JP6881079B2 - Antenna module and communication module - Google Patents

Description

The present invention relates to a wireless communication device such as an RFID tag that utilizes a plurality of communication frequency bands, and more particularly to an antenna module and a communication module used in the wireless communication device.

In recent years, in an article management system using an RFID tag, an RFID tag that can be shared by both an HF band RFID system and a UHF band RFID system has been used.

Such an RFID tag that can be shared between the HF band RFID system and the UHF band RFID system is disclosed in, for example, Patent Document 1.

The antenna shown in Patent Document 1 includes a coil antenna and a monopole antenna formed on a substrate. The monopole antenna is formed on the outer peripheral portion of the coil antenna and is grounded by the coil antenna.

Japanese Unexamined Patent Publication No. 2011-135307

However, in an antenna having a structure as shown in Patent Document 1, it is important to form the monopole antenna at a position away from the outer circumference of the coil antenna in order to secure the radiation efficiency as the monopole antenna. Therefore, a relatively large space is required to provide the monopole antenna on the outer peripheral portion of the coil antenna, and it is difficult to miniaturize the antenna. Further, when the external dimensions of the antenna are restricted, for the same reason, if the formation range of the coil antenna is reduced in order to secure a wide formation area of the monopole antenna, the gain of the coil antenna is lowered and the gain of the monopole antenna is reduced. When the formation region is made small, the gain of the monopole antenna decreases.

Therefore, an object of the present invention is an antenna module that can be miniaturized while ensuring the gain of each of two antennas having different frequency bands, or that the gain of each of two antennas having different frequency bands is increased without enlarging the outer shape. Is to provide. Furthermore, it is an object of providing a communication module including the antenna module.

(1) The antenna module of the present invention is
A first antenna connected to a first RFIC element having a first frequency band as a communication frequency band, and a second antenna connected to a second RFIC element having a second frequency band higher than the first frequency band as a communication frequency band. And with
The first antenna is a coil antenna formed on the main surface of the substrate.
The second antenna is arranged outside the coil antenna forming region in a plan view of the substrate, is connected to the coil antenna, and includes a part of the coil antenna to form a conductor loop, and the coil antenna is mounted on the coil antenna. It is composed of a matching conductor pattern that acts as a dipole antenna in the second frequency band and the coil antenna.
It is characterized by that.

With the above configuration, the matching conductor pattern constitutes a conductor loop including a part of the coil antenna, and the coil antenna is excited as a dipole antenna in the second frequency band while impedance matching is performed by the conductor loop. Since the matching conductor pattern itself does not directly contribute to radiation, it may be arranged outside the coil antenna forming region, and a large space is not required outside the coil antenna forming region. Further, since the conductor loop is arranged outside the formation region of the coil antenna, even if the coil antenna acts as an equivalent conductor flat plate in the second frequency band, the conductor loop is not affected by the action.

(2) For example, the first frequency band is an HF band, and the second frequency band is a UHF band. As a result, it can be used as an antenna module for RFID tags shared by HF band RFID tags and UHF band RFID tags.

(3) The outer shape of the coil antenna is a rectangular shape having a long side and a short side, the matching conductor pattern is formed along the long side, and the long side of the coil antenna is a dipole antenna. It is preferable to act as. As a result, in the second frequency band, the coil antenna acts as a dipole antenna in which the longitudinal direction of the coil antenna is the direction in which the current flows. Therefore, the longitudinal dimension of the coil antenna is effectively utilized, and the second frequency band has a higher gain while being smaller. Two antennas are configured.

(4) The coil antenna is composed of a spiral-shaped conductor pattern having a plurality of turns, and the conductor loop is connected to a first conductor portion which is a part of the spiral-shaped conductor pattern and the first conductor portion. It is preferably composed of a second conductor portion. As a result, the coil antenna and the conductor loop can be formed on the same plane, and the conductor pattern can be easily formed on the substrate.

(5) The length of the second conductor portion in the direction along the outer edge of the coil antenna is preferably shorter than the average diameter of the coil antenna in the direction. As a result, in the first frequency band, the second conductor portion does not interfere with the formation of the magnetic flux of the coil antenna.

