Radial Line Slot Antenna

X-band slotted waveguide marine radar antenna on ship, 8 - 12 GHz. The antenna radiates a narrow vertical fan-shaped beam of microwaves, scanning the entire 360° water surface around the ship with each rotation.

A good system of ground radials is installed, much of the power supplied to the. Since the magnetic slot is a balanced antenna, a 1:1 balun should be used if it is fed with coaxial cable, to avoid the possibility of feed-line radiation. A radial line slot antenna (CP-RLSA) is a slotted waveguide planar array for DBS reception. A number of designs have been devised, but these designs have pros and cons. In order to suppress grating lobes and increase the gain, this article will introduce a new wave material =1.06, arrange the angle and modify configurations of the slot sets. Finally, starting from the antenna end of the radial wires and about every three-to-four feet, hold the wire down with a radial wire staple while pulling the radial out from the antenna to keep it taut. Push it in as far as possible to get the wire as close to the grass roots as possible. I typically use a hammer or rubber mallet to drive it home.

Cross section of similar marine radar antenna with part of plastic radome removed, showing slots in waveguide.
Radial line slot antennasSlot

A slot antenna consists of a metal surface, usually a flat plate, with one or more holes or slots cut out. When the plate is driven as an antenna by an applied radio frequency current, the slot radiates electromagnetic waves in a way similar to a dipole antenna. The shape and size of the slot, as well as the driving frequency, determine the radiation pattern. Slot antennas are usually used at UHF and microwave frequencies at which wavelengths are small enough that the plate and slot are conveniently small. At these frequencies, the radio waves are often conducted by a waveguide, and the antenna consists of slots in the waveguide; this is called a slotted waveguide antenna. Multiple slots act as a directivearray antenna and can emit a narrow fan-shaped beam of microwaves. They are used in standard laboratory microwave sources used for research, UHF television transmitting antennas, antennas on missiles and aircraft, sector antennas for cellular base stations, and particularly marine radar antennas. A slot antenna's main advantages are its size, design simplicity, and convenient adaptation to mass production using either waveguide or PC board technology.

Structure[edit]

Slotted array UHF television broadcasting antenna

As shown by H. G. Booker in 1946, from Babinet's principle in optics a slot in a metal plate or waveguide has the same radiation pattern as a driven rod antenna whose rod is the same shape as the slot, with the exception that the electric field and magnetic field directions are interchanged; the antenna is a magnetic dipole instead of an electric dipole; the magnetic field is parallel to the long axis of the slot and the electric field is perpendicular. Thus the radiation pattern of a slot can be calculated by the same well-known equations used for rod element antennas like the dipole. The waves are linearly polarized perpendicular to the slot axis. Slots up to a wavelength long have a single main lobe with maximum radiation perpendicular to the surface.

Slot Antenna Design

Antennas consisting of multiple parallel slots in a waveguide are widely used array antennas. They have a radiation pattern similar to a corresponding linear array of dipole antennas, with the exception that the slot can only radiate into the space on one side of the waveguide surface, 180° of the surrounding space. There are two widely used types:

Radial Line Slot Antenna

  • Longitudinal slotted waveguide antenna - The slots' axis is parallel to the axis of the waveguide. This has a radiation pattern similar to a collinear dipole antenna, and is usually mounted vertically. The radiation pattern is almost omnidirectional in the horizontal plane perpendicular to the antenna over the 180° azimuth in front of the slot, but narrow in the vertical plane, with the vertical gain increasing approximately 3 dB with each doubling of the number of slots. The radiation is horizontally polarized. It is used for vertical omnidirectional transmitting antennas for UHF television stations. For broadcasting, a cylindrical or semicircular waveguide is sometimes used with several columns of slots cut in different sides to give an omnidirectional 360° radiation pattern.
  • Transverse slotted waveguide antenna - The slots are almost perpendicular to the axis of the waveguide but skewed at a small angle, with alternate slots skewed at opposite angles. This radiates a dipole pattern in the plane perpendicular to the antenna, and a very sharp beam in the plane of the antenna. Its largest use is for microwave marine radar antennas. The antenna is mounted horizontally on a mechanical drive that rotates the antenna about a vertical axis, scanning the antenna's vertical fan-shaped beam 360° around the water surface surrounding the ship out to the horizon with each revolution. The wide vertical spread of the beam ensures that even in bad weather when the ship and the antenna axis is being rocked over a wide angle by waves the radar beam will not miss the surface.

