JP7448002B2 - Impedance matching element and communication terminal equipment - Google Patents

Description

The present invention relates to an impedance matching element used in an impedance conversion circuit or the like, and a communication terminal device equipped with the same.

Patent Document 1 shows a transformer element used as an impedance conversion element. This Patent Document 1 discloses an autotransformer structure in which two transformers are connected in parallel, and by giving characteristics to the stacking order of the two coils forming the first transformer and the two coils forming the second transformer. , a method is used to determine the impedance conversion ratio. Specifically, in the laminated structure of the coil, the pattern of each layer is wound around one turn each, and the size of the inductance is adjusted by providing a parallel portion.

International Publication No. 2015/068614

FIG. 17 is a circuit diagram of an antenna device including an impedance conversion circuit shown in Patent Document 1. Impedance conversion circuit 100 is connected between power supply circuit 30 and antenna 40. In FIG. 17, the impedance conversion circuit 100 is composed of an autotransformer circuit including a first coil L1 and a second coil L2. This impedance conversion circuit 100 consists of an inductance of the first coil L1, an inductance of the second coil L2, and a mutual inductance M due to the combination thereof.

FIG. 18 is a Smith chart showing the reflection coefficient of impedance of the impedance conversion circuit having the configuration shown in FIG. 17 as viewed from the power supply circuit. Further, FIG. 19 is a diagram showing the frequency characteristics of the voltage standing wave ratio VSWR when looking at the impedance conversion circuit 100 from the power supply circuit 30. In FIGS. 18 and 19, characteristic A is the characteristic of the antenna 40 alone, and characteristic B is the characteristic with the impedance conversion circuit 100 inserted.

Since the antenna 40 constitutes a resonant circuit including an inductor and a capacitor, the impedance of the antenna 40 has frequency dependence. Therefore, in the examples shown in FIGS. 18 and 19, the impedance of the antenna 40 is inductive in a frequency band higher than the resonant frequency (3.59 GHz), but by using the impedance conversion circuit 100, the impedance of the antenna 40 is The difference with the characteristic impedance becomes larger in high frequency bands. This is due to the inductive component of the impedance conversion circuit 100. In other words, the impedance conversion circuit 100 is a transformer element, and in a transformer element with a small capacitance component, the self-resonance frequency is significantly higher than the communication frequency band.

Further, the impedance conversion ratio of the impedance conversion circuit itself is determined by the inductance and coupling coefficient of the first coil L1 and the second coil L2, but since the coupling coefficient k between the first coil L1 and the second coil L2 is less than 1, This impedance conversion circuit is equivalently composed of an ideal transformer and an inductive parasitic component. In a frequency band where the impedance conversion ratio is higher than the appropriate frequency, the impedance conversion ratio deviates further from the appropriate ratio due to the above-mentioned inductive parasitic component.

In the example shown in FIG. 19, the existence of the impedance conversion circuit 100 causes impedance mismatch in a frequency band higher than 3.76 GHz.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an impedance matching element that impedance matches an antenna and a feeding circuit over a wider band, and a communication terminal device equipped with the impedance matching element.

(1) An impedance matching element as an example of the present disclosure is
a first input/output terminal to which a power supply circuit is connected;
a second input/output terminal to which the antenna is connected;
A laminate in which a plurality of base material layers are laminated,
a first coil formed in the laminate, a first end connected to the first input/output terminal, a second end connected to the second input/output terminal, and a third end connected to the second input/output terminal. a second coil having a fourth end connected to a ground terminal and electromagnetically coupling to the first coil;
has
self-inductance of the first coil, self-inductance of the second coil, mutual inductance between the first coil and the second coil, and between the first input/output terminal and the ground terminal or the second input/output. The self-resonant frequency is determined by the capacitance configured between the terminal and the ground terminal.
It is characterized in that the self-resonant frequency is within a communication frequency band by the power feeding circuit.

(2) A communication terminal device as an example of the present disclosure includes an antenna that transmits and receives high-frequency signals, a feeding circuit for the antenna, and an impedance matching circuit connected between the antenna and the feeding circuit. In the communication terminal device, the impedance matching circuit is configured with the impedance matching element.

According to the present invention, it is possible to obtain an impedance matching element that impedance matches an antenna and a feeding circuit over a wider band, and a communication terminal device equipped with the impedance matching element.

