JP7811826B2 - Antenna module and IC card - Google Patents

Description

This disclosure relates to an antenna module and an IC card.

In recent years, contactless IC cards, contact IC cards, RFID tags, and other devices that use RFID (Radio Frequency Identification) technology have become widely used. Among these, contactless IC cards are particularly useful because they allow information to be exchanged simply by placing or holding the card over a card reader. Therefore, they are used in a wide variety of fields, primarily in transportation applications such as railway ticket gates, as well as in security systems for access control and product management systems in factories.

Furthermore, there are two communication methods for contactless IC cards: an electromagnetic induction method, which uses HF-band signals to communicate with a reader, and a radio wave method, which uses UHF-band signals to communicate. Recently, contactless IC cards have been developed that house an HF-band antenna and a UHF-band antenna inside the board, allowing communication using two different communication methods with a single card (see, for example, Patent Document 1).

Contactless IC cards, especially transportation IC cards, are often used while stored in a card case, pass case, or the like. It's also common for a single user to carry multiple IC cards and use them for different purposes. For this reason, some users store multiple contactless or contact IC cards in a card case or the like. However, when multiple IC cards are used stacked together, the antenna characteristics within the contactless IC card change due to the influence of the antennas (metal) of the other IC cards, which can prevent proper communication with the reader.

Publication No. 2019-169902

This disclosure was made in response to the above-mentioned problems, and aims to provide an antenna module and IC card that can improve communication performance.

In order to achieve the above-mentioned object, the antenna module of the present disclosure comprises a substrate, a first antenna provided on the substrate for transmitting and receiving signals, and a first IC chip electrically connected to the first antenna, wherein the first antenna is made of a thin metal film arranged on the surface of the substrate in a U-shape or C-shape when viewed in a plane.
Alternatively, the antenna module of the present disclosure comprises a substrate, a first antenna provided on the substrate for transmitting and receiving signals, a second antenna provided on the substrate for transmitting and receiving signals in a frequency band different from that of the first antenna, and an IC chip electrically connected to the first antenna and the second antenna, wherein the first antenna is made of a metal thin film arranged in a U-shape or C-shape in plan view on the surface of the substrate in an area that does not overlap with the second antenna in plan view.
The IC card of the present disclosure also includes the antenna module described above.

This disclosure provides an antenna module and IC card that can improve communication performance.

1 is an exploded perspective view of an IC card including an antenna module according to a first embodiment (Example 1). FIG. 2 is a plan view (surface view) of the antenna module shown in FIG. 1 . FIG. 2B is a plan view (surface view) of the first antenna shown in FIG. 2A. FIG. 2 is a diagram showing dimensions of an antenna portion of the antenna module shown in FIG. 1 . FIG. 10 is a plan view (surface view) of an antenna module according to a modified example (Example 2). FIG. 5 is a diagram showing dimensions of an antenna portion of the antenna module shown in FIG. 4 . FIG. 10 is a plan view (surface view) of the antenna module of Comparative Example 1. FIG. 7 is a diagram showing dimensions of the antenna portion of the antenna module shown in FIG. 6 . 10A and 10B are diagrams illustrating measurement results of communication performance of the antenna module of Example 1. 10A and 10B are diagrams illustrating measurement results of communication performance of the antenna module of Example 2. 10 is a diagram showing measurement results of communication performance of the antenna module of Comparative Example 1. FIG. 10 is a diagram showing measurement results of RSSI of the antenna modules of Example 1, Example 2, and Comparative Example 1. FIG. 10 is a diagram showing the difference in sensitivity between the antenna modules of Example 1, Example 2, and Comparative Example 1. FIG. FIG. 10 is a plan view (surface view) of an antenna module according to a second embodiment (Example 3). FIG. 14 is a diagram showing dimensions of the antenna portion of the antenna module shown in FIG. 13. 10A and 10B are diagrams illustrating measurement results of communication performance of the antenna module of Example 3. FIG. 10 is a diagram showing the measurement results of RSSI of the antenna modules of Example 3 and Comparative Example 1. FIG. 10 is a diagram showing the difference in sensitivity between the antenna modules of Example 3 and Comparative Example 1.

Embodiments will be described below with reference to the accompanying drawings. To facilitate understanding, identical components in each drawing will be assigned the same reference numerals wherever possible, and duplicate descriptions will be omitted.

(First embodiment)
Fig. 1 is an exploded perspective view of a contactless IC card (hereinafter, sometimes simply referred to as an "IC card") 100 including an antenna module 1 according to a first embodiment. Fig. 2A is a plan view (front view) of the antenna module 1 shown in Fig. 1, and Fig. 2B is a plan view (front view) of the first antenna 20 shown in Fig. 2A.

