US2378944A - Detector system for very short electric waves - Google Patents

Detector system for very short electric waves Download PDF

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Publication number
US2378944A
US2378944A US286530A US28653039A US2378944A US 2378944 A US2378944 A US 2378944A US 286530 A US286530 A US 286530A US 28653039 A US28653039 A US 28653039A US 2378944 A US2378944 A US 2378944A
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US
United States
Prior art keywords
lecher
contact
circuit
conductors
detector
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
US286530A
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English (en)
Inventor
Russell S Ohl
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AT&T Corp
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Bell Telephone Laboratories Inc
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Filing date
Publication date
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US286530A priority Critical patent/US2378944A/en
Priority to FR867725D priority patent/FR867725A/fr
Priority to BE440931D priority patent/BE440931A/xx
Application granted granted Critical
Publication of US2378944A publication Critical patent/US2378944A/en
Priority to ES176235A priority patent/ES176235A1/es
Priority to CH262414D priority patent/CH262414A/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D9/00—Demodulation or transference of modulation of modulated electromagnetic waves
    • H03D9/02—Demodulation using distributed inductance and capacitance, e.g. in feeder lines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D1/00—Demodulation of amplitude-modulated oscillations
    • H03D1/08—Demodulation of amplitude-modulated oscillations by means of non-linear two-pole elements
    • H03D1/10—Demodulation of amplitude-modulated oscillations by means of non-linear two-pole elements of diodes

