JP2014230023A - Matching circuit and antenna device having matching circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a matching circuit having a plurality of capacitance values, without using a variable element having a large loss, e.g., a varicap diode.SOLUTION: A matching circuit having a first passive element section and a second passive element section connected in parallel herewith includes a drive voltage supply terminal for applying a control voltage to the first and second passive element sections, a first voltage-dividing circuit having one end connected with the drive voltage supply terminal and the other end connected with one end of the first passive element section, and a second voltage-dividing circuit having one end connected with the drive voltage supply terminal and the other end connected with one end of the second passive element section. A magnetoresistance effect element is used as a resistor constituting the first and second voltage-dividing circuits, and the first and second passive element sections are controlled by switching the direction of magnetization of a magnetization free layer of the magnetoresistance effect element by means of a single switching current supply terminal.

Description

  The present invention relates to a matching circuit for adjusting the frequency of an antenna and an antenna device having the matching circuit in a wireless device such as a portable terminal.

In recent years, in wireless devices such as mobile phones, the number of antennas tends to increase as the number of wireless systems increases. Further, the occupied volume allowed for the antenna tends to be reduced, and there is a strong demand for downsizing the built-in antenna. However, the antenna characteristics generally have a trade-off relationship with the size of the antenna, and with the progress of miniaturization, narrowing of the frequency band and deterioration of efficiency are problematic.
As a method for solving this problem, a technique has been proposed in which a single antenna element is used and the capacitance value of a varicap diode is varied so that the tuning frequency corresponds to a plurality of frequencies (see Patent Document 1).

JP 2002-232313 A

  Patent Document 1 discloses an antenna device in which a varicap diode is connected as a variable capacitance element to a feeding portion of a monopole antenna. In this antenna, by changing the voltage applied to the varicap diode, it is possible to change the capacitance value which is a matching element to correspond to a desired frequency. However, in this method, the problem that the influence of the loss of the varicap diode directly deteriorates the characteristics of the antenna cannot be avoided. In particular, in an application with a frequency of 1 GHz or more where the loss of the varicap diode is large, the antenna characteristics are significantly deteriorated, which becomes a problem.

In addition, a switching element connected in series and a passive element portion having a passive element are connected in parallel, and the switching element is connected to each switching element from a single drive voltage supply terminal via a voltage dividing circuit having a different voltage dividing ratio. By controlling the ON / OFF state, it is conceivable to change the capacitance value by switching the states of the passive element units connected in parallel so as to correspond to a desired frequency. However, in this method, in order to turn on all the switching elements, it is necessary to supply a voltage at which the switching elements are turned on even in the voltage dividing circuit with the lowest voltage dividing ratio, and improvement is required from the viewpoint of power consumption. .

A switching element connected in series and a passive element having a passive element are connected in parallel, and a single drive voltage supply terminal is connected via a voltage dividing circuit using a magnetoresistive effect element for each switching element. Each passive element connected in parallel by controlling the ON / OFF of the switching element by switching the voltage dividing ratio of the voltage dividing circuit by switching the magnetization direction of the magnetization free layer of the magnetoresistive effect element A means for changing the capacitance value by switching the state of the unit to correspond to a desired frequency can be considered. However, this method requires the same number of switching current supply terminals and control devices as the magnetoresistive effect elements, and the complexity of the circuit and the accompanying increase in size cannot be avoided. Improvement is required for use in equipment.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a matching circuit with little characteristic deterioration in a high frequency band and an antenna device using the same.

The present invention for solving the above-described problems includes a first switching element having a first switching element and a first passive element connected in series, a second switching element and a second passive element connected in series. A second passive element unit connected in parallel to the first passive element unit, and a drive voltage supply terminal for applying a control voltage to the first passive element unit and the second passive element unit A first voltage dividing circuit having one end connected to the drive voltage supply terminal and the other end connected to one end of the first passive element unit; and one end connected to the drive voltage supply terminal. A second voltage dividing circuit having the other end connected to one end of the second passive element section, and the first voltage dividing circuit having the one end connected to the drive voltage supply terminal. One end of which is connected to the other end of the first resistor and the other end is connected to a reference voltage A second resistor connected to the drive voltage supply terminal, one end connected to the drive voltage supply terminal, and one end connected to the other end of the third resistor. And the other end is connected to a reference potential, at least one of the first or second resistors and at least one of the third or fourth resistors. One is a magnetoresistive effect element provided with a magnetization fixed layer and a magnetization free layer via a nonmagnetic spacer layer, and among the first to fourth resistances, the resistance constituted by the magnetoresistive effect element is respectively The matching circuit is characterized in that it has a magnetic field supply mechanism installed adjacently, and the magnetic field supply mechanism is connected to a single switching current supply terminal.

According to the matching circuit of the present invention having the above characteristics, among the first to fourth resistors, the resistors configured by the magnetoresistive effect element are induced by the magnetic field supply mechanisms installed adjacent to each other. By applying a magnetic field, the resistance value of the magnetoresistive effect element can be switched to a high resistance or low resistance state. Accordingly, since the voltage dividing ratio of the voltage applied to the first and second switching elements can be changed, the first and second switching elements can be applied in a state where a constant voltage is applied from the drive voltage supply terminal. The element can be arbitrarily switched ON and OFF. Therefore, when the present invention is combined with an antenna device, the connection of the passive element section can be configured in four ways as the state of the matching circuit, and the antenna frequency can be varied over a wide range. In addition, since there is no varicap diode in the high-frequency transmission line, transmission with less loss is possible. In addition, since the magnetization direction of the magnetization free layer of the magnetoresistive effect element can generally be reversed by a pulse current of 20 ns or less, it is applied to the magnetic field supply mechanism to reverse the magnetization direction of the magnetization free layer. The current does not consume a large amount of power, and the voltage that must always be applied from the drive voltage supply terminal during communication is constant and small, so that the power consumption of the entire circuit can be reduced. It becomes possible. In addition, since the switching current supply terminal for applying current to the magnetic field supply mechanism is single regardless of the number of the magnetoresistive effect elements, a single control device is required, and a simple circuit is configured. Therefore, downsizing can be realized.

In the present invention, the state in which the magnetoresistive effect element has a low resistance value means that the magnetization direction of the magnetization fixed layer of the magnetoresistive effect element is substantially parallel to the magnetization direction of the magnetization free layer of the magnetoresistive effect element. This means that the angle between the two directions is -30 degrees or more and +30 degrees or less. Further, in the present invention, the state in which the magnetoresistive effect element has a high resistance value means that the magnetization direction of the magnetization fixed layer of the magnetoresistive effect element and the magnetization direction of the magnetization free layer of the magnetoresistive effect element are substantially antiparallel. This means that the angle between the two directions is an angle of 150 degrees or more and 210 degrees or less.