As shown in FIG. 1, the IC card 100 according to the first embodiment comprises an antenna module 1 and a pair of cover sheets 2, 3 disposed on the upper and lower surfaces of the antenna module 1. While the IC card 100 is rectangular in plan view, it is not limited to a rectangular shape and can be shaped in a manner suited to the type of IC card 100 and its intended use. The size of the rectangular IC card 100 may be that of a typical IC card. Specifically, for example, the IC card 100 can be formed in accordance with JIS Type II (JIS-X6301) with a longitudinal length of 85.6 mm, a lateral length of 54.0 mm, and a thickness of 0.76 mm.

A pair of cover sheets 2, 3 are adhered to the top and bottom surfaces of the antenna module 1 by thermocompression or other methods to protect the antenna module 1. These cover sheets 2, 3 can be, for example, insulating resin sheets or plates. Suitable insulating resins include, but are not limited to, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyvinyl chloride (PVC), and polyimide (PI). The pair of cover sheets 2, 3 can have, for example, a length of 85.6 mm in the x direction, a length of 54.0 mm in the y direction, and a length (thickness) of 0.1 mm in the z direction.

As shown in Figures 1 and 2A, the antenna module 1 and cover sheets 2 and 3 are formed in a rectangular shape when viewed from above. In the following, for ease of explanation, the configuration of each part will be described with the longitudinal direction of the antenna module 1 and cover sheets 2 and 3 as the x-direction, the lateral direction of these and perpendicular to the x-direction as the y-direction, and the stacking direction of the antenna module 1 and cover sheets 2 and 3 and perpendicular to the x- and y-directions as the z-direction, as shown in Figures 1 and 2A. Furthermore, the direction from the antenna module 1 toward one cover sheet 2 is referred to as the z-positive direction, and the direction from the antenna module 1 toward the other cover sheet 3 is referred to as the z-negative direction, and the z-positive direction may also be referred to as upward and the z-negative direction as downward.

As shown in FIG. 2A, the antenna module 1 includes at least a substrate 10, a first antenna 20 for transmitting and receiving signals, and a first IC chip 30 electrically connected to the first antenna. The first antenna 20 transmits and receives signals, for example, using a radio wave method.

Furthermore, the antenna module 1 of this embodiment includes a second antenna 40 provided on the substrate 10 for transmitting and receiving signals in a frequency band different from that of the first antenna 20, and a second IC chip 50 electrically connected to this second antenna 40. The second antenna 40 transmits and receives signals using, for example, electromagnetic induction.

The substrate 10 is rectangular in plan view and is formed with the same dimensions as the cover sheets 2 and 3, or slightly smaller dimensions. Specifically, for example, if the dimensions are the same, the substrate 10 can have a length of 85.6 mm in the x direction and a length of 54.0 mm in the y direction. The thickness of the substrate 10 is preferably, for example, between 5 μm and 300 μm, which provides adequate strength to accommodate the first antenna 20 and second antenna 40 and to mount the first IC chip 30 and second IC chip 50.

The substrate 10 is preferably made of an insulating resin film. Specific examples include a single resin film such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene (PP), or polyethylene (PE), or a multilayer film made by laminating multiple such resin films.

The first antenna 20 is provided on the surface of the substrate 10 and is formed of a thin metal film. Suitable materials for the thin metal film of the first antenna 20 include, but are not limited to, an aluminum (Al) sheet. For example, the first antenna 20 can be formed by attaching an aluminum sheet to a substrate 10 made of PET film using dry lamination or the like. Figure 2B shows a plan view (surface view) of the first antenna 20. The solid line in Figure 2B represents the first antenna 20. This first antenna 20 is provided on a substrate 10 made of a resin film or the like, shown by the dashed line, and is a planar antenna for IC cards that are carried by people or attached to objects for purposes such as access control, logistics management, and product management for facilities. This first antenna 20 is planar (plate-like), and the surface view (plan view) and back view are depicted symmetrically. Therefore, Figure 2B shows the plan view (surface view) of the first antenna 20, with the back view omitted. Also, because it is a planar view, the four side views sandwiched between the front and back views have been omitted.

