US2258953A - Antenna system - Google Patents

Antenna system Download PDF

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Publication number
US2258953A
US2258953A US286680A US28668039A US2258953A US 2258953 A US2258953 A US 2258953A US 286680 A US286680 A US 286680A US 28668039 A US28668039 A US 28668039A US 2258953 A US2258953 A US 2258953A
Authority
US
United States
Prior art keywords
conductor
line
antenna
impedance
reactance
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
US286680A
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English (en)
Inventor
William H C Higgins
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.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
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 BE472233D priority Critical patent/BE472233A/xx
Priority to NL61318D priority patent/NL61318C/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US286680A priority patent/US2258953A/en
Priority to GB9995/40A priority patent/GB541870A/en
Priority to FR866476D priority patent/FR866476A/fr
Application granted granted Critical
Publication of US2258953A publication Critical patent/US2258953A/en
Priority to CH269953D priority patent/CH269953A/fr
Priority to ES176296A priority patent/ES176296A1/es
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
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/27—Adaptation for use in or on movable bodies
    • H01Q1/28—Adaptation for use in or on aircraft, missiles, satellites, or balloons
    • H01Q1/282—Modifying the aerodynamic properties of the vehicle, e.g. projecting type aerials

Definitions

  • FIG. 2C REFLECTING) sumac:
  • This invention relates to antenna systems and particularly to means and methods formatching the input impedance of an antenna to the impedance of the associated line at a large number of operating frequencies.
  • the input impedance of an antenna is usually matched in the case of a single frequency system by means of a coil type or distributed type transformer to the characteristic impedance of the associated transmission line, for the purpose of preventing reflection losses and the formation of standing waves on the line.
  • the antenna input impedance which ordinarily varies greatly with frequency, may in effect be matched to the line by connecting a separate impedance transformer for each operating frequency across the line, as disclosed in the copending application of P. H. Smith, Serial No.
  • the system comprises a tubular conductor, a quarter wave-length long at the mean frequency in the operating band and closed at one end by means of a plug or cap, and a solid pr tubular conductor approximately a half wavelength long having a smaller diameter than the tubular conductor and positioned coaxially therein.
  • the smaller conductor is supported in part by the plug or cap and a supporting insulator of relatively small size and capacity is in cluded between the open end of the tubular conductor and the approximate center portion of the half wave-length conductor.
  • the tubular conductor and the half wave-length conductor are connected, respectively, to the inner and outer conductors of a coaxial line from the transmitter or receiver, the outer surface of the tubular conductor constituting what may be termed the counter-poise radiator .of a doublet antenna system and the quarter wave-length exposed portion of the solid conductor'forming the driven or exciter portion.
  • the short-circuited coaxial line comprising the enclosed portion of the solid conductor and the inner surface of the tubular conductor is electrically less than a quarter wave-length long at the mean operating requency and constitutes an inductive compensator connected in shunt with the antenna and the insulator.
  • the ratio of the inner diameter of the tubular conductor and the diameter of the enclosed conductor has a particular value, such that a spacing and therefore a characteristic impedance for the compensator are obtained which renders the input impedance of the entire doublet system substantially resistive and of the proper value to match satisfactorily the line impedance at each frequency.
  • the compensator does not radiate energy and in no way affects the directive characteristic of the antenna.
  • the support for the half wave-length conductor provided by the end cap permits the utilization of an insulator having a small size and, therefore,
  • FIGS. 1A and 1B illustrate prior art systems used for explaining the invention.
  • Fig. 1C illustrate prior art systems used for explaining the invention.
  • Fig. 4 illustrates a preferred embodiment of the invention
  • Fig. 4A is a simplified cross-sectional view ofthe embodiment of Fig. 4.