FIG. 1 is a perspective view of an impedance matching element 101 according to the first embodiment. FIG. 2 is an exploded plan view of the impedance matching element 101. FIG. 3(A) is a circuit diagram of the impedance matching element 101. FIG. 3B is a circuit diagram of a circuit including the impedance matching element 101, the antenna 40, and the feeding circuit 30. FIG. 4 is a diagram showing the frequency characteristics of the reactance of the parallel LC circuit composed of the second coil L2 and the capacitor C2 shown in FIG. 3(B). FIG. 5 is a Smith chart showing the reflection coefficient of impedance when looking at the impedance matching element 101 from the feeder circuit 30. FIG. 6 is a diagram showing the frequency characteristics of the voltage standing wave ratio VSWR when looking at the impedance matching element 101 from the power supply circuit 30. FIG. 7 is a cross-sectional view of an impedance matching element 102A according to the second embodiment. FIG. 8 is a cross-sectional view of an impedance matching element 102B according to the second embodiment. FIG. 9 is a plan view showing one conductor pattern of the second coil in the impedance matching element according to the second embodiment. FIG. 10 is a plan view showing two conductor patterns of the second coil in the impedance matching element according to the second embodiment. FIG. 11 is a circuit diagram of a circuit including an impedance matching element 103A, an antenna 40, and a power feeding circuit 30 according to the third embodiment. FIG. 12 is a circuit diagram of a circuit including another impedance matching element 103B, an antenna 40, and a feeding circuit 30 according to the third embodiment. FIG. 13 is an exploded plan view showing an example of a conductive pattern for forming the capacitor C1 shown in FIG. 12. FIG. 14 is a circuit diagram of a circuit in which an additional circuit is connected to the impedance matching element 101 according to the fourth embodiment. FIG. 15 is a circuit diagram of another circuit in which an additional circuit is connected to the impedance matching element 101 according to the fourth embodiment. FIG. 16 is a diagram showing the configuration of a communication terminal device such as a mobile phone terminal according to the fifth embodiment. FIG. 17 is a circuit diagram of an antenna device including an impedance conversion circuit shown in Patent Document 1. FIG. 18 is a Smith chart showing the reflection coefficient of impedance of the impedance conversion circuit having the configuration shown in FIG. 17 as viewed from the power supply circuit. FIG. 19 is a diagram showing the frequency characteristics of the voltage standing wave ratio VSWR when looking at the impedance conversion circuit 100 from the power supply circuit 30 shown in FIG. 17.

Hereinafter, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings and some specific examples. In each figure, the same parts are given the same reference numerals. In consideration of easiness of explanation or understanding of the main points, the embodiment is shown divided into a plurality of embodiments for convenience of explanation, but it is possible to partially replace or combine the configurations shown in different embodiments. In the second embodiment and subsequent embodiments, descriptions of matters common to the first embodiment will be omitted, and only differences will be described. In particular, similar effects due to similar configurations will not be mentioned for each embodiment.

《First embodiment》
FIG. 1 is a perspective view of an impedance matching element 101 according to the first embodiment. The impedance matching element 101 is an element formed in a rectangular parallelepiped-shaped laminate 10 that is a laminate of base material layers S1 to S14, and has a first input/output terminal T1, a second input/output terminal T2, and a ground. A terminal GND is provided. Terminal NC in FIG. 1 is an empty terminal.

FIG. 2 is an exploded plan view of the impedance matching element 101. The impedance matching element 101 includes a first first coil L11, a second first coil L21, a first second coil L12, and a second second coil L22.

The first coil L11 includes conductor patterns P11 and P12 formed on base layers S2 and S3 and connected in series. The first second coil L12 includes conductor patterns P13, P14, P15, and P16 formed on base layers S4, S5, S6, and S7 and connected in series. Similarly, the second first coil L21 includes conductor patterns P21 and P22 formed on base layers S13 and S12 and connected in series. The second second coil L22 includes conductor patterns P23, P24, P25, and P26 formed on base layers S11, S10, S9, and S8 and connected in series.

The configuration of the first coil L21 with the conductor patterns P21 and P22 is the same as the configuration of the first coil L11 with the conductor patterns P11 and P12. Further, the configuration of the second coil L22 made up of the conductor patterns P23, P24, P25, and P26 is the same as the configuration of the second coil L12 made up of the conductor patterns P13, P14, P15, and P16.

