US2559693A - Antenna for broad frequency band operation - Google Patents

Antenna for broad frequency band operation Download PDF

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Publication number
US2559693A
US2559693A US636021A US63602145A US2559693A US 2559693 A US2559693 A US 2559693A US 636021 A US636021 A US 636021A US 63602145 A US63602145 A US 63602145A US 2559693 A US2559693 A US 2559693A
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United States
Prior art keywords
slot
antenna
plates
edges
frequency band
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
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US636021A
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English (en)
Inventor
Willoughby Eric Osborne
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.)
International Standard Electric Corp
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International Standard Electric Corp
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Filing date
Publication date
Priority claimed from GB9845A external-priority patent/GB590413A/en
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
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Publication of US2559693A publication Critical patent/US2559693A/en
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Expired - Lifetime legal-status Critical Current

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    • 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
    • H01Q13/20—Non-resonant leaky-waveguide or transmission-line antennas; Equivalent structures causing radiation along the transmission path of a guided wave
    • 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
    • H01Q13/08—Radiating ends of two-conductor microwave transmission lines, e.g. of coaxial lines, of microstrip lines
    • H01Q13/085—Slot-line radiating ends
    • 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

  • the present invention relates to antennae for operation over a broad band of frequencies and has for its object to provide an antenna which has directivity over a broad band of operational frequencies for modest dimensions.
  • An antenna according to this invention is of the end fire type and comprises in its broadest aspect two oppositely disposed edges of conduct ing areas with air or other dielectric therebetween;
  • the two oppositely disposed edges may be short circuited at one end or both ends and may hence be formed as a slot in a conducting sheet which may be plain or curved.
  • the edges may be the edges of a groove in a conducting sheet, said groove having depth dimensions substantially one-quarter of the operating wave length.
  • the most efficient antennae of this type from the directivity point of view are terminated at one or both ends in the characteristic impedance of the transmission line formed by the said opposing conductor edges, although such termination results in a loss of power of the order of 3 decibels (db).
  • Fig. 1 is a plan view of one embodiment of the invention
  • Figs. 2A-2F show graphical curves used in the description and obtained practically
  • Figs. 3A, 3B and 3C show graphical curves obtained theoretically
  • Fig. 4 is an end view of another embodiment
  • Fig. 5 shows a modification of the embodiment shown in Fig. 4;
  • Fig. 6 is a diagrammatic perspective view of another embodiment
  • Fig. 7 is a plan view of a modification of the antenna shown in Fig. 1;
  • Fig. 8 is a plan view of a modification of the antenna shown in Fig. 1;
  • Figs. 9-11 are diagrams used in the description of the theory of the invention and Fig. 12 illustrates the electric field distribution in the neighbourhood of the slot.
  • the antenna is formed by thin metal plates I, 2 whose adjacent edges 3, 4 oppositely disposed are separated by a narrow space 5.
  • the slot antenna thus formed is best terminated at each end in the characteristic impedance of the transmission line formed by the edges of the slot, although this results in a loss' of power of the order of 3 decibels (db).
  • a field is built up across the gap 34 which travels along the slot in opposite directions at the same velocity as the oncoming wave front; one portion in the same direction asthe received wave increases in the direction of propagation and gives a summation resultant at the end which is thus used as the receiving end or translating end of the slot while the other portion travelling in the opposite direction along the slot to the received wave is absorbed in the resistance 8 connected across the slot at the other or front end thereof.
  • This resistance B is equal to the characteristic impedance aforementioned.
  • a detector unit 9 connected across the slot.
  • the plates l2 or aerial may be placed over a parallel plate H3 at a distance less than ⁇ /2 from the plate, as shown in the end view diagram, Fig. 4 wherein dimension ll between the plates l2 and I9 is less than M2.
  • the wave front between the plates i2 and i I is suppressed due to the fact that the spacing H is less than the critical spacing for a wave of polarisation parallel to the plates and only the upper surfaces of the plates l-2 are active, a fact that can readily be illustrated experimentally by altering the spacing ll within a range of values below the critical spacing at the operating wave length. It will be noted then that there is no appreciable change in the polar diagram. Second order changes may be expected from modification of the discontinuity at the end of the slot by the presence of the parallel plate 10.
  • the antenna system shown in Fig. l will operate equally well if the edges of the plates I2 parallel to the slot are connected to the earth plate IO as shown in Fig. 5, and thus forms an open ended pipe structure having a longitudinal slot in the wall thereof.