The first antenna 20 is composed of a metal thin film arranged on the surface of the substrate 10 in a U-shape in plan view. It is preferable that the first antenna 20 be arranged so as to cover at least 50% of the surface of the substrate 10, and more preferably so as to cover 60% or more of the surface of the substrate 10. It is also preferable that the external dimensions of the first antenna 20 are approximately the same as or slightly smaller than the external dimensions of the substrate 10. Specifically, it is preferable that the external dimensions (maximum external dimensions) of the first antenna 20 in the x and y directions are approximately the same as or approximately 1 mm to 10 mm smaller than the external dimensions (maximum external dimensions) of the substrate 10 in the x and y directions.

Furthermore, the first antenna 20 preferably has a U-shape in plan view, as shown in Figure 2A, etc. That is, the first antenna 20 has a first region 21 that extends in the x direction along one long side of the substrate 10, in a strip shape of a predetermined width (e.g., approximately half or more of the short side), from one short side to the other short side, and a pair of second regions 22, 23 that extend in the y direction along one and the other short sides of the substrate 10 from both sides of the first region, in a strip shape of a predetermined width (e.g., approximately 1/4 or more of the long side), to the other long side. The second antenna 40 is then positioned between the pair of second regions 22, 23. The first antenna 20 also has a first slot 24 extending in the x direction.

As described above, the first antenna 20 is arranged so that, in a plan view, it covers almost the entire area of the surface of the substrate 10 except for the area where the second antenna 40 is provided. By forming the first antenna 20 with such an area, the first antenna 20 can be made larger than conventional antennas, thereby increasing the communication distance and improving communication performance. Furthermore, even when the IC card 100 of this embodiment is used in conjunction with another IC card, etc., the first antenna 20 encompasses the metal parts of the antennas of the other IC cards (the antennas of the other IC cards are housed inside the outer shape of the first antenna 20), so the impedance and other characteristics of the first antenna 20 are not affected, and excellent communication performance can be maintained.

The first antenna 20 transmits and receives signals to and from a radio wave reader or reader/writer (not shown) using radio wave technology. Signals are transmitted and received between the first antenna 20 and the reader or the like using a UHF frequency band (e.g., 920 MHz). The first antenna 20 outputs signals received from the radio wave reader or the like to the first IC chip 30.

The first IC chip 30 is mounted at a specified position on the first antenna 20. The first IC chip 30 stores various information, such as personal identification information and item management information. The first IC chip 30 is also equipped with a predetermined arithmetic processing function, and executes arithmetic processing based on commands contained in signals input from the first antenna 20, outputting the processing results to the first antenna 20. The first antenna 20 transmits a signal including the processing results input from the first IC chip 30 to a radio wave reader or the like.

The characteristics of the first IC chip 30 are as follows, but are not limited to these.
[Impedance frequency characteristics]
・866MHz: 15-j265 (Ω)
・915MHz: 14-j252 (Ω)
・953MHz: 13-j242 (Ω)
[Air Protocol]
・ISO 18000-6c

The impedance of the first antenna 20 is designed to match the impedance of the first IC chip 30 at 915 to 920 MHz. This impedance matching reduces current loss, and reducing loss increases the communication distance.

As described above, the second antenna 40 is located between the pair of second regions 22, 23 of the first antenna 20 in a planar view. As shown in FIG. 2A, this second antenna 40 is a coil antenna in which a conductor is wound in a loop shape. A suitable material for the second antenna 40 is, for example, aluminum (Al), but this is not limited thereto, and other conductive materials such as copper (Cu) can also be used as the material for the second antenna 40. The first antenna 20 and the second antenna 40 may be formed from the same material or different materials.

The second antenna 40 transmits and receives signals to and from an electromagnetic induction reader or reader/writer (not shown) using electromagnetic induction. Signals are transmitted and received between the second antenna 40 and the electromagnetic induction reader or similar device using an HF frequency (e.g., 13.56 MHz). Signals received by the second antenna 40 from the electromagnetic induction reader or similar device are output to the second IC chip 50. The air protocol of the second IC chip 50 connected to the second antenna 40 may be, for example, ISO 14443 Type A, but is not limited to this and may also be ISO 14443 Type B or ISO 15693.

Like the first IC chip 30, the second IC chip 50 stores various information such as personal identification information and item management information. The second IC chip 50 is also equipped with a predetermined arithmetic processing function, etc., and executes arithmetic processing based on commands contained in signals input from the second antenna 40, outputting the processing results to the second antenna 40. The second antenna 40 transmits signals including the processing results input from the second IC chip 50 to an electromagnetic induction reader or the like.