In the present invention, the passive element portion means a configuration in which a switching element and a passive element are adjacently connected.

Furthermore, the matching circuit according to the present invention is characterized in that the magnetic field supply mechanism is connected to the single switching current supply terminal via a single conducting wire.

According to the matching circuit of the present invention having the above characteristics, since the magnetic field supply mechanism is connected by a single conductor, it can be further downsized. In addition, since the transmission line is shortened, it is possible to further prevent deterioration of the antenna characteristics.

Furthermore, the matching circuit according to the present invention is characterized in that the first and second resistors are magnetoresistive elements each having a fixed magnetization layer and a free magnetization layer via a nonmagnetic spacer layer.

According to the matching circuit of the present invention having the above characteristics, since both of the first and second resistors are configured by magnetoresistive elements, the first voltage dividing circuit has a high resistance value. Only one of the first and second resistors is magnetized by setting the state and the other to a low resistance state, or setting one to a low resistance value and the other to a high resistance state. Compared to the case where the resistor element is used, the difference in the voltage division ratio can be increased. Thereby, the MR ratio (magnetoresistance ratio) of the magnetoresistive effect element is reduced, or the margin of the threshold voltage of the ON / OFF switching voltage of the first switching element is widened, and the manufacturing margin is greatly widened. Yield improvement, manufacturing power saving, resource saving, and cost reduction are possible.

Furthermore, the matching circuit according to the present invention applies a larger current in one direction than the single switching current supply terminal, and each of the adjacent magnetoresistors is adjacent to the direction of the magnetic field induced by all the magnetic field supply mechanisms. When the magnetization direction of the magnetization free layer of the effect element is switched to a direction that is substantially the same as the direction of the magnetic field, one of the first and second resistances is in a low resistance state and the other is a high resistance. It is characterized by being in a resistance value state.

According to the matching circuit of the present invention having the above characteristics, the difference in the voltage dividing ratio of the first voltage dividing circuit is that when a large positive current is applied and a large negative current is applied from the switching current supply terminal. The difference is the maximum. Therefore, since the current applied to the magnetic field supply mechanism installed adjacent to the first and second resistors to switch the first switching element does not require fine control, the control device can be easily designed. It becomes.

Furthermore, an antenna device according to the present invention has a fifth feature that includes an antenna and a matching circuit described in any one of the first to fourth features connected to the antenna.

According to the antenna device of the present invention having the above characteristics, an arbitrary matching element can be selected by controlling a supply current from a single switching current supply terminal. Therefore, an antenna device corresponding to a plurality of frequencies can be realized with one antenna element, and the device can be downsized and the number of parts can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the matching circuit with little characteristic deterioration in a high frequency band and an antenna apparatus using the same can be provided.

1 is a simplified diagram of a matching circuit according to an embodiment of the present invention. FIG. 3 is a circuit diagram illustrating a specific circuit configuration of the matching circuit according to the first embodiment of the present invention. It is the schematic diagram showing VSWR at the time of using the matching circuit which concerns on the 1st Embodiment of this invention for an antenna apparatus. It is the schematic diagram showing the efficiency at the time of using the matching circuit which concerns on the 1st Embodiment of this invention for an antenna apparatus. It is an illustration figure of the layout in the case of mounting the matching circuit which concerns on the 1st Embodiment of this invention in a mobile telephone as an antenna apparatus. FIG. 6 is a simplified diagram of a matching circuit according to a second embodiment of the present invention. FIG. 6 is a simplified diagram of a matching circuit according to third and fourth embodiments of the present invention. FIG. 10 is a simplified diagram of a matching circuit according to a fifth embodiment of the present invention. It is a simplified diagram of a matching circuit according to a conventional example.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. Further, various modifications can be made to the present embodiment without departing from the spirit of the present embodiment.

FIG. 1 is a simplified diagram of a matching circuit 20 for switching the operating frequency of an antenna mounted on a radio. The matching circuit 20 includes a first passive element unit 40a having a first PIN diode 3a that is a first switching element connected to an antenna 1 that transmits and receives radio waves, and a first capacitor 2a that is a first passive element. And a second passive element unit that is connected in parallel to the first passive element unit 40a and has a second PIN diode 3b that is a second switching element and a second capacitor 2b that is a second passive element. 40b, a drive voltage supply terminal 6 for applying a control voltage to the first passive element part 40a and the second passive element part 40b, one end connected to the drive voltage supply terminal 6, and the other end A first voltage dividing circuit 30a connected to one end of the first passive element section 40a, one end connected to the drive voltage supply terminal 6, and the other end connected to one end of the second passive element section 40b. Been And a second voltage dividing circuit 30b that.

The first voltage dividing circuit 30a includes a first resistor 4a having one end connected to the drive voltage supply terminal 6 via a second connection node 8, and one end connected to the first resistor 4a. The second resistor 5a is connected to the other end and the other end is connected to a reference potential. The second voltage dividing circuit 30b is driven at one end via the second connection node 8. The third resistor 4b is connected to the voltage supply terminal 6, and the fourth resistor 5b has one end connected to the other end of the third resistor 4b and the other end connected to the reference potential. ing. In the matching circuit 20, the second passive element unit 40b is further connected to the first passive element unit 40a via the first connection node 7 and the third capacitor 9 for DC cut.

