US2625654A - Slotted cylindrical antenna - Google Patents

Slotted cylindrical antenna Download PDF

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Publication number
US2625654A
US2625654A US640690A US64069046A US2625654A US 2625654 A US2625654 A US 2625654A US 640690 A US640690 A US 640690A US 64069046 A US64069046 A US 64069046A US 2625654 A US2625654 A US 2625654A
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US
United States
Prior art keywords
cylinder
antenna
frequency
slot
along
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US640690A
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English (en)
Inventor
Alford Andrew
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to NL66735D priority Critical patent/NL66735C/xx
Priority to BE472929D priority patent/BE472929A/xx
Priority to NL129712D priority patent/NL129712B/xx
Priority to US640690A priority patent/US2625654A/en
Application filed by Individual filed Critical Individual
Priority to CH259968D priority patent/CH259968A/de
Priority to FR940993D priority patent/FR940993A/fr
Priority to GB974/47A priority patent/GB637729A/en
Priority to ES179628A priority patent/ES179628A1/es
Application granted granted Critical
Publication of US2625654A publication Critical patent/US2625654A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
    • H01Q13/10—Resonant slot antennas
    • H01Q13/12—Longitudinally slotted cylinder antennas; Equivalent structures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
    • H01Q13/10—Resonant slot antennas

