US3835420A - Isolator - Google Patents

Isolator Download PDF

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Publication number
US3835420A
US3835420A US00381623A US38162373A US3835420A US 3835420 A US3835420 A US 3835420A US 00381623 A US00381623 A US 00381623A US 38162373 A US38162373 A US 38162373A US 3835420 A US3835420 A US 3835420A
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US
United States
Prior art keywords
isolator
branch line
conductor
dielectric substrate
line
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
US00381623A
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English (en)
Inventor
N Orime
H Kurebayashi
S Nakahara
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.)
Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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 claimed from JP7483272A external-priority patent/JPS4933539A/ja
Priority claimed from JP7814872A external-priority patent/JPS5228540B2/ja
Priority claimed from JP11271572A external-priority patent/JPS4970556A/ja
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Application granted granted Critical
Publication of US3835420A publication Critical patent/US3835420A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/32—Non-reciprocal transmission devices
    • H01P1/36—Isolators
    • H01P1/365—Resonance absorption isolators

Definitions

  • An isolator has a dielectric substrate such as a composite substrate or a single ferrimagnetic substrate; a magnetic material inserted in a hole of the dielectric substrate in the thickness direction thereof; a single plate conductor placed on one surface of the dielectric substrate; a main line conductor placed on the other surface of the dielectric substrate and over the magnetic material; a branch line conductor and a subbranch line conductor branching from the main line conductor; wherein one end of the line conductor is opened and the other end of the line conductor is con nected to the single plate conductor.
  • a strip line type isolator has a structure which included a main line (1a) and (1b), a branch line (4), and a sub-branch line for counterbalancing any reflection caused by the branch line (4).
  • a ferrimagnetic material (6) such as aferrite, yttrium-iron-garnet was placed on a dielectric substrate (2) at a junction point such that a magnetic field I-I for causing magnetic resonance absorption could be applied externally to the ferrimagnetic material.
  • a length of the branch line (4) was selected to be three-eights of a wavelength and in order to counterbalance the branch line (4), the length of the sub-branch line (5) was selected to be one-eight of a wavelength.
  • an isolator which includes a dielectric substrate and a magnetic material inserted in a hole of the dielectric substrate in the thickness direction thereof.
  • a single ground plate conductor is placed on one surface of the dielectric substrate and a main line conductor is placed on the other surface of the dielectric substrate and over the magnetic material.
  • a branch line conductor and a subbranch line conductor branch from the main line conductor and one end of the line conductor is opened and the'other end of the line conductor is connected to the single plate conductor.
  • FIG. 1(a) is a plan view of a conventional unilateral attenuator except for the magnet element thereof;
  • FIG. 1(b) is a sectional side view of the conventional unilateral attenuator of FIG. 1(0);
  • FIG. 2 is a schematic view of one preferred embodiment of an isolator according'to this invention.
  • FIGS. 3 (a) and (b) are. respectively schematic views showing the junction of FIG. 2;
  • FIG. 4 is a schmeatic view of another preferred embodiment of an isolator according to this invention.
  • FIG. 5 is a plan view of the isolator of FIG. 4;
  • FIGS. 6 (a),(b) and (c) respectively are plan views of the-isolator of FIG. 5;
  • FIG. 7 is a schematic view of still another preferred embodiment of the isolator of this inveniton.
  • FIG. 8 (a) is a plan view of yet another embodiment of the isolator of this invention and FIG. 8 (b) is a sectional side view of the isolator of FIG. 8(a);
  • FIG. 9 is a diagram of an electrical equivalent circuit of FIGS. 1(a) and (b);
  • FIG. 10 is a schematic view of one other preferred embodiment of the isolator of this invention.
  • FIG. 11 is a plan view of another preferred embodiment of the isolator of the present invention.
  • FIG. 12 is a schematic view of still one more preferred embodiment of the isolator of this invention.
  • FIG. 13 is a schematic view of one further preferred embodiment of the isolator of this invention.