(6) The first conductor portion is preferably a part of the outermost circumference of the spiral conductor pattern. As a result, the second conductor portion can be connected to the coil antenna in the same plane, and the conductor loop can be easily configured.

(7) The line width of the second conductor portion is preferably narrower than the line width of the coil antenna. As a result, the space outside the coil antenna forming region can be reduced, and the overall size can be avoided. Further, the second conductor portion 22 is less likely to block the magnetic flux of the coil antenna 10 in the first frequency band. Further, the inductance component can be set to a predetermined value even though the matching conductor pattern is provided in a small space.

(8) It is preferable that the matching conductor pattern further has an extending portion extending from the second conductor portion along the outer edge of the coil antenna. With this structure, the extending portion acts as a part of the radiating element of the second antenna, and the gain of the second antenna is increased.

(9) The length of the extending portion is preferably shorter than the 1/4 wavelength of the second frequency band. As a result, the space outside the coil antenna forming region can be reduced, and the overall size can be avoided.

(10) It is preferable that the coil antenna has a coil opening, and the connection position of the first RFIC element and the connection position of the second RFIC element are inside the coil opening of the coil antenna. With this configuration, it is not necessary to secure the mounting space for the first RFIC element and the second RFIC element outside the formation region of the coil antenna, and the overall size can be avoided.

(11) The communication module of the present invention is
A first RFIC element having a first frequency band as a communication frequency band, a first antenna connected to the first RFIC element, and a second RFIC element having a second frequency band higher than the first frequency band as a communication frequency band. A second antenna connected to the second RFIC element,
The first antenna is a coil antenna formed on the main surface of the substrate.
The second antenna is arranged outside the formation region of the coil antenna in a plan view of the substrate, is connected to the coil antenna, constitutes a conductor loop including a part of the coil antenna, and forms the coil antenna. It is composed of a matching conductor pattern that acts as a dipole antenna in the second frequency band and the coil antenna.
The first RFIC element is mounted on the substrate and connected to the coil antenna.
Wherein the 2RFIC element is connected to the matching conductor pattern are mounted on the substrate and having a capacitance component, in with the capacitive component and the conductor loop, LC resonant circuit which resonates at the second frequency band It is characterized by being configured.

With the above configuration, it can be used as a compact high-gain RFID tag that uses the first frequency band and the second frequency band.

(12) It is preferable that a resonance capacitor connected in parallel to the coil antenna is provided, and an LC resonance circuit is formed by the resonance capacitor and the inductance component of the coil antenna. As a result, the resonance current flowing through the coil antenna in the first frequency band can be increased, and the gain of the first antenna is increased.

(13) It is preferable to provide a filter element between the first RFIC element and the coil antenna that passes through the first frequency band and blocks the second frequency band. As a result, even when the circuit of the first frequency band including the first RFIC element has the characteristic of resonating at the second frequency, the energy of the second frequency band is not absorbed by the circuit of the first frequency band, and the second frequency band is not absorbed. Communication in the frequency band is not hindered.

(14) When the communication module is provided with a display device, it is preferable to arrange the display device at a position that overlaps with the coil antenna and does not overlap with the inner peripheral area of the conductor loop in the plan view of the substrate. With this configuration, when the entire surface of the display device has conductivity in the second frequency band, communication in the second frequency band is not hindered by the display device.

According to the present invention, it is possible to obtain a miniaturized antenna module and communication module while ensuring the gains of the two antennas having different frequency bands. Alternatively, an antenna module and a communication module in which the gains of the two antennas having different frequency bands are enhanced can be obtained without enlarging the outer shape.

FIG. 1A is a plan view of the antenna module 101 according to the first embodiment, and FIG. 1B is a plan view of the communication module 201 according to the first embodiment. FIG. 2 is an equivalent circuit diagram of the communication module 201. FIG. 3 is a plan view of the communication module 202A according to the second embodiment. FIG. 4 is a plan view of another communication module 202B according to the second embodiment. FIG. 5 is a plan view of the communication module 203 according to the third embodiment. FIG. 6 is a plan view of the communication module 204 according to the fourth embodiment. FIG. 7A is a plan view of the communication module 205A according to the fifth embodiment, and FIG. 7B is a plan view of another communication module 205B according to the fifth embodiment. FIG. 8A is a bottom view of the communication module 206 according to the sixth embodiment, and FIG. 8B is a plan view of the communication module 206.

