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Dipole antenna
About: Dipole antenna is a research topic. Over the lifetime, 38091 publications have been published within this topic receiving 513840 citations.
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Patent•
15 Jan 2007
TL;DR: An antenna for a communications device having configurable elements controlled to modify an antenna impedance and/or an antenna resonant frequency to improve performance of the communications device is described in this article, where the antenna impedance is controlled to substantially match to an output impedance of a power amplifier that supplies the antenna with a signal for transmission.
Abstract: An antenna for a communications device having configurable elements controlled to modify an antenna impedance and/or an antenna resonant frequency to improve performance of the communications device The antenna impedance is controlled to substantially match to an output impedance of a power amplifier that supplies the antenna with a signal for transmission The antenna resonant frequency is controlled to overcome the effects of various operating conditions that can detune the antenna or in response to an operable frequency band
574 citations
11 Jun 2001
TL;DR: An upper bound on the capacity that can be expressed as the sum of the logarithms of ordered chi-square-distributed variables is derived and evaluated analytically and compared to the results obtained by Monte Carlo simulations.
Abstract: We consider the capacity of multiple-input-multiple-output (MIMO) systems with reduced complexity. One link end uses all available antennas, while the other chooses the "best" L out of N antennas. As "best", we use those antennas that maximize capacity. We derive an upper bound on the capacity that can be expressed as the sum of the logarithms of ordered chi-squared variables. This bound is then evaluated analytically, and compared to results from Monte Carlo simulations. As long as L is at least as large as the number of antennas at the other link end, the achieved capacity is close to the capacity of a full-complexity system. We demonstrate, for example, that for L=3, N=8 at the receiver, and 3 antennas at the transmitter, the capacity of the reduced-complexity scheme is 20 bits/s/Hz compared to 23 bits/s/Hz of a full-complexity scheme.
557 citations
TL;DR: A circularly polarized antenna is described which makes possible bandwidths that a few years ago were considered to be impossible and an essentially constant radiation pattern and input impedance over bandwidths greater than 20 to 1.
Abstract: A circularly polarized antenna is described which makes possible bandwidths that a few years ago were considered to be impossible. The design of the antenna is based upon the simple fundamental principle that if the shape of the antenna were such that it could be specified entirely by angles, its performance would be independent of wavelength. Since all such shapes extend to infinity it is necessary to specify at least one length for an antenna of finite size. The one length in this antenna, the arm length, need only be of the order of one wavelength at the lowest frequency of operation to obtain operation essentially independent of frequency, and the geometry of the antenna allows this arm length to be spiraled into a maximum diameter of one half wavelength or less. Antennas have been constructed that have an essentially constant radiation pattern and input impedance over bandwidths greater than 20 to 1.
549 citations
TL;DR: In this article, a dominant mode leaky-wave antenna is proposed, which is a transmission line structure with radiating wavenumber increasing from negative to positive values, providing backward to forward scanning capability as the frequency is increased.
Abstract: A novel dominant mode leaky-wave antenna is proposed. This antenna is a transmission line structure with radiating wavenumber increasing from negative to positive values, providing backward to forward scanning capability as the frequency is increased. The characteristics and performances of the antenna are demonstrated by full-wave simulation and measurement results.
548 citations
TL;DR: In this paper, a 1:1.5 VSWR was achieved at operating frequencies around 2 GHz, which is nearly ten times that of a conventional microstrip-line-fed printed wide-slot antenna.
Abstract: Printed wide-slot antennas fed by a microstrip line with a fork-like tuning stub for bandwidth enhancement are proposed and experimentally investigated. Both the impedance and radiation characteristics of this antenna are studied. Experimental results indicate that a 1:1.5 VSWR bandwidth of 1 GHz is achieved at operating frequencies around 2 GHz, which is nearly ten times that of a conventional microstrip-line-fed printed wide-slot antenna. It also achieved a 2-dB gain bandwidth of at least 0.5 GHz.
525 citations