  • reference numeral l designates a half wave-length doublet antenna having an exciter or driven portion 2 and a counterpoise portion 3, each approximately a quarter wave-length long at the mean operating frequency, the exciter and counterpoise sections being connected respectively to the inner conductor l and the outer conductor I of a coaxial line i.
  • Theline is connected to a multifrequency transmitter or receiver, not illustrated. and the doublet is positioned parallel to, and
  • reference numeral I2 designates a distributed inductive impedance or short-circuited coaxial line, hereinafter termed a compensator, the compensator comprising an inner conductor I3 and an outer conductor I, each slightly less than a quarter wavelength long at the mean frequency.
  • the characteristic impedance of the compensator II has, in accordance with the invention, a critical value such that it renders at each frequency in a large band of operating frequencies the impedance of the doublet system including the insulator substantially equal to the impedance of the line C.
  • the characteristic impedance of the compensator is substantially different from the main line characteristic impedance.
  • a shield-l5 is preferably provided for the coaxial lines 6 and I 2 for the purpose of preventing distortion of the directive characteristic of the antenna-reflector system.
  • Figs. 2A, 2B and 2C illustrate, respectively, the calculated frequency-resistive characteristics, the frequency-reactance characteristics and the transmission line standing wave ratio characteristics for the systems of Figs. 1A, 1B and 1C, foran operating range of 420-445 megacycles.
  • the curves A, B and C in Figs. 2A, 2B and 2C correspond, respectively, to the systems of Figs. 1A, 1B and 1C.
  • the vertical reactance scale at the left applies to curves A, B, C, E, F and H and the vertical reactance scale at the right applies to the curves D.
  • These figures also illustrate-the ideal reactance and standing wave characteristics for a multifrequency system.
  • the input resistance has a constant value equal to the characteristic impedance of the line and, as shown in Figs. 23 and 2C. the ideal system has zero reactance and a standing a,ass,oss
  • the doublet has zero reactance at the mean frequency and a unity standing wave ratio. Its input resistance may be made equal to' that of the line. For the other frequencies, however,.the input reactance varies from l5 ohms to +15 ohms over the assumed operating range and the input resistance varies from 77 to 92 ohms.
  • the use of a compensator having a particular value, in accordance with the invention produces an input reactance for the entire system which is relatively low and, in fact, is theoretically zero for a large number of frequencies. Also, the input resistance curve is more horizontal and more nearly approaches the characteristic impedance of the line at each frequency. The line standing wave ratio is relatively small and is substantially equal to zero for a large number of frequencies.
  • the reactance value varies only from zero to -4.5 and the input resistance varies only from 82 to 96 ohms. Reflection losses are minimized at all frequencies and at a great number of frequencies. particularly those frequencies in th range of 420 to 440 megacycles, substantially eliminated.
  • I is the impedance ratio
  • Zr and Z2 are the characteristic impedances of noted that the compensation is substantially ideal over the band.
  • Thecharacteristic impedance of the shortcircuited quarter wave-length line or compensator should, therefore, have a value of about 20.6 ohms.
  • the ratio of conductor diameters for the compensator may be determined from the following equation:
  • X is the inner diameter .of the outer conductor and Y is the diameter of the inner conductor; thus and
  • the reactance variation with frequency for the compensator taken alone is illustrated by curve D of Fig. 2B and the reactance for the parallel combination is illustrated by curve E.
  • the impedance of the coaxial line of the compensator is made inductive by shortening the compensator or line a particular amount so as'to achieve resonance at the mean operating frequency.
  • the impedance looking into a shortcircuited quarter wave-length line is purely resistive, a short-circuited line slightly less than a quarter wave-length long inductive, and a shortcircuited line .slightly greater than a quarter wave-length capacitive.
  • the capacity reactance of the insulator is 460 ohms at the mean operating frequency of 432.5 megacycles.
  • the reactance of the compensator or shortcircuited line is given by the following equation:
  • reference numeral l6 designates a doublet comprising a tubular conductor l1 slightly less than a quarter wave-length long and closed at one end by a metallic cap or plug 18, and the exposed quarter wave-length portion IQ of a substantially half smaller diameter than the tubular conductor II, the conductors l1 and 20 being coaxially positioned and one-half of conductor 20 designated by numeral 2
