US2462865A - Center fed antenna - Google Patents

Center fed antenna Download PDF

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Publication number
US2462865A
US2462865A US595514A US59551445A US2462865A US 2462865 A US2462865 A US 2462865A US 595514 A US595514 A US 595514A US 59551445 A US59551445 A US 59551445A US 2462865 A US2462865 A US 2462865A
Authority
US
United States
Prior art keywords
radiators
shield
antenna
quarter wavelength
length
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
US595514A
Other languages
English (en)
Inventor
Himmel Leon
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.)
STC PLC
Federal Telephone and Radio Corp
Original Assignee
Standard Telephone and Cables PLC
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
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to US595514A priority Critical patent/US2462865A/en
Priority to GB15009/46A priority patent/GB630010A/en
Priority to FR951002D priority patent/FR951002A/fr
Priority to ES0181829A priority patent/ES181829A1/es
Application granted granted Critical
Publication of US2462865A publication Critical patent/US2462865A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P5/00—Coupling devices of the waveguide type
    • H01P5/02—Coupling devices of the waveguide type with invariable factor of coupling
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole

Definitions

  • This invention relates to antennas and more particularly to vertical antenna arrangements.
  • I provide two vertically arranged tubular radiators which are fed by a balanced dual transmission line passing through the lower of the two radiators and which is arranged to feed the radiators at their mid or junction point. Disposed within the two radiators are two concentrically arranged shields the outer of which acts as a supporting structure for the antenna.
  • outer shield is conductively connected to the' respective upper and lower radiators adjacent the mid or junction points thereof while the interna-1 or second shield is itself conductively connected to the outer or iirst shield at a point which is a quarter or if desired an odd multiple of a quarter wavelength at midfrequeney away from the nearest conductive contact between the outer shield and the radiators.
  • This distance is a quarter wavelength from the midpoint for a quarter wave antenna and for an antenna longer than a quarter wavelength for each of its two radiators, it is an odd multiple of a quarter Wavelength from the open end between the outer and inner shields.
  • Fig. 1 represents in diagrammatic form of an embodiment of the invention for an antenna having individual radiators substantially one quarter wavelength long at the midpoint frequency;
  • Fig. 2 is a diagrammatic representation of an embodiment of an antenna in accordance with my invention the individual radiators of which may be longer than a quarter wavelength.
  • the antenna structure is composed of radiators l and 2 which arestructurally supported by tubular shields 3 and 4 the former member 3 being shown supported on a' porting member 3.
  • the twoconductors of the transmission line may be made topass through the said insulator 9 to make Contact with conductive portions Hl and I I which provide a connection between the respective radiators and their corresponding shields and which may be in the form of conductive and supporting discs., adjacent the two sides of the insulator 9.
  • the transmission line conductors are further supplied with an additional or internal tubular shield I2 which is disposed within the outer shield .ii-Ll and.
  • each lata point which is located overalllengths ofthe individual radiators may be adjusted to a total length of. a quarter wave.- length of the maximum wavelength encountered inthe frequency band to be covered.
  • the inner and outer radiator portions have been furnished with insulating members.
  • members may be ⁇ provided las a support of the inner shield at 25a
  • the member 25 may be omitted if desiredand theinner shield terminatedl at the con- ⁇ ductivemember I5.
  • the upper shield. orsupport ⁇ thasE been provided with a closure orcap member 26.
  • the antenna structure of Fig. 2 is similar inall respects to that shown. in F'ig. 1 except that thev length of theupper and lower ⁇ radiating portions is a-multiple ofa quarter wavelength. where limitation in physical length is not critical.
  • the overall length of each radiator maybev expressed by theV general term:
  • the antenna as described hereinabove provides an outer quarter wave trap. and an inner quarter wave trap which are effective in preventing the appearance of radio frequency currents on the supporting tube and on the inner shield.l
  • the or if desired Aeiiect is such that the radiators are tuned to approximately a quarter wavelength with respect to the outer shield whereby a high impedance is seen at a point looking in at the open end of the radiators and similarly, a conductive contact between the inner shield and the outer shield is provided at a point substantially a quarter wavelength from the open end of the two shields which is at the antenna midpoint. A high impedance is thus seen between said inner and outer shield.
  • the antenna when looking in at the open end -or feed point. Over a given range oi frequencies the impedance between inner and outer shields varies from inductive to capacitive. However, both input lines have this impedancein shunt with theantenna to ground and therefore remain balanced. By givingv the coaxial section -a high surge impedance by means of high ratios of diameters the antenna may be made to cover a broad band. While the quarter wavelength radiators are the preferred form, it will be seen fromA the above that the principle outlined hereinabove has application in connection with radiators having a length which isa multiple of quarter wavelength.
  • a vertical dipole antenna comprising a pair of tubular radiators having outer ends and innerY substantially adjacent ends; a balanccddouble transmission line comprising two ⁇ conductors extending in part thru one of said radiators, said conductors being in conductive Contact one. with each of said radiators at said inner ends; an outer shield disposed coaxially within said radiators having a conductive connection therewith adjacent said inner ends, and an inner shield coaXially disposed within said outer shield having a conductive connection there-with a given.
  • connection comprises a structural portion -for each radiator and said outer shield constitutes a supportingstructure for said portions and said radiators.
  • An antenna according to claim 1 further including insulating ⁇ means disposed intermediate said inner ends.
  • said pair of radiators comprises a pair of tubular members having each an axial length substantially equal to one quarter wavelength at a representative midfrequency.
  • said pair of radiators comprises a pair of tubular members having an axial length substantially equal to one quarter wavelength at the highestl frequency in a given operation band further including a tubular sleeve slidably secured in coaxial relation to each of said radiators, whereby the effective length thereof may be adjusted in accordance with the operative wavelength.
  • a vertical dipole antenna comprising a pair of tubular radiators having outer ends and inner substantially adjacent ends, a balanced double transmission line comprising two conductors extending in part thru one of said radiators, said conductors being connected one to each of said radiators at said inner ends; outer shield means disposed coaxially within said radiators, inner shield means coaxially disposed within said outer shield, rst means forming a trap for a wave of a given length between said radiators and said outer shield, and second means forming a trap for a wave of a given length between said outer shield and said inner shield.
  • said rst and second means forming traps comprise conductive connections between said radiators and said outer shield and between said outer and said inner shield, and high effective impedances therebetween at the ends thereof which are not connected.
  • a vertical dipole antenna comprising a pair of tubular radiators having outer ends and inner substantially adjacent ends; a balanced double transmission line comprising two conductors extending in part thru one of said radiators, said conductors being connected one to each of said radiators at said inner ends; outer shield means disposed coaxially within said radiators conductively connected thereto respectively adjacent said inner ends, and inner shield means coaxially disposed within said outer shield means conductively connected thereto a distance from said inner ends which is equal to an odd multiple of a quarter wavelength at a representative midfrequency.

