Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 40 for “"Impedance bandwidth"”.
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Cavity-backed T-fed slot antenna
… slot antennas typically have a narrow impedance bandwidth of 1 to 6 percent of center frequency, which limits their usage. A new method of feeding a thin cavity slot antenna with a stripline leading to a T-bar, which lies beneath or in the slot, greatly enhances the impedance bandwidth …
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Analysis and Design of a Broadband Antenna for Software Defined Radio
… capable of achieving an instantaneous 3:1 VSWR bandwidth and omnidirectional radiation coverage spanning a bandwidth greater than 20:1. The antenna is designed to accommodate the very large bandwidth requirements of software-defined radios and to minimize the effective volume of the overall …
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Multimode and Multiband Microstrip Antennas
… One major restriction is their narrow impedance bandwidth. An effective method to resolve this is adding more resonators to the antenna structure to achieve multi-resonance and hence wider bandwidth. Structures such as circular, square and triangular patch antennas may support two …
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Enabling Hybrid Optical-Microwave Space Communications with Optically Transparent RF Components Using Indium Tin Oxide (ITO)
… solar cell standards. The simulated -10 dB impedance bandwidth was found to be 154\%, and the measured -10 dB impedance bandwidth was 156\%, covering a wide range from 1.4 GHz to 10.9 GHz. Additionally, the simulated peak antenna gain was observed to be 3.2 dBi at 6 GHz, indicating the …
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A Nonlinear Technique for Bandwidth Improvement in Narrowband Antennas
… one would also like to at least maintain antenna bandwidth and efficiency while reducing size. However, in theory, antenna performance degrades when it is miniaturized—impedance bandwidth decreases with the reduction in antenna size. This thesis investigates the possibility of increasing the input …
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Design of broad-band dual-polarized microstrip patch antennas with high port isolation for millimeter-wave 5G applications
… frequency reuse. Techniques for improving the impedance bandwidth is one of the most researched areas of microstrip antenna technology. New multi-layer dual linearly polarized design topologies are proposed in this thesis, based on substrate integrated waveguide (SIW) cavity-backed microstrip …
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STUDY OF MULTI- AND BROAD-BAND INTERNAL ANTENNAS FOR MOBILE APPLICATIONS
… to the radiating element. The measurement bandwidths of the Aperture Coupling Proximity Feed Hybrid MSA #1(ACPF-HMSA#1, design #1) and ACPF-HMSA #2 (design #2) are 185MHz (7%) and 105MHz (4.1%), VSWR in less than 2, respectively. Two layers Planar Inverted F Antenna (PIFA) with the …
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A Comprehensive Investigation of New Planar Wideband Antennas
… are low-profile, dual-polarization and wide bandwidth in a compact size. Many existing wideband antennas are large in size and some have only circular polarization. On the other hand low-profile, dual-polarized antennas frequently have limited bandwidth. This dissertation reports on results …
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Size reduction of vivaldi antenna array for microwave imaging
… (TSA) is a good candidate as it offers broad impedance bandwidth and stable radiation patterns, and high gain characteristics In this project, Vivaldi antenna array is designed, one antenna element is designed using FR-4 substrate which has relative permittivity of 4.3. and thickness of 1.6 …
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Analysis and design of electrically small, circularly polarized cylindrical microstrip antennas
… techniques for reducing the size, extending the bandwidth and achieving circular polarization for planar embodiments. Conformal microstrip antennas, on the other hand, have a much more limited body of literature spanning the last three decades. The conformal microstrip antenna literature has …
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Improving port isolation in dual-polarized microstrip patch antenna arrays
… in excess of 40dB was measured over the impedance bandwidth. The effects of excitation amplitude taper and excitation phase progression on port isolation performance of the array are examined and the results presented.
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Antenna design for ultra wideband radio
… design. Ultra Wideband Radio requires operating bandwidths up to greater than 100% of the center frequency. Successful transmission and reception of an Ultra Wideband pulse that occupies the entire 3.1-10.6 GHz spectrum require an antenna that has linear phase, low dispersion and VSWR [< or =] 2 …
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OPTIMAL ANTENNA DESIGNS FOR WIRELESS COMMUNICATION APPLICATIONS
… the phase velocity. The antenna has achieved an impedance bandwidth of 52.16% and a stable radiation patterns over a wider bandwidth with a size reduction about 88%. Optimization of a dielectric loaded antenna by using Covariance Matrix Adaptation Evolutionary Strategy (CMA-ES) technique to …
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Impact of ground plane serrations on radiation and impedance characteristics of a slot antenna over a conductive back plane
… is applied to a thin slot or dipole antenna, the bandwidth is significantly reduced. In the case of the slot antenna, this bandwidth reduction is due in part to reactive energy stored in parallel plate modes. The stored energy can be reduced by treating the edge of the ground plane with …
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Antenna design for 2.4 GHz ISM band
… of 0.8 mm. Simulated and measured results of the impedance properties are presented. Based on these designs, a new dual-band planar monopole antenna is proposed. It is designed to work in both 2.4 GHz ISM band and 5.3 GHz band. The size of the ground is purposely chosen to be same as a WLAN …
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Design and Analysis of a Cylindrical Dielectric Resonator Antenna Array and Its Feed Network
… A DRA element in this research is optimized for bandwidth and gain for use at x-band (8-12 GHz). The antenna feed network, being an integral part of all antenna arrays, is also considered. The primary causes of impedance mismatch in the feed network are identified and techniques to improve …
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A Radiation Reconfigurable Magnetic Line Source Antenna: Modeling, Integration With RF MEMS, and Applications
… Each configuration operates within an impedance bandwidth common to both states, and the desired radiation characteristics in both states occur in the same plane (principal plane) of the antenna with the same polarization (principal polarization). A unique analytical modeling …
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Development of an online broadband impedance spectroscopy extraction system of PV modules through switch-mode converters
… enable more detailed online diagnostics, linear impedance spectroscopy, a frequency-based characterization technique implemented through a DC-DC switch-mode converter, has been shown to provide fast and reliable impedance information that can be utilized to diagnose the condition of batteries and …
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THE USE OF CONDUCTIVE INK IN ANTENNA EDUCATION AND DESIGN
… antenna design attempts to find the maximum impedance bandwidth beyond the GNSS band. The inexpensive nature of conductive ink allows for its use in a classroom to demonstrate antenna behavior as part of antenna education. An inexpensive approach to the patch antenna using conductive ink is …
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Design and analysis of pattern null reconfigurable antennas
… at 2.42 GHz along the E plane within its common impedance bandwidth. In addition, careful consideration of the modes on the antenna illuminates the antenna's operating principles, yielding guidelines for simple NRA design at other frequencies. To improve the interference rejection capabilities of …
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