The first resistor 4a is composed of a first magnetoresistive element 15a having a fixed magnetization layer and a free magnetization layer via a nonmagnetic spacer layer, and is adjacent to the first magnetoresistive element 15a. Then, the first magnetic field supply mechanism 18a is installed, and is induced by driving the first magnetic field supply mechanism 18a by the current applied through the conducting wire connected to the first switching current supply terminal 14a. A magnetic field is applied to the first magnetoresistive element 15a. The direction of the magnetic field applied to the first magnetoresistive element 15a is switched by switching the polarity of the current applied from the first switching current supply terminal 14a, and the first magnetoresistive effect element 15a. The magnetization direction of the magnetization free layer is switched. By switching the magnetization direction of the magnetization free layer of the first magnetoresistance effect element 15a, the magnetization direction of the magnetization fixed layer of the first magnetoresistance effect element 15a and the magnetization of the first magnetoresistance effect element 15a are changed. Since the magnetization direction of the magnetization free layer is switched to a parallel or antiparallel state, the first magnetoresistive element 15a is switched between two resistance values, a low resistance value and a high resistance value. However, when switching the state of the resistance value of the first magnetoresistance effect element 15a, a magnetic field exceeding the coercive force (Hc) of the magnetization free layer of the first magnetoresistance effect element 15a is applied. It is necessary to apply an amount of current necessary for supplying from the magnetic field supply mechanism 18a from the first switching current supply terminal 14a. The third resistor 4b is composed of a third magnetoresistive effect element 15b having a fixed magnetization layer and a free magnetization layer via a nonmagnetic spacer layer, and is adjacent to the third magnetoresistive effect element 15b. Then, the third magnetic field supply mechanism 18b is installed, and is induced by driving the third magnetic field supply mechanism 18b by a current applied through a conducting wire connected to the first switching current supply terminal 14a. Is applied to the third magnetoresistive element 15b. The direction of the magnetic field applied to the third magnetoresistive element 15b is switched by switching the polarity of the current applied from the first switching current supply terminal 14a, and the third magnetoresistive effect element 15b. The magnetization direction of the magnetization free layer is switched. By switching the magnetization direction of the magnetization free layer of the third magnetoresistance effect element 15b, the magnetization direction of the magnetization fixed layer of the third magnetoresistance effect element 15b and the magnetization of the third magnetoresistance effect element 15b Since the magnetization direction of the magnetization free layer is switched to a parallel or antiparallel state, the third magnetoresistive effect element 15b is switched between two resistance values of a low resistance value or a high resistance value. However, when switching the state of the resistance value of the third magnetoresistive element 15b, a magnetic field exceeding the coercive force (Hc) of the magnetization free layer of the third magnetoresistive element 15b is applied. It is necessary to apply an amount of current necessary for supplying from the magnetic field supply mechanism 18b from the first switching current supply terminal 14a.

(First embodiment)
FIG. 2 shows a specific circuit configuration of the matching circuit 20 according to the first embodiment. The antenna 1 is connected to one end of each of the first passive element unit 40 a and the second passive element unit 40 b connected in parallel, and is connected to the transceiver 11 via the fourth capacitor 13.

Further, the matching circuit 20 is a first high-frequency cut element having one end connected to the other end of the first voltage dividing circuit 30a and the other end connected to one end of the first switching element 3a. 1 choke coil 12a and a second choke coil 12b which is a second high frequency cut element having one end connected to the other end of the first switching element 3a and the other end connected to a reference potential. And a third high-frequency cut element having one end connected to the other end of the second voltage dividing circuit 30b and the other end connected to one end of the second switching element 3b. A choke coil 12c, and a fourth choke coil 12d which is a fourth high frequency cut element having one end connected to the other end of the second switching element 3b and the other end connected to a reference potential. Yes. The first, second, third, and fourth choke coils 12a, 12b, 12c, and 12d play a role of preventing the passage of a high-frequency signal without affecting the DC signal. The first and third choke coils 12a and 12c prevent high-frequency components that have passed through the first connection node 7 from flowing into the voltage supply source 6, thereby stabilizing the voltage supply source 6. Play a role. The same effect can be obtained by using a resistance element instead of the choke coil.

The first and second PIN diodes 3 a and 3 b function as switching elements, and a voltage supply source 6 that controls ON / OFF of the first and second PIN diodes 3 a and 3 b is connected via the second connection node 8. The fourth capacitor 13 is for adjusting the impedance of the antenna.

As the resistance value of the first magnetoresistive element 15a changes, the voltage dividing ratio of the first voltage dividing circuit 30a changes. The resistance value of the second resistor 5a is preferably a resistance value between a low resistance value and a high resistance value of the first magnetoresistive element 15a. As a result, the amount of change in the voltage dividing ratio of the first voltage dividing circuit 30a increases. As the resistance value of the third magnetoresistance effect element 15b changes, the voltage dividing ratio of the second voltage dividing circuit 30b changes. The resistance value of the fourth resistor 5b is preferably a resistance value between a low resistance value and a high resistance value of the third magnetoresistance effect element 15b. As a result, the amount of change in the voltage dividing ratio of the second voltage dividing circuit 30b increases. It is preferable that the amount of change in the voltage dividing ratio of the first voltage dividing circuit 30a is close to the amount of change in the voltage dividing ratio of the second voltage dividing circuit 30b. As a result, it is possible to use the same PIN diode for the first PIN diode 3a as the first switching element and the second PIN diode 3b as the second switching element.

In order to switch the magnetization directions of the magnetization free layers of the first and third magnetoresistance effect elements 15a and 15b, the critical current amount that needs to be applied to the first and third magnetic field supply mechanisms 18a and 18b is The first magnetoresistive element 15a is smaller than the third magnetoresistive element 15b. For this reason, when the direction of magnetization of the magnetization free layers of the first and third magnetoresistance effect elements 15a and 15b is different from the direction of the magnetic field emitted from the first and third magnetic field supply mechanisms 18a and 18b, When the amount of current applied from the first switching current supply terminal 14a is increased, the orientation of the magnetization free layer of the first magnetoresistance effect element 15a is such that the direction of the third magnetoresistance effect element 15b is It switches before the direction of the magnetization free layer.

The first and second voltage dividing circuits 30a and 30b need to independently change the voltage dividing ratio. For this purpose, the first and third magnetoresistive elements 15a and 15b need to independently switch the magnetization direction of the magnetization free layer. For this purpose, criticality that must be applied to the first and third magnetic field supply mechanisms 18a and 18b in order to switch the magnetization directions of the magnetization free layers of the first and third magnetoresistive elements 15a and 15b. Although the amount of current needs to be different, there are many methods as described below, and the present invention does not limit the method.

