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Antenna factor

About: Antenna factor is a(n) research topic. Over the lifetime, 26328 publication(s) have been published within this topic receiving 349043 citation(s).

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Open accessJournal ArticleDOI: 10.1063/1.1715038
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.

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Topics: Antenna gain (67%), Directional antenna (66%), Antenna measurement (66%) ...read more

1,844 Citations


Journal ArticleDOI: 10.1109/JRPROC.1947.226199
01 Dec 1947-
Abstract: A capacitor or inductor operating as a small antenna is theoretically capable of intercepting a certain amount of power, independent of its size, on the assumption of tuning without circuit loss. The practical efficiency relative to this ideal is limited by the "radiation power factor" of the antenna as compared with the power factor and bandwidth of the antenna tuning. The radiation power factor of either kind of antenna is somewhat greater than (1/6π) (Ab/l2) in which Ab is the cylindrical volume occupied by the antenna, and l is the radianlength (defined as 1/2π wavelength) at the operating frequency. The efficiency is further limited by the closeness of coupling of the antenna with its tuner. Other simple formulas are given for the more fundamental properties of small antennas and their behavior in a simple circuit. Examples for 1-Mc. operation in typical circuits indicate a loss of about 35 db for the I.R.E. standard capacitive antenna, 43 db for a large loop occupying a volume of 1 meter square by 0.5 meter axial length, and 64 db for a loop of 1/5 these dimensions.

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Topics: Antenna efficiency (70%), Loop antenna (70%), Antenna measurement (68%) ...read more

1,151 Citations


Journal ArticleDOI: 10.1049/EL:19850034
David M. Pozar1Institutions (1)
Abstract: A new technique for feeding printed antennas is described A microstrip antenna on one substrate is coupled to a microstripline feed on another parallel substrate through an aperture in the ground plane which separates the two substrates A simple theory explaining the coupling mechanism is presented, as well as measurements of a prototype aperture-fed antenna

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Topics: Microstrip antenna (70%), Patch antenna (68%), Antenna factor (63%) ...read more

832 Citations


Open accessJournal ArticleDOI: 10.1109/8.664115
Abstract: The multiband behavior of the fractal Sierpinski (1915) antenna is described. Due to its mainly triangular shape, the antenna is compared to the well-known single-band bow-tie antenna. Both experimental and numerical results show that the self-similarity properties of the fractal shape are translated into its electromagnetic behavior. A deeper physical insight on such a behavior is achieved by means of the computed current densities over the antenna surface, which also display some similarity properties through the bands.

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  • Fig. 2. Input reflection coefficient (referred to 50 ) of five bow ties at scaled as each one of the five subgaskets on the Sierpinski monopole (89, 44.5, 22.3, 11.1, and 5.5 mm). The bottom plot corresponds to the input reflection coefficient of the Sierpinski monopole.
    Fig. 2. Input reflection coefficient (referred to 50 ) of five bow ties at scaled as each one of the five subgaskets on the Sierpinski monopole (89, 44.5, 22.3, 11.1, and 5.5 mm). The bottom plot corresponds to the input reflection coefficient of the Sierpinski monopole.
  • Fig. 3. Input resistance (top) and reactance (bottom) of the five-iteration Sierpinski monopole. Frequency is shown in logarithmic scale to stress the log-periodic behavior of the antenna.
    Fig. 3. Input resistance (top) and reactance (bottom) of the five-iteration Sierpinski monopole. Frequency is shown in logarithmic scale to stress the log-periodic behavior of the antenna.
  • Fig. 4. Main cuts of the Sierpinski monopole radiation pattern (E component). From left to right, each column corresponds to one cut (' = 0 ; ' = 90 ; = 90 ) at each one of the four upper bands (from top to bottomf = 1:74 GHz, f = 3:51 GHz, f = 6:95 GHz, and f = 13:89 GHz). Each pattern is normalized with respect to its own maximum.
    Fig. 4. Main cuts of the Sierpinski monopole radiation pattern (E component). From left to right, each column corresponds to one cut (' = 0 ; ' = 90 ; = 90 ) at each one of the four upper bands (from top to bottomf = 1:74 GHz, f = 3:51 GHz, f = 6:95 GHz, and f = 13:89 GHz). Each pattern is normalized with respect to its own maximum.
  • Fig. 5. Front to back cut (' = 0 ) of both the (a) Sierpinski dipole radiation pattern and the (b) bow-tie antenna. The patterns correspond to theE component. Each row displays three cuts within one band. Notice the similarity between rows (multiband behavior) as opposed to the differences betwe columns (not a frequency-independent behavior) on the Sierpinski antenna.
    Fig. 5. Front to back cut (' = 0 ) of both the (a) Sierpinski dipole radiation pattern and the (b) bow-tie antenna. The patterns correspond to theE component. Each row displays three cuts within one band. Notice the similarity between rows (multiband behavior) as opposed to the differences betwe columns (not a frequency-independent behavior) on the Sierpinski antenna.
  • Fig. 6. Left to right cut (' = 90 ) of both the (a) Sierpinski dipole radiation pattern and the (b) bow-tie antenna. The patterns correspond to theE component. Each row displays three cuts within one band. Notice the similarity between rows (multiband behavior) as opposed to the differences betwe columns (not a frequency-independent behavior) on the Sierpinski antenna.
    Fig. 6. Left to right cut (' = 90 ) of both the (a) Sierpinski dipole radiation pattern and the (b) bow-tie antenna. The patterns correspond to theE component. Each row displays three cuts within one band. Notice the similarity between rows (multiband behavior) as opposed to the differences betwe columns (not a frequency-independent behavior) on the Sierpinski antenna.
Topics: Fractal antenna (74%), Coaxial antenna (63%), Antenna factor (63%) ...read more

725 Citations


Journal ArticleDOI: 10.1049/EL:19950950
T. Huynh, Kai-Fong Lee1Institutions (1)
Abstract: A coaxially-fed single-layer single-patch wide-band microstrip antenna in the form of a rectangular patch with a U-shaped slot is discussed. Measurements showed that this antenna can attain 10-40% impedance bandwidth without the need of adding parasitic patches in another layer or in the same layer.< >

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Topics: Microstrip antenna (77%), Patch antenna (76%), Coaxial antenna (64%) ...read more

704 Citations


Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20214
20208
201911
201849
20171,406
20162,249

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Topic's top 5 most impactful authors

Kwai-Man Luk

186 papers, 7K citations

Kin-Lu Wong

116 papers, 5.1K citations

Mohammad Tariqul Islam

78 papers, 1.6K citations

Tayeb A. Denidni

70 papers, 1.2K citations

Qing-Xin Chu

47 papers, 1.3K citations

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