A first end E11 of the first coil L11 is connected to the first input/output terminal T1, and a second end E12 is connected to the second input/output terminal T2. A third end E13 of the second coil L12 is connected to the ground terminal GND, and a fourth end E14 of the second coil L12 is connected to the second input/output terminal T2. Similarly, the first end E21 of the first coil L21 is connected to the first input/output terminal T1, and the second end E22 is connected to the second input/output terminal T2. The third end E23 of the second coil L22 is connected to the ground terminal GND, and the fourth end E24 of the second coil L22 is connected to the second input/output terminal T2. Broken lines in FIG. 2 indicate connection relationships by interlayer connection conductors.

FIG. 3(A) is a circuit diagram of the impedance matching element 101. FIG. 3B is a circuit diagram of a circuit including the impedance matching element 101, the antenna 40, and the feeding circuit 30. In FIG. 3A, capacitance C12 is a parasitic capacitance due to interlayer capacitance of the first and second coils L12. Further, the capacitance C22 is a parasitic capacitance of the second second coil L22. The capacitance C12 is a parasitic capacitance due to the interlayer capacitance of the first second coil L12, and the capacitance C22 is a parasitic capacitance due to the interlayer capacitance of the second second coil L22. It can be expressed as a single capacitor (inter-terminal capacitance) connected between the terminal T2 and the ground terminal GND.

Note that although parasitic capacitance occurs in the first first coil L11 and the second first coil L21, it is small in this embodiment, so it is not shown in FIGS. 3(A) and 3(B).

As shown in FIG. 3(A), the first first coil L11 and the second first coil L21 are connected in parallel, and the first second coil L12 and the second second coil L22 are connected in parallel. connected in parallel. Therefore, the impedance matching element 101 can be expressed as the impedance matching element 101 in FIG. 3(B). In this way, the impedance matching element 101 includes an autotransformer circuit including the first coil L1 and the second coil L2, and a capacitor C2. The self-inductance of the first coil L1 is the self-inductance due to the first coils L11 and L21, the self-inductance of the second coil L2 is the self-inductance due to the second coils L12 and L22, and the capacitance of the capacitor C2 is the self-inductance due to the first coils L11 and L21. is the capacitance due to In this way, a parallel LC circuit is configured by the second coil L2 and the capacitor C2. Therefore, the self-resonant frequency of the impedance matching element 101 is mainly determined by the resonant frequency of the parallel LC circuit.

FIG. 4 is a diagram showing the frequency characteristics of the reactance of the parallel LC circuit composed of the second coil L2 and the capacitor C2 shown in FIG. 3(B). In this example, the inductance of the second coil L2 is 0.8 nH, and the capacitance of the capacitor C2 is 2.6 pF. The resonant frequency of the parallel LC circuit is 3.49 GHz, and it becomes inductive in a lower frequency band and capacitive in a higher frequency band. That is, the parallel LC circuit acts as a capacitive element shunt-connected to ground in a frequency band higher than its resonant frequency.

FIG. 5 is a Smith chart showing the reflection coefficient of impedance when looking at the impedance matching element 101 from the feeder circuit 30. Further, FIG. 6 is a diagram showing the frequency characteristics of the voltage standing wave ratio VSWR when looking at the impedance matching element 101 from the power supply circuit 30. In FIGS. 5 and 6, characteristic A is the characteristic of the antenna 40 alone, characteristic B is the characteristic with the impedance conversion element without capacitance C2 inserted, and characteristic C is the characteristic of the impedance matching element 101 of this embodiment. This is the characteristic with the inserted. Here, the self-inductance of the first coil L1 is 1.2 nH, the self-inductance of the second coil L2 is 0.8 nH, and the coupling coefficient between the first coil L1 and the second coil L2 is 0.6. Further, the equivalent circuit of the antenna 40 includes a series-connected inductor of 3.9 nH, a resistor of 5 Ω, and a shunt-connected capacitor of 0.5 pF.

Here, the communication frequency band is 3.1 GHz to 4.1 GHz, and the self-resonant frequency of the impedance matching element 101 is 3.49 GHz within the communication frequency band. This improves impedance matching in the frequency band that falls within the inductive region of the Smith chart, and ensures impedance matching between the feeder circuit 30 and the antenna 40 over a wider band.

In particular, in the frequency band higher than 3.76 GHz among inductive frequencies, impedance mismatching occurs in the conventional example, but this embodiment improves this and shows that matching is achieved over a wide band. Recognize.