For example, as shown in FIG. 2, as the first and third magnetic field supply mechanisms 18a and 18b, magnetic poles made of a soft magnetic material wound with a coil are used as the first and third magnetoresistance effect elements 15a. And 15b, and by connecting a conductive wire connected to the first switching current supply terminal 14a to the coil, a magnetic field induced from the coil and emitted via the magnetic pole is generated by the first and third magnetic fields. There is a method of switching the magnetization directions of the magnetization free layers of the first and third magnetoresistance effect elements 15a and 15b by applying them to the magnetization free layers of the magnetoresistance effect elements 15a and 15b. In this case, by changing the aspect ratio of the vertical and horizontal sizes of the first and third magnetoresistive elements 15a and 15b, the magnetization free layers of the first and third magnetoresistive elements 15a and 15b are changed. Since the coercive force (Hc) can be changed, the critical current amounts that need to be applied to the magnetic field supply mechanism in order to switch the magnetization direction of the magnetization free layer are set to the first and third magnetoresistance effects. It is possible to have different values between the elements 15a and 15b. As a result, by adjusting the amount of current applied from the first switching current supply terminal 14a, the first and third magnetoresistance effect elements 15a and 15b can be independent of the magnetization free layer. It is possible to switch the direction of magnetization. Also, a magnetic field supply is provided to switch the magnetization direction of the magnetization free layer by forming a soft magnetic cover layer for absorbing a magnetic field made of a soft magnetic material so as to cover the first magnetoresistive effect element 15a. The amount of critical current that needs to be applied to the mechanism may be a value different between the first and third magnetoresistive elements 15a and 15b. When a soft magnetic cover layer for absorbing a magnetic field made of a soft magnetic material is formed so as to cover the first and third magnetoresistive elements 15a and 15b, the vertical and horizontal sizes of the soft magnetic cover layer are formed. By changing the aspect ratio, the critical current amount that needs to be applied to the magnetic field supply mechanism in order to switch the magnetization direction of the magnetization free layer is set to the value of the first and third magnetoresistance effect elements 15a and 15b. Different values may be used. Also, by changing the cross-sectional area of the magnetic pole tips of the first and third magnetic field supply mechanisms 18a and 18b, the magnitude of the magnetic field emitted from the magnetic pole tips when the same current flows through the coil is changed. As a result, the critical current amount that needs to be applied to the magnetic field supply mechanism in order to switch the magnetization direction of the magnetization free layer may be different between the first and third magnetoresistance effect elements 15a and 15b. good. Further, by changing the distance from the tips of the magnetic poles of the first and third magnetic field supply mechanisms 18a and 18b to the first and third magnetoresistive elements 15a and 15b, the same current is supplied to the coils. By changing the magnitude of the magnetic field applied to the magnetization free layer of the magnetoresistive element when flowing, the amount of critical current that needs to be applied to the magnetic field supply mechanism in order to switch the magnetization direction of the magnetization free layer is reduced. The first and third magnetoresistive elements 15a and 15b may have different values. Also, a flux guide that is made of a soft magnetic material and guides magnetic flux between the first and third magnetoresistive elements 15a and 15b at the tips of the magnetic poles of the first and third magnetic field supply mechanisms 18a and 18b. (FluxGuide) is formed, and by changing the cross-sectional area of the flux guide tip or the distance from the tip of the flux guide to the magnetoresistive element, the magnetization free of the magnetoresistive element when the same current flows through the coil By changing the magnitude of the magnetic field applied to the layer, the critical current amount that needs to be applied to the magnetic field supply mechanism in order to switch the magnetization direction of the magnetization free layer is set to the first and third magnetoresistance effects. Different values may be used between the elements 15a and 15b. Further, by changing the number of turns of the coils of the first and third magnetic field supply mechanisms 18a and 18b, the magnitude of the magnetic field emitted from the tip of the magnetic pole when the same current flows through the coils is changed. The critical current amount that needs to be applied to the magnetic field supply mechanism in order to switch the magnetization direction of the magnetization free layer may be a value that differs between the first and third magnetoresistance effect elements 15a and 15b. Further, by using a combination of the above methods, the critical current amount that needs to be applied to the magnetic field supply mechanism in order to switch the magnetization direction of the magnetization free layer is set to the first and third magnetoresistance effect elements 15a and 15a. It is good also as a different value between 15b.

Further, for example, as the first and third magnetic field supply mechanisms 18a and 18b, a conducting wire is disposed immediately above or directly below the first and third magnetoresistance effect elements 15a and 15b, and the first switching current supply terminal 14a is provided. By applying to the magnetization free layers of the first and third magnetoresistive effect elements 15a and 15b, a magnetic field induced annularly around the conductor when a current flows through the conductor is obtained. There is a method for switching the magnetization directions of the magnetization free layers of the first and third magnetoresistance effect elements 15a and 15b. In this case, by changing the aspect ratio of the vertical and horizontal sizes of the first and third magnetoresistive elements 15a and 15b, the magnetization free layers of the first and third magnetoresistive elements 15a and 15b are changed. Since the coercive force (Hc) can be changed, the critical current amounts that need to be applied to the magnetic field supply mechanism in order to switch the magnetization direction of the magnetization free layer are set to the first and third magnetoresistance effects. It is possible to have different values between the elements 15a and 15b. As a result, by adjusting the amount of current applied from the first switching current supply terminal 14a, the first and third magnetoresistance effect elements 15a and 15b can be independent of the magnetization free layer. It is possible to switch the direction of magnetization. Further, the first magnetoresistive element 15a and the first magnetic field supply mechanism 18a disposed immediately above or directly below the conducting wire as the first magnetic field supply mechanism 18a are converged so as to converge a magnetic field composed of a soft magnetic material. By forming the soft magnetic yoke, the critical current amount that needs to be applied to the magnetic field supply mechanism in order to switch the magnetization direction of the magnetization free layer is set between the first and third magnetoresistive elements 15a and 15b. Different values may be used. The first and third magnetoresistive elements 15a and 15b and the first and third magnetic field supply mechanisms 18a and 18b arranged immediately above or immediately below the conductive wires are covered so as to cover together. When a soft magnetic yoke for converging a magnetic field composed of a material is formed, a magnetic field supply mechanism is used to change the magnetization direction of the magnetization free layer by changing the aspect ratio of the vertical and horizontal sizes of the soft magnetic yoke. The critical current amount that needs to be applied to the first and third magnetoresistive elements 15a and 15b may be different from each other. Further, by changing the thickness of the conducting wire which is the first and third magnetic field supply mechanisms 18a and 18b disposed immediately above or immediately below the first and third magnetoresistance effect elements 15a and 15b, The criticality that must be applied to the magnetic field supply mechanism to change the direction of magnetization of the magnetization free layer by changing the magnitude of the magnetic field induced in a ring around the conductor when the same current flows through the conductor. The amount of current may be a value different between the first and third magnetoresistive elements 15a and 15b. Further, by inserting a gap layer made of a specific magnetic material between the first magnetoresistive element 15a and the conducting wire which is the first magnetic field supply mechanism 18a disposed immediately above or below the first magnetoresistive element 15a. When the same current flows through the conductor by changing the distance between the first magnetoresistive element 15a and the conductor that is the first magnetic field supply mechanism 18a disposed immediately above or below the magnetoresistive element 15a. By changing the magnitude of the magnetic field applied to the magnetization free layer of the magnetoresistive effect element, the critical current amount that needs to be applied to the magnetic field supply mechanism in order to switch the magnetization direction of the magnetization free layer is set to the first value. The third magnetoresistive elements 15a and 15b may have different values. Further, by using a combination of the above methods, the critical current amount that needs to be applied to the magnetic field supply mechanism in order to switch the magnetization direction of the magnetization free layer is set to the first and third magnetoresistance effect elements 15a and 15a. It is good also as a different value between 15b.

