design is a class-E power amplifier placed in a positive feedback configuration. This circuit achieves the highest reported output power (8.2 dBm) and efficiency (15.64%) to date for monolithic silicon-based millimeter-wave VCOs. Results are provided for the standalone VCO as well as after packaging in a liquid crystal polymer (LCP) substrate. In addition, a high-power high-efficiency (5.2 dBm/6.1%) injection locked oscillator is presented. Finally, the design of a 2-channel 45-GHz vector modulator in 45-nm SOI CMOS for LINC transmitters is presented. A zero-power passive IQ generation network and a low-power Gilbert cell modulator are used to enable continuous 360° vector generation. The IC is packaged with a Wilkinson power combiner on LCP and driven by external DACs to demonstrate the first ever 16-QAM generated by outphasing modulation in CMOS in the Q-band.
44

Integrated antennas on organic packages and cavity filters for millimeter-wave and microwave communications systems

Amadjikpe, Arnaud Lucres 18 January 2012 (has links)
Driven by the ever growing consumer wireless electronics market and the need for higher speed communications, the 60-GHz technology gifted with an unlicensed 9 GHz frequency band in the millimeter-wave spectrum has emerged as the next-generation Wi-Fi for short-range wireless communications. High-performance, cost-effective, and small form-factor 60-GHz antenna systems for portable devices are key enablers of this technology. This work presents various antenna architectures built on low-cost organic packages. Planar end-fire switched beam antenna modules that can easily conform to various surfaces inside a wireless device platform are developed. The planar antenna package is realized on thin flexible LCP dielectrics. One design is based on a planar Yagi-Uda antenna element and the second on a tapered slot antenna element. A low-loss microstrip-to-slot via transition is designed to provide wide impedance matching for end-fire antenna paradigms. The novel transition utilizes the slow-wave concept to provide unbalanced to balanced mode conversion as well as impedance matching. It is demonstrated that the planar antenna packages may be even integrated with active circuits that are cavity recessed inside the thin dielectric. A compact switched-beam antenna module is demonstrated. The first-ever integrated mm-wave active antenna module on organic package capable of generating both broadside and end-fire radiation is also developed in this work. Both broadside and end-fire radiators are co-designed and integrated into a single multilayer package to achieve optimal directivity, efficiency and frequency bandwidth and yet maintain excellent isolation between the two radiators. Post-wall cavities, image theory and dielectric slab modes concepts are invoked to optimize these functions. Active circuitry are integrated into the same package to add control functions such as beam switching, and also amplify the packaged-antenna gain when operated either as a transmitter or a receiver. A significant challenge in the design of antenna systems for wireless platforms is the assessment of embedded antenna performance, that is, the proximity effects of the platform chassis on the embedded antenna. Various antennas are mounted at different locations inside a laptop computer chassis: modeling and experimental studies are carried out to characterize this problem that is apparent to an antenna behind a radome. Air traffic control radars usually require cavity filters that can handle high power and low in-band insertion loss while providing enough out-band rejection to prevent interference with neighboring channels. Such radars that operate in the S-band consist of filter banks frequency micro electromechanical systems (RF-MEMS) switches. Evanescent-mode mode cavity resonators are loaded with RF-MEMS tuning capacitance networks to control the resonant frequency of a second-order bandpass filter. The second part is the design of a novel cavity filter architecture for enhanced selectivity near the passband. It is a second-order folded cavity resonator bandpass filter with magnetic source-load cross coupling. This filter can have at least two finite transmission zeros near the passband.
45

Frontiers of optical networking technologies: millimeter-wave radio-over-fiber and 100g transport system for next-generation high-data-rate applications

Hsueh, Yu-Ting 04 April 2012 (has links)
The enabling technologies and the issues of next-generation millimeter-wave wireless access network and 100G long-haul optical transport network were developed and identified. To develop a simple and cost-effective millimeter-wave optical-wireless system, all-round research on the technical challenges of optical millimeter-wave generation, transmission impairments compensation, and simple base station design were discussed. Several radio-over-fiber systems were designed to simultaneously deliver multi-band wireless services on a single optical infrastructure, enabling converged system control and quality maintenance in central office. For the 100G optical transport network, the issues related to successful implementations of transmitter, fiber link, and receiver of a 112-Gb/s polarization-division multiplexing-quadrature phase shift keying (PDM-QPSK) system were comprehensively explored. The experimental results based on the constructed 112-Gb/s testbed indicated that careful dispersion management can effectively increase nonlinearity tolerance. Furthermore, the special emphasis on the two impairments of the 100G network with reconfigurable optical add-drop multiplexers: passband narrowing and in-band crosstalk, was studied. The results demonstrated that these impairments can be readily predicted with proper experimental and simulation efforts.
46

