JP2000174510A - Irreversible circuit element and mobile communication unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance an insertion loss characteristic of an isolator that is one of major components of a mobile communication unit such as an automobile telephone set and a portable telephone set used at VHF/UHF band by improving the magnetization distribution of a ferrite disk in the isolator. SOLUTION: In the irreversible circuit element consisting of a center conductor section 4, where three strip lines are placed in contact onto an upper face of a ferrite disk at an angular distance of 120 degrees through electric insulation, one terminal of which is connected to a matching capacitor and the other terminal of which is connected to a ground face 3, the matching capacitors, a termination resistor 24 connected in parallel with one of the three matching capacitors, input output terminals 22, 23, ground terminals 25, 26, and magnetic cases 1, 14 that have shield and magnetic path effects, a dielectric layer with an excellent high frequency characteristic is placed between a lower side of the ferrite disk and the ground face 3 opposite thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an isolator which is one of the main components of a mobile communication device such as a mobile phone and a mobile phone used in the VHF and UHF bands.

[0002]

2. Description of the Related Art Hitherto, a non-reciprocal circuit device used in a high-frequency region of a cellular phone or the like is a lumped-constant isolator configured as shown in FIGS. This conventional example is shown in FIG.
The configuration will be described with reference to FIG. This isolator is connected to the ground plane 3 of the dielectric substrate 29 by the inner surface of the lower part 28 of the metallic magnetic case.
The 0 side is connected by soldering, the center conductor portion 32 is inserted into the center hole 31 of the dielectric substrate 29, and the circular ground plate 33 is soldered to the inner surface of the lower side 28 of the case made of a metal magnetic material. As shown in FIG. 7, the center conductor portion 32 has a ferrite disk 34 disposed on a circular grounding plate 33, and insulates three strip lines 35, 36, 37 from each other via insulating sheets 38, 39 to form a 120 ° Cross each other, ferrite disk 3
4 is bent and arranged along the upper surface. A DC magnetic field is applied to the ferrite disk 34 by a permanent magnet 40 in a direction perpendicular to the plane. The permanent magnet 40 is disposed on the opposite side of the ferrite disk 34 with respect to the strip lines 35, 36, and 37, and is placed in contact with the inside of the upper portion 41 of the metallic magnetic case.

[0003] On the upper surface of the dielectric substrate 29, three electrode surfaces 421, 431, 441 for soldering one terminal of the matching capacitors 42, 43, 44 are formed. These electrodes are connected to the grounding electrode surface 30 on the back surface through respective through holes.

The connection terminals 45, 46, 47 at the ends of the strip lines bent on the ferrite are each soldered to the other terminals of the three matching capacitors. Of these matching capacitors 42 and 43, they are respectively connected to input and output terminals 48 and 49 for external connection with extensions of the strip line terminals. A terminating resistor 50 is connected in parallel to the matching capacitor 44, and the other end is grounded. The external connection ground terminals 51 and 52 are connected to the ground electrode 30 provided on the back surface of the dielectric substrate 29. In the case, the case upper side 41 made of a metallic magnetic material is wrapped around a permanent magnet, and the case lower side 28 is overlapped with the end, and then the part is connected by soldering.

[0005]

However, in the structure of the conventional isolator, since the distance between the ferrite disk 34 and the lower side 28 of the case is small, the magnetic flux generated from the permanent magnet 40 is a metal magnetic material. Upper side 41, lower side 28
When the magnetic flux passes through the ferrite disk 34 through the ferrite disk 34, the magnetic flux density in the outer peripheral portion becomes higher than the central portion of the ferrite disk 34, and the magnetization distribution in the ferrite disk 34 deteriorates.

In view of the above problems of the conventional isolator, the present invention improves the magnetization distribution in the ferrite disk, greatly reduces the insertion loss, which is the isolator characteristic, and provides an irreversible having excellent transmission characteristics. It is an object to provide a circuit element.

[0007]

According to the present invention, a dielectric layer having excellent characteristics against high frequencies is sandwiched between a ferrite disk and a circular grounding plate, and the distance between the lower case of the metallic magnetic material and the ferrite disk is increased. By providing them, the magnetization distribution of the ferrite disk is improved, and the insertion loss of the isolator is reduced.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are views for explaining the configuration of an isolator as a non-reciprocal circuit device according to an embodiment of the present invention. The lower surface of the dielectric substrate 2 is solder-connected to the lower surface 1 of the metallic magnetic material on the side of the ground electrode 3, and the center conductor 4 is inserted into the center hole 27 of the dielectric substrate 2 so that the circular ground plate 5 Is soldered to the inner surface of the lower side 1 of the case made of a metal magnetic material. The ground electrode surface 3 has a dielectric substrate 2
The same hole as the center hole 27 is provided.

As shown in FIG. 2, the center conductor portion 4 has a dielectric layer 6 disposed on a circular ground plate 5 and between a ferrite disk 7 and three strip lines 8, 9 and 10 to form an insulating sheet. They are insulated from each other via 11 and 12 and intersect every 120 degrees, and are bent and arranged along the upper surface of the ferrite disk 7.

A DC magnetic field is applied to the ferrite disk 7 by a permanent magnet 13 in a direction perpendicular to the plane. At this time, the permanent magnet 13 is arranged on the opposite side of the ferrite disk 7 with respect to the strip lines 8, 9 and 10, and is placed in contact with the inside of the upper portion 14 of the metal magnetic case.