  • the doublet is supported by means of the metallic transmission line housing 22 attached to plate and metallic airplane wing 24 and is spaced a quarter wave-length from the wing which functions as a reflector.
  • the doublet is preferably, although not necessarily, positioned perpendicular to the longitudinal axis of the aircraft.
  • the arrows 6 are parallel to the longitudinal axis.
  • the tubular conductor I! is supported by the housing 22 and metallic block 25.
  • the member 20 is supported at one end by the end plug II and at its approximate center point by means of the insulator 26 which is attached to the block 2
  • permits the utilization of an insulator 26 having a size and, therefore, a capacity smaller than otherwise would be required.
  • Reference numeral 21 designates a plexiglass doublet housing supported by metallic plug 25.
  • the housing prevents the accumulation of moisture and the formation of ice on the antenna elements and associated insulator.
  • the antenna housing 21 and also the transmission housing 22 each have a streamlined shape modified as shown by the end section 28 of the antenna housing to have at the front an exceedingly sharp straight line edge whereby the formation of ice thereon is substantially prevented.
  • the transmission line 28 comprising inner conductor 30 and outer conductor II, and enclosed by the housing 22, is connected to a multifrequency transmission device 32.
  • the device may be designed to supply or receive a large number of frequencies simultaneously or as in the altimeter system mentioned above, a frequency which varies repeatedly over a given range.
  • the coaxial line constituting the compensator has an electrical length slightly less than a quarter wave-length at the mean frequency since the dielectric utilized is air and the velocity of the waves in the compensator is substantialy equal to the velocity of a space wave.
  • the oounterpoise element or surface 33 of this same conductor II has an electrical length substantially equal to a quarter wave-length since at the mean frequency the velocity on a radiating element is less than that of a wave in space. See “Electric Oscillations and Electric Waves" by G. W. Pierce, 1st edition pages 332-334 and the article, "Impedance of Antennas, equation 30, by E. Siegel and J.
  • the ratio of the inner diameter of outer conductor of the compensator to the outer diameter of the inner conductor is approximately 2. It may be desired to utilize a single rod or member for the elements l9 and 2
  • the curves H of Figs. 2A, 2B and 2C are measured characteristics for a system utilizing the invention and constructed in accordance with Figs. 4 and 4A. It will be observed that as compared to the characteristics of the prior art systems of Figs. 1A and 13 illustrated by curves A and B the measured input resistance for the system of Figs. 4 and 4A is more uniform, the measured input reactance more nearly approaches the ideal zero reactance and at substantially all frequencies the measured standing wave ratio more nearly approaches the ideal unity value.
  • Figs. 4 and 4A have several distinct advantages.
  • compensation for matching an exceedingly large number of frequencies is accomplished with a minimum amount of apparatus.
  • distortion of the directive characteristic of the antenna by the compensator or impedance transformation apparatus is entirely prevented by including the compensator entirely within one element of the radiating system.
  • a highly satisfactory end support is obtained for the member 20 and exciter l3 whereby a relatively small central supporting insulator may be utilized.
  • the capacity of the small insulator is such that resonance may be easily obtained without unfavorably changing the length of the counterpoise surface.
  • the invention has been described in connection with certain specific embodiments and apparatus, it should be understood that it is not to be limited to these embodiments inasmuch as other structures may be successfully employed without exceeding the scope of the invention.
  • compensation may be applied to other types of antennas and the compensator may comprise a two-wire line or a lump reactance.
  • a method of matching a load comprising an antenna input impedance to the impedance of a 2.
  • a method of matching the impedance of a load comprising an antenna, an auxiliary line and an insulator, all connected in parallel, to the impedance of the line connected to the load over a band of frequencies, which comprises matching the combined input impedance of the antenna and auxiliary line to the line impedance in accordance with claim 1 and shortening said line a particular amount dependent upon the reactance of said insulator.