With these structures, by adjusting the amount of current applied from a single switching current supply terminal and the positive / negative direction of the current in a state where a constant voltage is simultaneously supplied to two PIN diodes from a single voltage supply source, The matching element can be arbitrarily selected. Thus, low power consumption, circuit simplification, miniaturization, cost and circuit loss can be reduced.

Specific operations of the matching circuit 20 according to the first embodiment are shown in Table 1. By controlling the amount of current applied to the first switching current supply terminal 14a and the positive / negative direction of the current, the ON / OFF states of the first and second PIN diodes 3a and 3b are controlled, Have a state. When a large current is applied in the negative direction, as the state 1, both the PIN diodes 3a and 3b are turned off and the capacitance becomes zero. When a small current is applied in the positive direction after a large current is applied in the negative direction, in state 2, only the PIN diode 3a is turned on and the capacitance is C1. When a large current is applied in the positive direction, as the state 3, both the PIN diodes 3a and 3b are turned on and the capacitance becomes C1 + C2. When a large current is applied in the positive direction and then a small current is applied in the negative direction, in state 4, only the PIN diode 3b is turned on and the capacitance is C2.

FIG. 3 is a schematic diagram showing VSWR characteristics when the matching circuit of FIG. 2 is used in an antenna device. In this figure, the vertical axis represents VSWR (voltage standing wave ratio) and the horizontal axis represents frequency.

FIG. 4 is a schematic diagram showing radiation efficiency characteristics when the matching circuit of FIG. 2 is used in an antenna device. In this figure, the vertical axis represents radiation efficiency and the horizontal axis represents frequency.

The indications of the states 2 and 3 shown in the graphs of FIGS. 3 and 4 indicate the ON / OFF states of the first and second PIN diodes 3a and 3b as switching elements. As can be seen from these figures, switching from the GPS frequency band (1.575 GHz) to the W-LAN frequency band (2.44 GHz) by switching the matching circuit according to the two states of the first and second PIN diodes 3a and 3b. Variable frequency 2 state is realized. The frequency changes in FIGS. 3 and 4 show an example and are adjusted according to the actual antenna configuration and the wireless device terminal. Although not described in FIG. 3 and FIG. 4, by changing the capacitance values of C1 and C2, it is possible to realize the variable of the frequency 2 state which is further different as the state 1 and the state 4, so that the GPS frequency band and the W− It is also possible to simultaneously support a standard that uses a frequency different from the LAN frequency band.

For example, the resistance value of this example is the resistance value of the first magnetoresistive element 15a, which is the first resistor 4a, in which the magnetization direction of the magnetization free layer and the magnetization fixed layer is parallel = 200Ω, and the resistance value in the antiparallel state = 500Ω, the second resistance 5a = 320Ω, the resistance value when the magnetization direction of the magnetization free layer and the magnetization fixed layer of the third magnetoresistive effect element 15b, which is the third resistor 4b, is parallel = 200Ω, the antiparallel state Resistance value = 500Ω, fourth resistance 5b = 320Ω, supply voltage applied from the drive voltage supply terminal is set to 1.2V as a standard forward voltage, and magnetization of the first magnetoresistance effect element 15a In order to switch the magnetization direction of the free layer of the third magnetoresistive effect element 15b, the critical current amount required to be applied to the first magnetic field supply mechanism 18a to switch the magnetization direction of the free layer is 4 mA. 3 magnetic field supply mechanism 1 That must be applied to b and the critical current amount = 8 mA. In this case, when a current of −8 mA → + 4 mA is applied to the first switching current supply terminal 14a, the resistance value of each resistor is 200Ω for the first resistor 4a and is lower than 320Ω for the second resistor 5a. The third resistor 4b has a resistance value of 500Ω, which is higher than the 320Ω of the fourth resistor 5b. Therefore, the voltage dividing ratio is higher in the first voltage dividing circuit 30a (ratio 0.62) than in the second voltage dividing circuit 30b (ratio 0.39). As a result, the matching circuit 20, the first PIN diode 3 a is turned on and the second PIN diode 3 b is turned off.

The first and second capacitors 2a and 2b connected in parallel to the antenna 1 are matching elements for frequency adjustment, and the fourth capacitor 13 connected in series is a matching element for impedance adjustment. The capacitance values in this example are, for example, the first capacitor 2a = 0.1 pF, the second capacitor 2b = 1.5 pF, and the fourth capacitor 13 = 0.5 pF. That is, in the W-LAN frequency band (state 2), the parallel connection capacitor selects C1 (0.1 pF), and in the GPS frequency band (state 3), the parallel connection capacitor selects C1 + C2 (1.6 pF). It is possible to select two different applications. Since the capacitance values of these capacitors depend on the distance between the antenna element and the GND, the capacitance values are adjusted to match the characteristics of each antenna when connected to an actual antenna.

FIG. 5 shows an example of a mounting layout when the matching circuit 20 is mounted on a mobile phone as an antenna device. A feeding point 21, a matching circuit 20, and a transceiver 11 are provided on the mounting substrate 22. The mounting substrate 22 is a substrate on which general-purpose electronic components are mounted, and is built in the mobile phone. The antenna element is connected to the feeding point 21. As a material of the mounting substrate 22, ABS resin, FR4, or the like can be used.

In the first embodiment of the present invention, a varicap diode is not used as a variable matching element for changing the frequency, and a matching circuit is realized by selecting a capacitor using a PIN diode as a switching element. According to this configuration, since no varicap diode is used, it is possible to avoid deterioration of antenna characteristics due to loss of the varicap diode. This avoidance of characteristic deterioration is particularly useful at a frequency of 1 GHz or more. Furthermore, since the capacitance value can be changed larger than that of the varicap diode, the frequency can be varied over a wide frequency range.

In the first embodiment of the present invention, a capacitor is used as a passive element and the matching circuit is configured by changing the impedance to be capacitive. However, the present invention is not limited to this. The same effect can be obtained even if the matching circuit is configured by using an inductor as a passive element and changing the impedance inductively.

In the first embodiment of the present invention, as a magnetic field supply mechanism, a magnetic wire made of a soft magnetic material wound with a coil is disposed in the vicinity of a magnetoresistive effect element, and a conducting wire connected to a switching current supply terminal Is connected to the coil to induce a magnetic field induced by the coil through the magnetic pole, but the present invention is not limited to this. The same effect can be obtained if the structure is driven by electric current and emits a magnetic field.

In the first embodiment of the present invention, the first and third magnetic field supply mechanisms 18a and 18a are used to switch the magnetization directions of the magnetization free layers of the first and third magnetoresistance effect elements 15a and 15b. The amount of critical current that needs to be applied to 18b is smaller in the first magnetoresistive element 15a than in the third magnetoresistive element 15b, but the present invention is not limited to this. Even if the third magnetoresistance effect element 15b is smaller than the first magnetoresistance effect element 15a, the same effect can be obtained.

