Topic
Feed horn
About: Feed horn is a research topic. Over the lifetime, 2395 publications have been published within this topic receiving 26548 citations. The topic is also known as: feedhorn.
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TL;DR: In this paper, a 1-18 GHz broadband double-ridged horn antenna with coaxial input feed section is investigated and it is found that the radiation pattern, contrary to common belief, does not maintain a single main lobe in the direction of the horn axis over the full frequency range.
Abstract: A 1-18-GHz broadband double-ridged horn antenna with coaxial input feed section is investigated. For the ridged horn antenna it is found that the radiation pattern, contrary to common belief, does not maintain a single main lobe in the direction of the horn axis over the full frequency range. Instead, at frequencies above 12 GHz, the main lobe in the radiation pattern starts to split into four large side lobes pointing in off-axis directions with a dip of up to 6 dB between them along the main axis. Although this type of horn is the preferred test antenna, which is in common use for over four decades, no explanation for this unwanted behavior was found in the open literature. To investigate this phenomenon in detail, a method of moments approach has been adopted to simulate the complete antenna system. The simulations are in good agreement with the measurements over the 1-18-GHz operational bandwidth and indicate that the use of this type of horn antenna in EMC applications remains questionable.
196 citations
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23 May 2001
TL;DR: In this article, a dual band, higher and lower frequency range transducer with a circular coaxial waveguide feed is described having a first junction for connection of a lower frequency-range outer waveguide of the coaxial feed to at least two rectangular or ridge waveguides offset from the longitudinal axis of the transducers, and a second junction for connecting the at least rectangular-or ridge waveguide to a further waveguide.
Abstract: A dual band, higher and lower frequency range transducer with a circular coaxial waveguide feed is described having a first junction for connection of a lower frequency range outer waveguide of the coaxial waveguide feed to at least two rectangular or ridge waveguides offset from the longitudinal axis of the transducer and a second junction for connection of the at least two rectangular or ridge waveguides to a further waveguide. A third junction is provided for connecting an inner waveguide of the coaxial waveguide feed to a higher frequency range waveguide. The transducer comprises at least first and second parts joined across a first plane substantially perpendicular to the longitudinal axis and including at least a portion of the higher frequency range waveguide extending within the first plane of the join. A seal such as an “O” ring seal may be placed easily in the plane of the join thus preventing moisture ingress. Similarly, a feed horn and input and output ports may be sealingly attached to the first and second parts of the transducer. The first and second junctions are preferably impedance matched turnstile junctions.
189 citations
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TL;DR: In this paper, a smooth-walled spline-profile horn for specific application in the 80-120 GHz band was proposed. But the results of a theoretical and measurement study of the smooth-wall spline profile horn were presented.
Abstract: At millimeter-wave frequencies, corrugated horns can be difficult and expensive to manufacture. As an alternative we present here the results of a theoretical and measurement study of a smooth-walled spline-profile horn for specific application in the 80-120 GHz band. While about 50% longer than its corrugated counterpart, the smooth-walled horn is shown to give improved performance across the band as well as being much easier to manufacture.
181 citations
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10 Feb 2000TL;DR: In this article, an azimuthally tunable resistivity measurement tool comprising transmitter coils and receiver coils, wherein at least some of the transmitter coils or receiver coils are skewed and oriented in differing aziruthal directions, is disclosed.
Abstract: An azimuthally tunable resistivity measurement tool comprising transmitter coils and receiver coils, wherein at least some of the transmitter coils or receiver coils are skewed and oriented in differing azimuthal directions, is disclosed. The transmitter coils transmit radio-frequency signals that propagate through a formation surrounding a borehole and the receiver coils measure the relative amplitude and phase of signals received from the surrounding formation. A method for detecting the location of a bed boundary relative to a borehole is also disclosed, including the steps of: generating first and second signals representing azimuthally sensitive measurements of phase shift and attenuation of an electromagnetic signal propagating through a formation around a borehole, wherein the azimuthal sensitivity of the first measurement is in a direction different than that of the second measurement, and receiving electromagnetic signals on first and second skewed receiver antennas respectively oriented in first and second azimuthal directions.
180 citations
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01 Sep 1964TL;DR: In this article, the beam shift and degradation of a paraboloidal reflector with an offset feed is analyzed by the scalar plane wave theory, and the beam characteristics for a tapered circularly symmetric illumination are presented.
Abstract: The beam shift and degradation of a paraboloidal reflector with an offset feed is analyzed by the scalar plane wave theory. Higher order coma terms are included with the feed at its optimum axial position. The beam characteristics for a tapered circularly symmetric illumination are presented. The range of validity of the approximate analysis is indicated.
177 citations