In an IC card 100 equipped with an antenna module 1 configured in this way, the first antenna 20, which transmits and receives signals using radio waves, is formed in a U-shape in plan view and covers at least 50% or more of the surface area of the substrate 10, making the area of the first antenna 20 as large as possible. This improves the communication performance of the first antenna 20, extends the distance over which wireless communication with a radio wave reader or reader/writer is possible, and enables more appropriate reading of information by the reader, etc. As a result, a contactless IC card 100 with excellent communication performance can be provided.

(Modification)
The shape of the first antenna 20 shown in Figures 2A and 2B is merely an example and is not limited to this shape. Figure 4 is a plan view (surface view) showing an example of an antenna module 1A having a first antenna 20A of another different shape (variant). The first antenna 20A of the antenna module 1A shown in Figure 4 has a second slot 25 parallel to a first slot 24 extending in the x-direction. As with the first embodiment, the first antenna 20A of the variant shown in Figure 4 is provided on a substrate 10 such as a resin film and is a planar antenna for IC cards that is carried by a person or attached to an object for purposes such as access control, logistics management, and product management for facilities. To illustrate the design of this planar antenna, the solid lines indicating parts other than the first antenna 20A, such as the substrate 10 and the second antenna 40 in Figure 4, can be represented by dashed lines or omitted.

In the antenna module 1A and IC card shown in Figure 4, the area of the first antenna 20A is made as large as possible, thereby improving the communication performance of the first antenna 20A. Furthermore, even if the IC card is stacked with another IC card, the communication performance of the first antenna 20A is not affected by that antenna. This increases the distance over which wireless communication is possible between the IC card and a radio wave reader, etc., allowing the reader, etc., to read information more appropriately.

Second Embodiment
Next, an antenna module 1B and a contactless IC card 100 according to a second embodiment of the present disclosure will be described with reference to FIG. 13 . FIG. 13 is a plan view (surface view) of the antenna module 1B according to the second embodiment. In the antenna modules 1 and 1A according to the first embodiment and the modified example shown in FIGS. 2A and 4 , a first IC chip 30 and a second IC chip 50 are mounted on the first antenna 20, 20A, and the second antenna 40, respectively. In contrast, the antenna module 1B according to the second embodiment shown in FIG. 13 is an antenna module mounted with only one IC chip (third IC chip 60). As with the first embodiment and the modified example, the first antenna 20B according to the second embodiment shown in FIG. 13 is provided on a substrate 10 such as a resin film, and is a planar antenna for an IC card that is carried by a person or attached to an object for purposes such as access control, logistics management, and product management for facilities. In order to represent the design of the first antenna 20B, which is a planar antenna, the solid lines indicating parts other than the first antenna 20B, such as the substrate 10 and the second antenna 40 in Figure 13, can be represented by dashed lines or omitted.

The configuration of the antenna module 1B shown in Figure 13 will now be described. This antenna module 1B is U-shaped in plan view, similar to the modified antenna module 1A shown in Figure 4, and has a first antenna 20B made of a thin metal film that is disposed on the surface of the substrate 10 and has first and second slots 24, 25. Furthermore, this first antenna 20B is preferably disposed on the substrate 10 so as to cover at least 50% or more, and more preferably 60% or more, of one surface of the substrate 10. A third IC chip 60 is mounted at a specified position on this first antenna 20B.

The antenna module 1B also has a second antenna 40B wound in a coil shape on the other side of the substrate 10. The substrate 10 also has through-holes 11 and 12 that penetrate the substrate 10 near both ends of the second antenna 40B, and the second antenna 40B and the third IC chip 60 are electrically connected via these through-holes 11 and 12 and connection lines 13 and 14. A pair of capacitors 15 for rectifying signals are also provided on both side surfaces of the substrate 10, and are electrically connected to the third IC chip 60.

This third IC chip 60 transmits and receives signals using radio waves at UHF frequencies (860-960 MHz), and also transmits and receives signals using electromagnetic induction at HF frequencies (13.56 MHz).

The characteristics of the third IC chip 60 are as follows, but are not limited to these.
[Impedance frequency characteristics]
・866MHz 19.1-j286Ω
・915MHz 17.6-j273Ω
[Air Protocol]
・ISO 15693 and 18000-63

In the antenna module 1B of the second embodiment and the IC card 100 equipped with it, the area of the first antenna 20B is made as large as possible, which increases the communication distance of the first antenna 20B and improves communication performance. Furthermore, even if the IC card is stacked with another IC card, the communication performance of the first antenna 20B is not affected by that antenna. As a result, the IC card 100 of the second embodiment has a longer distance over which wireless communication with a radio wave reader or reader/writer is possible, allowing the reader to read information more appropriately.

