page_title: Horn antenna
section_title: Description
hierarchical_section_title: Horn antenna / Description
caption_attribution_description: English: A family of microwave horn antennas manufactured by Tactron Electronik GmBH, Germany. These are pyramidal horn antennas with flanges to bolt onto standard waveguide. Deutsch: Horn Antennen
context_page_description: A horn antenna or microwave horn is an antenna that consists of a flaring metal waveguide shaped like a horn to direct radio waves in a beam. Horns are widely used as antennas at UHF and microwave frequencies, above 300 MHz. They are used as feed antennas for larger antenna structures such as parabolic antennas, as standard calibration antennas to measure the gain of other antennas, and as directive antennas for such devices as radar guns, automatic door openers, and microwave radiometers. Their advantages are moderate directivity, low standing wave ratio, broad bandwidth, and simple construction and adjustment.
  One of the first horn antennas was constructed in 1897 by Bengali-Indian radio researcher Jagadish Chandra Bose in his pioneering experiments with microwaves. The modern horn antenna was invented independently in 1938 by Wilmer Barrow and G. C. Southworth The development of radar in World War 2 stimulated horn research to design feed horns for radar antennas. The corrugated horn invented by Kay in 1962 has become widely used as a feed horn for microwave antennas such as satellite dishes and radio telescopes.
context_section_description: A horn antenna is used to transmit radio waves from a waveguide (a metal pipe used to carry radio waves) out into space, or collect radio waves into a waveguide for reception.  It typically consists of a short length of rectangular or cylindrical metal tube (the waveguide), closed at one end, flaring into an open-ended conical or pyramidal shaped horn on  the other end.  The radio waves are usually introduced into the waveguide by a coaxial cable attached to the side, with the central conductor projecting into the waveguide to form a quarter-wave monopole antenna.  The waves then radiate out the horn end in a narrow beam.  In some equipment the radio waves are conducted between the transmitter or receiver and the antenna by a waveguide; in this case the horn is attached to the end of the waveguide.  In outdoor horns, such as the feed horns of satellite dishes, the open mouth of the horn is often covered by a plastic sheet transparent to radio waves, to exclude moisture.
caption: Pyramidal horn antennas for a variety of frequencies. They have flanges at the top to attach to standard waveguides.
exif: {"Image Make": "NIKON CORPORATION", "Image Model": "NIKON D700", "Image Orientation": "Horizontal (normal)", "Image XResolution": "150", "Image YResolution": "150", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CS4 Windows", "Image DateTime": "2009:09:24 11:32:39", "Image Artist": "", "Image WhitePoint": "[313/1000, 329/1000]", "Image PrimaryChromaticities": "[16/25, 33/100, 21/100, 71/100, 3/20, 3/50]", "Image YCbCrCoefficients": "[299/1000, 587/1000, 57/500]", "Image YCbCrPositioning": "Co-sited", "Image Copyright": "", "Image ExifOffset": "480", "GPS GPSVersionID": "[2, 2, 0, 0]", "Image GPSInfo": "1144", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "1258", "Thumbnail JPEGInterchangeFormatLength": "3106", "EXIF ExposureTime": "1/160", "EXIF FNumber": "9", "EXIF ExposureProgram": "Manual", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2009:09:23 13:13:19", "EXIF DateTimeDigitized": "2009:09:23 13:13:19", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "4", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "3", "EXIF MeteringMode": "Spot", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire", "EXIF FocalLength": "36", "EXIF SubSecTime": "25", "EXIF SubSecTimeOriginal": "25", "EXIF SubSecTimeDigitized": "25", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "886", "EXIF ExifImageLength": "672", "Interoperability InteroperabilityIndex": "R03", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "1112", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CVAPattern": "[0, 2, 0, 2, 0, 1, 1, 2]", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Manual Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF FocalLengthIn35mmFilm": "36", "EXIF SceneCaptureType": "Standard", "EXIF GainControl": "None", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal", "EXIF SubjectDistanceRange": "0", "EXIF Gamma": "11/5"}