Radial Line Slot Antenna Plasma

History[edit]

The slot antenna was invented in 1938 by Alan Blumlein, while working for EMI. He invented it in order to produce a practical type of antenna for VHF television broadcasting that would have horizontal polarization, an omnidirectional horizontal radiation pattern and a narrow vertical radiation pattern.[1][2]

Prior to its use in surface search radar, such systems used a parabolic segment reflector, or 'cheese antenna'. The slotted waveguide antenna was the result of collaborative radar research carried on by McGill University and the National Research Council of Canada during World War II.[3] The co-inventors, W.H. Watson and E.W. Guptill of McGill, were granted a United States patent for the device, described as a 'directive antenna for microwaves', in 1951.[4]

Slotted waveguide antenna for 2.4 GHz.

Other uses[edit]

In a related application, so-called leaky waveguides are also used in the determination of railcar positions in certain rapid transit applications. They are used primarily to determine the precise position of the train when it is being brought to a halt at a station, so that the doorway positions will align correctly with queuing points on the platform or with a second set of safety doors should such be provided.

Vertical Antenna Radials

See also[edit]

  • Microwave Radiometer (Juno) (has a slot array antenna)
  • RIMFAX (radar for Mars rover has slot antenna design)

References[edit]

Antenna Ground Radials

  1. ^Blumlein, Alan (1938-03-07), 'Improvements in or relating to high frequency electrical conductors or radiators', British patent no. 515684
  2. ^Burns, Russell (2000). The life and times of A.D. Blumlein. Institution of Engineering and Technology. ISBN0-85296-773-X.
  3. ^Covington, Arthur E. (1991). 'Some recollections of the radio and electrical engineering division of the National Research Council of Canada, 1946-1977'. Scientia Canadensis: Canadian Journal of the HIstory of Science, Technology and Medicine. 15 (2): 155–175. doi:10.7202/800334ar.
  4. ^Watson, William Heriot; Guptill, Ernest Wilmot (6 November 1951), Directive Antenna for Microwaves, retrieved 20 December 2016

Radial Line Slot Antenna For Sale

Slot

External links[edit]

