WO2011118278A1 - Nonreciprocal circuit element - Google Patents

Abstract

Disclosed is a nonreciprocal circuit element that achieves broadband with insertion loss and isolation characteristics, and easily adjusts port unit impedance. A circulator has at least one-turn winding of a first, a second and a third center electrode (21), (22), (23) on ferrite (25) charged with a direct current field by a permanent magnet. Each of a first matching capacitor element (C1), (C2), (C3) is connected between ends of each center electrode (21), (22), and (23) and a ground. A second matching capacitor element (Cs1) is connected between a first port (P1) and the first center electrode (21); a second matching capacitor element (Cs2) is connected between a second port (P2) and the second center electrode (22); and a second matching capacitor element (Cs3) is connected between a second port (P3) and the third center electrode (23).

Description

Non-reciprocal circuit element

The present invention relates to non-reciprocal circuit elements, and more particularly to non-reciprocal circuit elements such as isolators and circulators used in the microwave band.

Conventionally, as a circulator (non-reciprocal circuit element) employed in a mobile communication device such as a mobile phone, as described in Patent Document 1, a permanent magnet and a ferrite to which a DC magnetic field is applied by the permanent magnet are used. There are known ones composed of three center electrodes arranged on ferrite and matching capacitors electrically connected to the respective center electrodes.

This circulator is a three-port lumped constant circulator, and the three central electrodes are arranged so as to cross each other in an electrically insulated state on one surface of the ferrite. Then, the operating frequency is adjusted by the capacitance value of a capacitor arranged in parallel with the three center electrodes.

However, in the circulator, since the center electrode is placed flat on one surface of the ferrite, the impedance of the center electrode is inevitably low, and it is difficult to increase the insertion loss and the isolation characteristics in a wide band. Further, the parameter for adjusting the impedance of the port is only the center electrode, and the restrictions on the design of the center electrode have become severe.

JP 2003-110309 A

Therefore, an object of the present invention is to provide a non-reciprocal circuit device that can achieve a wide band of insertion loss and isolation characteristics and can easily adjust the impedance of a port portion.

The non-reciprocal circuit device according to one aspect of the present invention is
With permanent magnets,
A ferrite to which a DC magnetic field is applied by the permanent magnet;
First, second, and third center electrodes, each of which is disposed in an insulating state on the ferrite, and whose other end is electrically connected to the ground;
A first matching capacitor element connected between one end of each of the first, second, and third center electrodes and the ground;
A second matching capacitor element connected between the first port portion and the first center electrode, between the second port portion and the second center electrode, and between the third port portion and the third center electrode; ,
With
Each of the first, second and third center electrodes is wound around the ferrite for at least one turn;
It is characterized by.

In the non-reciprocal circuit device, the first, second, and third center electrodes are wound around the ferrite for at least one turn, so that the impedance is increased and the insertion loss and the isolation characteristics are widened. Further, a second matching capacitor element is connected between the first port portion and the first center electrode, between the second port portion and the second center electrode, and between the third port portion and the third center electrode. Therefore, the impedance of each port portion can be easily adjusted by the capacitance value of the second matching capacitor element, the deterioration of insertion loss can be suppressed, and the degree of freedom in designing the center electrode is improved. Furthermore, by considering the balance between the inductance of the center electrode and the capacitance value of the first matching capacitor element, the frequency of the insertion loss and the isolation characteristic can be adjusted to the operating frequency band.

According to the present invention, it is possible to achieve a wide band of insertion loss and isolation characteristics and to easily adjust the impedance of the port portion.

It is a disassembled perspective view which shows 1st Example. The center electrode assembly which comprises 1st Example is shown, (A) is the perspective view seen from the upper surface, (B) is the perspective view seen from the bottom face. It is a disassembled perspective view which shows the said center electrode assembly. It is an equivalent circuit diagram showing the first embodiment. It is a graph which shows the insertion loss of the 1st port part of 1st Example. It is a graph which shows the insertion loss of the 2nd port part of 1st Example. It is a graph which shows the isolation characteristic of 1st Example. FIG. 6 is an equivalent circuit diagram showing a second embodiment. It is a graph which shows the insertion loss of the 1st port part of 2nd Example. It is a graph which shows the insertion loss of the 2nd port part of 2nd Example. It is a graph which shows the isolation characteristic of 2nd Example. It is a graph which shows the insertion loss of the 1st port part made to respond | correspond to UMTS. It is a graph which shows the insertion loss of the 2nd port part made to respond | correspond to UMTS. It is a graph which shows the isolation characteristic matched with UMTS.

Hereinafter, embodiments of a non-reciprocal circuit device according to the present invention will be described with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same member and the overlapping description is abbreviate | omitted.

(First embodiment, FIGS. 1 to 7)
The first embodiment of the non-reciprocal circuit device according to the present invention is configured as a three-port type lumped constant circulator as shown in FIG. 1, and is roughly composed of a circuit board 10, a center electrode assembly 20, and a permanent magnet. 30, an upper yoke 41, and a lower yoke 42. The upper yoke 41 and the lower yoke 42 are integrally coupled in a state where the circuit board 10, the center electrode assembly 20, and the permanent magnet 30 are accommodated, and function as an electromagnetic shield and a ground conductor. The lower yoke 42 is integrally molded with a resin member 43 and provided with external connection terminals Ant, Tx, Rx, and G.