Furthermore, because the IC card 100 of the second embodiment is equipped with only one third IC chip 60, the IC card 100 can be provided at a lower cost. In addition, the mounting process of mounting the IC chip (third IC chip 60) on the antenna (first antenna 20B) and the converting process of incorporating the antenna module 1B into the IC card 100 can be performed only once, thereby reducing the manufacturing costs of the antenna module 1B and the IC card 100. Furthermore, because the IC cards 100 of the first embodiment and the modified examples are equipped with two first and second IC chips 30, 50, when writing information such as identification information to these using a writing device, writing must be performed twice per IC card 100. In contrast, the IC card 100 of the second embodiment requires writing to the third IC chip 60 only once per IC card 100, improving writing efficiency and more appropriately suppressing writing errors, etc.

As explained above, the antenna modules 1, 1A, 1B of the first embodiment, modified example, and second embodiment of the present disclosure, and the contactless IC card 100 equipped with them, can improve communication performance, particularly when transmitting and receiving signals using radio waves, and can extend the communication distance. Moreover, excellent communication performance can be maintained even when used in conjunction with a transportation IC card or the like.

As a result, the information on the IC card can be properly read by simply passing near the reader, without having to perform any reading operations such as placing the IC card over the reader or holding it over the reader. Therefore, for example, by carrying the IC card 100 of the above embodiment, even wheelchair users, elderly people, people with disabilities, etc. can simply pass near the reader and the reader will read the information with high sensitivity and accuracy, without having to remove the IC card or perform any reading operations. This allows elderly people, etc. to smoothly enter and exit facilities, hospitals, etc., and to be automatically checked in. Furthermore, when used as a transportation IC card, elderly people, etc. will be able to smoothly board and disembark trains and buses. Furthermore, within factories and workplaces, the system can easily track the presence and movement of employees, etc.

Furthermore, in addition to the first antennas 20, 20A, and 20B that transmit and receive signals using radio waves, each of the above embodiments and variations also includes a second antenna 40, 40B that transmits and receives signals using electromagnetic induction. This allows the IC card 100 to transmit and receive signals using UHF band frequencies, as well as HF band frequencies. For example, HF band frequencies can be used for security management, such as controlling entry and exit to a factory, while UHF band frequencies can be used to track the presence and movement of employees, etc., making it possible to use different frequencies depending on the purpose. Furthermore, even if the IC card 100 is accidentally left behind, it can be easily found by using UHF band frequencies.

The IC card 100 of each of the above embodiments and modifications can be used as an ID card for public facilities, a patient registration card for hospitals, and the like. By installing a reader for this IC card 100 at the entrances, exits, reception areas, etc. of public facilities and hospitals, wheelchair users, the elderly, and physically disabled persons can automatically enter and be accepted for medical examinations without having to perform any reading operations. This also allows public facility staff to easily and appropriately manage entry and exit. Even if the IC card 100 is placed on top of a transportation IC card in a pass case, the reader can properly read the information on the IC card 100. Furthermore, the IC card 100 of each of the above embodiments and modifications can also be used as an IC card for managing boarding and disembarking on public transportation. In this case, too, the reader can properly read the information on the IC card 100 even if the IC card 100 is placed on top of other transportation IC cards in a pass case.

Next, examples of the present disclosure will be described in detail. The inventors fabricated antenna modules and IC cards according to Examples 1 to 3 and Comparative Example 1 as follows, and verified their communication performance at UHF band frequencies.

[Example 1]
The antenna module 1 and IC card 100 of Example 1 were fabricated with a configuration similar to that of the first embodiment shown in Figures 2A to 3. The antenna module 1 was fabricated by dry laminating a 10 μm thick aluminum sheet onto a 38 μm thick PET film having a length of 85.6 mm in the x direction, a length of 54.0 mm in the y direction, and a thickness of 38 μm, to form a first antenna 20. A coil-shaped second antenna 40 was provided between the second regions 22 and 23 of the first antenna 20, and first and second IC chips 30 and 50 were mounted at specified positions on the first and second antennas 20 and 40. As shown in Figure 3, the first antenna 20 had a length of 75.5 mm in the x direction and a length of 43.50 mm in the y direction. The x direction length of the first slot 24 was 34.0 mm, the x direction distance between the second regions 22 and 23 was 40.5 mm, and the x direction length of the second regions 22 and 23 was 17.5 mm. The dimension (diameter) of the second antenna 40 was set to 20.0 mm.

