JPH0716404U - Strip line type non-reciprocal circuit device - Google Patents

Abstract

(57) [Abstract] [Purpose] It is easy to prevent the frequency band in which unwanted radiation from permanent magnets is generated from overlapping the frequency band used, and to prevent the characteristics from changing depending on the state of the case that covers the element. PROBLEM TO BE SOLVED: To provide a non-reciprocal circuit element [Configuration] A permanent magnet 2 for forming a strip line of a predetermined pattern on a surface of a ferrite substrate 1 and applying a magnetic field perpendicular to the substrate surface at a predetermined position of the substrate.
In the strip line type non-reciprocal circuit element in which the metal disks 6 are integrally bonded, the metal disk 6 is integrally bonded to an appropriate position of the permanent magnet 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a strip line type nonreciprocal circuit device which is one of the components of a microwave integrated circuit.

[0002]

[Prior art]

 Stripline nonreciprocal circuit elements such as isolators and circulators of the type illustrated in FIG. 5 are used in microwave integrated circuits in microwave band communication equipment and the like. FIG. 1A shows a type called a carrier-less substrate type, in which a ground conductor film is formed on the lower surface of the ferrite substrate 1 and a conductor of a predetermined pattern that forms a strip line for an isolator or circulator on the upper surface. A film is formed (all are not shown).

A cylindrical permanent magnet 2 is integrally bonded to the center of the isolator / circulator pattern on the upper surface of the ferrite substrate 1 with an insulating spacer 4 interposed therebetween, and similarly, a cylinder is formed on the lower surface of the ferrite substrate 1 at the center. Shaped permanent magnets 3 are integrally joined. By these permanent magnets 2 and 3, a magnetic field perpendicular to the substrate surface is applied to the central portion of the isolator / circulator pattern of the ferrite substrate 1. There is also a configuration in which only one of the upper and lower permanent magnets is provided.

FIG. 1B shows an element with a carrier. There is no permanent magnet on the lower surface side of the ferrite substrate 1, and the entire ferrite substrate 1 and the upper permanent magnet 2 are integrally mounted on a carrier 5 made of a metal plate.

[0005]

[Problems to be solved by the device]

 In the strip line type non-reciprocal circuit device as described above, the permanent magnet 2 is bonded to the surface of the ferrite substrate 1 on which the strip line is formed almost in close contact. The permanent magnet 2 is electromagnetically coupled to the strip line. The permanent magnet 2 acts as an antenna or a resonator for the microwaves that are coupled and transmitted to the strip line, causing unnecessary radiation loss in this portion.

Therefore, as shown by the dotted line in FIG. 2, in the insertion loss / frequency characteristic of the non-reciprocal circuit device, the insertion loss becomes significantly large in a specific frequency band. There is no problem if most of this insertion loss is different from the used frequency band, but the increase of insertion loss in the used frequency band is a serious problem.

The frequency at which the radiation loss is increased by the permanent magnet is strongly related to the characteristic value of the permanent magnet. If the strip line pattern of the ferrite substrate 1 is the same and the material of the permanent magnet 2 is the same, the frequency at which unnecessary radiation (unnecessary mode) occurs is almost determined by the size, shape and volume of the permanent magnet 2.

[0008] In recent communication devices and the like, the usage band has been increasing from quasi-millimeter wave to millimeter wave. In order to cope with higher frequency in the strip line type non-reciprocal circuit device as described above, it is necessary to increase the DC magnetic field applied to the ferrite substrate 1. Therefore, the permanent magnet 2 combined with the ferrite substrate 1 is It will be larger. As the permanent magnet 2 becomes larger, the unnecessary radiation by the magnet becomes larger, the frequency range in which the adverse effect is exerted becomes wider, and the permanent magnet 2 often overlaps with the used frequency band.

Further, in the conventional strip line type nonreciprocal circuit element, when a metal case approaches the permanent magnet 2 when a microwave circuit is formed together with other elements in a predetermined case structure. It is also electromagnetically coupled to the case to generate unwanted radiation. At that time, the characteristics of the insertion loss change before and after mounting the case, but the circuit design must be made in consideration of this, and if the case structure or mounting condition changes, the insertion loss of the circuit changes and The characteristics may deteriorate.