As shown in FIG. 2, the center electrode assembly 20 includes a first center electrode 21, a second center electrode 22, and a third center electrode 23 on insulating sheets 26a to 26d (see FIG. 3), with each other intersecting at a predetermined angle. The central electrodes 21 to 23 are electrically connected by a conductor film provided on the side surfaces of the ferrite 25 and the disconnection sheets 26a to 26d, and are wound around the surface of the ferrite 25 by 1.5 turns. One end of the first center electrode 21 is connected to the external connection transmission terminal Tx, one end of the second center electrode 22 is connected to the antenna terminal Ant for external connection, and one end of the third center electrode 23 is reception for external connection. It is connected to the terminal Rx.

The circuit of this circulator is configured as shown in the equivalent circuit of FIG. That is, the first matching capacitor elements C1, C2, and C3 are connected between one end portions of the first, second, and third center electrodes 21, 22, and 23 and the ground, respectively. A second matching capacitor element Cs1 is provided between the first port part P1 (terminal Tx) and the first center electrode 21, and a second matching capacitor element is provided between the second port part P2 (terminal Ant) and the second center electrode 22. The second matching capacitor element Cs3 is connected between the capacitor element Cs2, the third port portion P3 (terminal Rx) and the third center electrode 23, respectively.

The various capacitor elements are built in the circuit board 10 having a multilayer structure, and form an equivalent circuit shown in FIG. 4 through the center electrodes 21, 22 and 23 and terminal electrodes formed on the surface of the circuit board 10. So connected. The center electrodes 21, 22, and 23 are formed on the ferrite 25 as a thin film conductor, a thick film conductor, or a conductor foil.

The operation of the three-port type circulator having the above configuration is basically the same as the conventional one, and the high-frequency signal input from the transmission terminal Tx (first port portion P1) is the antenna terminal Ant (second port portion). The high-frequency signal output from the antenna terminal Ant (second port part P2) is output from the reception terminal Rx (third port part P3).

The first matching capacitor elements C1, C2, and C3 form a parallel resonant circuit with the first, second, and third center electrodes 21, 22, and 23, respectively, and adjust the operating frequency according to the respective capacitance values. The first, second, and third center electrodes 21, 22, and 23 are wound around the ferrite 25 by 1.5 turns, respectively, and an increase in impedance increases the insertion loss and isolation characteristics. Then, the second matching capacitor element Cs1 is inserted between the first port part P1 and the first center electrode 21, and the second matching capacitor element Cs2 is inserted between the second port part P2 and the second center electrode 22. And the second matching capacitor element Cs3 is inserted between the third port portion P3 and the third center electrode 23. Therefore, the port portions P1, P2 are changed depending on the capacitance values of the second matching capacitors Cs1, Cs2, Cs3. , P3 can be easily adjusted, deterioration of insertion loss can be suppressed, and the design freedom of the center electrodes 21, 22, and 23 is improved. Further, by considering the balance between the inductance of the center electrodes 21, 22, 23 and the capacitance values of the first matching capacitor elements C1, C2, C3, the frequency of the insertion loss and the isolation characteristic can be adjusted to the operating frequency band. Is possible.

Here, the characteristics of the first embodiment are shown in FIGS. 5 to 7 in comparison with the conventional example. In the conventional example, the number of turns of the center electrodes 21, 22, 23 is 0.5 turns, and the second matching capacitor elements Cs1, Cs2, Cs3 are not provided. Incidentally, the number of turns of the center electrodes 21, 22, 23 in the first embodiment is 1.5 turns.

FIG. 5 shows insertion loss from the first port part P1 (transmission terminal Tx) to the second port part P2 (antenna terminal Ant). FIG. 6 shows insertion loss from the second port part P2 (antenna terminal Ant) to the third port part P3 (reception terminal Rx). FIG. 7 shows the isolation characteristics from the first port part P1 (transmission terminal Tx) to the third port part (reception terminal Rx). In both cases, the curve A is the first embodiment and the curve B is the conventional example.

As shown in FIG. 5, the bandwidth when the insertion loss is 1.5 dB is 252.8 MHz in the conventional example, as shown in FIG. 5, whereas 273.4 MHz in the first example. It has become wider. Similarly, in the second port portion P2, as shown in FIG. 6, the bandwidth is 455.8 MHz in the conventional example, but the bandwidth is increased to 826.4 dB in the first embodiment. Further, as is clear from FIG. 7, the bandwidth when the isolation characteristic is 15 dB is 386.3 MHz in the conventional example, whereas the bandwidth is increased to 494.0 MHz in the first embodiment.