  • an antenna comprising only a radiator or collector, a line connected thereto and means for matching the antenna and line impedances over a band of frequencies,' said means comprising a line connected to the input terminals of the antenna and having a characteristic impedance dependent upon the termination resistance value of a properly terminated smooth line having a frequency-input reactance characteristic similar to the frequency-input characteristic of the antenna.
  • a line, a doublet radiator or collector comprising a tubular'conductor and a second conductor of smaller diameter, said conductors having a common axis, and means for matching the line impedance and the impedance of the radiator or collector over a band of operating frequencies comprising a conductor enclosed by said tubular conductor and connected to the second couductor.
  • a system comprising an antenna and a supporting insulator, a line connected to said antenna, and means for matching the impedance of said system and the impedance of said line over a frequency band having any width from one cycle to at least twentyfive megacycles, substantially, said means comprising a line connected to the antenna input terminals and having an input inductive reactance equal and opposite to the capacity reactance of said insulator and a characteristic impedance related to the input impedance of the antenna.
  • an antenna system comprising an antenna and a supporting insulator, a multifrequency translation device, a line connecting said antenna and device, and an auxiliary line for minimizing the line standing wave ratio at the operating frequencies, said line havput impedance of said antenna and a length depending upon the capacitive reactance of said insulator.
  • an antenna comprising two sections, an insulator includedbctween said sections, a line connecting said sections to a multifrequencytranslation device, a means connected to the input terminals of said antenna for minimizing at each frequency the standing wave ratio on said line, said means comprising a distributed reactance having a characteristic impedance depending upon the input impedance of said antenna and a length depending upon the capacitive reactance of said insulator.
  • a multifrequency translation device a tubular conductor approximately a quarter wave-length long and having one end closed, a second conductor approximately a half wave-length long and positioned coaxially within the tubular conductor and having one extremity connected to the closed 'end of the tubular conductor, an insulator connected between the open end of said tubular conductor and the approximate center point of the second conductor, whereby the outside surface of the tubular conductor and the exposed half of the second conductor constitute a doublet antenna and the enclosed half of the second conductor and the inner surface of the tubular conductor constitute an auxiliary line approximately a quarter wavelength long and connected in shunt to said insulator and doublet.
  • a doublet antenna system comprising a tubular counterpoise conductor approximately a quarter wave-length long and a second conductor approximately a half wavelength long and having a smaller diameter than that of the tubular conductor and means for supporting the second conductor coaxially with respect to the tubular conductor so that a quarter wave-length portion of the second conductor is exposed and forms the exciter element of the doublet, said means comprising an insulator included between one end of the tubular conductor and the center portion of the second conductor and a metallic member included between the ing a characteristic impedance related to the inother end of said tubular conductor and one end of said second conductor.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Fluid Mechanics (AREA)
  • Astronomy & Astrophysics (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Transmitters (AREA)
  • Details Of Aerials (AREA)
US286680A 1939-07-26 1939-07-26 Antenna system Expired - Lifetime US2258953A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
BE472233D BE472233A (en(2012)) 1939-07-26
NL61318D NL61318C (en(2012)) 1939-07-26
US286680A US2258953A (en) 1939-07-26 1939-07-26 Antenna system
GB9995/40A GB541870A (en) 1939-07-26 1940-06-07 Improved antenna systems
FR866476D FR866476A (fr) 1939-07-26 1940-07-26 Perfectionnement aux antennes
CH269953D CH269953A (fr) 1939-07-26 1946-12-14 Dispositif pour adapter une antenne électriquement à son conducteur d'alimentation sur une large bande de fréquences.
ES176296A ES176296A1 (es) 1939-07-26 1946-12-18 Perfeccionamientos en las antenas