In addition, in FIG. 2, the first autotransformer includes a first coil L11 and a second coil L12, and a second autotransformer includes a first coil L21 and a second coil L22. Although an example has been shown, the impedance matching element may be configured with a single autotransformer. For example, in FIG. 2, the impedance matching element may be configured by providing only the first coil L11 and the second coil L12 formed on the base material layers S2 to S7.

《Second embodiment》
In the second embodiment, several configuration examples for intentionally forming a capacitance in the second coil of the impedance matching element shown in the first embodiment will be shown.

FIG. 7 is a cross-sectional view of an impedance matching element 102A according to the second embodiment. The planar shape of each conductor pattern provided in the laminate 10 is the same as that of the impedance matching element 101 shown in the first embodiment.

The interlayer spacing between the conductive patterns P13, P14, P15, and P16 constituting the first second coil L12 is narrower than the interlayer spacing between the conductive patterns P11 and P12 constituting the first first coil L11. Further, the layer spacing between the conductor patterns P12 and P13 between the first coil L11 and the second coil L12 is narrower. Similarly, the layer spacing between the conductor patterns P23, P24, P25, and P26 constituting the second second coil L22 is narrower than the layer spacing between the conductor patterns P21 and P22 constituting the second first coil L21. Further, the layer spacing between the conductive patterns P22 and P23 between the first coil L21 and the second coil L22 is narrower.

Since the capacitance formed between the second input/output terminal T2 and the ground terminal GND is the interlayer capacitance of the second coils L12 and L22, as shown in FIG. By intentionally narrowing the layer spacing of the pattern, it is possible to effectively increase the capacitance connected in parallel to the second coils L12 and L22.

FIG. 8 is a cross-sectional view of an impedance matching element 102B according to the second embodiment. The planar shape of each conductor pattern provided in the laminate 10 is basically the same as that of the impedance matching element 101 shown in the first embodiment. In the impedance matching element 102B, the second coils L12 and L22 form a single circuit path when viewed in the direction of lamination of the base material layers. That is, in the impedance matching element 102B, except for the connection portion of the interlayer connection conductor, the inner edge and outer edge of the conductor pattern of each layer match when viewed in the stacking direction of the base material layers. As is clear from a comparison between FIGS. 7 and 8, the circuit paths of the conductor patterns P13, P14, P15, and P16 constituting the second coil L12 are the same, and as a result, the circuit paths of the conductor patterns P13, P14, P15, and P16 are the same. The facing area between layers is increased. Similarly, the circuit paths of the conductor patterns P23, P24, P25, and P26 constituting the second coil L22 are equal, and the interlayer facing area of the conductor patterns P23, P24, P25, and P26 is increased. In this way, the capacitance connected in parallel to the second coils L12 and L22 can be effectively increased.

FIG. 9 is a plan view showing one representative conductor pattern of the second coil in the impedance matching element according to the second embodiment. FIG. 9 shows that the line widths of the conductor patterns formed on each base material layer constituting the second coil are made thicker. This allows the capacitance connected in parallel to the second coil to be effectively increased.

FIG. 10 is a plan view showing two conductor patterns of the second coil in the impedance matching element according to the second embodiment. These two conductor patterns face each other between layers. The conductive pattern P15 formed on the base material layer S6 and the conductive pattern P16 formed on the base material layer S7 are the same as the conductive patterns P15 and P16 shown in FIG. In FIG. 10, the conductor pattern P16E is a dummy conductor pattern for imparting capacitance to the second coil, and is extended from the conductor pattern P16. The conductor pattern P16E has a shape that interpolates the circular path formed by the second coil when the second coil is viewed in the stacking direction. Therefore, this conductor pattern P16E faces the conductor pattern P15 in the interlayer direction. Therefore, the current circulating around the second coil does not flow through the conductor pattern P16E, and the conductor pattern P16E acts as a capacitive electrode.

In this way, by providing the dummy conductor pattern for forming capacitance in the conductor pattern constituting the second coil, the capacitance connected in parallel to the second coil can be effectively increased.

《Third embodiment》
In the third embodiment, an impedance matching element is shown in which the capacitance is provided at a different position from the examples shown so far.

FIG. 11 is a circuit diagram of a circuit including an impedance matching element 103A, an antenna 40, and a power feeding circuit 30 according to the third embodiment. In FIG. 11, a capacitor C1 is a capacitor formed between the first input/output terminal T1 and the ground. The impedance matching element 103A includes a first coil L1, a second coil L2, and a capacitor C1. This is the same as the example shown in the first and second embodiments in that the first coil L1 and the second coil L2 constitute an autotransformer type impedance conversion circuit.