The first IC chip 30 uses UCODE8 (UCODE is a registered trademark) manufactured by NXP. This first IC chip 30 transmits and receives signals using a radio wave method, using a UHF band frequency (920 MHz). The second IC chip 50 uses NTAG213 (NTAG is a registered trademark) manufactured by NXP. The second IC chip 50 transmits and receives signals using an HF band frequency (13.56 MHz) using an electromagnetic induction method. The characteristics of the first IC chip 30 and the second IC chip 50 are as described in the first embodiment above. In Example 2 and Comparative Example 1 described below, the same products as those used in Example 1 were used as the first and second IC chips 30 and 50.

The antenna module 1 produced as described above was sandwiched between a pair of cover sheets 2, 3 formed from PVC plates measuring 85.6 mm in the x direction and 54.0 mm in the y direction, and then bonded together to produce the IC card 100 of Example 1. The communication performance of this IC card 100 was measured in an anechoic chamber using an RFID tag performance testing device (Tagformance Pro, manufactured by Voyantic) when the IC card 100 was used alone, when inserted into a pass case, and when inserted into the pass case together with a transportation IC card. The measurement frequency band for wireless communication radio waves during measurement was 700 to 1,200 MHz, and the EIRP (Equivalent Isotropically Radiated Power) was 3.28 W.

Furthermore, for the IC card 100 of Example 1, the change in RSSI (Received Signal Strength Indicator) and sensitivity difference due to distance were measured using a reader (Impinj Speedway, manufactured by Impinj). This measurement was carried out in the applicant's office, assuming normal use. This reader uses a TIMES-7 A5020 (circularly polarized) antenna, with an output of 20 dBm. Furthermore, the distance from the reader antenna to the IC card when measuring the sensitivity difference was 20 cm.

[Example 2]
Except for the fact that the shape of the first antenna 20 was the same as that of the first antenna 20A of the modified example shown in Figures 4 and 5, the antenna module 1A and the IC card 100 were fabricated in the same manner as in Example 1, and the communication performance, RSSI change, and sensitivity difference were measured in the same manner as in Example 1. In Example 2, the length of the second slot 25 in the x direction was set to 20.5 mm.

[Comparative Example 1]
An antenna module 1' of Comparative Example 1 was fabricated by setting the shape of the first antenna 20' as shown in FIG. 6 and the dimensions of each element as shown in FIG. 7 , and an IC card of Comparative Example 1 was fabricated using this antenna module 1'. In Comparative Example 1, the length of the first antenna 20' in the y direction is shorter than half the length of the substrate 10 in the y direction, and the surface area of the metal thin film is less than half (less than 50%) of the surface area of the substrate 10. Furthermore, the second antenna 40 is not sandwiched between the first antennas 20' but is provided adjacent to the first antennas 20'. The communication performance, RSSI change, and sensitivity difference of this IC card of Comparative Example 1 were measured in the same manner as in Example 1.

The following describes the measurement results of the communication performance, RSSI change, and sensitivity difference for Example 1, Example 2, and Comparative Example 1. Figures 8 and 9 are diagrams showing the communication performance at UHF band frequencies for IC cards 100 of Examples 1 and 2. The thin lines in the graphs in Figures 8 and 9 represent the communication performance when IC card 100 communicates alone, the medium lines represent the communication performance when IC card 100 is inserted into a pass case, and the thick lines represent the communication performance when IC card 100 and a transportation IC card are placed on top of each other and inserted into the pass case. The horizontal axis of Figures 8 and 9 represents the frequency of the wireless communication radio waves, and the vertical axis represents the communicable distance from IC card 100 to the reader (theoretical read range forward).

Figure 10 shows the communication performance of the IC card of Comparative Example 1 at UHF band frequencies. The thin line in the graph in Figure 10 indicates the communication performance when communicating with the IC card of Comparative Example 1 alone. The medium line in the graph in Figure 10 indicates the communication performance when communicating with the IC card of Comparative Example 1 inserted in a pass case. The thick dashed line in the graph in Figure 10 indicates the communication performance when communicating with the IC card of Comparative Example 1 inserted in a pass case and sandwiched between credit cards with an IC chip. The thick line in the graph in Figure 10 indicates the communication performance when communicating with the IC card of Comparative Example 1 inserted in a pass case and sandwiched between a credit card with an IC chip and a transportation IC card. In Figure 10, the horizontal axis also represents the frequency of the radio waves for wireless communication, and the vertical axis represents the communication distance from the IC card of Comparative Example 1 to the reader.