In the first embodiment of the present invention, when a large current in the positive direction is applied to the first and third magnetic field supply mechanisms 18a and 18b, the first and third magnetoresistance effect elements 15a and Although the magnetization directions of the magnetization free layer 15b and the magnetization fixed layer 15b are parallel to each other and have a low resistance value, the present invention is not limited to this. When a large current in the negative direction is applied to the first and third magnetic field supply mechanisms 18a and 18b, the magnetizations of the magnetization free layers and the magnetization fixed layers of the first and third magnetoresistance effect elements 15a and 15b The same effect can be obtained even if the directions are parallel and become a low resistance state. Further, when a large positive current is applied to the first and third magnetic field supply mechanisms 18a and 18b, the magnetization free layers and the magnetization fixed layers of the first and third magnetoresistance effect elements 15a and 15b The same effect can be obtained even if the magnetization direction is parallel to one and the other is antiparallel.

In the first embodiment of the present invention, the first and third resistors 4a and 4b are composed of magnetoresistive elements, but the present invention is not limited thereto. Even if the second and fourth resistors 5a and 5b are composed of magnetoresistive elements, the same effect can be obtained. In addition, even if either one of the first and second resistors 4a and 5a and one of the third and fourth resistors 4b and 5b are configured by magnetoresistive elements, the same effect can be obtained. can get.

(Second Embodiment)
FIG. 6 shows a simplified diagram of a matching circuit according to the second embodiment. The difference from the matching circuit according to the first embodiment shown in FIG. 2 is that the first and third magnetic field supply mechanisms 15a and 15b are connected to the first switching current supply terminal 14a via a single conductor. It is a point connected to. Other points are the same as those of the matching circuit according to the first embodiment. For this reason, it becomes possible to reduce in size. In addition, since the transmission line is shortened, it is possible to further prevent deterioration of the antenna characteristics.

(Third embodiment)
FIG. 7 shows a simplified diagram of a matching circuit according to the third embodiment. The difference from the matching circuit according to the second embodiment shown in FIG. 6 is that the first, second, third and fourth resistors 4a, 5a, 4b and 5b are the first, second, third and second. 4 magnetoresistive effect elements 15a, 16a, 15b and 16b, and adjacent to each magnetoresistive effect element, the first, second, third and fourth magnetic field supply mechanisms 18a, 19a, 18b and 19b is installed, and the first, second, third, and fourth magnetic field supply mechanisms 18a, 19a, 18b, and 19b are connected by a current applied through a conducting wire connected to the first switching current supply terminal 14a. The magnetic field induced by driving is applied to the first, second, third and fourth magnetoresistance effect elements 15a, 16a, 15b and 16b. The other points are the same as those of the matching circuit according to the second embodiment.

As the resistance values of the first and second magnetoresistive elements 15a and 16a change, the voltage dividing ratio of the first voltage dividing circuit 30a changes. The critical current amount that needs to be applied to the first magnetic field supply mechanism 18a in order to switch the magnetization direction of the magnetization free layer of the first magnetoresistance effect element 15a is that of the second magnetoresistance effect element 16a. This is smaller than the critical current amount that needs to be applied to the second magnetic field supply mechanism 19a in order to switch the magnetization direction of the magnetization free layer. Thereby, the current applied from the first switching current supply terminal 14a is adjusted, and one of the first and second magnetoresistive elements 15a and 16a is in a low resistance state, and the other is high. By setting the resistance value, the amount of change in the voltage dividing ratio of the first voltage dividing circuit 30a is increased. As the resistance values of the third and fourth magnetoresistive elements 15b and 16b change, the voltage dividing ratio of the second voltage dividing circuit 30b changes. The critical current amount that needs to be applied to the third magnetic field supply mechanism 18b to switch the magnetization direction of the magnetization free layer of the third magnetoresistive effect element 15b is that of the fourth magnetoresistive effect element 16b. It is smaller than the critical current amount that needs to be applied to the fourth magnetic field supply mechanism 19b in order to switch the magnetization direction of the magnetization free layer. As a result, the current applied from the first switching current supply terminal 14a is adjusted, and one of the third and fourth magnetoresistive elements 15b and 16b is in a low resistance state and the other is high. By setting the resistance value, the amount of change in the voltage dividing ratio of the second voltage dividing circuit 30b increases. The critical current amount that needs to be applied to the second magnetic field supply mechanism 19a in order to switch the magnetization direction of the magnetization free layer of the second magnetoresistive effect element 16a is that of the third magnetoresistive effect element 15b. It is smaller than the critical current amount that needs to be applied to the third magnetic field supply mechanism 18b in order to switch the magnetization direction of the magnetization free layer. Thereby, it is possible to independently change the voltage dividing ratio of the first and second voltage dividing circuits 30a and 30b by adjusting the current applied from the first switching current supply terminal 14a.

Table 2 shows specific operations of the matching circuit 20 according to the third embodiment. The critical current amount that needs to be applied to the first magnetic field supply mechanism 18a to switch the magnetization direction of the magnetization free layer of the first magnetoresistance effect element 15a is defined as the current (1) and the second magnetoresistance. In order to switch the magnetization direction of the magnetization free layer of the effect element 16a, the critical current amount necessary to be applied to the second magnetic field supply mechanism 19a is the current (2), and the magnetization free of the third magnetoresistive effect element 15b. The critical current amount necessary to be applied to the third magnetic field supply mechanism 18b in order to switch the magnetization direction of the layer is the current (3), and the magnetization direction of the magnetization free layer of the fourth magnetoresistance effect element 16b is The critical current amount that needs to be applied to the fourth magnetic field supply mechanism 19b for switching is defined as current (4), and current (1) <current (2) <current (3) <current (4). By controlling the amount of current applied to the first switching current supply terminal 14a and the positive / negative direction of the current, the ON / OFF states of the first and second PIN diodes 3a and 3b are controlled, Have a state.

With these structures, it is possible to increase the difference in the voltage division ratio as compared with the second embodiment. Thereby, the MR ratio (magnetoresistance ratio) of the magnetoresistive effect element is reduced, or the margin of the threshold voltage of the ON / OFF switching voltage of the first switching element is widened, and the manufacturing margin is greatly widened. Yield improvement, manufacturing power saving, resource saving, and cost reduction are possible.