Definitions

  • This invention relates to reception of high frequency oscillations and more particularly to receiving systems for selecting and detecting oscillations in the range of centimeter and millimeter wave-lengths.
  • An object of the invention is to provide an efficient selective absorbing system for very high frequency electromagnetic waves in space.
  • the detection or measurement of electromagnetic waves in the centimeter and millimeter wave-lenth ranges requires apparatus sensitive at the frequencies involved and free from excessive capacitance. If the detection is to be preceded by a frequency selective operation, the selecting or tuning feature should preferably be of such character as not to greatly impair the sensitivity of the detecting system or to introduce excessive capacitance. Hitherto the technique of electromagnetic wave reception has centered very largely about the electron discharge device which long ago superseded the early contact rectifiers or detectors of the general types developed by Dunwoody and ,Pickard.
  • a contact rectifying device may, under certain conditions, be regarded as an asymmetric rectiher with a shunt path comprising series resistance and capacitance.
  • the shunt path causes a decrease in sensitivity and a change in the exponetial response characteristic as the frequency is increased beyond certain limits.
  • the high frequency limit at which a contact rectifier remains effective depends upon the area relations at the rectifying contact. For instance, if a point contact be made at an area which is wholly active, a very desirable characteristic may be obtained If, on the other hand. the contact be made at an area which is partly active and partly inactive, the inactive portion will introduce an effective shunt path thus decreasing the sensitivity of the device as a whole.
  • the general class-of materials sometimes; known as semiconductors such as iron-pyrite or semiconducting metals including boron, silicon, ar-
  • senic and tellurium are all stable in varying degrees for use in point contact detectors.
  • a current is drawn through abody of such a substance with one contact to the material large in area and very intimate while the other contact is relatively small and ata rather low pressure, an effect similar to a space charge effect is produced. That is, when a direct current passing through the contact in one direction is increased the resistance of the body drops, while, if current is caused to flow in the opposite direction, an increase in current causes the resistance to increase.
  • the body have a satisfactory front-to-back resistance ratio or asymmetry of conductivity.
  • the semi-metals which have been mentioned all have these characteristics in varying degrees and of them silicon appears to be fairly suitable. It is hard. inert chemically at low temperatures, not too high in specific resistance and has a satisfactory front-to. back resistance ratio. Applicant has discovered that this material has very desirable characteristics in rectification of extremely short electrical waves.
  • noise introduced by the detector is dependent upon the particular substance employed and also upon the amplitude of the currents to which the detector is subjected. For example, if a superheterodyne system with a beating oscillator is employed, the noise increases with the input of beating oscillations in such a way that for low levels of oscillation current the signal gain due to the increasing amplitude of the beating oscillations is more rapid thanthe increase in noise whereas for high levels of oscillation currents, the signal gain with increase of the beating oscillations is small but the noise increase is large.
  • the back contact Another important factor in the production of noise in the operation of a rectifying contact detector isthe character of what we may term the back contact. This is the contact which the semi-conductor body makes with the matrix of conducting material in which it is commonly embedded. If the back contact is somewhat imperfeet the noise factor is high. If, on the contrary, the back contact is made with a matrix of cOnducting material which forms a substantially integral mass with the semi-conductor the noise is greatly reduced. Such a back contact may be secured in'the case of silicon by electroplating the silicon body with chromium. In the case of iron-pyrite a similar low noise back contact may be attained by gold plating. These particular combinations of materials appear to make molecularly intimate contacts. If the semi-conductor body be so exceedingly small that it is impracticable to electroplate it a fairly satisfactory result may be had by dipping the unit in aquadag to form the back contact.
  • Thepoint contact member should be inert chemically so that no oxide forms on its surface which might make possible a nonrectifying stable metallic contact.
  • the point contact member must be ductile so that small wires of it are available and it must be strong and flexible enough to provide a contact having a steady pressure.
  • an additional object of the invention is to provide a metallic point contact with which it may be possible to assure uniform contact with the surface of the semi-metallic body agddto adjust the pressure of the contact as des e 'It.
  • a detector of very high frequency electrical oscillations a body of a substance such as the semi-conductors silicon or iron-pyrite'connected in the high frequency oscillation circuit by one large back contact and one small rectifying contact which may be obtained at the tip of a very fine tungsten wire.