Antenna Radial Wire

  • 'Slot Antennas'. Antenna Theory.
  • Slotted Waveguide Antennas Antenna-Theory.com
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Slot_antenna&oldid=990966954'
  1. Akiyama A et al (1988) Numerical optimisation of slot parameters for a concentric array radial line slot antenna. Microwaves Antennas Propag IEE Proc 145(2):141–146MathSciNetCrossRefGoogle Scholar
  2. Akiyama A et al (2000) High gain radial line slot antennas for millimetre wave applications. Microwaves Antennas Propag IEE Proc 147(2):134–138CrossRefGoogle Scholar
  3. Albani M et al (2006) An efficient full-wave method of moments analysis for RLSA antennas. IEEE Trans Antennas Propag 54(8):2326–2336MathSciNetCrossRefGoogle Scholar
  4. Albani M et al (2009) Asymptotic approximation of mutual admittance involved in MoM analysis of RLSA antennas. IEEE Trans Antennas Propag 57(4):1057–1063CrossRefGoogle Scholar
  5. Albani M et al (2011) Rigorous MoM analysis of finite conductivity effects in RLSA antennas. IEEE Trans Antennas Propag 59(11):4023–4032MathSciNetCrossRefGoogle Scholar
  6. Ando M et al (1985) A radial line slot antenna for 12 GHz satellite TV reception. IEEE Trans Antennas Propag 33(12):1347–1353CrossRefGoogle Scholar
  7. Ando M et al (1986) Characteristics of a radial line slot antenna for 12 GHz band satellite TV reception. IEEE Trans Antennas Propag 34(10):1269–1272CrossRefGoogle Scholar
  8. Ando M et al (1988) A linearly polarized radial line slot antenna. IEEE Trans Antennas Propag 36(12):1675–1680CrossRefGoogle Scholar
  9. Arai H, Goto N (1995) Novel feed circuit for radial-line waveguide. In: Proceedings of the ninth international conference on antennas and propagation, Eindhoven, vol 1, pp 231–234Google Scholar
  10. Bialkowski ME et al (2002) Analysis of a circular patch antenna radiating in a parallel-plate radial guide. IEEE Trans Antennas Propag 50(2):180–187MathSciNetCrossRefGoogle Scholar
  11. Cheng WY et al (2013) Designs and experiments of a novel radial line slot antenna for high-power microwave application. IEEE Trans Antennas Propag 61(10):4940–4946CrossRefGoogle Scholar
  12. Davis PW et al (1997) Experimental investigations into a linearly polarized radial slot antenna for DBS TV in Australia. IEEE Trans Antennas Propag 45(7):1123–1129CrossRefGoogle Scholar
  13. Davis PW et al (1999) Linearly polarized radial-line slot-array antennas with improved return-loss performance. IEEE Antennas Propag Mag 41(1):52–61CrossRefGoogle Scholar
  14. Ettorre M et al (2014) On the near-field shaping and focusing capability of a radial line slot array. IEEE Trans Antennas Propag 62(4):1991–1999CrossRefGoogle Scholar
  15. Gonzalez JMF et al (2011) Lightweight portable planar slot array antenna for satellite communications in X-band. IEEE Antennas Wirel Propag Lett 10:1409–1412CrossRefGoogle Scholar
  16. Herranz JI et al (2010) Optimization of beam-tilted linearly polarized radial-line slot-array antennas. IEEE Antennas Wirel Propag Lett 9:1165–1168CrossRefGoogle Scholar
  17. Hirokawa J, Ando M (2000) Sidelobe suppression in 76 GHz post-wall waveguide-fed parallel plate slot arrays. IEEE Trans Antennas Propag 48(11):1727–1732CrossRefGoogle Scholar
  18. Hirokawa J et al (1990) Analysis of slot coupling in a radial line slot antenna for DBS reception. Microwaves Antennas Propag IEE Proc H 137(5):249–254CrossRefGoogle Scholar
  19. Hirokawa J et al (1992) Waveguide-fed parallel plate slot array antenna. IEEE Trans Antennas Propag 40(2):218–223CrossRefGoogle Scholar
  20. Junfeng X et al (2013) Xianming Qing 270-GHz LTCC-integrated strip-loaded linearly polarized radial line slot array antenna. IEEE Trans Antennas Propag 61(4, Part 1):1794–1801CrossRefGoogle Scholar
  21. Kelly KC, Goebels F (1964) Annular slot monopulse antenna arrays. IEEE Trans Antennas Propag 12(4):391–403CrossRefGoogle Scholar
  22. Kigure Y et al (1998) A radial line slot antenna fed by a ring slot coupled planar circuit. In: Korea Japan joint conference ‘98, Sep, PusanGoogle Scholar