Hereinafter, a plurality of embodiments for carrying out the present invention will be shown with reference to the drawings with reference to some specific examples. The same reference numerals are given to the same parts in each figure. Although the embodiments are shown separately for convenience in consideration of the explanation of the main points or the ease of understanding, partial replacement or combination of the configurations shown in the different embodiments is possible. In the second and subsequent embodiments, the description of matters common to the first embodiment will be omitted, and only the differences will be described. In particular, the same action and effect due to the same configuration will not be mentioned sequentially for each embodiment.

<< First Embodiment >>
FIG. 1A is a plan view of the antenna module 101 according to the first embodiment, and FIG. 1B is a plan view of the communication module 201 according to the first embodiment.

The antenna module 101 of the present embodiment includes a flat substrate 9, a coil antenna 10 formed on the surface of the substrate 9, and a matching conductor pattern 20 arranged outside the formation region of the coil antenna 10.

The coil antenna 10 is a first antenna for the HF band. The matching conductor pattern 20 is connected to the coil antenna 10 and includes a part of the coil antenna 10 to form a conductor loop, so that the coil antenna 10 acts as a dipole antenna in the UHF band. The matching conductor pattern 20 and the coil antenna 10 are second antennas for the UHF band. A parallel resonant circuit including an inductance component of the conductor loop itself and a capacitive component of the second RFIC element itself is formed in the matching conductor pattern 20, and the resonance frequency of this parallel resonant circuit is communication in the second frequency band. It corresponds to the frequency, that is, the UHF band frequency.

The HF band is the "first frequency band" of the present invention, and the UHF band is the "second frequency band" of the present invention.

In this example, the coil antenna 10 is composed of a spiral conductor pattern of about 3 turns. The matching conductor pattern 20 extends along the outer edge of the coil antenna 10, the first conductor portion 21 which is a part of the spiral conductor pattern, the second conductor portion 22 connected to the first conductor portion 21, and the coil antenna 10. It is composed of an extension portion 23. A conductor loop is formed by the first conductor portion 21 and the second conductor portion 22. The length of the second conductor portion 22 in the direction (X-axis direction) along the outer edge of the coil antenna 10 is shorter than the average diameter D of the coil antenna 10 in this direction. As a result, in the first frequency band, the second conductor portion 22 does not interfere with the formation of the magnetic flux of the coil antenna 10.

Further, the line width of the second conductor portion 22 is narrower than the line width of the coil antenna 10. As a result, the space outside the forming region of the coil antenna 10 can be reduced, and the overall size can be avoided. Further, the second conductor portion 22 is less likely to block the magnetic flux of the coil antenna 10 in the first frequency band. Further, the inductance component can be set to a predetermined value even though the matching conductor pattern 20 is provided in a small space. While a current is required for the coil antenna 10, a very weak current may flow through the second conductor portion 22, so that there is no problem of loss even if the line width of the second conductor portion 22 is thin.

As shown in FIG. 1A, the conductor loop is an open loop in a state before connecting the second RFIC element 2 shown later.

According to this embodiment, since the conductor loop is formed in the same plane as the coil antenna 10, it can be easily formed on the substrate 9. Further, since the first conductor portion 21 is a part of the outermost circumference of the spiral conductor pattern, the second conductor portion 22 can be connected to the coil antenna 10 in the same plane, and the conductor loop can be easily performed. Can be configured.

As shown in FIG. 1A, the outer shape of the coil antenna 10 is a rectangular shape having a long side along the X-axis direction and a short side along the Y-axis direction, and is a matching conductor. The pattern 20 is formed on the outside of the coil antenna 10 along the long side of the coil antenna. The center position of the matching conductor pattern 20 is substantially the same as the center position of the long side.

The first conductor portion 21 is a part of the outermost circumference of the spiral conductor pattern of the coil antenna 10. The first conductor portion 21 and the second conductor portion 22 are formed on the same surface as the coil antenna 10.

The coil antenna 10 has a coil opening CO. The connection position CP1 of the first RFIC element shown later and the connection position CP3 of the filter element shown later are inside the coil opening CO of the coil antenna 10. Further, the connection position CP2 of the second RFIC element, which will be described later, is outside the formation region of the coil antenna 10.

