997 resultados para Locally Compact Spaces
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A novel compact single-layer dual frequency microstrip antenna which uses an H-shaped geometry with two U-shaped slots embedded near the radiation edges, is presented. By changing the design parameters, the lower and higher resonant frequencies can be controlled easily, and a range of frequency ratios (1.716-2.363) can be obtained in this design. For the two operating frequencies of the proposed antenna, the same polarization planes and broadside radiation patterns are achieved. Compared to the regular dualfrequency patch antenna, this antenna can realize a significant size reduction
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A novel design of a computer electronically reconfigurable dual frequency dual polarized single feed hexagonal slot loaded microstrip antenna in L-band is introduced in this chapter. pin diodes are used to switch the operating frequencies considerably without much affecting the radiation characteristics and gain. the antenna can work with a frequency ratio varying in the wide range from 1.2 to 1.4. the proposed design has an added advantage of size reduction up to 72.21% and 46.84% for the two resonating frequencies compared to standard rectangular patches. the design also gives considerable bandwidth of up to 2.82% and 2.42 % for the operating frequencies.
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A new compact microstrip antenna element is analyzed. The analysis can accurately predict the resonant frequency, input impedance, and radiation patterns. The predicted results are compared with experimental results and excellent agreement is observed . These antenna elements are more suitable in applications where limited antenna real estate is available
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A compact single - feed muttiband planar antenna configuration suitable for GPS, DCS. 2.4/5.8 GHz WLAN applications is presented. The antenna has dimensions 38 x 3 x 1.6 mm and offers good radiation and reflection characteristics in the above frequency bands. The antenna has a simple geometry and can be easily fed using a 50 coaxial probe.
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A novel compact wideband antenna for wireless local area network (WLAN) applications in the 2.4 GHz band is presented. The proposed low profile antenna of dimensions 15 x 14.5 x 1.6 mm offers 18.6% bandwidth and an average gain of -5 dBi. The antenna can be excited directly using a 50 coaxial probe
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In this study we combine the notions of fuzzy order and fuzzy topology of Chang and define fuzzy ordered fuzzy topological space. Its various properties are analysed. Product, quotient, union and intersection of fuzzy orders are introduced. Besides, fuzzy order preserving maps and various fuzzy completeness are investigated. Finally an attempt is made to study the notion of generalized fuzzy ordered fuzzy topological space by considering fuzzy order defined on a fuzzy subset.
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Antennas are indispensable component of any wireless communication device. An antenna is a transducer between the transmitter and the free space waves and vice versa. They efficiently transfer electromagnetic energy from a transmission line into free space. But the present day communication applications require compact and ultra wide band designs which cannot be catered by simple microstrip based designs. PIFAs have solved the problem to some extend, but the field of antennas needs more innovative designs In this thesis the design and development of compact planner antenna are presented. Emphasis is given to the design of the feed as well as the radiator resulting in simple compact uniplanar geometries. The Asymmetric coplanar feed used to excite the antennas is found to be a suitable choice for feeding compact antennas.The main objectives of the study are the design of compact single, dual and multi band antennas with uniplanar structure and extension of the design for practical GSM/WLAN applications and Ultra compact antennas using the above techniques and extension of the design to antennas for practical applications like RFID/DVB-H. All the above objectives are thoroughly studied. Antennas with ultra compact dimensions are obtained as a result of the study. Simple equations are provided to design antennas with the required characteristics. The design equations are verified by designing different antennas for different applications.
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Department of Electronics, Cochin University of Science and Technology
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The thesis is the outcome of the experimental and theoretical investigations carried out on a novel slotted microstrip antenna.The antenna excites two resonance frequencies and provides orthogonal polarization. The radiation characteristics of the antenna are studied in detail. The antenna design is optimized using IE3D electromagnetic simulation tool. The frequency-Difference Time-Domain (FDTD) method is employed for the analysis of the antenna.The antenna can be used for personal and satellite communication applications.
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The thesis is the outcome of the experimental and theoretical investigations on a new compact drum-shaped microstrip antenna. A new compact antenna suitable for personal communication system(PCS), Global position System(GPS) and array applications is developed and analysed. The generalised cavity model and spatial fourier transform technique are suitably modified for the analysis of the antenna. The predicted results are compared with experimental results and excellent agreement is observed. The experimental work done by the author in related fields are incorporated as three appendices in this thesis. A single feed dual frequency microstrip antenne is presented in appendix A.Appendix B describes a new broadband dual frequeny microstrip antenna. The bandwidth enhancement effect of microstrip antennas through dielectric resonator loading is demonstarted in Appendix C.
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Design of a compact microstrip-fed ultra-wideband antenna suitable for USB dongle and other such space constraint applications is presented. The structure consists of a pentagonal monopole element and a modified ground plane that gives an impedance bandwidth from 2.8 to 12 GHz. Radiation patterns are stable and omni-directional throughout the band with an average gain of 2.84 dBi. The antenna occupies only 11 × 30 mm2 on FR4 substrate with permittivity 4.4.
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The thesis is the outcome of the theoretical and experimental investigations on mocrostrip-fed printed strip monopole antenna.Finite ground plane has been effectively utilized to excite a new resonance near the fundamental mode by introducing another extended strip from the ground plane,without affecting compactness.Further size reduction was achieved by carrying out folding analysis on dual strip antenna and a compact folded dual strip antenna has been designed.Design methodologies for both the compact dual band antennas are presented.The proposed antennas can be used for mobile and WLAN applications due to wide bandwidth,moderate gain and omnidirectional radiation coverage.