Landscapes

  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Details Of Aerials (AREA)
US595514A 1945-05-24 1945-05-24 Center fed antenna Expired - Lifetime US2462865A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US595514A US2462865A (en) 1945-05-24 1945-05-24 Center fed antenna
GB15009/46A GB630010A (en) 1945-05-24 1946-05-17 Centre fed antenna
FR951002D FR951002A (fr) 1945-05-24 1947-08-05 Antennes alimentées en leur milieu
ES0181829A ES181829A1 (es) 1945-05-24 1948-01-24 SISTEMA DE ANTENA DE ALIMENTACIoN CENTRAL

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US595514A US2462865A (en) 1945-05-24 1945-05-24 Center fed antenna

Publications (1)

Publication Number Publication Date
US2462865A true US2462865A (en) 1949-03-01

Family

ID=24383534

Family Applications (1)

Application Number Title Priority Date Filing Date
US595514A Expired - Lifetime US2462865A (en) 1945-05-24 1945-05-24 Center fed antenna

Country Status (4)

Country Link
US (1) US2462865A (fr)
ES (1) ES181829A1 (fr)
FR (1) FR951002A (fr)
GB (1) GB630010A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2700112A (en) * 1949-03-07 1955-01-18 Alford Andrew Antenna structure
US2726388A (en) * 1951-07-26 1955-12-06 Itt Antenna system combinations and arrays
US2973515A (en) * 1957-04-05 1961-02-28 Alford Andrew Omnidirectional vertically polarized antenna

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2111636A (en) * 1936-01-20 1938-03-22 Rca Corp Antenna
US2113136A (en) * 1936-02-03 1938-04-05 Rca Corp Antenna
US2184729A (en) * 1937-04-15 1939-12-26 Bell Telephone Labor Inc Antenna system
US2229733A (en) * 1938-05-13 1941-01-28 Internat Telephone Dev Co Inc Antenna structure
US2267951A (en) * 1938-11-24 1941-12-30 Telefunken Gmbh Antenna
US2323641A (en) * 1940-01-26 1943-07-06 Bell Telephone Labor Inc Antenna system
US2385783A (en) * 1942-09-30 1945-10-02 Standard Telephones Cables Ltd Antenna construction

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2111636A (en) * 1936-01-20 1938-03-22 Rca Corp Antenna
US2113136A (en) * 1936-02-03 1938-04-05 Rca Corp Antenna
US2184729A (en) * 1937-04-15 1939-12-26 Bell Telephone Labor Inc Antenna system
US2229733A (en) * 1938-05-13 1941-01-28 Internat Telephone Dev Co Inc Antenna structure
US2267951A (en) * 1938-11-24 1941-12-30 Telefunken Gmbh Antenna
US2323641A (en) * 1940-01-26 1943-07-06 Bell Telephone Labor Inc Antenna system
US2385783A (en) * 1942-09-30 1945-10-02 Standard Telephones Cables Ltd Antenna construction

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2700112A (en) * 1949-03-07 1955-01-18 Alford Andrew Antenna structure
US2726388A (en) * 1951-07-26 1955-12-06 Itt Antenna system combinations and arrays
US2973515A (en) * 1957-04-05 1961-02-28 Alford Andrew Omnidirectional vertically polarized antenna

Also Published As

Publication number Publication date
GB630010A (en) 1949-10-04
ES181829A1 (es) 1948-03-01
FR951002A (fr) 1949-10-13

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