As shown in Figure 8, with the IC card 100 of Example 1, the communication distance at a predetermined frequency of 920 MHz included in the UHF band was approximately 11 m when used alone, approximately 10 m when placed in a pass case, and approximately 9 m when placed in a pass case together with a transportation IC card. There was almost no reduction in the communication distance, and excellent communication performance was demonstrated in all cases.

As shown in Figure 9, the communication distance of the IC card 100 of Example 2 at the predetermined frequency of 920 MHz included in the UHF band was approximately 7 m, whether the card was alone, inserted in a pass case, or placed on top of a transportation IC card in the pass case. This meant that there was almost no reduction in the communication distance, and excellent communication performance was demonstrated in all cases.

On the other hand, as shown in Figure 10, the communication distance for the IC card of Comparative Example 1 was approximately 12 m when it was alone, approximately 12.5 m when it was placed in a pass case, and approximately 13 m when it was sandwiched between credit cards and placed in the pass case. In contrast, when the IC card of Comparative Example 1 was placed in a pass case sandwiched between a credit card and a transportation IC card, the communication distance was approximately 5 m, a significant decrease in the communication distance. Because the built-in antenna of a credit card is small, it has little effect on the IC card, and it is presumed that this significant decrease in communication distance is due to the influence of the transportation IC card.

Figure 11 shows the RSSI measurement results for the antenna modules of Example 1, Example 2, and Comparative Example 1. In Figure 11, the horizontal axis represents the distance from the antenna of the fixed card reader to the IC card, and the vertical axis represents the RSSI. Figure 12 shows the difference in sensitivity between the antenna modules of Example 1, Example 2, and Comparative Example 1.

As shown in Figure 11, the IC cards 100 of Examples 1 and 2 achieved high communication strength not only when used alone, but also when used in close contact with a transportation IC card, even when the distance from the antenna was long. In contrast, in Comparative Example 1, when used overlapping with a transportation IC card, the strength was significantly reduced compared to when used alone, even when the distance from the antenna was short (specifically, the RSSI was "-55" when the distance from the antenna was 1 cm).

Furthermore, as shown in Figure 12, in Examples 1 and 2, there was almost no difference in the sensitivity of the fixed card reader between when it was used alone and when it was attached closely to a transportation IC card, demonstrating that excellent communication performance could be obtained. In contrast, in Comparative Example 1, there was a large difference in the sensitivity of the fixed card reader between when it was used alone and when it was attached closely to a transportation IC card.

The above results demonstrate that antenna modules 1, 1A and IC cards 100 of Examples 1 and 2, which comprise a substrate 10, a first antenna 20, 20A provided on the substrate 10 for transmitting and receiving signals, and a first IC chip 30 electrically connected to the first antenna 20, 20A, and in which the first antenna 20, 20A is formed of a metal thin film that is U-shaped in plan view and covers at least 50% of the surface of the substrate 10, can provide excellent communication performance, particularly improved communication performance in the UHF band. In particular, it was demonstrated that even when the IC card 100 is used in a pass case or stacked with a transportation IC card, there is almost no decrease in communication distance or communication sensitivity, and excellent communication performance can be maintained.

[Example 3]
An antenna module 1B and an IC card 100 of Example 3 were fabricated with a configuration similar to that of the second embodiment shown in Figures 13 and 14. The antenna module 1B was fabricated by providing a first antenna 20B by dry laminating a 10 μm thick aluminum sheet on a PET film having a length of 85.6 mm in the x direction, a length of 54.0 mm in the y direction, and a thickness of 38 μm, and by providing a coil-shaped second antenna 40 between second regions 22 and 23 of the first antenna 20B, mounting a third IC chip 60 at a specified position on the first antenna 20B, and electrically connecting the third IC chip 60 and the second antenna 40B via through holes 11 and 12 and connection lines 13 and 14. 3, the first antenna 20B had a length in the x direction of 75.5 mm and a length in the y direction of 43.50 mm, the length in the x direction of the first slot 24 was 34.0 mm, the length in the x direction of the second slot 25 was 20.5 mm, the distance in the x direction between the second regions 22 and 23 was 40.5 mm, and the length in the x direction of the second regions 22 and 23 was 17.5 mm. The second antenna 40 had a length in the x direction of 31.5 mm and a length in the y direction of 12.5 mm.

The third IC chip 60 uses the EM4425 manufactured by Microelectronics. This third IC chip 60 transmits and receives signals using radio waves at frequencies in the UHF band (860-960 MHz), and also transmits and receives signals using electromagnetic induction at frequencies in the HF band (13.56 MHz). The characteristics of the third IC chip 60 are as described in the second embodiment above.