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US286680A US2258953A (en) 1939-07-26 1939-07-26 Antenna system

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US2258953A true US2258953A (en) 1941-10-14

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US286680A Expired - Lifetime US2258953A (en) 1939-07-26 1939-07-26 Antenna system

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US (1) US2258953A (en(2012))
BE (1) BE472233A (en(2012))
CH (1) CH269953A (en(2012))
ES (1) ES176296A1 (en(2012))
FR (1) FR866476A (en(2012))
GB (1) GB541870A (en(2012))
NL (1) NL61318C (en(2012))

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2446436A (en) * 1943-04-19 1948-08-03 Gen Electric Beam antenna system
US2449562A (en) * 1944-10-03 1948-09-21 Us Sec War Antenna
US2471515A (en) * 1944-07-25 1949-05-31 Rca Corp Antenna
US2480143A (en) * 1946-09-11 1949-08-30 Standard Telephones Cables Ltd Directive antenna system
US2496643A (en) * 1944-10-14 1950-02-07 Bell Telephone Labor Inc Impedance matching system
US2503952A (en) * 1946-03-19 1950-04-11 Rca Corp Traveling wave antenna
US2512137A (en) * 1944-06-16 1950-06-20 Us Sec War Antenna
US2514020A (en) * 1945-11-16 1950-07-04 Rca Corp Upsilon-dipole antenna
US2539680A (en) * 1945-11-26 1951-01-30 Rca Corp Ultra high frequency antenna
US2562296A (en) * 1946-06-21 1951-07-31 John W Christensen Antenna
US2573460A (en) * 1945-08-25 1951-10-30 Rca Corp Antenna
US2575377A (en) * 1945-11-13 1951-11-20 Robert J Wohl Short wave antenna
US2603754A (en) * 1945-03-17 1952-07-15 Univ Leland Stanford Junior High-frequency apparatus
US2611869A (en) * 1944-04-21 1952-09-23 Int Standard Electric Corp Aerial system
US2626353A (en) * 1947-12-18 1953-01-20 John W Mcgee Antenna mast
US2627026A (en) * 1945-04-23 1953-01-27 Standard Telephones Cables Ltd High altitude antenna
US2643334A (en) * 1948-10-23 1953-06-23 Zenith Radio Corp Turnstile antenna
US2646505A (en) * 1946-03-01 1953-07-21 Us Sec War Broad band bidirectional antenna
US2755467A (en) * 1946-05-15 1956-07-17 Leonard J Eyges Broadband linear array
US3713166A (en) * 1970-12-18 1973-01-23 Ball Brothers Res Corp Flush mounted antenna and receiver tank circuit assembly
CN111737330A (zh) * 2020-06-19 2020-10-02 广联达科技股份有限公司 一种空间数据标准化方法、装置、计算机设备和存储介质

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2446436A (en) * 1943-04-19 1948-08-03 Gen Electric Beam antenna system
US2611869A (en) * 1944-04-21 1952-09-23 Int Standard Electric Corp Aerial system
US2512137A (en) * 1944-06-16 1950-06-20 Us Sec War Antenna
US2471515A (en) * 1944-07-25 1949-05-31 Rca Corp Antenna
US2449562A (en) * 1944-10-03 1948-09-21 Us Sec War Antenna
US2496643A (en) * 1944-10-14 1950-02-07 Bell Telephone Labor Inc Impedance matching system
US2603754A (en) * 1945-03-17 1952-07-15 Univ Leland Stanford Junior High-frequency apparatus
US2627026A (en) * 1945-04-23 1953-01-27 Standard Telephones Cables Ltd High altitude antenna
US2573460A (en) * 1945-08-25 1951-10-30 Rca Corp Antenna
US2575377A (en) * 1945-11-13 1951-11-20 Robert J Wohl Short wave antenna
US2514020A (en) * 1945-11-16 1950-07-04 Rca Corp Upsilon-dipole antenna
US2539680A (en) * 1945-11-26 1951-01-30 Rca Corp Ultra high frequency antenna
US2646505A (en) * 1946-03-01 1953-07-21 Us Sec War Broad band bidirectional antenna
US2503952A (en) * 1946-03-19 1950-04-11 Rca Corp Traveling wave antenna
US2755467A (en) * 1946-05-15 1956-07-17 Leonard J Eyges Broadband linear array
US2562296A (en) * 1946-06-21 1951-07-31 John W Christensen Antenna
US2480143A (en) * 1946-09-11 1949-08-30 Standard Telephones Cables Ltd Directive antenna system
US2626353A (en) * 1947-12-18 1953-01-20 John W Mcgee Antenna mast
US2643334A (en) * 1948-10-23 1953-06-23 Zenith Radio Corp Turnstile antenna
US3713166A (en) * 1970-12-18 1973-01-23 Ball Brothers Res Corp Flush mounted antenna and receiver tank circuit assembly
CN111737330A (zh) * 2020-06-19 2020-10-02 广联达科技股份有限公司 一种空间数据标准化方法、装置、计算机设备和存储介质

Also Published As

Publication number Publication date
FR866476A (fr) 1941-08-14
CH269953A (fr) 1950-07-31
GB541870A (en) 1941-12-15
ES176296A1 (es) 1947-07-16
NL61318C (en(2012))
BE472233A (en(2012))

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