  • Fig. '7 shows a modification of the arrangement shown in Fig. 1 in which the forward end as regards the direction of propagation of the received waves of the slot is flared out so as to increase the impedance to the backward portion of the energy induced in the plates l, 2.
  • This also increases the radiation damping of the front termination when the antenna is to be used for transmitting, the flare, however, should be made but a small portion of the slot length so that the impedance of the flare portion matches the impedance of the slot portion to assist the phasing of the waves which gives the directivity.
  • Provided wide operating band widths are not required, however, it is always possible to obtain good directivity by adjustment of slot length to a value which makes the best use of any reflections in aiding forward directivity, the slot length being determined experimentally.
  • transmission line is coupled to the edges of the slot at the translatin end.
  • the two conductors of the line i 2 are connected directly to the respective edges of the slot as shown in Fig. 1.
  • the transmission line is then connected to the edges of the slot at a distance from the end of the slot equal to one quarter of the operating wavelength as shown in Fig. 8 where the slot is shown closed at the end i 3 and the transmission line is indicated at I2.
  • Case III The purpose of this case is to consider the effect on the radiation pattern when the forward end of the slot is terminated in an impedance ZR, the receiving end being of impedance Z matching the slot as before.
  • the E. M. F, 651 at distance I from the left hand side of theplates is composed of two E. M. F.s, one acting to the left and one to the right.
  • the E. M. F. acting to the left is Z+Z tanh 71 in which v is the propagation constant in the slot and this E. M. F. is applied to Zia-through a length of line Z.
  • the E. M. F. to the right is (Z+Z tanh 71) (Z-l-Z) (1+tanh v1) and this looks into a matching impedance Z through a length of line Z.
  • the current in ZR is given by Z +Z tanh 5 1 51 1 -(Z-l-Z) (1+tanh 7t) 6 Z cosh l-l-Z sinh l i. e. by
  • the curve in Fig. 3A is for the case in which a matching resistance 8 is connected across the front end of the slot.
  • the curve in Fig. 3B is for the case in which the front end of the slot is short circuited and the curve in Fig. 3C is for the case in which the front end of the slot is open.
  • the length of the slot is 95 cms. and the operating wave length is 45.2 cms. It will be observed that the curves obtained practically and shown in Figs. 2AF approximate very near to the curves in Figs. 3A-B obtained theoretically.
  • the curves in Fig. 2 relate to an approximately matched slot line and if the slot is relatively long and the plates wide, the field plot in the vicinity of the slot is as shown in Fig. 12 which indicates the concentration of the field near the slot, and shows that if such a field is formed on an electrostatic basis, the characteristic impedance of the slot for the end fire mode of operation is substantially independent of wavelength for wavelengths small compared with the slot length but large compared to slot width.
  • Two nodal points NN On the field plot indicate the boundaries of the zones associated with the field across the slot.
  • slot aerial is useful for moderate directivity but has a law of decreasing returns for large increases of slot length.
  • Case V A general theory could be evolved very similar to that given hereinbefore for plates inclined at an obtuse angle to form a slot or curved plate sections of a cylinder arranged to form a slot therebetween. Both these arrangements are similar in general principles to that of the plane slot, but have the disadvantage of causing greater distortion to the polarisation of the wave front.
  • the active portion of the plate on either side of the slot 3-4, Fig. 1, is determined from electrostatic considerations as shown by the field plot in Fig. 12, and this enables the capacity per unit length of slot to be obtained, and thereby the effective characteristic impedance of the active portion between the nodal lines NN.
  • an antenna according to this invention may comprise a groove in a conducting sheet providing the groove has a depth substantially equal to an odd number of quarter wave lengths at the operating frequency and said groove may be closed or open at one or both ends so as to short circuit the sides of the groove and as with the slot antennae, the groove may be terminated at one or both ends by its characteristic impedance.
  • An end fire type of antenna system for broad frequency band operation comprising a of conducting sheets arranged with oppositely disposed edges coplanar and spaced to form a slot, an impedance substantially equal to the characteristic impedance of said slot connected across each end of the edges of said sheets formim said slot. a source of high frequency energy, and means for feeding said antenna system with said high frequency energy at given points on the edges of said sheets.
  • An end fire type of antenna system further comprising a conducting sheet mounted on one side of said first mentioned sheets and at a distance therefrom less than half a wave length at the operating frequency.
  • An end fire type of antenna system according to claim 1 comprising a further conducting sheet mounted on one side of the first mentioned sheets and at a distance therefrom greater than one wave length at the operating frequency.
  • An end fire type of antenna system for broad frequency band operation comprising a pair of conducting sheets arranged with oppositely disposed edges coplanar and spaced to form a slot, an impedance substantially equal 1 to the characteristic impedance of said slot connected across one end of the edges of said sheets forming said slot, at source of high frequency energy, and means for feeding said antenna system with said high frequency energy at given points on the edges of said sheets.