As shown in FIGS. 1A and 1B, the first RFIC element 1 is connected to the connection position CP1, and the filter element 3 is connected to the connection position CP3. As a result, the first RFIC element 1 is balancedly connected to the coil antenna 10 via the filter element 3. When a current of a uniform magnitude flows through the coil antenna 10 along the spiral conductor pattern of the coil antenna 10, that is, in the direction in which the current flows, and the length of the coil conductor is equal to or less than the wavelength. Such a current distribution along the conductor pattern does not occur.

Further, as shown in FIGS. 1A and 1B, the resonance capacitor 4 is connected in the vicinity of the first RFIC element 1 and the filter element 3 in the spiral conductor pattern of the coil antenna 10. .. Further, the second RFIC element 2 is connected to the connection position CP2 of the second conductor portion 22.

The second RFIC element 2 gives a potential difference to the first conductor portion 21 of the coil antenna 10 by feeding a signal of the second frequency band to the conductor loop composed of the first conductor portion 21 and the second conductor portion 22. As a result, the coil antenna 10 (spiral conductor pattern) is excited by the signal of the second frequency band. The conductor loop acts as a matching element that matches the impedance of the second RFIC element 2 and the spiral conductor pattern. The impedance of the conductor loop is mainly determined by the distance between the conductor loop and one connection point of the coil antenna 10 and the other connection point, that is, the length of the first conductor portion 21. When the length of the first conductor portion 21 is long, the frequency characteristic of the gain of the second antenna is wide, and when the length of the first conductor portion 21 is short, the frequency characteristic of the gain of the second antenna tends to be narrow. ..

The maximum diameter of the conductor loop is smaller than the average diameter of the coil antenna. Therefore, in the first frequency band, the formation of magnetic flux of the coil antenna 10 is not hindered.

In the second frequency band, the coil antenna 10 does not act as a coil, but the formed region of the coil antenna 10 acts as an equivalent conductor plate. Therefore, a current is induced in the direction indicated by the arrow AL in FIG. 1 (B), and the coil antenna 10 (equivalent conductor plate) acts as a dipole antenna. The long side of the coil antenna 10 is preferably defined to have dimensions corresponding to about 1/2 wavelength of the second frequency band. As a result, the longitudinal dimension of the coil antenna 10 is effectively utilized at the second frequency, and a second antenna having a higher gain while being smaller is formed.

Since the matching conductor pattern 20 itself does not directly contribute to the radiation of the signal in the second frequency band, it may be arranged outside the formation region of the coil antenna 10, and is large outside the formation region of the coil antenna 10. No space needed. Further, since the conductor loop is arranged outside the formation region of the coil antenna 10, even if the coil antenna 10 acts as an equivalent conductor flat plate in the second frequency band, the conductor loop is not affected by the action.

The extending portion 23 acts as a part of the radiating element of the second antenna to increase the gain of the second antenna. Alternatively, the extension 23 acts as an open stub to adjust impedance matching. The extension portion 23 is shorter than the 1/4 wavelength of the second frequency band. As a result, the space outside the forming region of the coil antenna 10 can be reduced, and the size of the antenna module 101 and the communication module 201 as a whole can be avoided. When the extending portion 23 is long to some extent and a potential difference is generated between the vicinity of the tip thereof and the outer edge of the coil antenna 10, the matching conductor pattern 20 and the coil antenna 10 are like an inverted F antenna. The extension portion 23 acts as a radiation element.

If necessary, the surface of the substrate 9 shown in FIG. 1B may be coated with a resist film to protect each conductor pattern and each element.

FIG. 2 is an equivalent circuit diagram of the communication module 201. The coil antenna 10 and the resonance capacitor 4 form an LC resonance circuit that resonates in the first frequency band (for example, 13.56 MHz band). The first RFIC element 1 is connected to the LC resonance circuit via a filter element 3. The filter element 3 is a low-pass filter composed of a parallel-connected inductor and a series-connected capacitor, and allows signals in the first frequency band to pass through and blocks signals in the second frequency band (for example, 860 MHz band to 920 MHz band). To do. The second RFIC element 2 is connected to a part of the coil antenna 10 via the second conductor portion 22. A capacitance component 2C is provided inside the second RFIC element 2. The first conductor portion 21, the second conductor portion 22, and the capacitance component 2C form an LC resonance circuit that resonates in the second frequency band (for example, 860 MHz band to 920 MHz band).