Since the impedance matching element 103A is an LC circuit including the first coil L1, second coil L2, and capacitor C1, it has a self-resonant frequency. As shown in the first embodiment, in a frequency band higher than the resonant frequency, the capacitor C1 acts as a capacitive element shunt-connected to ground. Furthermore, since the reactance of the second coil L2 is not canceled by the reactance of the capacitor C2 shown in FIG. 3(B), the reduction in the transformation ratio due to the first coil L1 and the second coil L2 can be eliminated Can be done. Therefore, when the impedance viewed from the first input/output terminal T1 to the impedance matching element 103A is expressed on a Smith chart, the impedance matching in the frequency band that falls within the inductive region of the Smith chart is improved, and the impedance matching is improved over a wider band. Thus, impedance matching between the feeder circuit 30 and the antenna 40 is ensured.

FIG. 12 is a circuit diagram of a circuit including another impedance matching element 103B, an antenna 40, and a feeding circuit 30 according to the third embodiment. In FIG. 12, a capacitor C1 is a capacitor formed between the first input/output terminal T1 and ground, and a capacitor C2 is a capacitor formed between the second input/output terminal T2 and ground. The impedance matching element 103B includes a first coil L1, a second coil L2, a capacitor C1, and a capacitor C2. This is the same as the example shown in the first and second embodiments in that the first coil L1 and the second coil L2 constitute an autotransformer type impedance conversion circuit.

Since the impedance matching element 103B is an LC circuit including the first coil L1, the second coil L2, the capacitor C1, and the capacitor C2, it has a self-resonant frequency. As shown in the first embodiment, in a frequency band higher than the resonant frequency, the capacitor C1 acts as a capacitive element shunt-connected to ground. Therefore, when the impedance viewed from the first input/output terminal T1 to the impedance matching element is expressed on a Smith chart, the impedance matching in the frequency band that falls within the inductive region of the Smith chart is improved, and the impedance matching is improved over a wider band. , impedance matching between the feeder circuit 30 and the antenna 40 is ensured.

The configuration for forming the capacitor C2 shown in FIG. 12 is as shown in the first and second embodiments.

FIG. 13 is an exploded plan view showing an example of a conductive pattern for forming the capacitor C1 shown in FIG. 12. The impedance matching element 103B includes a first first coil L11, a second first coil L21, a first second coil L12, and a second second coil L22. Each conductor pattern constituting these coils is the same as the example shown in FIG. 2 in the first embodiment. The difference from the example shown in FIG. 2 is that conductor patterns PC11, PC12, PC21, and PC22 are provided.

The conductor pattern PC11 is electrically connected to the first input/output terminal T1 via the first end E11 of the first coil L11, and the conductor pattern PC12 is electrically connected to the GND terminal. Similarly, the conductor pattern PC21 is electrically connected to the first input/output terminal T1 via the first end E21 of the first coil L21, and the conductor pattern PC12 is electrically connected to the GND terminal. The conductor patterns PC11 and PC12 are opposed to each other in the lamination direction, and the conductor patterns PC21 and PC22 are opposed to each other in the lamination direction. In this way, the capacitor C1 can be formed.

《Fourth embodiment》
The fourth embodiment shows an example in which an additional circuit is provided in the impedance matching element.

FIG. 14 is a circuit diagram of a circuit in which an additional circuit is connected to the impedance matching element 101 according to the fourth embodiment. In this example, a series circuit including a capacitor C3 and a switch SW1 is connected between the first input/output terminal T1 and the second input/output terminal T2 of the impedance matching element 101. Further, a circuit including a switch SW2 and a capacitor C4 is connected between the ground terminal GND of the impedance matching element 101 and the ground.

In FIG. 14, when switch SW1 is turned on, capacitor C3 is connected in parallel to first coil L1. When the switch SW2 selects the capacitor C4 (on one side), the capacitor C4 is inserted between the parallel circuit of the second coil L2 and the capacitor C2 and the ground. Furthermore, if the switch SW2 selects the other side, the ground terminal GND of the impedance matching element 101 is directly connected to the ground. In this way, frequency dependence can be imparted to the matching characteristics of the impedance matching element 101 by selecting the switches SW1 and SW2.