  • the detector is preferably mounted between the open ends of two miniature Lecher circuit conductors which serve as the high frequency oscillation selecting circuit and, also, as the receiving antenna or electromagnetic wave absorber. Tuningis accomplished by variation of the position of a conducting plate or wall through which the high frequenc short-circuited terminal ends of the Lecher circuit conductors extend.
  • a conducting chamber of variable length for tuning purposes one end of which is open to permit entrance of electromagnetic wave energy. At its open endthe chamber is provided with an iris to determine the magnitudeof the opening.
  • Fig. 1 illustrates schematically a superheterodyne receiving set for electromagnetic waves of millimeter wave-length range
  • Fig. 2 shows the frequency selective apparatus employed in the system of Fig. 1 as the receiving antenna and radio frequency selective circuit
  • Fig. 3 illustrates details of the Lecher circuit constituting the receiving antenna of the apparatus of Fig. 2;
  • Fig. 5 shows in longitudinal section, an alternative structure to that shown in Fig. 4, and
  • Fig. 6 is an end view of the detector of Fig. 5.
  • the receiving apparatus for very short waves comprises a receiving chamber l constituted by electrically conducting surfaces and including a Lecher circuit 2 which serves as a receiving antenna for absorbing the energy of electromagnetic waves.
  • the two semi-circular Lecher conductors 2 may be formed fromwire of a highly conducting alloy comprising gold, 25% silver, and 5% platinum.
  • Connected to the antenna structure is a contact rectifier 30 (Fig.
  • a local mediate frequency oscillations which are supplied from the Lecher circuit 2 by way of conductors 5 to the input circuit of intermediate frequency amplifier 6, the output circuit of which includes a resonant loop circuit I tuned to the intermedi- .open outer end a ate frequency.
  • a second detector I which may be of the iron-pyrite or silicon contactor rectifier type is connected across the tuned-loop 1 and audio frequency demodulated waves in its output circuit are amplified by audio frequency amplifier ducting casing ll provided with an aperture through which the Lecher circuit conductors project, carries an annular conducting ring l2 of brass or other conducting material which serves as a high frequency short-circuiting member for the Lecher circuit conductors.
  • the annular member I2 is spaced from the Lecher conductors just sufiiciently to prevent its acting as a short-circuiting path for intermediate frequency oscillations.
  • the capacitance between it and the conductors of the Lecher circuit is, however, sumcient so that the Lecher circuit is efiectively terminated for millimeter-length waves at the outer face of the annular member l2.
  • the member I 2 is externally threaded to provide an adjusting feature for the tubular conducting shell l4 which projects forwardly from the casing II and carries at its plate It on which is mounted the iris member l8.
  • tubular member I4 may be adjusted to extend the chamber I in the axial direction of the Lecher conductors 2 and the iris It may be adjusted to fix the area of the opening into the chamber. It is possible to adjust or tune effectively to oscillations of a given wave-length by adjusting the tubular member I4 and to cause a maximum quantity of energy of oscillations of that wave-length to be absorbed by the Lecher conductors 2, by iris member ll.
  • the Lecher conductors 2 are electrically separated-by a strip I1 of mica or other dielectric material as illustrated in Fig. 3.
  • a tubular sleeve is of dielectric material surrounds the Lecher conductors very closely to hold them firmly clamped together as a unit and is in turn enclosed in a tightly fitting metallic tube IS a fianged end oi which is attached to an enlarged circular dielectric block 20 having an opening at one side through which pass the leads 5 that connect the Lecher conductors to the external circuit.
  • the position of the Lecher conductors is determined by a bell crank 23 hearing against the reaction bolt 24 and hingedat 25.
  • Theposition of the bell crank is fixed by the adjusting screw 28 and theretracting spring 21. It is. therefore, possible to nicely adjust the position of the Lecher conductors with respect to chamber I.
  • the Lecher system is tuned to V wave-length or wave-length as indicated by maximum response indications.
  • the chamber I to a multiple of a half wavemum.
  • the iris l 6 is adjusted to obtain the most favorable impedance condition.
  • Fig. 4 which is a section in the plane 4-4 of Fig. 3, 'shows the structure of the contact rectifier-detector. It consists of a cylindrical the system to respond most plating the back surface suitably varying the opening of which is firmly fixed block II of the semi-conducting materiaiscated closely in a circular recess in one of the Lecher conductors.
  • the other Lecher conductor is provided with an opening in which is inserted a spring 3
  • the spring II is held in position by a small plug II of electrically conducting material, fitting i htly in the hole and staked therein to secure the spring in position.
  • the block 30 may consist of any of a number of semi-conducting materials as has previ ly above the 60 to kilocycle range and at two megacycles it is useless. Iron-pyrites is also effective and its effectiveness maybe increased by electrowith gold as has already been stated. Silicon, however, is preferable.
  • the detector Since the detector is near the open end of the Lecher system it is at a point of substantially maximum voltage.