Landscapes

  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Waveguide Aerials (AREA)
US636021A 1945-01-01 1945-12-19 Antenna for broad frequency band operation Expired - Lifetime US2559693A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9845A GB590413A (en) 1945-01-01 Antennae for broad frequency band operation

Publications (1)

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US2559693A true US2559693A (en) 1951-07-10

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US636021A Expired - Lifetime US2559693A (en) 1945-01-01 1945-12-19 Antenna for broad frequency band operation

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US (1) US2559693A (enrdf_load_stackoverflow)
BE (1) BE476546A (enrdf_load_stackoverflow)
CH (1) CH278795A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2781512A (en) * 1951-12-05 1957-02-12 Jr Ralph O Robinson Cylindrical notch antenna
US2942263A (en) * 1957-02-25 1960-06-21 Gen Dynamics Corp Antennas
US5519408A (en) * 1991-01-22 1996-05-21 Us Air Force Tapered notch antenna using coplanar waveguide
US20050052329A1 (en) * 2003-09-09 2005-03-10 Sony Corporation Wireless communication apparatus
US12009600B1 (en) 2022-06-08 2024-06-11 First Rf Corporation Broadband antenna structure and associated devices

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR818696A (fr) * 1936-03-07 1937-10-01 Pintsch Julius Kg Dispositif et procédé pour concentrer en faisceau des ondes électromagnétiques ultra-courtes
US2206923A (en) * 1934-09-12 1940-07-09 American Telephone & Telegraph Short wave radio system
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
US2400867A (en) * 1942-06-27 1946-05-21 Rca Corp Antenna
US2402622A (en) * 1940-11-26 1946-06-25 Univ Leland Stanford Junior Radiating electromagnetic wave guide
US2407068A (en) * 1942-09-15 1946-09-03 Gen Electric Wave transmitting system
US2414266A (en) * 1942-06-27 1947-01-14 Rca Corp Antenna
US2433368A (en) * 1942-03-31 1947-12-30 Sperry Gyroscope Co Inc Wave guide construction

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2206923A (en) * 1934-09-12 1940-07-09 American Telephone & Telegraph Short wave radio system
FR818696A (fr) * 1936-03-07 1937-10-01 Pintsch Julius Kg Dispositif et procédé pour concentrer en faisceau des ondes électromagnétiques ultra-courtes
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
US2402622A (en) * 1940-11-26 1946-06-25 Univ Leland Stanford Junior Radiating electromagnetic wave guide
US2433368A (en) * 1942-03-31 1947-12-30 Sperry Gyroscope Co Inc Wave guide construction
US2400867A (en) * 1942-06-27 1946-05-21 Rca Corp Antenna
US2414266A (en) * 1942-06-27 1947-01-14 Rca Corp Antenna
US2407068A (en) * 1942-09-15 1946-09-03 Gen Electric Wave transmitting system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2781512A (en) * 1951-12-05 1957-02-12 Jr Ralph O Robinson Cylindrical notch antenna
US2942263A (en) * 1957-02-25 1960-06-21 Gen Dynamics Corp Antennas
US5519408A (en) * 1991-01-22 1996-05-21 Us Air Force Tapered notch antenna using coplanar waveguide
US20050052329A1 (en) * 2003-09-09 2005-03-10 Sony Corporation Wireless communication apparatus
US7161548B2 (en) * 2003-09-09 2007-01-09 Sony Corporation Wireless communication apparatus
US12009600B1 (en) 2022-06-08 2024-06-11 First Rf Corporation Broadband antenna structure and associated devices

Also Published As

Publication number Publication date
CH278795A (fr) 1951-10-31
BE476546A (enrdf_load_stackoverflow)

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