JP2606381Y2 - Stripline type non-reciprocal circuit device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a strip line type non-reciprocal circuit device which is one of components of a microwave integrated circuit.

[0002]

2. Description of the Related Art A strip line type non-reciprocal circuit device such as an isolator or a circulator as shown in FIG. 5 is used in a microwave integrated circuit in a communication device in a microwave band. FIG. 1A shows a type called a substrate type without a carrier. A ground conductor film is formed on the lower surface of the ferrite substrate 1, and a conductor film of a predetermined pattern constituting a strip line for an isolator or a circulator is formed on the upper surface. (All are not shown).

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 via an insulating spacer 4 therebetween.
Similarly, a columnar permanent magnet 3 is integrally joined to the center of the lower surface of the ferrite substrate 1. These permanent magnets 2 and 3
As a result, a magnetic field perpendicular to the substrate surface is applied to the center of the isolator / circulator pattern of the ferrite substrate 1. There is 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 upper permanent magnet 2 are integrally mounted on a carrier 5 made of a metal plate.

[0005]

In the strip line type non-reciprocal circuit device as described above, the ferrite substrate 1
The permanent magnet 2 is almost in close contact with the strip line forming surface on the surface of the solid line, and the permanent magnet 2 is electromagnetically coupled to the strip line to prevent the microwave transmitted to the strip line from the permanent magnet 2. Acts as an antenna or a resonator, and unnecessary radiation loss occurs in this portion.

Therefore, as indicated by the dotted line in FIG. 2, the insertion loss in a specific frequency band is significantly increased in the insertion loss / frequency characteristics of the nonreciprocal circuit device. There is no problem if the increased portion of the insertion loss is different from the used frequency band, but it is a serious problem that the insertion loss increases in the used frequency band.

[0007] The frequency at which 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 substantially determined by the size, shape, and volume of the permanent magnet 2.

[0008] In recent communication equipment and the like, the frequency band used has been increasing from quasi-millimeter waves to millimeter waves. In order to cope with a higher frequency in the stripline type nonreciprocal circuit element as described above, it is necessary to increase the DC magnetic field applied to the ferrite substrate 1, and therefore, the permanent magnet 2 combined with the ferrite substrate 1 has a larger size. Will be transformed. As the size of the permanent magnet 2 increases, the unnecessary radiation from the above-described magnet increases, the frequency range in which adverse effects are affected is widened, and the frequency range often overlaps with the used frequency band.

In a conventional strip line type non-reciprocal circuit device, when a microwave circuit is formed together with other devices and housed in a predetermined case structure, when a metal case approaches the permanent magnet 2, the case may be changed. Electromagnetic coupling causes unwanted radiation. At that time, the insertion loss characteristics change before and after the case is attached, but the circuit design must be made in consideration of this fact, and if the case structure or mounting condition changes, the circuit insertion loss will change and the operating characteristics will change. May worsen.

The present invention has been made in view of the above-mentioned background, and an object of the present invention is to make it possible to easily prevent a frequency band in which unnecessary radiation by a permanent magnet is generated from overlapping with a used frequency band. It is another object of the present invention to provide a strip line type non-reciprocal circuit device capable of preventing a characteristic from changing according to a state of a case covering the device.

[0011]

In order to achieve the above object, in a strip line type nonreciprocal circuit device according to the present invention, a strip line having a predetermined pattern is formed on a surface of a ferrite substrate and a predetermined position of the substrate is determined. In a strip line type non-reciprocal circuit device integrally joined with a permanent magnet for applying a magnetic field perpendicular to the substrate surface, unnecessary radiation by the permanent magnet is provided at an appropriate position of the permanent magnet.
Conductive members that change the frequency characteristics of the
Frequency band where unnecessary radiation is generated by the permanent magnet and usage frequency
The wavebands were configured differently.

[0012]

When the appropriate conductive member is integrally joined to the permanent magnet, the resonance frequency viewed from the strip line on the ferrite substrate is greatly changed from that of the magnet alone, and the frequency of unnecessary radiation by the magnet is therefore reduced. Characteristics and loss amount change. As a result, the adverse effect of the insertion loss due to the magnet in the operating frequency band can be eliminated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a first embodiment of the present invention, which is a substrate type embodiment without a carrier.
As in 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 forming a strip line for an isolator or a circulator is formed on the upper surface (both are not shown). ). In addition, the isolator on the top surface of the ferrite substrate 1
Cylindrical permanent magnet 2 in the center of the circulator pattern
Are integrally joined via an insulating spacer 4 therebetween, and similarly, a columnar permanent magnet 3 is integrally joined to the lower surface of the ferrite substrate 1 (the same position as the center of the isolator / circulator pattern on the upper surface). I have. By these permanent magnets 2 and 3, a DC magnetic field perpendicular to the substrate surface is applied to the center of the isolator / circulator pattern of the ferrite substrate 1.

