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Showing 1 to 20 of 20 for “"Helical Antenna"”.
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The spherical helical antenna
The spherical helical antenna is investigated as a new variation of the conventional helical antenna. The spherical helix is a wire antenna in a helix shape that is wound over a spherical surface instead of the standard cylindrical one. Analysis of this structure requires numerical methods and …
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The Spiro-Helical Antenna
A novel antenna made of a spiral wire wrapped into a larger helical shape is introduced. The geometry of this antenna, which is a doubly helical structure, is fully described by five independent parameters, including two radial dimensions, two pitch angles, and the number of turns. Radiation …
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Helical Antenna Optimization Using Genetic Algorithms
The genetic algorithm (GA) is used to design helical antennas that provide a significantly larger bandwidth than conventional helices with the same size. Over the bandwidth of operation, the GA-optimized helix offers considerably smaller axial-ratio and slightly higher gain than the conventional …
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The Stub Loaded Helix: A Reduced Size Helical Antenna
… development of a novel reduced size axial mode helical antenna called the Stub Loaded Helix (SLH). The SLH achieves a significant reduction in helix size, both diameter and length, compared to the conventional axial mode helix antenna with only small compromises in performance. The SLH achieves …
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Numerical Analysis of Helical and Log-periodic Antennas for Short Pulse Applications
The planar log-periodic (LP) and helical antennas are numerically studied as two antennas with a wide range of applications. The advantages of the LP antenna are the large adjustable bandwidth as a frequency independence radiator, its low profile, and that it can be made to be elliptically …
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Optimization of a helicon plasma source for maximum density with minimal ion heating
… helicon plasma are presented for five different antennas: A Nagoya type III antenna, a double-saddle antenna, a 19 cm long m = +1 helical antenna, a 30 cm long m = +1 helical antenna and a 19 cm m = +1 helical antenna with wide straps. Electromagnetic wave measurements in the range from 100 kHz …
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A broadband Microwave Transceiver Front-end for an Airborne Software Defined Radio Experiment
… band receiver. The receiver input is fed by a helical antenna and the outputs are digitized for use in the SDR. The transmitter is fed by a complex baseband output from a Digital-to-Analog Converter (DAC) and its output fed to another helical antenna. The requirements for the transceiver were …
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Design of hybrid optio-vision tracking system with active RFID
… simpler RSSI model suggest a dynamic positioned antenna to enhance the accuracy of simple star-shape networks. The design focuses on a double helical antenna positioned on a motorized dual axis controller.
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Conformal antenna-based wireless telemetry system for capsule endoscopy
… and performance characterisation of a helical antenna placed conformally outside an endoscopic capsule, and the characterisation in-silico, in-vitro and in-vivo of the telemetry system in alive and euthanised pigs. This method does not use the internal volume of the capsule, but does …
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Design of anechoic chamber instrumentation and data acquisition module for testing and analysis of the CTHA
The backbone of wireless communication is an antenna, a device that converts electromagnetic energy to electric energy and vice versa, to transmit and receive the signals. The effectiveness of a communication system depends largely on the effectiveness of the antenna used in them. The effectiveness …
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Investigation, design and implementation of circular-polarised antennas for satellite mobile handset and wireless communications. Simulation and measurement of microstrip patch and wire antennas for handheld satellite mobile handsets and investigations of polarization polarity, specific absorption rate, and antenna design optimization using genetic algorithms.
… design and implement circularly-polarized antennas to be used for handheld satellite mobile communication and wireless sensor networks. Several antennas such as Quadrifilar Spiral Antennas (QSAs), two arm Square Spiral and stripline or coaxially-fed microstrip patch antennas are developed …
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Impedance effects of metallic ground plane on the CTHA antenna
… development of the communication industry, antennas have become an indispensable part of daily life. However, everyone may have experienced the malfunction of a communication system or radio due to a nearby human body or building or automobile. Then comes the question of how adjacent objects …
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Characterization of The Role of The Pkm101-Encoded T4Ss Outer Membrane Core Complex In Substrate Transfer, Pilus Biogenesis, and Recipient Cell Contact
… the role of an OMCC cap region formed by alpha helical antenna projections (AP) found in VirB10 and TraF<sub>pKM101</sub>. I introduced various internal deletions, truncations, and substitutions between TraF<sub>pKM101</sub> and VirB10 to study the role of the AP cap in (i) substrate transfer to …
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Design and analysis of ultra-wide band and millimeter-wave antennas
Ultra-wideband (UWB) antennas and 60-GHz millimeter-wave antennas and arrays are analyzed and designed in this thesis for developing high-speed short-range wireless communications. Firstly, a probe-fed crossed circle-disk monopole UWB antenna with stable omnidirectional radiation pattern was …
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Helical Antennas with Truncated Spherical Geometry
A new variation of the spherical helical antenna made of a wire wound over a hemispherical surface and backed by a conducting ground plane is introduced. A constant spacing is maintained between the turns of winding. The geometry of this antenna is fully described by the number of turns and the …
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Design and Modelling of Passive UHF RFID Tags for Energy Efficient Liquid Level Detection Applications. A study of various techniques in the design, modelling, optimisation and deployment of RFID reader and passive UHF RFID tags to achieve effective performance for liquid sensing applications
… application requirements. An in-manhole chamber antenna for an underground communication system is analysed, designed, deployed and measured. The antenna covers dual-band impedance bandwidths (i.e. 824 to 960 MHz, and 1710 to 2170 MHz). The results show that the antenna prototype exhibits …
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New Designs for Wideband Hemispherical Helical Antennas
A unique property of spherical and hemispherical helical antennas is that they provide very broad half-power beamwdiths and circular polarization over a narrow bandwidth. In this thesis, new designs for hemispherical helical antennas are introduced that provide significant improvement in bandwidth, …
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Advancing high power microwave spark-gap technology : design and analysis of a coaxial ringdown oscillator
… a high-pressure hydrogen spark gap switch and a helical antenna, which collectively improve breakdown voltage, Q, and mitigate conductor build up issues. The CRO design successfully addresses the big-picture HPM challenges by generating more powerful and reliable electromagnetic pulses, extending …
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Zkušební FM vysílač řízený rezonátorem SAW
Práce se zabývá návrhem FM vysílače s rezonátorem SAW. Teoreticky rozebírá vlastnosti mikrofonu, oscilátorů a vhodný výběr antén, kde rozebírá jejich výhody a nevýhody. Vysílač disponuje elektretový mikrofonem. Pro jeho zesílení je využit předzesilovač OPA134. Dále se práce zabývá realizací …