The three electrodes 161, 171 and 181 provided on the upper surface 15 of the dielectric substrate 2
17 and 18 are connected by soldering. These three electrodes are connected to the grounding electrode surface 3 on the back surface by through holes in the main body 200 of the dielectric substrate 2.

The connection terminals 19 at the ends of the strip lines 8, 9, 10 bent on the ferrite disk 7,
20, 21 are matching capacitors 16, 17, 18 respectively.
Are soldered to the upper surface terminals 162, 172, 182. Of these terminals, 19 and 20, respectively, are connected to input and output terminals 22 and 23 for external connection with extensions of the terminals of each strip line.

A terminating resistor 24 is connected in parallel to the matching capacitor 18 and the other end is grounded. The external connection ground terminals 25 and 26 are connected to the ground electrode 3 provided on the back surface of the dielectric substrate 2. Upper case 1 made of magnetic metal
4 is put on the permanent magnet 13 so that the lower part 1 of the case and the end are overlapped, and the part is connected with solder.

FIG. 3 shows a dielectric layer 6 according to the present embodiment.
The magnetization distribution in the radial direction of the ferrite disk 7 when the distance between the lower surface of the ferrite disk 7 and the circular ground plate 3 was changed by changing the thickness of the ferrite disk 7 was shown. Distance from 50 μm
As the diameter increases to 150 μm, the magnetization distribution in the ferrite improves. However, when the thickness is set to 200 μm, the entire magnetization intensity of the ferrite disk 7 becomes weak.

FIG. 4 shows the insertion loss of the isolator when the distance is changed by changing the thickness of the dielectric layer 6. When the thickness is 200 μm, the insertion loss becomes worse.
This is because the distance was increased and the magnetization intensity of the ferrite disk 7 was weakened. The strength could be slightly improved by increasing the strength of the permanent magnet 13, but good characteristics such as 50 μm to 150 μm could not be obtained.

FIGS. 3 and 4 show the results obtained by changing the thickness of the dielectric layer 6 such as polyimide or Teflon between the ferrite disk 7 and the inner surface 3 on the lower side of the case. When the used glass epoxy is used for the dielectric layer 6, the insertion loss becomes worse than the former. This is because the dielectric loss at high frequencies is large.

FIG. 5 compares the insertion loss of the isolator at a distance of 100 μm when using three types of polyimide, Teflon, and glass epoxy.

The dielectric layer 6 may have a tacky adhesive on both sides and may be bonded in advance to the lower surface of the ferrite or the ground plane facing the lower surface of the ferrite.

[0020]

As is apparent from the above description, the present invention can provide a non-reciprocal circuit device which stably achieves high performance without deteriorating the size as well as the thickness.

[Brief description of the drawings]

FIG. 1 is a structural diagram of a non-reciprocal circuit device of the present invention.

FIG. 2 is a structural diagram of a center conductor according to the present invention.

FIG. 3 is a graph showing a magnetization distribution in a radial direction of a ferrite disk.

FIG. 4 is a graph showing the insertion loss of the distance between the bottom surface of the ferrite disk and the bottom surface of the case.

FIG. 5 is a graph showing insertion loss when a polyimide, Teflon, or glass epoxy material having a thickness of 100 μm is inserted between the bottom surface of the ferrite disk and the bottom surface of the case.

FIG. 6 is a structural view of a conventional example.

FIG. 7 is a structural diagram of a center conductor of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower case 2 Dielectric substrate 3 Ground electrode of dielectric substrate 2 4 Center conductor 5 Circular ground plate 6 Dielectric layer 7 Ferrite disk 8, 9, 10 Strip line 11, 12 Insulating sheet 13 Permanent magnet 14 Upper case 15 Upper surface of the dielectric substrate 2 16, 17, 18 Matching capacitors 19, 20, 21 Terminals for connecting strip line ends 22, 23 Input and output terminals for external connection 25 Terminating resistors 25, 26 Ground terminals for external connection

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuhiko Horio 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 5J013 EA01 FA06

Claims (5)

[Claims] 1. One end of each of three strip lines arranged so as to be insulated and in contact with an upper surface of a ferrite disk at an interval of 120 degrees is connected to three matching capacitors and the other end. A center conductor having an end connected to the ground plane, a matching capacitor, a terminating resistor connected in parallel to one of the three matching capacitors, an input / output terminal, and a ground. In a non-reciprocal circuit device including a terminal for use, a shield and a magnetic case having the effect of a magnetic path, a dielectric material having a predetermined high-frequency characteristic is provided between the lower surface of the ferrite disk and the ground surface opposed thereto. A non-reciprocal circuit device comprising a body layer. 2. The non-reciprocal circuit device according to claim 1, wherein said dielectric layer is made of polyimide or Teflon. 3. The thickness t of the dielectric layer is 0 <t ≦ 150.
2. The non-reciprocal circuit device according to claim 1, wherein the thickness is μm. 4. The non-reciprocal circuit according to claim 1, wherein the dielectric layer has an adhesive on both sides and is bonded in advance to a lower surface of the ferrite or a ground plane facing the lower surface of the ferrite. element. 5. A mobile communication device using the non-reciprocal circuit device according to claim 1 as an isolator.