<< Second Embodiment >>
The second embodiment shows a partial modification of the antenna module and the communication module shown in the first embodiment.

FIG. 3 is a plan view of the communication module 202A according to the second embodiment. It differs from the example shown in FIG. 1 (B) in the first embodiment in that the extension portion 23 is not provided. In the present embodiment, the matching conductor pattern 20 includes a first conductor portion 21 which is a part of the coil antenna 10 (spiral conductor pattern) and a second conductor portion 22 connected to the first conductor portion 21. Consists of.

Since the conductor loop composed of the first conductor portion 21 and the second conductor portion 22 does not directly contribute as a radiating element in the second frequency band, as in this example, even if the extension portion 23 is not provided. , The matching conductor pattern 20 and the coil antenna 10 can be used as the second antenna.

FIG. 4 is a plan view of another communication module 202B according to the second embodiment. It differs from the example shown in FIG. 3 in that the filter element 3 is not provided. When the circuit of the first frequency band including the first RFIC element 1 has a characteristic that it does not resonate at the second frequency, the energy of the signal of the second frequency band is not absorbed by the circuit of the first frequency band, so that the filter element 3 has Not needed.

<< Third Embodiment >>
The third embodiment shows an example in which the shape of the matching conductor pattern and the connection relationship of the second RFIC element 2 are different from those of the first and second embodiments.

FIG. 5 is a plan view of the communication module 203 according to the third embodiment. In this example, the matching conductor pattern 20 is composed of a first conductor portion 21 which is a part of the coil antenna 10 (spiral conductor pattern) and a second conductor portion 22 connected to the first conductor portion 21. It is composed. The second RFIC element 2 is connected in the middle of the second conductor portion 22. Then, in the second RFIC element 2, the coil antenna 10 is arranged in the coil opening CO. With this configuration, it is not necessary to secure the mounting space for the first RFIC element 1 and the second RFIC element 2 outside the forming region of the coil antenna 10, and the overall size can be avoided.

In the present embodiment as well, as in the first and second embodiments, the second RFIC element 2 feeds the signal of the second frequency band to the conductor loop composed of the first conductor portion 21 and the second conductor portion 22. By doing so, a potential difference is given to the first conductor portion 21 of the coil antenna 10, thereby exciting the coil antenna 10 with a signal in the second frequency band.

Since the conductor portion in the formation region of the coil antenna 10 of the second conductor portion is covered with the coil antenna 10 (equivalent conductor plate) in the second frequency band, the inductance component is not effectively used, but the second conductor portion. It acts as a current path for signals in the frequency band.

<< Fourth Embodiment >>
The fourth embodiment shows an example in which the shape of the matching conductor pattern and the connection relationship of the second RFIC element 2 are different from those of the first, second, and third embodiments.

FIG. 6 is a plan view of the communication module 204 according to the fourth embodiment. In this example, the matching conductor pattern 20 is composed of a first conductor portion 21 which is a part of the coil antenna 10 (spiral conductor pattern) and a second conductor portion 22 connected to the first conductor portion 21. It is composed. The second RFIC element 2 is connected in the middle of the second conductor portion 22. Then, in the second RFIC element 2, the coil antenna 10 is arranged in the coil opening CO. Although the first conductor portion 21 is a part of the coil antenna 10, it has a protruding shape outside the forming region of the main portion of the coil antenna 10.

Also in this embodiment, it is not necessary to secure the mounting space for the first RFIC element 1 and the second RFIC element 2 outside the forming region of the coil antenna 10, and the overall size can be avoided.

<< Fifth Embodiment >>
The fifth embodiment shows an example in which the connection relationship of the matching conductor pattern to the coil antenna is different from that of the first to fourth embodiments.

