US2585636A - Receiving antenna - Google Patents

Receiving antenna Download PDF

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Publication number
US2585636A
US2585636A US36860A US3686048A US2585636A US 2585636 A US2585636 A US 2585636A US 36860 A US36860 A US 36860A US 3686048 A US3686048 A US 3686048A US 2585636 A US2585636 A US 2585636A
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United States
Prior art keywords
conductors
antenna
frequency
pairs
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
Application number
US36860A
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English (en)
Inventor
Robert B Dome
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General Electric Co
Original Assignee
General Electric Co
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Filing date
Publication date
Priority to BE489963D priority Critical patent/BE489963A/xx
Application filed by General Electric Co filed Critical General Electric Co
Priority to US36860A priority patent/US2585636A/en
Application granted granted Critical
Publication of US2585636A publication Critical patent/US2585636A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • H01Q9/26—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/28—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using a secondary device in the form of two or more substantially straight conductive elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/30—Arrangements for providing operation on different wavebands
    • H01Q5/307—Individual or coupled radiating elements, each element being fed in an unspecified way
    • H01Q5/342—Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes
    • H01Q5/357—Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes using a single feed point

Definitions

  • My invention relates to antennas and, in particular, to antennas for the reception of high frequency waves occurring over a broad band of frequencies, such as the television frequency bands. It is an object of my invention to provide a new and improved high frequency receiving antenna which affords improved operating characteristics over a plurality of high frequency bands displaced in frequency by a substantial frequency difference.
  • Television signals are broadcast at present in two high frequency bands, one of which covers the range from 54 to 88 megacycles and the other of which is displaced from the first band by a substantial frequency difference and covers the range from 174 to 216 megacycles. It is desirable to provide television receivers which are adapted to receive signals occurring in either of these bands.
  • the strength of signals which are obtained on these bands is controlled in the first instance by the antenna which intercepts the high frequency signals and translates them to the television receiver. It has been customary to use for this purpose a straight folded half-wave dipole, each arm of the dipolemeasured from the center to either end having a length equal to onequarter wavelength at a frequency of approximately 65 megacycles. It has been found that such an antenna provides satisfactory reception of all signals occurring in the lower frequency band of the two bands in which the television signals occur. However, in the higher frequency band, i. e., in the band from 174 to 216 megacycles,
  • this type of antenna operates as a three-halves voltage at its output terminals which is only approximately one-third that-which is provided by an antenna of this type having a maximum possible eificiency. Accordingly, it is an object of my invention to provide a new and improved television receiving antenna which provides a large I 'voltage'at its output terminals for received signals varying over a wide range of frequency.
  • a folded dipole type of antenna is formed as'a'V type antenna having a vertex angle such that a maximumvoltage is provided at its output terminals.
  • my invention provides a folded .dipole formed as a V antenna which is providedwith a driven reflector also of the V type.
  • FIG. 1 is a schematic perspective view of the antenna of my invention
  • Fig. 2 is a schematic perspective view of a modification of the antenna of Fig. 1
  • Fig. 3 is a schematic perspective view of another embodiment of my invention including a driven type reflector
  • Figs. 4-6 are diagrams illustrating certain characteristics of my antenna structure.
  • a folded dipole type of antenna comprising four oplanar conductors
  • Conductors 2, 3 are connected at their adjacent ends, while conductors l and 4 are provided at their adjacent ends with output terminals 5, 6 to which are connected the conductors I, 8 of a transmission line.
  • the conductors l-4 are illustrated as being arranged in a horizontal plane parallel with a ground plane illustrated as the plane 9.
  • the conductors may be supported by any conventional type of supporting means, such as a mast (not shown).
  • the pairs of conductors 2 and 3, 4 are arranged, respectively, at an angle to each other to form a V type of antenna, conductors 2 and 3 being joined at the vertex of the V and the output terminals 5, 5 being provided at the vertex of the angle formed by conductors 3, 4.
  • the pairs of conductors l, 2 and 3, 4 are spaced apart in the plane by a relatively small distance.
  • the length of each of the conductors l-4 is made approximately equal to a quarter wavelength of a high frequency wave having a frequency of 65 megacycles.
  • the space phases are such that there is no complete cancellation of one of the two in-phase portions of the current wave by the out-of-phase portion of the current wave.
  • the relation of the relative responses i. e., the voltage at the output terminal with the vertex angle of the V, may best be shown by the following table:
  • a folded dipole type of antenna in which the arms of the dipole are arranged to form a V type of antenna and also in which the conductors which form the respective arms are arranged in vertical
  • the conductors In, H which form one arm of the V an- 'tenna are arranged in a first vertical plane
  • conductors l2, 13 which form the other arm of the V antenna are arranged in a second vertical plane which is displaced from the first vertical plane by the angle 0.