Silicon-based millimeter-wave front-end development for multi-gigabit wireless applications

Sarkar, Saikat 02 November 2007 (has links)
With rapid advances in semiconductor technologies and packaging schemes, wireless products have become more versatile, portable, inexpensive, and user friendly over last few decades. However, the ever-growing demand of consumers to share information efficiently at higher speeds requires higher data rates, increased functionality, lower cost, and more reliability. The 60-GHz-frequency band, with 7 GHz license-free bandwidth addresses, such demands, and promises a low-cost multi-Gbps wireless transmission with a power budget in the order of 100 mW. This dissertation presents the systematic development of key building blocks and integrated 60-GHz-receiver solutions. Two different approaches are investigated and implemented in this dissertation: (1) low-cost SiGe-based direct-conversion low-power receiver front-end utilizing gain-boosting techniques in the front-end low-noise amplifier, and (2) CMOS-based heterodyne receiver front-end suitable for high-performance single-chip 60 GHz transceiver solution. The ASK receiver chip, implemented using 0.18 ?m SiGe, presents a complete antenna-to-baseband multi-gigabit 60 GHz solution with the lowest reported power budget (25 pJ/bit) to date. The subharmonic direct conversion front-end, implemented using 0.18 ?m SiGe, presents excellent conversion properties with a 4 GHz DSB RF bandwidth. On the other hand, the CMOS heterodyne implementation of the 60 GHz front-end receiver, targeted towards a robust, single-chip, high-performance, low-power, and integrated 60 GHz transceiver solution, presents the most wideband receiver front-end reported to date. Finally, different multi-band and tunable millimeter-wave circuits are presented towards the future implementation of cognitive and multi-band millimeter-wave radio.
47

Sensing of Irregularities on Fast Moving Surfaces by Microwaves and Millimeterwaves

Ishii, T. Koryu 10 1900 (has links)
International Telemetering Conference Proceedings / October 17-20, 1988 / Riviera Hotel, Las Vegas, Nevada / Fine cracks and irregularities on a fast moving conducting surface were detected by the use of microwave and millimeter wave radio responder techniques. The interrogation angle was restricted to an oblique incidence angle less than ±0.5 degree from the surface. The fast moving conducting surface was surrounded by both fast moving and stationary reflective conducting structures. Experimental methods and results from a fine crack 0.1 mm wide, 0.9 mm deep, and 25 mm long on a conducting surface travelling with a speed of 20.23 m/s and measured at 10.525 GH(z) and 73 GH(z) are presented. The reflection-type microwave radio responder consisted of a 10.525 GH(z) 50 mW Gunn diode cw transmitter, a circulator, and a horn antenna used as the interrogator. The receiver in the same responder consisted of the same horn antenna, the circulator and detector diode. The detector diode output was observed with a Norland 3106R digital memory oscilloscope. A reflex kylstron VA 250 was used as the transmitter signal source for the millimeter wave responder. There was a distinct difference between the responder output patterns with uncracked and cracked surfaces. It is therefore possible to use this type of responder for hair-line crack detection of fast moving conducting surfaces. It was also found that this type of radio responder can detect the surface irregularity even before the hairline crack actually occurs.
48

Millimeter Wave Radar Interfacing with Android Smartphone

Gholamhosseinpour, Ali January 2015 (has links)
Radar system development is generally costly, complicated and time consuming. This has kept its presence mostly inside industries and research centers with the necessary equipment to produce and operate such a system. Until recent years, realization of a fully integrated radar system on a chip was not feasible, however this is no longer the case and there are several types of sensors available from different manufacturers. Radar sensors offer some advantages that are unmatched by other sensing and imaging technologies such as operation in fog, dust and over long distances. This makes them suitable for use in Navigation, Automation, Robotics, and Security systems applications. The purpose of this thesis is to demonstrate the feasibility of a simplified radar system’s user interface via integration with the most common portable computer, a Smartphone, to make it possible for users with minimal knowledge of radar systems design and operation to use it in different applications. Smartphones are very powerful portable computers equipped with a suite of sensors with the potential to be used in a wide variety of applications. It seems logical to take advantage of their computing power and portability. The combination of a radar sensor and a smartphone can act as a demonstrator in an effort to bring radar sensors one step closer to the hands of the developers and consumers. In this study the following areas are explored and proper solutions are implemented; Design of a control board with capability to drive a radar sensor, capture the signal and transfer it to a secondary device (PC or Smartphone) both wired and wirelessly e.g. Bluetooth. A firmware that is capable of driving the control board and can receive, interpret and execute messages from a PC and or a Smartphone A cross compatible master software that can run on Linux, Windows, Mac and Android OSs and is capable of communication with the firmware/control board Proper analysis methods for signal capture and process purposes Automation of some parameter adjustment for different modes of operation of the Radar System in order to make the user interface as simple as possible A user friendly user-interface and API that can run on both PC and Smartphone
49

Materials for millimetre wave detection using femtosecond optical pulses.