In the third embodiment of the present invention, a critical current amount that needs to be applied to the first magnetic field supply mechanism 18a in order to switch the magnetization direction of the magnetization free layer of the first magnetoresistive effect element 15a. The current (1), the critical current amount that needs to be applied to the second magnetic field supply mechanism 19a to switch the magnetization direction of the magnetization free layer of the second magnetoresistive element 16a, is defined as the current (2), The critical current amount that needs to be applied to the third magnetic field supply mechanism 18b in order to switch the magnetization direction of the magnetization free layer of the third magnetoresistive element 15b is defined as the current (3), and the fourth magnetoresistive effect. When the critical current amount that needs to be applied to the fourth magnetic field supply mechanism 19b to switch the magnetization direction of the magnetization free layer of the element 16b is defined as current (4), current (1) <current (2) < Current (3) <Current (4 It is set to, but is not limited to it. If both the current (3) and the current (4) are small or large compared to both the current (1) and the current (2), the amount of current applied to the first switching current supply terminal 14a and The same effect can be obtained by controlling the positive and negative directions of the current. For example, current (2) <current (1) <current (4) <current (3) may be satisfied, or current (3) <current (4) <current (1) <current (2) may be satisfied.

In the third embodiment of the present invention, when a large current in the negative direction is applied to the first, second, third, and fourth magnetic field supply mechanisms 18a, 19a, 18b, and 19b, the first In the present invention, the magnetization directions of the magnetization free layers and the magnetization fixed layers of the second, third, and fourth magnetoresistance effect elements 15a, 16a, 15b, and 16b are parallel to each other, and are in a low resistance state. It is not limited to it. When applying a large negative current to the first, second, third and fourth magnetic field supply mechanisms 18a, 19a, 18b and 19b, the first, second, third and fourth magnetisms Even if the magnetization direction of the magnetization free layer and the magnetization fixed layer of any one of the resistance effect elements 15a, 16a, 15b and 16b is antiparallel and becomes a high resistance state, it is applied to the first switching current supply terminal 14a. The same effect can be obtained by controlling the amount of current and the positive / negative direction of the current.

In the third embodiment of the present invention, the first, second, third and fourth resistors 4a, 5a, 4b and 5b are composed of magnetoresistive elements, but the present invention is not limited thereto. Not. Even if the first, second, and third resistors 4a, 5a, and 4b are composed of magnetoresistive elements, a certain effect can be obtained. Further, a certain effect can be obtained if the first, third and fourth resistors 4a, 4b and 5b are composed of magnetoresistive elements.

(Fourth embodiment)
A simplified diagram of the matching circuit according to the fourth embodiment is also shown in FIG. The difference from the matching circuit according to the third embodiment is that a larger current is applied in one direction than the first switching current supply terminal 14a, and the first, second, third and fourth magnetic field supply mechanisms are applied. The direction of magnetization of the magnetization free layers of the first, second, third and fourth magnetoresistive elements 15a, 16a, 15b and 16b with respect to the direction of the magnetic field induced by 18a, 19a, 18b and 19b Is switched to a direction that is substantially the same as the direction of the magnetic field, the magnetization direction of the magnetization free layer and the magnetization direction of the magnetization fixed layer in the first and second magnetoresistive elements 15a and 16a are either Becomes parallel and the other becomes antiparallel, and the magnetization direction of the magnetization free layer and the magnetization direction of the magnetization fixed layer in the third and fourth magnetoresistive elements 15b and 16b are parallel. Next the other is a point that is configured to become anti-parallel state. Other points are the same as those of the matching circuit according to the third embodiment.

The critical current amount that needs to be applied to the first and second magnetic field supply mechanisms 18a and 19a in order to switch the magnetization directions of the magnetization free layers of the first and second magnetoresistive elements 15a and 16a is: More than the critical current amount that needs to be applied to the third and fourth magnetic field supply mechanisms 18b and 19b in order to switch the magnetization directions of the magnetization free layers of the third and fourth magnetoresistance effect elements 15b and 16b. small. Therefore, the magnetization directions of the magnetization free layers of the first, second, third and fourth magnetoresistance effect elements 15a, 16a, 15b and 16b, and the first, second, third and fourth When the directions of the magnetic fields emitted from the magnetic field supply mechanisms 18a, 19a, 18b and 19b are different, and when the amount of current applied from the first switching current supply terminal 14a is increased, the first and second The directions of the magnetization free layers of the magnetoresistive effect elements 15a and 16a are switched before the directions of the magnetization free layers of the third and fourth magnetoresistance effect elements 15b and 16b. Thereby, it is possible to independently change the voltage dividing ratio of the first and second voltage dividing circuits 30a and 30b by adjusting the current applied from the first switching current supply terminal 14a.

Table 3 shows specific operations of the matching circuit 20 according to the fourth embodiment. By controlling the amount of current applied to the first switching current supply terminal 14a and the positive / negative direction of the current, the ON / OFF states of the first and second PIN diodes 3a and 3b are controlled, Have a state.

With these structures, compared with the third embodiment, the current applied from the first switching current supply terminal 14a to switch the first and second switching elements requires fine control. Therefore, the control device can be easily designed.

In the fourth embodiment of the present invention, the first and second magnetic field supply mechanisms 18a and 19a are used to switch the magnetization directions of the magnetization free layers of the first and second magnetoresistive elements 15a and 16a. Critical current amount to be applied to the third and fourth magnetic field supply mechanisms 18b and 19b to switch the magnetization directions of the magnetization free layers of the third and fourth magnetoresistive elements 15b and 16b. However, the present invention is not limited to this. The critical current amount that needs to be applied to the first and second magnetic field supply mechanisms 18a and 19a in order to switch the magnetization directions of the magnetization free layers of the first and second magnetoresistive elements 15a and 16a is: More than the critical current amount that needs to be applied to the third and fourth magnetic field supply mechanisms 18b and 19b in order to switch the magnetization directions of the magnetization free layers of the third and fourth magnetoresistance effect elements 15b and 16b. Even if it is large, the same effect can be obtained.

In the fourth embodiment of the present invention, when a large current in the negative direction is applied to the first, second, third and fourth magnetic field supply mechanisms 18a, 19a, 18b and 19b, the second Although the magnetization directions of the magnetization free layer and the magnetization fixed layer of the fourth magnetoresistance effect elements 16a and 16b are parallel to each other and become a low resistance value, the present invention is not limited to this. A large current is applied in one direction from the first switching current supply terminal 14a, in the direction of the magnetic field induced by the first, second, third and fourth magnetic field supply mechanisms 18a, 19a, 18b and 19b. On the other hand, when the magnetization direction of the magnetization free layers of the first, second, third and fourth magnetoresistive elements 15a, 16a, 15b and 16b is switched to a direction substantially the same as the direction of the magnetic field. In the first and second magnetoresistive elements 15a and 16a, one of the magnetization direction of the magnetization free layer and the magnetization direction of the magnetization fixed layer becomes parallel and the other becomes antiparallel, and the third and In the fourth magnetoresistive elements 15b and 16b, the magnetization direction of the magnetization free layer and the magnetization direction of the magnetization fixed layer are maintained in a configuration in which one is parallel and the other is antiparallel. Thus, when applying a large negative current to the first, second, third and fourth magnetic field supply mechanisms 18a, 19a, 18b and 19b, the first and third magnetoresistive elements The same effect can be obtained even if the magnetization direction of either or both of the magnetization free layer 15a and 15b and the magnetization fixed layer are in parallel and have a low resistance value.