  • the conductors 10, II and [2, I3, respectively, are conductively connected at their outer extremities.
  • Conductors II and I2 are connected at their adjacent extremities, while conductors l0, [3 are provided with output terminals l4, H3 at their adjacent terminals.
  • the pairs of conductors I0, J3 and H, l2 are arranged in parallel horizontal planes which, preferably, are parallel with the ground plane 9.
  • the conventional type of output transmission lines 1, 8 may be attached to the output terminals l4, I5. I have found that the construction illustrated in Fig. 2 gives added rigidity in a vertical plane to aid in preventing sagging of the respective conductors.
  • This structure comprises a folded dipole antenna of the V type, the component conductors of which may be arranged in the configurations of either 4 Fig. l or Fig. 2 and which are illustrated as conductors l4 arranged similarly to those illustrated in Fig. l.
  • Arranged parallel with the respective arms of the V antenna are the arms I6. I! of a composite reflector structure.
  • Each of the arms I6, I1 comprises a plurality of parallel conductors, the exact number of which is arranged to give a desired output impedance value at the terminals "3, [9.
  • All but one of the component conductors of the arms l6, I! are continuous between their outer extremities 20, 2
  • the one of the component conductors which is not continuous is open at its center point to provide the terminals l8, l9.
  • the component conductors are conductively connected at the outer extremities '20, 2
  • the conductors [-4 and the component conductors of the arms l6, I! each have a length equal to a quarter wavelength at one of the frequencies within the-lower band of television signal frequency, for example 65 megacycles.
  • the distance, therefore, between the extremities 20, 21 through one of the continuous conductors of the arm I6, l! is then equal to a half wavelength at this frequency.
  • the spacing between the V antenna and the driven reflecting element is made equal to a quarter wavelength at this same frequency.
  • the output terminals 5, 6 of the folded V doublet' are connected to the terminals l8, IQ of the reflector by a quarter wavelength of the transmission line comprising conductors 22, 23.
  • the output voltage of the antenna is obtained by mean of a transmission line 1, 8 connected to terminals !8, [9.
  • an antenna of the type illustrated, it is customary to connect the output terminals of the antenna to a transmission line which has a characteristic impedance of 300 ohms. Accordingly, the antennas of Figs. 1 and 2 are both constructed to have an impedance at their output terminals of this value.
  • the antenna structure l4 has a radiation resistance of approximately 408 ohms. Consequently, I have found that, when the arms [6, l1 comprise five conductors, a driven reflector may be obtained which has a resistance of approximately 1000 ohms. A parallel combination of this resistance with the resistance of the antenna elements gives an effective resistance of 300 ohms at the terminals I8, I 9 for matching with the transmission line 1, 8.
  • An important advantage of my improved construction is that it provides a receiving antenna particularly useful for the reception of television signals which has a' broad band characteristic and which provides improved reception in both bands of frequencies set aside for television signals.
  • the antenna s.ructures are relatively simple in nature and easily constructed.
  • the structures of Figs. 1 and 2 provide bidirectivity in the lower frequency band and substantially unidirectivity in the upper frequency band, whereas the structure of Fig. 3 has a unidirectional characteristic frequency in both bands which makes it particularly suitable for receiving signals coming from a particular direction on either hand.
  • Diagrams illustrating the characteristic of the antennas of Figs. 1 and 2 are shown in Figs. 4-6.
  • Fig. 4 shows the reception characteristic of these antennas at the low television frequencies, that is, at about 50 megacycles; Fig.
  • Fig. 5 illustrates the characteristic of these antennas at an intermediate frequency of about 90 megacycles
  • Fig. 6 illustrates the characteristic of the antennas at the highest band television frequencies of approximately 206 megacycles.
  • Fig. 4 illustrates that structures of the antennas of Figs. 1 and 2 are bidirectional at the lower television frequencies. That reception from one direction is reduced somewhat at a slightly higher frequency is illustrated by the characteristic shown in Fig. 5.
  • the characteristic shown in Fig. 6 indicates the relative unidirectivity of the structure. It is apparent that the antennas of Figs. 1 and 2 require no reflector in this high frequency band to provide a good unidirectivity characteristic.
  • An antenna for operation over a relatively low frequency band and a relatively high frequency band, said high frequency band being approximately three times the frequency of said low frequency band comprising two parallel pairs of angularly disposed closely spaced conductors, said conductors being connected together at their outer extremities, one of the conductors of each of said pairs being conductively connected at their adjacent ends, a reflector comprising two groups of parallel conductors, the conductors of each of said groups being parallel respectively with conductors of one of said pairs of conductors, one conductor of each of said groups having the inner end thereof connected to the adjacent end of the corresponding other conductor of each of said pairs of conductors, corresponding ones of the remaining conductors of said groups being conductively connected at their adjacent ends, all of the conductors of said groups being connected together at their outer ends, the spacing between each of said groups of conductors and a corresponding one of said pairs of conductors being equal to substantially a quarter wavelength at a particular frequency within said low frequency band, the conductors of said groups'and of