FIG. 7A is a plan view of the communication module 205A according to the fifth embodiment, and FIG. 7B is a plan view of another communication module 205B according to the fifth embodiment. In the example shown in FIG. 7A, one end of the second conductor portion 22 is connected to the outermost circumference of the coil antenna 10 (spiral-shaped conductor pattern), and the other end is connected to the coil antenna 10 (spiral-shaped conductor pattern). It is connected to a position other than the outermost circumference of. In the example shown in FIG. 7B, both ends of the second conductor portion 22 are connected to the outermost circumference of the coil antenna 10 (spiral conductor pattern).

In both FIGS. 7 (A) and 7 (B), in terms of low frequency, the conductor pattern for one turn of the coil antenna 10 is connected between both ends of the second conductor portion 22, but in the second frequency band. Since the coil antenna 10 acts as an equivalent conductor flat plate, the matching conductor pattern 20 is formed by the first conductor portion 21 and the second conductor portion 22 connected to the first conductor portion 21.

Also in the present embodiment, the second RFIC element 2 supplies the signal of the second frequency band to the conductor loop composed of the first conductor portion 21 and the second conductor portion 22, thereby supplying the signal of the second frequency band to the first conductor portion of the coil antenna 10. A potential difference is applied to 21 to excite the coil antenna 10 with a signal in the second frequency band.

<< 6th Embodiment >>
A sixth embodiment shows an example of a communication module having a display device.

FIG. 8A is a bottom view of the communication module 206 according to the sixth embodiment, and FIG. 8B is a plan view of the communication module 206.

The basic configuration of the antenna module included in the communication module 206 is the same as the antenna module shown in FIG. 1A in the first embodiment. In the example shown in FIG. 8A, a circuit for presenting predetermined information such as tag information to the display device is provided on the substrate 9. FIG. 8A shows, as main components, a display control IC 5, other chip components 6, a connector 7 for connecting a flat cable 8 drawn from the display device 30, and the like.

As shown in FIG. 8B, the display device 30 is superposed on the upper surface of the substrate 9. The display device 30 is so-called electronic paper, and the display content is rewritten by the output signal of the display control IC 5. For example, the instruction content received by the RFID system in the first frequency band (HF band) is displayed.

The display device 30 is in the state shown in FIG. 8 (B) when the flat cable 8 is connected to the connector 7 and then folded back onto the upper surface of the substrate 9. In FIG. 8A, the broken line indicates the position of the display device 30. As described above, in the plan view of the substrate 9, the display device 30 is arranged at a position that does not protrude from the formation region of the coil antenna 10. Therefore, in the plan view of the substrate 9, the display device 30 does not overlap with the inner peripheral area of the conductor loop formed by the first conductor portion 21 and the second conductor portion 22.

A conductor thin film is formed on the entire surface of the display device 30, but since this conductor thin film does not cover the conductor loop formed by the first conductor portion 21 and the second conductor portion 22, the coil antenna has the matching conductor pattern 20. The excitation of 10 is not hindered. In the first frequency band, the magnetic flux transmission of the coil antenna 10 is somewhat hindered, but if the electric resistance value of the thin film conductor of the display device 30 is high to some extent, the eddy current generated in the thin film conductor is small, and communication in the first frequency band is performed. Does not cause any problems. The display device 30 may be a liquid crystal display element, an organic EL display element, or the like, in addition to the electronic paper.

The communication signal in the first frequency band (HF band) using the coil antenna 10 is also used for power reception, and the display device 30 uses the power of the signal in the first frequency band during communication in the first frequency band. Power is secured for rewriting. Therefore, the substrate 9 is configured with a rectifying and smoothing circuit that rectifies and smoothes the voltage induced in the coil antenna 10, a DC / DC converter that converts the output voltage into a predetermined stabilized voltage, and the like.

<< Other Embodiments >>
In each of the above embodiments, an example in which the chip capacitor is mounted on the substrate 9 as the resonance capacitor 4 is shown, but the resonance capacitor 4 may be configured by a conductor pattern formed on the substrate 9.

The first antenna and the second antenna shown in each embodiment can be applied to either the transmission (transmission) side or the reception (power reception) side of the signal (or power). For example, even if an antenna is described as an antenna that emits magnetic flux, the antenna is not limited to being a source of magnetic flux or electromagnetic waves. The same effect is obtained even when the transmission partner antenna device receives the generated magnetic flux or electromagnetic wave, that is, even if the transmission / reception relationship is reversed.