  23. Kim Y et al (2002) 60 GHz band radial line slot array antenna fed by rectangular waveguide. Electron Lett 38(2):59–60CrossRefGoogle Scholar
  24. Mazzinghi A et al (2010) Influence of the finite slot thickness on RLSA antenna design. IEEE Trans Antennas Propag 58(1):215–218CrossRefGoogle Scholar
  25. Nakano H et al (1992) Low-profile helical array antenna fed from a radial waveguide. IEEE Trans Antennas Propag 40:279–284CrossRefGoogle Scholar
  26. Nguyen T et al (2013) An equivalent double layer model for a fast design and analysis of high gain multilayer radial line slot antennas. IEICE Trans Commun 96(11):2891–2900CrossRefGoogle Scholar
  27. Ohmi T (1997) Preface in New era of semiconductor manufacturing I. Ultra Clean Tech 9(Suppl 1):1–5Google Scholar
  28. Pla V et al (2006) Dual linearly polarized single-layer radial-line slot-array antenna. IEEE Antennas Wirel Propag Lett 5(1):120–122CrossRefGoogle Scholar
  29. Ronghong J et al (2001) A feeding circuit with CPW for CA-RLSA. IEEE Trans Antennas Propag 49(12):1862–1867CrossRefGoogle Scholar
  30. Sasazawa H et al (1988) Slot coupling in a radial line slot antenna for 12-GHz band satellite TV reception. IEEE Trans Antennas Propag 36(9):1221–1226CrossRefGoogle Scholar
  31. Sekine K et al (2000) Highly robust ultrathin silicon nitride films grown at low-temperature by microwave-excitation high-density plasma for giga scale integration. IEEE Trans Electron Device 47(7):1370–1374CrossRefGoogle Scholar
  32. Shibata O et al (1993) Radiation properties of microstrip array antennas fed by radial line. Electron Commun Jpn 76(12):93–102, Wiley InterSci, pt. 1CrossRefGoogle Scholar
  33. Subbarao B, Fusco VF (2003) Probe-fed circularly polarised monopulse radial line slot antenna. Electron Lett 39(21):1495–1496CrossRefGoogle Scholar
  34. Sudo K et al (2002) An analysis and a design for excitation of a rotating mode in a radial waveguide by a cross slot-coupled rectangular waveguide. In: IEICE technical report, AP2001-206, Feb (in Japanese), TokyoGoogle Scholar
  35. Sudo K et al (2007) Reduction of azimuthal amplitude ripple in the rotating-mode feed to a radial waveguide by using a crossed dog-bone slot. IEEE Trans Antennas Propag 55(9):2618–2622CrossRefGoogle Scholar
  36. Sumiyoshi H et al (1993) The feed circuit for exciting a rotating electric field in a radial waveguide. In: IEICE spring national conference, B-51, Mar (in Japanese), NagoyaGoogle Scholar
  37. Takada J et al (1988) A beam-tilted linearly polarized radial line slot antenna. In: IEICE spring national conference, B-107, Mar (in Japanese), TokyoGoogle Scholar
  38. Takada J et al (1992) A reflection cancelling slot set in a linearly polarized radial line slot antenna. IEEE Trans Antennas Propag 40(4):433–438CrossRefGoogle Scholar
  39. Takada J et al (1994) Circularly polarised conical beam radial line slot antenna. Electron Lett 30(21):1729–1730CrossRefGoogle Scholar
  40. Takada J et al (1997) Method of moments analysis of a small aperture radial line slot antenna using the rectangular cavity Green’s function. Microwaves Antennas Propag IEE Proc 144(6):498–500CrossRefGoogle Scholar
  41. Takahashi M et al (1991) A slot design for uniform aperture field distribution in single-layered radial line slot antennas. IEEE Trans Antennas Propag 39(7):954–959CrossRefGoogle Scholar
  42. Takahashi M et al (1992) Characteristics of small-aperture, single-layered, radial-line slot antennas. Microwaves Antennas Propag IEE Proc 139(1):79–83CrossRefGoogle Scholar
  43. Takahashi M et al (1993) A planar antenna for ECR plasma system. In: IEICE spring national conference, B-65, Mar (in Japanese), NagoyaGoogle Scholar
  44. Takahashi M et al (1995) Dual circularly polarized radial line slot antennas. IEEE Trans Antennas Propag 43(8):874–876CrossRefGoogle Scholar
  45. Takahashi M et al (1997) Low sidelobes for radial line slot antennas. Electron Commun Jpn 80(7):70–76, Wiley InterSci, pt. 13.0.CO%3B2-9'>CrossRefGoogle Scholar