(Refer to the second embodiment, FIGS. 8 to 11)
In the second embodiment of the nonreciprocal circuit device according to the present invention, as shown in the equivalent circuit of FIG. 8, the third matching capacitor device Cj21 is electrically connected between the first port portion P1 and the second port portion P2. , A third matching capacitor element Cj32 is electrically connected between the second port portion P2 and the third port portion, and a third matching capacitor is connected between the third port portion and the first port portion P1. The capacitor element Cj13 is electrically connected. Other configurations are the same as those of the first embodiment.

Note that at least one of the third matching capacitor elements Cj21, Cj32, and Cj13 may be provided. Therefore, in the second embodiment, as a circuit configuration, (a) when only Cj13 is connected, (b) when only Cj21 is connected, (c) when only Cj32 is connected, (D) When Cj13 and Cj21 are connected, (e) When Cj21 and Cj32 are connected, (f) When Cj32 and Cj13 are connected, (g) Cj13, Cj21 and Cj32 are connected If there are, there are seven ways.

The operation and effects of the second embodiment are the same as those of the first embodiment. In particular, by selectively inserting the third matching capacitor elements Cj13, Cj21, Cj32, the port portions P1, P2, P3 Therefore, it is possible to achieve a wide band of isolation characteristics without degrading insertion loss. Increasing the number of capacitor elements impairs downsizing of the circulator itself. Therefore, capacitor elements Cj13, Cj21, and Cj32 to be inserted may be selected in consideration of required electrical characteristics.

Here, the characteristics of the second embodiment will be described. FIG. 9 shows insertion loss from the first port part P1 (transmission terminal Tx) to the second port part P2 (antenna terminal Ant). FIG. 10 shows insertion loss from the second port part P2 (antenna terminal Ant) to the third port part P3 (reception terminal Rx). FIG. 11 shows the isolation characteristic from the first port part P1 (transmission terminal Tx) to the third port part (reception terminal Rx). In any case, when the curve C inserts only the third matching capacitor element Cj21, when the curve D inserts only the third matching capacitor element Cj32, when the curve E inserts the third matching capacitor element Cj13, A curve F is a case where all of the third matching capacitor elements Cj21, Cj32, Cj13 are inserted. The bandwidth for each of the circuit configurations (a) to (g) is as shown in Table 1 below.

(Response to UMTS, see Figs. 12-14)
In recent years, UMTS (Universal Mobile Telecommunications System) has been put into practical use as a wireless access method for mobile phones, and bands 1, 2, 3, and 4 are defined. In the first and second embodiments, by adjusting the inductance values of the center electrodes 21, 22, 23 and the capacitance values of the first matching capacitor elements C1, C2, C3 connected in parallel therewith, A single circulator can be used as a frequency divider capable of supporting a wideband UMTS. Of course, it is possible to deal with GSM and the like.

In the second embodiment, the insertion loss from the first port portion P1 to the second port portion P2 when the third matching capacitor elements Cj21, Cj32, Cj13 are inserted is as shown in FIG. Can cover up to 4 transmission bands. Similarly, the insertion loss from the second port portion P2 to the third port portion P3 is as shown in FIG. 13, and can cover the reception bands of bands 1 to 4. Similarly, the isolation characteristics from the first port part P1 to the third port part P3 are as shown in FIG. 14, and the bands 1 to 4 can be covered.

In this way, by making it possible to support a wide band, it is possible to replace a plurality of duplexers and their peripheral elements that are conventionally arranged in a communication terminal in order to support a plurality of frequency bands with a single circulator. This contributes to downsizing and cost reduction, and the insertion loss is also reduced.

(Other examples)
The nonreciprocal circuit device according to the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the gist thereof.

For example, the configuration and shape of the center electrode are arbitrary. Further, the matching capacitor element may be mounted on the circuit board as a chip type in addition to being built in the circuit board.

DESCRIPTION OF SYMBOLS 20 ... Center electrode assembly 21 ... 1st center electrode 22 ... 2nd center electrode 23 ... 3rd center electrode 25 ... Ferrite 30 ... Permanent magnet P1, P2, P3 ... Port part C1, C2, C3 ... 1st matching capacitor Element Cs1, Cs2, Cs3 ... Second matching capacitor element Cj21, Cj32, Cj13 ... Third matching capacitor element

Claims (3)

With permanent magnets,
A ferrite to which a DC magnetic field is applied by the permanent magnet;
First, second, and third center electrodes, each of which is disposed in an insulated state on the ferrite, and whose other end is connected to the ground;
A first matching capacitor element connected between one end of each of the first, second, and third center electrodes and the ground;
A second matching capacitor element connected between the first port portion and the first center electrode, between the second port portion and the second center electrode, and between the third port portion and the third center electrode; ,
With
Each of the first, second and third center electrodes is wound around the ferrite for at least one turn;
A nonreciprocal circuit device characterized by the above. A third matching capacitor element is provided between at least one of the first port portion and the second port portion, between the second port portion and the third port portion, and between the third port portion and the first port portion. The nonreciprocal circuit device according to claim 1, wherein the nonreciprocal circuit device is connected. The nonreciprocal circuit device according to claim 1 or 2, wherein the first port portion is a transmission port, the second port portion is an antenna port, and the third port portion is a reception port.

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