Definitions

  • This invention relates to antennas for ultrahigh frequencies, and more particularly'to antennas for radiating horizontally polarized waves at ultrahigh frequencies.
  • My invention makes use of a length of a waveguide which is provided with a longitudinal slot through which coupling is obtained between cur.-
  • the antenna radiates nearly equal energy in different directions of the compass.
  • the antenna depends on metal parts ,for its mechanical strength and does not require the" use of insulating materials at points where there is substantial mechanical stress.
  • Figs. 1, 1a and 1b are explanatory of the nature of the invention, Fig. 1a being a perspective view of a simple embodiment of the invention;
  • Figs. 2 and 2a are transverse cross sections of a simple embodiment of the invention illustrating the approximate distribution and electric field at a distance from the antenna when plotted in polar coordinates, Fig. 2 illustrating a cylinder whose'diameter is more than .15 of the operating wave length and Fig. one whose diameter is .138 of the operating wave length;
  • Figs. 3 and 3a illustrate, respectively, the distribution of voltage along the slotted part of the antenna and the distribution of the radiant field in a plane drawn through the longitudinal axis of the antenna;
  • Fig. 4 is a side elevationof a practical embodiment of my antenna
  • FIG. 7 illustrates the voltage distribution characteristicsunder various frequency conditions.
  • I represents a two-wire transmission line which is shunted by a number of loops of wire, such as 2, 3 and d.
  • 5 is a source of ultrahigh frequency power which transmits an electromagnetic wave that propagates towards short-circuited terminal 6 of transmission line I. If the loops of wire 2, 3, 4, are sufficiently small in comparison with the wave length of the ultrahigh frequency source 5 they will have inductive input impedances as measured at terminals like I.
  • the dashed curve 8 in Fig. 1 indicates the voltagedistribution along transmission line I when a large number of loops 2, 3 and 4 are connected in shunt with it, while the dashed line 9 indicates the distribution of voltage which would be obtained along the same transmission line I if the loops were removed.
  • the loops 2, 3 and 4 are, in accordance with the present invention, replaced by a continuous sheet of metal It as shown in Fig. 1a In this figure, the edges] and I2 of the continuous sheet In formed into a longitudinally slotted cylinder perform the same function as transmission line I in Fig.1.
  • Short-circuited end I 3 corresponds to the short-circuited end
  • 6, and generator I 4 corresponds to generator 5 in Fig. 1.
  • the effect of the shunted inductance of the metal sheet Ill is to increase the phase velocity of the wave. propagating along transmission line ll, [2 so that the distribution of voltage is substantially as indicated by dotted line IS.
  • the distance of the point such as [6 (which is the point of voltage maximum) from the shortcircuited end I3 is accordingly greater than the space quarter-wave length of the output of ultrahigh frequency generator l4.
  • the exact distance between point I6 and short-circuited end l3 depends on the inductanceof the metal sheet. per unit length of transmission line H, I2.
  • the transmission line degenerates into one which is in a general way equivalent to the transmission line shown in Figblb.
  • Such antenna is particularly suitable for broadcasting ultrahigh frequency signals.
  • the effect of such a metal rod or tube is to decrease the shunt inductance per unit length and is, in substance, similar to decreasing the diameter of the cylinder. Since a rod or tube of .02) in diameter has a n0- ticeable effect when inserted into the cylinder the details of the transmission line which is used to supply power to the antenna, in order to avoid the inconvenience of placing the generator itself at M as shown in Figs. 1a and 3, have some effect on the exact dimensions which are chosen so as to get the most eihcient voltage distribution along edges H, 12.
  • Fig. 4 One convenient arrangement of the transmission line is shown in Fig. 4 in which concentric line 21 is brought in through the metal bottom 28 of the cylinder a short distance, of the order of .02 wave length, from edge H of the longitudinal gap up to the end of the cylinder where the inner conductor 29 of the concentric line 21 is connected to edge 12 of the cylinder.
  • This arrangement provides means for applying the generator voltage to the open end of the transmission line H, 2.
  • the opposite end is short-circulted by means of plate 28 which is conductively connected to cylinder l0. Since there is substantially no voltage across the short circuited end of transmission line ll 12, the outer conductor of line 21 is not energized and, therefore, does not act as a radiator and does not disturb the radiation patternof the antenna.
  • the transmission line 21 may be mounted also 6 lowest frequency and curve 51 is obtained at the highest frequency.
  • the transmission line 21 is of the cylinder is of the distance between the brought into contact with edge 36, and the inner short-circuited end and the minimum. conductor 29 of said transmission line is 0011-
  • the voltage distribution is Substantially p n i l, as is The effect of increased thickness of edges is Shown y 9 in i B a y 45 i AS similar to the effect of decrease in the gap width.
  • the frequency is increased, the voltage distribu- Table II compares cylinders having elliptical tion changes progressively, as shown in Fig. '7 by cross sections with an antenna having a circular curves 55, 55 and 51. Curve 45 is obtained at the 0 cross section.
  • Antenna in Fig. 6 has a rectangular cross section.
  • 4l,'42i are the edges of the gap.
  • Metal sheet 43 is the short-circuiting' bottom and 21 is the concentric transmission line used to energize the transmitter.
  • The-emcie'nt voltage distributionl s one in which voltage-minimum is not less than .3 o'f the maximum and preferably not less than .5 of the maximum.
  • An antenna for radiating horizontally polarized high frequency radio waves of a given band comprising a conducting cylinder having a longitudinal slot and having ashort circuit across the slot at one end of the cylinder and means for feeding the cylinderat its other end across the slot, said cylinder having an efiective cross sectional area between .OI'IBA and .0112).
  • A is the free space wave length corresponding to a frequency of the given band, said cylinder having a length equivalent to substantially .9 of the half standing wave lengthestablished along said cylinder by said frequency of the given band.
  • An antenna for radiating horizontally polarized high frequency radio wavesof a given band comprising a conducting cylinder having a longitudinal slot, means closing the cylinder at one end having conductive means connected across space wavelengths'the"voltagedistribution would be represented by a substantially smooth expothe slot, a concentric cable extending through the closed end of the cylinder to the opposite end having one conductor connected to one side of the slot and the other conductor to the other side of the slot, said cylinder having an effective cross sectional area between .0178). and .0112k where k is the free space wave length corresponding to a frequency of the given band, said cylinder having a length equivalent to substantially .9 of the half standing wave length established along said cylinder by said frequency of the given band.
  • An antenna for radiating horizontally polarized high frequency radio waves of -a given band comprising a conducting cylinder having a longitudinal slot, means closing the cylinder at one end only by conductive means connected across the slot, a concentric cable extending through the closed end of the cylinder to th -Iopposite end having one conductor connected to one side of the slot and the other conductor to the other side of the slot at the other end, said cylinder having an effective cross sectional "area between .0178A and .0112A where A is the free space wave length corresponding to a frequency of the given band, said cylinder having a length not substantially greater than 1.05A.
  • An antenna for radiating horizontally polarized high frequency radio waves of a given band comprising a conducting cylinder having a longitudinal slot, means closing the cylinder at one end having conductive means connected across the slot, a concentric cable extending ;through the closed end of the cylinder to the opposite end having one conductor connected to one side of the slot and the other conductor to the other side of the slot, said cylinder having an effective cross sectional area between .0178)?
  • An antenna for radiating horizontally polarized high frequency radio Waves of a given band comprising a conducting cylinder having a longitudinal slot and having a short circuit across the slot at one end of the cylinder and means for feeding the cylinder at its other end across the slot, said cylinder having an efiective diameter between .15A and .12A where A is the free space wave length corresponding to a frequency of the given band, said cylinder having a length equivalent to substantially .9 of the half standing wave length established along said cylinder by said frequency of the given band, said longitudinal slot having a width substantially one sixth of the diameter of the cylinder or less.