The present invention has been made in view of the above background, and an object of the present invention is to easily prevent a frequency band in which unnecessary radiation due to a permanent magnet is generated from overlapping a used frequency band. Another object of the present invention is to provide a strip line type non-reciprocal circuit device capable of preventing the characteristics from changing depending on the state of the case covering the device.

[0011]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, in the stripline nonreciprocal circuit device according to the present invention, a stripline having a predetermined pattern is formed on the surface of a ferrite substrate, and a magnetic field perpendicular to the substrate surface is placed at a predetermined position on the substrate. In a strip line type non-reciprocal circuit device in which a permanent magnet for applying a voltage is integrally joined, a conductive member is integrally joined at an appropriate position of the permanent magnet.

[0012]

[Action]

 By integrally joining an appropriate conductive member to the permanent magnet, the resonance frequency seen from the strip line on the ferrite substrate greatly changes as compared with the case of the magnet alone, and therefore the frequency characteristics of unnecessary radiation by the magnet and The amount of loss changes. This makes it possible to eliminate the adverse effects of insertion loss due to the magnet in the used frequency band.

[0013]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a first embodiment of this idea, which is a carrier-less substrate-type embodiment. Similar to the above-described conventional configuration, a ground conductor is formed on the lower surface of the ferrite substrate 1, and a conductor film having a predetermined pattern that forms a strip line for an isolator or a circulator is formed on the upper surface (both shown in the drawings). Omitted). In addition, a cylindrical permanent magnet 2 is integrally joined to the center of the isolator / circulator pattern on the upper surface of the ferrite substrate 1 with an insulating spacer 4 interposed therebetween. A cylindrical permanent magnet 3 is integrally joined to the center portion of the isolator / circulator pattern). A DC magnetic field perpendicular to the surface of the ferrite substrate 1 is applied to the central portion of the isolator / circulator pattern of the ferrite substrate 1 by these permanent magnets 2 and 3.

In the embodiment of FIG. 3, the metal disk 6 as the above-mentioned conductive member is integrally joined to the upper end surface of the permanent magnet 2 on the upper surface side of the substrate 1. The diameter of the metal disk 6 is larger than that of the cylindrical magnet 2, and the metal disk 6 is concentrically joined to the magnet 2 and the outer periphery thereof projects like a flange around the magnet 2. The means for joining the metal disk 6 to the magnet 2 may be adhesion or welding.

By integrally bonding the metal disk 6 to the upper end surface of the permanent magnet 2 as described above, the resonance frequency seen from the strip line (the circuit pattern of the isolator or the circulator) on the ferrite substrate 1 is increased. There is a large change from the case of using a magnet alone, and therefore the amount of loss with respect to the frequency characteristics of unwanted radiation by the magnet changes. As a result, as shown by the solid line in FIG. 2, the adverse effect of insertion loss due to the magnet in the used frequency band can be eliminated. That is, such unnecessary radiation does not affect the characteristics because it moves to outside the passage area of the isolator / circulator.

Moreover, since the upper surface side of the magnet 2 is previously covered with the metal disk 6, when the nonreciprocal circuit device is mounted on a device board together with other devices and housed in a case, Even if the case is very close to the non-reciprocal circuit element, unnecessary radiation does not increase due to the case.

FIG. 3 shows a nonreciprocal circuit device with a carrier according to a second embodiment of the present invention. Here, there is no permanent magnet on the lower surface side of the ferrite substrate 1, and the ferrite substrate 1 is integrally mounted on the carrier 5 made of a metal plate. Also in this type, as in FIG. 1, the metal disk 6 is integrally joined to the upper surface of the cylindrical permanent magnet 2.