In the fourth embodiment of the present invention, the first, second, third and fourth resistors 4a, 5a, 4b and 5b are composed of magnetoresistive elements, but the present invention is not limited thereto. Not. Even if the first, second, and third resistors 4a, 5a, and 4b are composed of magnetoresistive elements, a certain effect can be obtained. Further, a certain effect can be obtained if the first, third and fourth resistors 4a, 4b and 5b are composed of magnetoresistive elements.

(Fifth embodiment)
FIG. 8 shows a simplified diagram of a matching circuit according to the fifth embodiment. The difference from the matching circuit according to the fourth embodiment shown in FIG. 7 is that the passive element section and the voltage dividing circuit are connected in three stages in parallel. Other points are the same as those of the matching circuit according to the fourth embodiment. In the matching circuit according to the fourth embodiment, four states can be switched. Further, six states can be switched by connecting the third voltage dividing circuit 30c and the third passive element unit 40c in parallel. Become.

(Comparative example)
FIG. 9 shows a simplified diagram of a circuit of an antenna device not using the present invention as a comparative example. According to this structure, the same number of switching current supply terminals and control devices as the magnetoresistive effect elements are required. However, in the present invention, since the switching current supply terminal 14a is single even though there are a plurality of magnetoresistance effect elements, a single control device is sufficient. Therefore, the complexity of the circuit and the increase in circuit loss can be avoided. Further, downsizing can be realized. In addition, the cost can be reduced because the number of parts is reduced.

In the present invention, when all the PIN diodes are ON, the state of the lowest frequency is obtained. At this time, since all the PIN diodes are connected in parallel, the high frequency resistance of the PIN diode is minimized. This can reduce the loss of the entire PIN diode. Further, since the capacitor 13 for impedance adjustment is connected immediately before the transmitter / receiver 11 separately from the matching circuit 20, adjustment according to the individual antenna and the transmitter / receiver is easy.

The present invention is effective for an application of 1 GHz or higher (for example, a composite antenna that switches multi-frequency antenna frequencies such as GPS, W-LAN, Bluetooth (registered trademark)) mounted on a portable wireless device.

The present invention can also be configured in one chip with a thin film structure. By configuring in one chip, the height and size can be reduced, and the line loss can be reduced.

Although the preferred embodiments of the present invention have been described above, modifications other than those described above can be made.

As described above, the matching circuit according to the present invention is a low-loss matching circuit capable of adjusting the antenna frequency over a wide band. With this matching circuit, an antenna that can be used for a plurality of applications using a single antenna element can be realized. Therefore, the antenna can be reduced in size, the number of parts can be reduced, and the added value of the antenna can be greatly improved.

DESCRIPTION OF SYMBOLS 1 Transmission / reception antenna 2a 1st capacitor | condenser, 2b 2nd capacitor | condenser, 2c 5th capacitor | condenser 3a 1st PIN diode, 3b 2nd PIN diode 3c 3rd PIN diode 4a 1st resistance, 4b 3rd Resistor, 4c fifth resistor 5a second resistor, 5b fourth resistor, 5c sixth resistor 6 driving voltage supply terminal 7 first connection node 8 second connection node 9 third capacitors 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h Reference potential (GND)
11 transceiver 12a first choke coil, 12b second choke coil 12c third choke coil, 12d fourth choke coil 13 fourth capacitor 14a first switching current supply terminal 14b second switching current supply terminal 15a 1st magnetoresistive effect element, 15b 3rd magnetoresistive effect element 16a 2nd magnetoresistive effect element, 16b 4th magnetoresistive effect element 17 6th capacitor | condenser 18a 1st magnetic field supply mechanism, 18b 3rd Magnetic field supply mechanism 19a Second magnetic field supply mechanism, 19b Fourth magnetic field supply mechanism 20 Matching circuit 21 Feeding point 22 Mounting substrate 30a First voltage divider circuit, 30b Second voltage divider circuit, 30c Third voltage divider Circuit 40a First passive element part, 40b Second passive element part 40c Third passive element part

Claims (5)

A first passive element unit having a first switching element and a first passive element connected in series; a second switching element and a second passive element connected in series; and the first passive element A second passive element unit connected in parallel to the unit, a drive voltage supply terminal for applying a control voltage to the first passive element unit and the second passive element unit, and one end of the drive voltage supply terminal A first voltage dividing circuit having the other end connected to one end of the first passive element section, one end connected to the drive voltage supply terminal, and the other end connected to the second passive element portion. A second voltage-dividing circuit connected to one end of the element section; the first voltage-dividing circuit as a first resistor whose one end is connected to the drive voltage supply terminal; A second resistor connected to the other end of the resistor and having the other end connected to the reference potential As the second voltage dividing circuit, one end is connected to the driving voltage supply terminal, one end is connected to the other end of the third resistor, and the other end is a reference. A fourth resistor connected to a potential, wherein at least one of the first or second resistor and at least one of the third or fourth resistor is interposed via a nonmagnetic spacer layer. A magnetoresistive effect element having a magnetization fixed layer and a magnetization free layer, and a magnetic field supply mechanism installed adjacent to each of the first to fourth resistances constituted by the magnetoresistive effect element And the magnetic field supply mechanism is connected to a single switching current supply terminal. The matching circuit according to claim 1, wherein the magnetic field supply mechanism is connected to the single switching current supply terminal via a single conducting wire. 3. The matching circuit according to claim 1, wherein the first and second resistors are magnetoresistive elements each having a magnetization fixed layer and a magnetization free layer via a nonmagnetic spacer layer. A large voltage is applied in one direction by the single voltage supply mechanism, and the magnetization of the magnetization free layer of the magnetoresistive effect element adjacent to the direction of the magnetic field induced by all the magnetic field supply mechanisms is applied. When the direction is switched to a direction that is substantially the same as the direction of the magnetic field, one of the first and second resistors is in a low resistance state and the other is in a high resistance state. 4. The matching circuit according to claim 3, wherein 5. An antenna device comprising an antenna and a matching circuit according to claim 1 connected to the antenna.

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