Landscapes

  • Waveguide Aerials (AREA)
US640690A 1946-01-12 1946-01-12 Slotted cylindrical antenna Expired - Lifetime US2625654A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
NL66735D NL66735C (xx) 1946-01-12
BE472929D BE472929A (xx) 1946-01-12
NL129712D NL129712B (xx) 1946-01-12
US640690A US2625654A (en) 1946-01-12 1946-01-12 Slotted cylindrical antenna
CH259968D CH259968A (de) 1946-01-12 1946-12-30 Antenne, die elektromagnetische Wellen hoher Frequenz aussendet oder empfängt.
FR940993D FR940993A (fr) 1946-01-12 1947-01-08 Antennes particulièrement destinées aux très hautes fréquences
GB974/47A GB637729A (en) 1946-01-12 1947-01-10 Antenna
ES179628A ES179628A1 (es) 1946-01-12 1947-09-08 Mejoras en antenas

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US640690A US2625654A (en) 1946-01-12 1946-01-12 Slotted cylindrical antenna

Publications (1)

Publication Number Publication Date
US2625654A true US2625654A (en) 1953-01-13

Family

ID=24569312

Family Applications (1)

Application Number Title Priority Date Filing Date
US640690A Expired - Lifetime US2625654A (en) 1946-01-12 1946-01-12 Slotted cylindrical antenna

Country Status (7)

Country Link
US (1) US2625654A (xx)
BE (1) BE472929A (xx)
CH (1) CH259968A (xx)
ES (1) ES179628A1 (xx)
FR (1) FR940993A (xx)
GB (1) GB637729A (xx)
NL (2) NL129712B (xx)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5946610A (en) * 1994-10-04 1999-08-31 Seiko Epson Corporation Portable radio apparatus having a slot antenna
US20100090924A1 (en) * 2008-10-10 2010-04-15 Lhc2 Inc Spiraling Surface Antenna
US20100188308A1 (en) * 2009-01-23 2010-07-29 Lhc2 Inc Compact Circularly Polarized Omni-Directional Antenna
US7948440B1 (en) 2006-09-30 2011-05-24 LHC2 Inc. Horizontally-polarized omni-directional antenna

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2196796A (en) * 1986-10-27 1988-05-05 Jaybeam Limited Antennas and antenna arrays

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2234293A (en) * 1939-09-19 1941-03-11 Rca Corp Antenna system
US2238770A (en) * 1938-03-07 1941-04-15 Emi Ltd High frequency electrical conductor or radiator
US2321454A (en) * 1941-11-22 1943-06-08 Rca Corp Multiple section antenna
US2400867A (en) * 1942-06-27 1946-05-21 Rca Corp Antenna
US2414266A (en) * 1942-06-27 1947-01-14 Rca Corp Antenna
US2415094A (en) * 1938-01-17 1947-02-04 Board Radio measurement of distances and velocities
US2513007A (en) * 1945-05-11 1950-06-27 Rca Corp Broadcast antenna

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2415094A (en) * 1938-01-17 1947-02-04 Board Radio measurement of distances and velocities
US2238770A (en) * 1938-03-07 1941-04-15 Emi Ltd High frequency electrical conductor or radiator
US2234293A (en) * 1939-09-19 1941-03-11 Rca Corp Antenna system
US2321454A (en) * 1941-11-22 1943-06-08 Rca Corp Multiple section antenna
US2400867A (en) * 1942-06-27 1946-05-21 Rca Corp Antenna
US2414266A (en) * 1942-06-27 1947-01-14 Rca Corp Antenna
US2513007A (en) * 1945-05-11 1950-06-27 Rca Corp Broadcast antenna

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5946610A (en) * 1994-10-04 1999-08-31 Seiko Epson Corporation Portable radio apparatus having a slot antenna
US7948440B1 (en) 2006-09-30 2011-05-24 LHC2 Inc. Horizontally-polarized omni-directional antenna
US20100090924A1 (en) * 2008-10-10 2010-04-15 Lhc2 Inc Spiraling Surface Antenna
US8570239B2 (en) 2008-10-10 2013-10-29 LHC2 Inc. Spiraling surface antenna
US20100188308A1 (en) * 2009-01-23 2010-07-29 Lhc2 Inc Compact Circularly Polarized Omni-Directional Antenna
US8203500B2 (en) 2009-01-23 2012-06-19 Lhc2 Inc Compact circularly polarized omni-directional antenna

Also Published As

Publication number Publication date
GB637729A (en) 1950-05-24
ES179628A1 (es) 1947-10-16
NL129712B (xx)
BE472929A (xx)
NL66735C (xx)
FR940993A (fr) 1948-12-29
CH259968A (de) 1949-02-15

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