By the way, if the thin metal disk 6 as described above is used as the conductive member joined to the permanent magnet 2, the increase in the overall height of the circuit element can be minimized. However, the form of the conductive member is not limited to the metal disk 6, and various forms as illustrated in FIG. 4 are conceivable. That is, in FIG. 1A, a cylindrical cap 7 made of sheet metal is adopted as the conductive member, and the upper end portion of the cylindrical permanent magnet 2 is covered with the conductive cap from above. In this embodiment, the effect of preventing the characteristic change due to the case described above is particularly large. Further, in FIG. 2B, a metal ring 8 is used as the conductive member, and this is fitted into the outer periphery of the upper end of the cylindrical permanent magnet 2. This embodiment does not increase the overall height of the circuit element at all. Further, as shown in FIG. 3C, the outer circumference of the cylindrical permanent magnet 2 is covered with a cylindrical holder 9 made of an insulating material such as plastic or ceramics, and the holder 9 and the upper end surface of the magnet 2 are covered with metal. Various aspects such as the arrangement of the disc 6 may be adopted. In the case of the structure shown in FIG. 6C, the insulating spacer 4 can be omitted by bonding the permanent magnet 2 to the metal disk 6 indicated by the holder 9.

[0019]

[Effect of device]

 As described in detail above, according to the present invention, an extremely simple improvement in which a conductive member is integrally joined to an appropriate position of a permanent magnet for applying a DC magnetic field to a ferrite substrate which constitutes an isolator or a circulator. By doing so, the resonance frequency seen from the strip line on the ferrite substrate changes significantly as compared with the case of the magnet alone, and therefore the loss amount with respect to the frequency characteristic of unnecessary radiation by the magnet changes. This can eliminate the adverse effects of insertion loss due to magnets in the operating frequency band. Further, it is possible to prevent the characteristics from changing depending on the state of the case that covers the circuit element.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of a nonreciprocal circuit device according to a first embodiment of the present invention.

FIG. 2 is a graph showing insertion loss / frequency characteristics of a conventional non-reciprocal circuit device and a non-reciprocal circuit device obtained by improving the present invention.

FIG. 3 is a front view showing a schematic configuration of a nonreciprocal circuit device according to a second embodiment of the present invention.

FIG. 4 is a partial front view showing an essential part of a non-reciprocal circuit device according to another embodiment of the present invention.

FIG. 5 is a front view showing a schematic configuration of a conventional non-reciprocal circuit device.

[Explanation of symbols]

1 Ferrite Substrate 2 Permanent Magnet 3 Permanent Magnet 4 Insulating Spacer 5 Carrier 6 Metal Disk (Conductive Member) 7 Cylindrical Cap Made of Sheet Metal (Conductive Member) 8 Metal Ring (Conductive Member) 9 Made of Insulating Material such as Plastic / Ceramics Cylindrical holder

Claims (4)

[Scope of utility model registration request] 1. A strip line type non-woven fabric comprising a ferrite substrate on which a strip line having a predetermined pattern is formed, and a permanent magnet for applying a magnetic field perpendicular to the surface of the substrate is integrally joined to a predetermined position of the substrate. In the reversible circuit element, a strip line type non-reciprocal circuit element, characterized in that a conductive member is integrally joined to an appropriate position of the permanent magnet. 2. The permanent magnet has a cylindrical shape, the lower end surface side thereof is joined to the ferrite substrate side, and the conductive member is formed in a disk shape having a diameter larger than that of the cylindrical permanent magnet. The strip line type nonreciprocal circuit device according to claim 1, wherein a plate-shaped conductive member is concentrically joined to an upper end surface of the cylindrical permanent magnet. 3. The permanent magnet has a cylindrical shape, the lower end surface side thereof is joined to the ferrite substrate side, and the conductive member is formed in a cylindrical cap shape whose inner diameter is slightly larger than that of the cylindrical permanent magnet. 2. The strip line type nonreciprocal circuit device according to claim 1, wherein the cap-shaped conductive member is fitted and joined to the upper end of the cylindrical permanent magnet. 4. The permanent magnet has a cylindrical shape, the lower end surface side thereof is joined to the ferrite substrate side, and the conductive member is formed in a ring shape having an inner diameter slightly larger than that of the cylindrical permanent magnet. The strip line type nonreciprocal circuit device according to claim 1, wherein a ring-shaped conductive member is fitted and joined to an outer peripheral portion of an upper end of the cylindrical permanent magnet.