  • unilateral attentuator of an isolator should have the branch line (4) at a length of three-eights wavelengths and an end which is opened-As a result thereof, the impedance from the joining point of the main line (la) and (1b) to the open end, will act as an inductive reactance whose absolute value is equal to the value of the characteristic impedance of the branch line.
  • the current passing through the main line (la) and (lb) should be equal to the current passing around the junction point to the branch line (4), so that when a load is equal to the characteristic impedance of the main line (1a) and (lb), the characteristic impedance of the branch line (4) should be equal to that of the main line (1a) and (1b).
  • the branch line (4) has an end which is connected to the base.
  • the phase constant of the branch line (4) is [3 the characteristic impedance is Z the length is I then the impedance Z from the joining point of the main line (la) and (lb) to the end, can be given as follows assuming a loss free transmission line.
  • V/ZL j l B111 The condition for forming a circularly polarized wave is i mi (3) wherein the phase difference of I,, and I, is 90.
  • I In order to minimize the dimensions of the isolator, I should be decreased. However, in order to satisfy the equation (4), Z should be increased, that is the width of the branch line (4) should be decreased in the case of a substrate having a specific thickness.
  • the width of the branch line (4) should not be too narrow. Moreover if the branch line (4) is too narrow, losses will occur. Accordingly, the size of Z is limited.
  • the sub-branch line (5) is a line having an opened end. Accordingly, when the length is 1 and the characteristic impedance is Z and the phase constant is B then the impedance Z, of the sub-branch line (5) from the junction of the main line (la) and (lb) can be given as follows:
  • branch line (4) need not have a length of three-eights of a wavelength and that a unilateral attenuation of an isolator having a line shorter than one-fourth wavelength can be formed by using one end as a short circuit line.
  • the line width of the branch line (4) and the subbranch line (5) should be changed depending'upon' the selected length.
  • the unilateral attenuator can be considered as follows.
  • the length of the end short branch line I is decreased and the length of the end open sub-branch line 1 is increased, as far as possible, in the range of the equations (1) and (2) so as to decrease the inductance L of the resonance circuit and to increase capacitance C of the resonance circuit.
  • the characteristic impedances Z, and Z of the branch line (4) and the sub-branch line (5) are respectively decreased.
  • FIG. 4 shows a schematic view of an isolator for improving the Figure of merit.
  • the end open sub-branch line (5) is connected to the junction, and the ferrimagnetic material (6), whose area is not much larger than the area of the junction or is smaller than the area of the junction, is fitted around the junction and a magnetic field forming magnetic resonance absorption is externally applied to the ferrimagnetic material.
  • the end short circuit branch line (14) is formed by the shorted side broad conductor (11) and the end short circuit line (4), while the end open subbranch line (15) is formed by the broad open side conductor (l2) and the end open line (5).
  • FIG. 4 a ground plate conductor (3), magnet (7a) and (7b) and a composite substrate (16) consisting of ferrimagnetic material (6) filled in the dielectric substrate (2), are combined.
  • FIG. 5 is a plan view for illustrating in detail the isolator of FIG. 4.
  • the forward loss which is dependent upon the distribution of the circularly polarized waves in the ferrimagnetic material (6) is decreased by the use of the broad conductors (l1) and (12) on the shorted and open sides, and the frequency characteristics of the parallel resonance circuit is improved by the appropriate selection of the length and characteristic impedances of short circuit line (4) and the open line (5), whereby the fundamental contradiction of no improvements in the characteristics of the conventional isolator, can be overcome so as to result in an isolator having a compact size, a broad range and an excellent Figure of merit.
  • FIGS. 6 (a), (b) and (c) are respectively plan views of another preferred embodiment of the isolator of the present invention, wherein the broad conductor (11) on the short circuit side and the broad conductor (12) on the open side are changed in shape.
  • This embodiment can be applied to the isolator having the end open branch line.
  • the present embodiment is shown with the ferrimagnetic material (6) filled in the dielectric substrate (2), it should be understood that it is possible to substitute the dielectric substrate and the ferrimagnetic material by one magnetic plate.