  • the semi-circular Lecher conductors 2 extend back through the casing II, and the annular member I 2 as has previously been explained, is so nearly in contact with them that it serves as a short-circuiting path for high frequency energy thus determining the electrical tuning frequency of the Lecher circuit. Since the separation between conductors is sufiicient to maintain them electransmitted by the Iecher conductors back to the ing material in contact with which is the tip 40 of a U-shaped contact wire 4
  • of Fig. 8 and the spring contact member ll of Fig. 4 both preferably consist of tungsten wire may also be used.
  • the Lecher conductors 2 with their intervening mica strip II had a diameter of .053 inch;
  • the silicon crystal employed as the element ll of Fig. 4 was was wound on a form piece protruded from of which presses down on the the member l2 and the Lecher one end of the spring. This end was cut of! with a small scissors.
  • the contact resistance between the silicon cylinder and its supporting Lecher conductor is reduced to a minimum by an aquadag coating on the cylinder.
  • is carefully ground at the base end of the coil to have a large flat surface which may contact with the plug 33 at its base.
  • has sufficient torsional elasticity at the very small wire diameters employed to exert sumcient pressure on the crystal block to effect and maintain a satisfactory rectifying contact.
  • the pressure although not particularly critical, is, in general, so adjusted as to amount to about 250 grams per square centimeter.
  • a tunable Lecher circuit serving as a selective electromagnetic wave energy-absorbing system and a rectifying contact detector connected thereto at substantially the maximum potential difference points of the Lecher circuit.
  • 'tunable Lecher circuit constituting an electromagnetic wave-absorbing antenna, a rectifying detector connected thereto at points between which there is a large difference of potential, an
  • electromagnetic wave reflector surrounding the Lecher circuit and means for varying the length .of the reflector to obtain maximum energy absorption at the Lecher circuit.
  • a receiving system for short waves comprising a tunable Lecher circuit constituting an electromagnetic wave-absorbing antenna, a rectifying detector connected to the Lecher circuit at points between which there is a substantial difference of potential, a variable length electromagnetic wave reflector open at one end surrounding the Lecher circuit and a variable iris member connected to the reflector at its open end to tune it for maximum energy reception by the Lecher circuit.
  • tunable Lecher circuit serving asan energy-absorbing device for incoming electromagnetic waves, a rectifying detector connected thereto at points between which substantially maximum potential difference exists and means for projecting locally generated oscillations of frequency different from the frequency of said incoming waves upon the Lecher circuit whereby the output of the detector contains a component of the difference frequency of the received electromagnetic waves and the locally generated oscillations.
  • a conducting chamber having an aperture to permit ingress of electromagnetic waves
  • a pair of Lecher circuit conductors projecting into the chamber through an aperture inthe wall of the chamber, the wall of said second-named aperture being separated from the conductors by such a small spacing as to effecof the chamber for varying the tuning of the Lecher circuit by varying the length of the Lecher circuit conductors extending into the chamber.
  • a receiving system for electromagnetic waves of the millimeter wave-length range characterized in this, that the receiving antenna and the radio frequency selecting circuit comprise a pair of Lecher conductors of variable length dis-- posed within an electrically conducting chamber which is closed except for an aperture for ingress of electromagnetic waves the pair of Lecher conductors extending through an aperture in a wall of the electrically conducting chamber, the margin of the aperture being so close to the Lecher conductors as to cause the capacitance between the wall and the Lecher circuit conductors to substantially shortcircuit the Lecher circuit at the frequency to which it is most highly respon-' sive.
  • a receiving system for electromagnetic waves of extremely short wave-length characterized in this, that two Lecher circuit conductors constituting the antenna and selective receiving circuit support between them a contact rectifier to set up in the Lecher circuit detected modulation currents corresponding to modulations of the received electromagntic waves.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Electromagnetism (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Nonlinear Science (AREA)
  • Measurement Of Resistance Or Impedance (AREA)
US286530A 1939-07-26 1939-07-26 Detector system for very short electric waves Expired - Lifetime US2378944A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US286530A US2378944A (en) 1939-07-26 1939-07-26 Detector system for very short electric waves
FR867725D FR867725A (fr) 1939-07-26 1940-11-18 Systèmes récepteurs d'ondes électromagnétiques à fréquence élevée
BE440931D BE440931A (enrdf_load_stackoverflow) 1939-07-26 1941-03-20
ES176235A ES176235A1 (es) 1939-07-26 1946-12-13 Un aparato receptor y detector para ondas eléctricas muy cortas
CH262414D CH262414A (fr) 1939-07-26 1946-12-18 Redresseur à contact pour ondes électriques très courtes.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US286530A US2378944A (en) 1939-07-26 1939-07-26 Detector system for very short electric waves