January 1999 (has links)
by Chi Sang Wong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references. / Abstract also in Chinese. / Abstract --- p.ii / Acknowledgements --- p.vii / Table of Contents --- p.viii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Organisation of Thesis --- p.4 / References --- p.6 / Chapter 2 --- Principles and Theories --- p.8 / Chapter 2.1 --- Device Concepts --- p.9 / Chapter 2.2 --- Picosecond Photoconductors --- p.14 / Chapter 2.3 --- Photoconducting Antennas --- p.18 / Chapter 2.4 --- Summary --- p.20 / References --- p.21 / Chapter 3 --- Self-mode-locked Ti:sapphire (Ti:Al203) Laser --- p.24 / Chapter 3.1 --- Introduction --- p.25 / Chapter 3.2 --- Self-mode-locked Ti:sapphire Laser Cavity --- p.26 / Chapter 3.3 --- Negative Dispersion Using Pairs of Prisms --- p.28 / Chapter 3.4 --- Kerr-lens Mode-Locked Model: Role of Space-time Effects --- p.33 / Chapter 3.5 --- Initiation of Self-mode-locked Pulses --- p.37 / Chapter 3.6 --- 39-fs Pulses from A Self-mode-locked Ti:sapphire Laser --- p.38 / Chapter 3.7 --- Summary --- p.42 / References --- p.43 / Chapter 4 --- Photoconductive Detection of Millimetre Waves Using LT-GaAs --- p.46 / Chapter 4.1 --- Introduction --- p.47 / Chapter 4.2 --- Devices Structures --- p.48 / Chapter 4.3 --- Experimental Setup --- p.52 / Chapter 4.4 --- Results and Discussion --- p.54 / Chapter 4.5 --- Summary --- p.57 / References --- p.58 / Chapter 5 --- Investigation of Other Materials for THz Detection --- p.60 / Chapter 5.1 --- Introduction --- p.61 / Chapter 5.2 --- Material Preparation --- p.62 / Chapter 5.3 --- Devices Structures --- p.64 / Chapter 5.4 --- Experimental Setup --- p.68 / Chapter 5.5 --- Results and Discussion --- p.69 / Chapter 5.6 --- Investigation of Other Materials --- p.72 / Chapter 5.7 --- Summary --- p.73 / References --- p.74 / Chapter 6 --- Characteristics of Millimetre Waves --- p.76 / Chapter 6.1 --- Introduction --- p.77 / Chapter 6.2 --- Experimental Setup --- p.78 / Chapter 6.3 --- Experimental Results --- p.80 / Chapter 6.4 --- Experimental Setup --- p.83 / Chapter 6.5 --- Experimental Results --- p.85 / Chapter 6.6 --- Summary --- p.86 / References --- p.87 / Chapter 7 --- Conclusion and Future Work --- p.88 / Chapter 7.1 --- Conclusion --- p.88 / Chapter 7.2 --- Future Work --- p.91 / Appendixes --- p.A-l / Chapter Appendix A: --- Hall Effect Measurement System --- p.A-l / Chapter Appendix B: --- Photography of Device Structures --- p.A-2 / Chapter Appendix C: --- Fast Fourier Transform Program --- p.A-3 / Chapter Appendix D: --- List of Publications --- p.A-4
50

Extremely High Frequency (EHF) Low Probability of Intercept (LPI) communication applications

Belcher, Robert W. January 1990 (has links) (PDF)
Thesis (M.S. in Telecommunications Systems Management)--Naval Postgraduate School, March 1990. / Thesis Advisor(s): Schwendtner, Thomas A. Second Reader: Davidson, K. L. "March 1990." Description based on title screen as viewed on August 25, 2009. DTIC Descriptor(s): Interception probabilities, communication and radio systems, communications networks, spectra, command and control systems, extremely high frequency, naval operations, tactical warfare, low rate, theses, scenarios, line of sight, military applications. Author(s) subject terms: Millimeter wave, EHF, Extremely High Frequency, LPI, Low Probability of Intercept. Includes bibliographical references (p. 68-70). Also available print.

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