Finally, the description of the embodiments described above is exemplary in all respects and is not restrictive. Modifications and changes can be made as appropriate for those skilled in the art. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims. Further, the scope of the present invention includes modifications from the embodiment within the scope of the claims and within the scope of the claims.

CO ... Coil opening CP1, CP2, CP3 ... Connection position 1 ... 1st RFIC element 2 ... 2nd RFIC element 2C ... Capacitive component 3 ... Filter element 4 ... Resonant capacitor 5 ... Display control IC
6 ... Chip component 7 ... Connector 8 ... Flat cable 9 ... Board 10 ... Coil antenna 20 ... Matching conductor pattern 21 ... First conductor part 22 ... Second conductor part 23 ... Extension part 30 ... Display device 101 ... Antenna module 201 , 202A, 202B, 203, 204, 205 ... Communication module

Claims (14)

A first antenna connected to a first RFIC element having a first frequency band as a communication frequency band, and a second antenna connected to a second RFIC element having a second frequency band higher than the first frequency band as a communication frequency band. And with
The first antenna is a coil antenna formed on the main surface of the substrate.
The second antenna is arranged outside the formation region of the coil antenna in a plan view of the substrate, is connected to the coil antenna, constitutes a conductor loop including a part of the coil antenna, and forms the coil antenna. It is composed of a matching conductor pattern that acts as a dipole antenna in the second frequency band and the coil antenna.
An antenna module characterized by that. The antenna module according to claim 1, wherein the first frequency band is an HF band, and the second frequency band is a UHF band. The outer shape of the coil antenna is a rectangular shape having a long side and a short side, the matching conductor pattern is formed along the long side, and the long side of the coil antenna acts as a dipole antenna. , The antenna module according to claim 1 or 2. The coil antenna is composed of a multi-turn spiral conductor pattern.
The conductor loop according to any one of claims 1 to 3, wherein the conductor loop is composed of a first conductor portion that is a part of the spiral conductor pattern and a second conductor portion connected to the first conductor portion. Described antenna module. The antenna module according to claim 4, wherein the length of the second conductor portion in the direction along the outer edge of the coil antenna is shorter than the average diameter of the coil antenna in the direction. The antenna module according to claim 4 or 5, wherein the first conductor portion is a part of the outermost circumference of the spiral conductor pattern. The antenna module according to any one of claims 4 to 6, wherein the line width of the second conductor portion is narrower than the line width of the coil antenna. The antenna module according to any one of claims 4 to 7, wherein the matching conductor pattern further has an extending portion extending from the second conductor portion along the outer edge of the coil antenna. The antenna module according to claim 8, wherein the length of the extending portion is shorter than the 1/4 wavelength of the second frequency band. The antenna module according to any one of claims 1 to 9, wherein the coil antenna has a coil opening, and the connection position of the first RFIC element and the connection position of the second RFIC element are inside the coil opening of the coil antenna. .. A first RFIC element having a first frequency band as a communication frequency band, a first antenna connected to the first RFIC element, and a second RFIC element having a second frequency band higher than the first frequency band as a communication frequency band. A second antenna connected to the second RFIC element,
The first antenna is a coil antenna formed on the main surface of the substrate.
The second antenna is arranged outside the formation region of the coil antenna in a plan view of the substrate, is connected to the coil antenna, constitutes a conductor loop including a part of the coil antenna, and forms the coil antenna. It is composed of a matching conductor pattern that acts as a dipole antenna in the second frequency band and the coil antenna.
The first RFIC element is mounted on the substrate and connected to the coil antenna.
Wherein the 2RFIC element is connected to the matching conductor pattern are mounted on the substrate and having a capacitance component, in with the capacitive component and the conductor loop, LC resonant circuit which resonates at the second frequency band A configured communication module. The communication module according to claim 11, further comprising a resonance capacitor connected in parallel to the coil antenna, and an LC resonance circuit composed of the resonance capacitor and an inductance component of the coil antenna. The communication module according to claim 11 or 12, wherein a filter element that passes through the first frequency band and blocks the second frequency band is provided between the first RFIC element and the coil antenna. The communication module according to any one of claims 11 to 13, further comprising a display device arranged at a position overlapping the coil antenna and not overlapping the inner peripheral area of the conductor loop in a plan view of the substrate.

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