  • the present embodiment can be used for a high power isolator.
  • it is necessary to decrease the heat per volume of ferrimagnetic material. It is important to increase the volume of the ferrimagnetic material without increasing the insertion loss.
  • the heat per volume of the ferrimagnetic material can be decreased without substantially changing the condition of the circularly polarized wave so that an isolator suitable for high power can be obtained by increasing the area of junction size in the width direction as shown in FIG. 7.
  • the structure is shown as being applied to both the end short circuit branch line and the end open branch line, however, it is possible to apply it to either of the branch lines.
  • a hole is formed in the dielectric substrate (2) and a ferrimagnetic material (6) is inserted and adhered to it and the surface is processed to form a composite plate or substrate (16).
  • a desirable conductive pattern is formed on the composite substrate (16) by metallizing, metal plating, etching or printing.
  • the shape of the inserted ferrimagnetic material (6) can be other than disc, as shown in FIG. 2.
  • the ferrimagnetic material (6) can be of a square shape.
  • the end connection of the branch line (4) of FIG. 2 can be formed by metal plating, etching, and the like and also by forming a hole in the dielectric substrate and inserting a metallic screw to form a shortcircuit to the ground plate conductor (3).
  • a metal plate (8) is inserted between the upper magnetic pole (7a) and the surface of the dielectric substrate (2) adhering the main line (la) and (lb) and the branch line (4), the sub-branch line (5), etc., by departing from the surface of the dielectric substrate in a direction substantially parallel to it, whereby certain disturbances which may be caused by the outside are prevented, certain affects of wave leakage to the outside are prevented and certain structural advantages are provided.
  • an embodiment to result in miniaturization can be provided by using a lumped constant alternative device for the branch line and the sub-branch line.
  • FIGS. 1 (a) and (b) can be shown as by equilavent circuit in FIG. 9. Accordingly, the same operation can be obtained by using lumped constant elements without using a distribution constant line to provide a miniaturized and compact unit particularly for low frequency use.
  • FIG. 10 is a schematic view of an isolator similar to that of FIG. 1 except that the branch line (4) is substituted with an inductance (4a), such as a coil, and the sub-branch line (5) is substituted with a condenser (50).
  • branch line (4) is substituted with an inductance (4a), such as a coil
  • sub-branch line (5) is substituted with a condenser (50).
  • FIG. 11 shows a preferred embodiment of an isolator wherein a ferrimagnetic material (6) is placed in the dielectric substrate (2) and the main line (la) and (lb), the inductance (4a) and the condenser (5a) are formed on the surface in a conductive pattern by employing metallization. metal plating, etching or printing technology.
  • the ferrimagnetic material is placed in the dielectric substrate (2), it is to be understood that it is possible to substitute the dielectric substrate and the ferrimagnetic material by a single sheet of a ferrimagnetic substrate. Also the embodiments of FIGS. 10 and 11 can be applied to not only the microstrip type line but also to the triplate type strip line. Various types of inductances and condensers can be used and it is preferable to select them so as to be convenient for the particular use desired.
  • FIG. 12 is a schematic view of another preferred embodiment of the isolator of the present invention wherein two unilateral attenuators are-connected in series so that it is unnecessary to have as great an inverse loss for each one. Accordingly, the forward loss for each attenuator can be overly small, and it is possible to use the part having'superior frequency characteristics of forward loss. Accordingly, as a whole, it is possible to obtain an isolator having a miniaturized compact size and high frequency characteristics of forward loss and a broad band zone of inverse loss.
  • FIG. 13 is a schematic view of yet another preferred embodiment of the isolator of the present invention wherein different lengths of the end short-circuit branch line (8a) and (8b) or different lengths of the end open sub-branch line are formed so as to deviate the frequency causing the circularly polarized radio frequency magnetic field.
  • the frequency band of the inverse loss becomes a broader band then that of FIG. 12, though the forward loss and VSWR frequency characteristics are relatively lower than those of FIG. 12.
  • An isolator which comprises:

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US00381623A 1972-07-26 1973-07-23 Isolator Expired - Lifetime US3835420A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP7483272A JPS4933539A (enrdf_load_stackoverflow) 1972-07-26 1972-07-26
JP7814872A JPS5228540B2 (enrdf_load_stackoverflow) 1972-08-04 1972-08-04
JP11271572A JPS4970556A (enrdf_load_stackoverflow) 1972-11-10 1972-11-10

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US3835420A true US3835420A (en) 1974-09-10

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US00381623A Expired - Lifetime US3835420A (en) 1972-07-26 1973-07-23 Isolator

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US (1) US3835420A (enrdf_load_stackoverflow)
DE (2) DE2366544C2 (enrdf_load_stackoverflow)
FR (1) FR2197245B1 (enrdf_load_stackoverflow)
GB (1) GB1446778A (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3978433A (en) * 1974-05-15 1976-08-31 Yoshiyuki Naito Magnetic transmission devices using the edge-guided mode of propagation
US4101850A (en) * 1977-04-18 1978-07-18 Motorola, Inc. Uhf isolator using stacked conductor sheets
US4110712A (en) * 1975-05-14 1978-08-29 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Microstrip circuit having coplanar waveguide port
US5293140A (en) * 1991-01-02 1994-03-08 Motorola, Inc. Transmission line structure
EP1939973A4 (en) * 2005-10-21 2008-12-24 Murata Manufacturing Co IRREVERSIBLE CIRCUIT ELEMENT, METHOD FOR MANUFACTURING SAME, AND COMMUNICATION DEVICE
US20120056690A1 (en) * 2010-09-03 2012-03-08 Murata Manufacturing Co., Ltd. Magnetic resonance type isolator
US8319576B2 (en) * 2009-12-26 2012-11-27 Murata Manufacturing Co., Ltd. Magnetic resonance isolator
WO2014083881A1 (ja) * 2012-11-27 2014-06-05 株式会社村田製作所 フェライト吸収型アイソレータ

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2131627B (en) * 1982-12-03 1987-08-26 Raytheon Co A magnetically tuned resonant circuit
US4600906A (en) * 1982-12-03 1986-07-15 Raytheon Company Magnetically tuned resonant circuit wherein magnetic field is provided by a biased conductor on the circuit support structure
US4543543A (en) * 1982-12-03 1985-09-24 Raytheon Company Magnetically tuned resonant circuit
JPH01186001A (ja) * 1988-01-20 1989-07-25 Hitachi Metals Ltd 共鳴吸収型マイクロストリップラインアイソレータ

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3289112A (en) * 1964-08-31 1966-11-29 Charles E Brown Strip transmission line ferrite filterlimiter having a ferrite sphere positioned beneath overlapping conductors
US3560892A (en) * 1967-12-06 1971-02-02 Lignes Telegraph Telephon Microstrip devices having strip conductor coated on ferrite substrate

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR75174E (enrdf_load_stackoverflow) * 1956-09-24 1961-09-08
FR1572321A (enrdf_load_stackoverflow) * 1968-04-04 1969-06-27

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3289112A (en) * 1964-08-31 1966-11-29 Charles E Brown Strip transmission line ferrite filterlimiter having a ferrite sphere positioned beneath overlapping conductors
US3560892A (en) * 1967-12-06 1971-02-02 Lignes Telegraph Telephon Microstrip devices having strip conductor coated on ferrite substrate

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Marriage et al., Some Non Reciprocal Coaxial Devices at 2 Gc/s, Part B Supple., Int l. Conf. on Components & Mat ls. used in Elect. Engr., June 1961. *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3978433A (en) * 1974-05-15 1976-08-31 Yoshiyuki Naito Magnetic transmission devices using the edge-guided mode of propagation
US4110712A (en) * 1975-05-14 1978-08-29 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Microstrip circuit having coplanar waveguide port
US4101850A (en) * 1977-04-18 1978-07-18 Motorola, Inc. Uhf isolator using stacked conductor sheets
US5293140A (en) * 1991-01-02 1994-03-08 Motorola, Inc. Transmission line structure
EP1939973A4 (en) * 2005-10-21 2008-12-24 Murata Manufacturing Co IRREVERSIBLE CIRCUIT ELEMENT, METHOD FOR MANUFACTURING SAME, AND COMMUNICATION DEVICE
US8319576B2 (en) * 2009-12-26 2012-11-27 Murata Manufacturing Co., Ltd. Magnetic resonance isolator
US20120056690A1 (en) * 2010-09-03 2012-03-08 Murata Manufacturing Co., Ltd. Magnetic resonance type isolator
US8279017B2 (en) * 2010-09-03 2012-10-02 Murata Manufacturing Co., Ltd. Magnetic resonance type isolator
WO2014083881A1 (ja) * 2012-11-27 2014-06-05 株式会社村田製作所 フェライト吸収型アイソレータ

Also Published As

Publication number Publication date
FR2197245A1 (enrdf_load_stackoverflow) 1974-03-22
DE2338014C2 (de) 1983-03-24
GB1446778A (en) 1976-08-18
DE2366544C2 (de) 1984-09-13
DE2338014A1 (de) 1974-02-07
FR2197245B1 (enrdf_load_stackoverflow) 1980-04-11

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