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

By integrally joining the metal disk 6 to the upper end surface of the permanent magnet 2 as described above, the resonance frequency viewed from the strip line (isolator or circulator circuit pattern) on the ferrite substrate 1 is reduced by the magnet. This greatly changes from the single case, and accordingly, the amount of loss with respect to the frequency characteristics of unnecessary radiation by the magnet changes. Thereby, as shown by the solid line in FIG. 2, it is possible to eliminate the adverse effect of the insertion loss due to the magnet in the operating frequency band. That is, the unnecessary radiation moves outside the passage area of the isolator / circulator, and does not affect the characteristics.

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

FIG. 3 shows a non-reciprocal 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 a carrier 5 made of a metal plate. Also in this type, as in FIG.
A metal disk 6 is integrally joined to the upper surface of the cylindrical permanent magnet 2.

If the thin metal disk 6 is used as the conductive member to be joined to the permanent magnet 2, an 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, but various forms as illustrated in FIG. That is, in FIG. 1A, a cylindrical cap 7 made of sheet metal is employed as the conductive member, and the cylindrical cap 7 is placed on the upper end of the cylindrical permanent magnet 2 from above. In this embodiment, the effect of preventing the characteristic change due to the case described above is particularly large. In FIG. 1B, a metal ring 8 is employed as the conductive member, and is fitted on the outer periphery of the upper end of the columnar permanent magnet 2. In this embodiment, the overall height of the circuit element is not increased at all. Further, as shown in FIG. 3C, the outer periphery of the cylindrical permanent magnet 2 is covered with a cylindrical holder 9 made of an insulating material such as plastic or ceramic. Various modes can be taken, for example, the plate 6 may be arranged. In the case of the structure shown in FIG. 3C, the insulating spacer 4 can be omitted by bonding the permanent magnet 2 to the metal disk 6 indicated by the holder 9.

[0019]

As described above in detail, according to the present invention, a conductive member is integrally joined to an appropriate position of a permanent magnet for applying a DC magnetic field to a ferrite substrate constituting an isolator or a circulator. By making a simple improvement, the resonance frequency viewed from the strip line on the ferrite substrate greatly changes as compared with the case of using only the magnet, and therefore, the amount of loss with respect to the frequency characteristic of unnecessary radiation by the magnet changes. As a result, the adverse effect of the insertion loss due to the magnet in the operating frequency band can be eliminated. Further, it is possible to prevent the characteristics from being changed depending on the state of the case covering the circuit element.

[Brief description of the drawings]

FIG. 1 is a front view showing a schematic configuration of a non-reciprocal 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 non-reciprocal circuit device according to a second embodiment of the present invention.

FIG. 4 is a partial front view showing a main 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]

Reference Signs List 1 ferrite substrate 2 permanent magnet 3 permanent magnet 4 insulating spacer 5 carrier 6 metal disk (conductive member) 7 sheet metal cylindrical cap (conductive member) 8 metal ring (conductive member) 9 made of insulating material such as plastic or ceramic Cylindrical holder

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-216402 (JP, A) JP-A-3-84606 (JP, U) JP-A-1-149107 (JP, U) 48441 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01P 1/32-3/397

Claims (4)

(57) [Scope of request for utility model registration] 1. A strip line type non-linear type wherein a strip line of a predetermined pattern is formed on a surface of a ferrite substrate and a permanent magnet for applying a magnetic field perpendicular to the substrate surface is integrally joined to a predetermined position of the substrate. In the reversible circuit element, unnecessary radiation caused by the permanent magnet is provided at an appropriate position of the permanent magnet.
Conductive members that change the frequency characteristics of radiation
However, the frequency band in which unnecessary radiation is
A strip line type non-reciprocal circuit device characterized by having different frequency bands for use . 2. The permanent magnet has a cylindrical shape, and a lower end surface thereof is joined to the ferrite substrate, and the conductive member is formed in a disk shape having a larger diameter than the cylindrical permanent magnet. 2. The strip line type non-reciprocal circuit device according to claim 1, wherein a plate-shaped conductive member is concentrically joined to an upper end surface of the columnar permanent magnet. 3. The permanent magnet has a cylindrical shape, a lower end surface 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 the cylindrical permanent magnet. 2. The strip line type non-reciprocal circuit device according to claim 1, wherein said cap-shaped conductive member is fitted and joined to an upper end portion of said cylindrical permanent magnet. 4. The permanent magnet has a cylindrical shape, a lower end surface thereof is joined to the ferrite substrate side, and the conductive member is formed in a ring shape whose inner diameter is slightly larger than the cylindrical permanent magnet. The strip line type non-reciprocal 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 columnar permanent magnet.