Topic
Antenna gain
About: Antenna gain is a research topic. Over the lifetime, 7964 publications have been published within this topic receiving 94804 citations.
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TL;DR: In this article, the statistical characteristics of the fields and signals in the reception of radio frequencies by a moving vehicle are deduced from a scattering propagation model, assuming that the field incident on the receiver antenna is composed of randomly phased azimuthal plane waves of arbitrary angle angles.
Abstract: The statistical characteristics of the fields and signals in the reception of radio frequencies by a moving vehicle are deduced from a scattering propagation model. The model assumes that the field incident on the receiver antenna is composed of randomly phased azimuthal plane waves of arbitrary azimuth angles. Amplitude and phase distributions and spatial correlations of fields and signals are deduced, and a simple direct relationship is established between the signal amplitude spectrum and the product of the incident plane waves' angular distribution and the azimuthal antenna gain. The coherence of two mobile-radio signals of different frequencies is shown to depend on the statistical distribution of the relative time delays in the arrival of the component waves, and the coherent bandwidth is shown to be the inverse of the spread in time delays. Wherever possible theoretical predictions are compared with the experimental results. There is sufficient agreement to indicate the validity of the approach. Agreement improves if allowance is made for the nonstationary character of mobile-radio signals.
2,087 citations
TL;DR: In this paper, the physical limitations of omni-directional antennas are considered and the potentiality of a broad band width of an antenna with the maximum dimension of 2a has been shown.
Abstract: The physical limitations of omni‐directional antennas are considered. With the use of the spherical wave functions to describe the field, the directivity gain G and the Q of an unspecified antenna are calculated under idealized conditions. To obtain the optimum performance, three criteria are used, (1) maximum gain for a given complexity of the antenna structure, (2) minimum Q, (3) maximum ratio of G/Q. It is found that an antenna of which the maximum dimension is 2a has the potentiality of a broad band width provided that the gain is equal to or less than 4a/λ. To obtain a gain higher than this value, the Q of the antenna increases at an astronomical rate. The antenna which has potentially the broadest band width of all omni‐directional antennas is one which has a radiation pattern corresponding to that of an infinitesimally small dipole.
1,954 citations
TL;DR: In this article, a simple formulation to compute the envelope correlation of an antenna diversity system is derived, which does not require the computation nor the measurement of the radiation pattern of the antenna system.
Abstract: A simple formulation to compute the envelope correlation of an antenna diversity system is derived. It is shown how to compute the envelope correlation from the S-parameter description of the antenna system. This approach has the advantage that it does not require the computation nor the measurement of the radiation pattern of the antenna system. It also offers the advantage of providing a clear understanding of the effects of mutual coupling and input match on the diversity performance of the antenna system.
1,004 citations
TL;DR: A novel fully integrated passive transponder IC with 4.5- or 9.25-m reading distance at 500-mW ERP or 4-W EIRP base-station transmit power, operating in the 868/915-MHz ISM band with an antenna gain less than -0.5 dB.
Abstract: This paper presents a novel fully integrated passive transponder IC with 4.5- or 9.25-m reading distance at 500-mW ERP or 4-W EIRP base-station transmit power, respectively, operating in the 868/915-MHz ISM band with an antenna gain less than -0.5 dB. Apart from the printed antenna, there are no external components. The IC is implemented in a 0.5-/spl mu/m digital two-poly two-metal digital CMOS technology with EEPROM and Schottky diodes. The IC's power supply is taken from the energy of the received RF electromagnetic field with help of a Schottky diode voltage multiplier. The IC includes dc power supply generation, phase shift keying backscatter modulator, pulse width modulation demodulator, EEPROM, and logic circuitry including some finite state machines handling the protocol used for wireless write and read access to the IC's EEPROM and for the anticollision procedure. The IC outperforms other reported radio-frequency identification ICs by a factor of three in terms of required receive power level for a given base-station transmit power and tag antenna gain.
875 citations
01 Apr 1966
TL;DR: The theoretical basis of antenna tolerance theory is reviewed in this paper, where the axial loss of gain and pattern degradation as a function of the reflector surface rms error and the surface spatial correlation are discussed.
Abstract: The theoretical basis of antenna tolerance theory is reviewed. Formulas are presented for the axial loss of gain and the pattern degradation as a function of the reflector surface rms error and the surface spatial correlation. Methods of determining these quantities by astronomical or ground-based electrical measurements are described. Correlation between the theoretical predictions and the performance of actual large antenna structures is presented.
686 citations