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  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Details Of Aerials (AREA)
  • Aerials With Secondary Devices (AREA)
US36860A 1948-07-03 1948-07-03 Receiving antenna Expired - Lifetime US2585636A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
BE489963D BE489963A (fr) 1948-07-03
US36860A US2585636A (en) 1948-07-03 1948-07-03 Receiving antenna

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US36860A US2585636A (en) 1948-07-03 1948-07-03 Receiving antenna

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US2585636A true US2585636A (en) 1952-02-12

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2761140A (en) * 1952-04-23 1956-08-28 George B Ashton Antenna
US2887682A (en) * 1954-06-18 1959-05-19 Emi Ltd Aerials

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1934182A (en) * 1928-02-02 1933-11-07 Rca Corp Antenna
US2039295A (en) * 1930-08-09 1936-05-05 Rca Corp Antenna heating
US2212625A (en) * 1939-02-23 1940-08-27 Gen Electric Television antenna
US2243677A (en) * 1939-05-13 1941-05-27 Rca Corp Wide band antenna
US2258406A (en) * 1938-04-16 1941-10-07 Rca Corp Wide band antenna
US2258407A (en) * 1938-07-28 1941-10-07 Rca Corp Wide band antenna
US2352977A (en) * 1942-09-18 1944-07-04 Gen Electric Self-compensating video antenna
US2452073A (en) * 1944-11-17 1948-10-26 Schivley George William Folded dipole

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1934182A (en) * 1928-02-02 1933-11-07 Rca Corp Antenna
US2039295A (en) * 1930-08-09 1936-05-05 Rca Corp Antenna heating
US2258406A (en) * 1938-04-16 1941-10-07 Rca Corp Wide band antenna
US2258407A (en) * 1938-07-28 1941-10-07 Rca Corp Wide band antenna
US2212625A (en) * 1939-02-23 1940-08-27 Gen Electric Television antenna
US2243677A (en) * 1939-05-13 1941-05-27 Rca Corp Wide band antenna
US2352977A (en) * 1942-09-18 1944-07-04 Gen Electric Self-compensating video antenna
US2452073A (en) * 1944-11-17 1948-10-26 Schivley George William Folded dipole

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2761140A (en) * 1952-04-23 1956-08-28 George B Ashton Antenna
US2887682A (en) * 1954-06-18 1959-05-19 Emi Ltd Aerials

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Publication number Publication date
BE489963A (fr) 1900-01-01

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