Publications (1)

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US2378944A true US2378944A (en) 1945-06-26

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US286530A Expired - Lifetime US2378944A (en) 1939-07-26 1939-07-26 Detector system for very short electric waves

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US (1) US2378944A (enrdf_load_stackoverflow)
BE (1) BE440931A (enrdf_load_stackoverflow)
CH (1) CH262414A (enrdf_load_stackoverflow)
ES (1) ES176235A1 (enrdf_load_stackoverflow)
FR (1) FR867725A (enrdf_load_stackoverflow)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2436830A (en) * 1943-04-19 1948-03-02 Bell Telephone Labor Inc Transmission system and method
US2466439A (en) * 1944-04-27 1949-04-05 Bell Telephone Labor Inc Resonant wave guide switching
US2501093A (en) * 1945-05-30 1950-03-21 Us Sec War High-frequency mixer
US2502456A (en) * 1943-04-02 1950-04-04 Sperry Corp Ultra high frequency discriminator and apparatus
US2518113A (en) * 1945-06-23 1950-08-08 Gen Electric Ultra high frequency receiver
US2557122A (en) * 1951-06-19 Coaxial crystal detector and line
US2571163A (en) * 1946-02-18 1951-10-16 Robert H Rines Electric system
US2629822A (en) * 1947-01-31 1953-02-24 Motorola Inc High-frequency coupling circuits
US2664502A (en) * 1945-06-23 1953-12-29 Roberts Shepard Ultrahigh-frequency mixer
US2673311A (en) * 1948-07-24 1954-03-23 Sylvania Electric Prod Crystal amplifier
US2673930A (en) * 1948-08-08 1954-03-30 Westinghouse Freins & Signaux Ultrahigh-frequency crystal device of the asymmetrical conductivity type
US2704340A (en) * 1953-06-05 1955-03-15 Rca Corp Semiconductor devices and their manufacture
US2717341A (en) * 1949-10-11 1955-09-06 Gen Electric Asymmetrically conductive device
US2731561A (en) * 1949-02-10 1956-01-17 Gen Electric Co Ltd Crystal contact devices
US2921184A (en) * 1950-02-09 1960-01-12 Fruengel Frank System for signaling by light impulses
US20030109183A1 (en) * 2001-09-14 2003-06-12 Stmicroelectronics S.R.I. Process for bonding and electrically connecting microsystems integrated in several distinct substrates

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2557122A (en) * 1951-06-19 Coaxial crystal detector and line
US2502456A (en) * 1943-04-02 1950-04-04 Sperry Corp Ultra high frequency discriminator and apparatus
US2436830A (en) * 1943-04-19 1948-03-02 Bell Telephone Labor Inc Transmission system and method
US2466439A (en) * 1944-04-27 1949-04-05 Bell Telephone Labor Inc Resonant wave guide switching
US2501093A (en) * 1945-05-30 1950-03-21 Us Sec War High-frequency mixer
US2664502A (en) * 1945-06-23 1953-12-29 Roberts Shepard Ultrahigh-frequency mixer
US2518113A (en) * 1945-06-23 1950-08-08 Gen Electric Ultra high frequency receiver
US2571163A (en) * 1946-02-18 1951-10-16 Robert H Rines Electric system
US2629822A (en) * 1947-01-31 1953-02-24 Motorola Inc High-frequency coupling circuits
US2673311A (en) * 1948-07-24 1954-03-23 Sylvania Electric Prod Crystal amplifier
US2673930A (en) * 1948-08-08 1954-03-30 Westinghouse Freins & Signaux Ultrahigh-frequency crystal device of the asymmetrical conductivity type
US2731561A (en) * 1949-02-10 1956-01-17 Gen Electric Co Ltd Crystal contact devices
US2717341A (en) * 1949-10-11 1955-09-06 Gen Electric Asymmetrically conductive device
US2921184A (en) * 1950-02-09 1960-01-12 Fruengel Frank System for signaling by light impulses
US2704340A (en) * 1953-06-05 1955-03-15 Rca Corp Semiconductor devices and their manufacture
US20030109183A1 (en) * 2001-09-14 2003-06-12 Stmicroelectronics S.R.I. Process for bonding and electrically connecting microsystems integrated in several distinct substrates
US20070254454A1 (en) * 2001-09-14 2007-11-01 Stmicroelectronics S.R.L. Process for bonding and electrically connecting microsystems integrated in several distinct substrates
US7595223B2 (en) 2001-09-14 2009-09-29 Stmicroelectronics S.R.L. Process for bonding and electrically connecting microsystems integrated in several distinct substrates

Also Published As

Publication number Publication date
ES176235A1 (es) 1947-02-01
BE440931A (enrdf_load_stackoverflow) 1941-04-30
CH262414A (fr) 1949-06-30
FR867725A (fr) 1941-11-25

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