FIG. 15 is a circuit diagram of another circuit in which an additional circuit is connected to the impedance matching element 101 according to the fourth embodiment. In this example, a circuit including a capacitor C3, an inductor L3, and a switch SW1 is connected between the first input/output terminal T1 and the second input/output terminal T2 of the impedance matching element 101. Further, a circuit including a switch SW2, a capacitor C4, and an inductor L4 is connected between the ground terminal GND of the impedance matching element 101 and the ground. Therefore, by selecting the switches SW1 and SW2, various frequency dependencies can be imparted to the matching characteristics of the impedance matching element 101.

In the examples shown in FIGS. 14 and 15, matching circuits are provided between the feeding circuit 30 and the impedance matching element 101 and between the impedance matching element 101 and the antenna 40, respectively.

《Fifth embodiment》
In the fifth embodiment, a communication terminal device including an impedance conversion element will be exemplified.

FIG. 16 is a diagram showing the configuration of a communication terminal device such as a mobile phone terminal according to the fifth embodiment. FIG. 16 shows the main parts inside the casing of the communication terminal device. An antenna 40 and a circuit board are provided inside the housing, and a ground conductor 50, an impedance matching element 101, and a feeder circuit 30 are provided on the circuit board. Antenna 40 is a T-branch type antenna. The ground conductor 50 serves as an image forming conductor for the antenna 40 or together with the antenna 40 as a radiating element.

The impedance of the antenna 40 is, for example, 20Ω, the impedance of the feeder circuit 30 is 50Ω, and the impedance matching element 101 converts the impedance at a ratio of 2.5:1.

According to this embodiment, it is possible to obtain a communication terminal device in which an antenna circuit is equipped with an impedance conversion circuit with low insertion loss and small variations in electrical characteristics.

Finally, the invention is not limited to the embodiments described above. Appropriate modifications and changes can be made by those skilled in the art. The scope of the invention is indicated by the claims rather than the embodiments described above. Furthermore, the scope of the present invention includes modifications and changes from the embodiments within the scope of the claims and equivalents.

C1, C2, C12, C22... Capacitance C3, C4... Capacitor E11, E21... First end E12, E22... Second end E13, E23... Third end E14, E24... Fourth end GND... Ground terminal L1... First Coil L2...Second coil L11...First first coil L12...First second coil L21...Second first coil L22...Second second coil L3, L4...Inductor NC...Empty terminal P11, P12 , P13, P14, P15, P16... Conductor pattern P16E... Conductor pattern P21, P22, P23, P24, P25, P26... Conductor pattern PC11, PC12, PC21, PC22... Conductor pattern S1 to S14... Base layer SW1, SW2... Switch T1...First input/output terminal T2...Second input/output terminal 10...Laminated body 30...Feeding circuit 40...Antenna 50...Ground conductor 100...Impedance conversion circuit 101, 102A, 102B, 103A, 103B...Impedance matching element

Claims (5)

a first input/output terminal to which a power supply circuit is connected;
a second input/output terminal to which the antenna is connected;
A laminate in which a plurality of base material layers are laminated,
a first coil formed in the laminate, a first end connected to the first input/output terminal, a second end connected to the second input/output terminal, and a third end connected to the second input/output terminal. a second coil having a fourth end connected to a ground terminal and electromagnetically coupling to the first coil;
has
self-inductance of the first coil, self-inductance of the second coil, mutual inductance between the first coil and the second coil, and between the first input/output terminal and the ground terminal or the second input/output. The self-resonant frequency is determined by the capacitance configured between the terminal and the ground terminal.
the self-resonant frequency is within a communication frequency band by the power supply circuit;
Impedance matching element. A capacitance configured between the second input/output terminal and the ground terminal is an interlayer capacitance of the second coil.
The impedance matching element according to claim 1. Viewed in the direction of the stacking, the second coil forms a single circumferential path;
The impedance matching element according to claim 1 or 2. A dummy having a shape that interpolates the circuit path formed by the second coil when viewed in the direction of the lamination, on any of the conductor patterns formed on the plurality of base materials of the laminate that constitute the second coil. The conductor pattern is formed as an extension,
The impedance matching element according to any one of claims 1 to 3. A communication terminal device comprising: an antenna for transmitting and receiving high frequency signals; a power supply circuit for the antenna; and an impedance matching circuit connected between the antenna and the power supply circuit.
The impedance matching circuit is an impedance matching element according to any one of claims 1 to 4.
Communication terminal equipment.

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