The antenna module 1B produced as described above was sandwiched between a pair of cover sheets 2, 3 formed from PVC plates 85.6 mm long in the x direction and 54.0 mm long in the y direction, and these were then adhered to each other to produce the IC card 100 of Example 3. As with Example 1, the communication performance, RSSI changes, and sensitivity differences of this IC card 100 were measured when the IC card 100 was used alone, when it was inserted into a pass case, and when it was inserted into the pass case together with a transportation IC card. For comparison, the measurement results of Comparative Example 1 above were used.

The following describes the measurement results of the communication performance, RSSI change, and sensitivity difference of Example 3. Figure 15 is a diagram showing the communication performance of IC card 100 of Example 3 at UHF band frequencies. The thin line in the graph in Figure 15 indicates the communication performance when communicating with IC card 100 alone, the medium line indicates the communication performance when communicating with IC card 100 inserted in a pass case, and the thick line indicates the communication performance when communicating with IC card 100 and a transportation IC card placed on top of each other and inserted in the pass case. The horizontal axis of Figure 15 represents the frequency of the radio waves for wireless communication, and the vertical axis represents the communicable distance from IC card 100 to the reader (theoretical read range forward).

As shown in Figure 15, the communication distance of the IC card 100 of Example 3 at a predetermined frequency of 920 MHz included in the UHF band was approximately 7 m when used alone, approximately 6 m when placed in a pass case, and approximately 5.5 m when placed in the pass case together with a transportation IC card, meaning that the communication distance was hardly reduced. This shows that the communication distance of the IC card 100 of Example 3 was not reduced even when compared to the IC card of Comparative Example 1 shown in Figure 10.

Figure 16 shows the RSSI measurement results for the antenna modules of Example 3 and Comparative Example 1. In Figure 16, the horizontal axis represents the distance from the reader antenna to the IC card, and the vertical axis represents the RSSI. Figure 17 shows the difference in sensitivity between the antenna modules of Example 3 and Comparative Example 1.

As shown in Figure 16, compared to Comparative Example 1, the IC card 100 of Example 3 achieved high communication strength not only when used alone, but also when the IC card was overlapped with a transportation IC card and at a long distance from the antenna. Furthermore, as shown in Figure 17, in Example 3, there was almost no difference in reader sensitivity between when the IC card was used alone and when it was closely attached to a transportation IC card, demonstrating that excellent communication performance was achieved.

The antenna module and IC card of the present disclosure have been described above based on embodiments and examples, but the specific configurations are not limited to these examples. Design changes and additions are permitted as long as they do not deviate from the gist of the invention as defined in each claim.

1, 1A, 1B: Antenna module 10: Substrate 20, 20B, 20C: First antenna 21: First region 22, 23: Second region 30: First IC chip 40, 40B: Second antenna 50: Second IC chip 60: Third IC chip 100: Contactless IC card

Claims (5)

A substrate;
a first antenna provided on the substrate for transmitting and receiving signals;
a first IC chip electrically connected to the first antenna;
the first antenna is made of a metal thin film provided on the surface of the substrate, the first slot being arranged in a U-shape in plan view and extending along one long side of the substrate, and a second slot being parallel to the first slot , and the first antenna is arranged so as to cover at least 50% or more of the surface of the substrate;
An antenna module characterized by: a second antenna provided on the substrate for transmitting and receiving signals in a frequency band different from that of the first antenna;
a second IC chip electrically connected to the second antenna;
the first antenna and the second antenna are provided at positions on the substrate where they do not overlap each other in a plan view,
2. The antenna module according to claim 1, wherein the first antenna is disposed in an area on the surface of the substrate other than an area where the second antenna is provided. A substrate;
a first antenna provided on the substrate for transmitting and receiving signals;
a second antenna provided on the substrate for transmitting and receiving signals in a frequency band different from that of the first antenna;
an IC chip electrically connected to the first antenna and the second antenna,
The first antenna is formed of a metal thin film on the surface of the substrate in a region that does not overlap with the second antenna in a plan view, and is provided with a first slot that is arranged in a U-shape in a plan view and that extends along one long side of the substrate, and a second slot that is parallel to the first slot , and is arranged so as to cover at least 50% or more of the surface of the substrate.
An antenna module characterized by: The substrate is rectangular,
The antenna module described in any one of claims 1 to 3, characterized in that the first antenna is U-shaped in a planar view, having a first region extending in a strip of a predetermined width along one long side of the substrate from one short side to the other short side, and a pair of second regions extending in strips of a predetermined width from both sides of the first region along one and the other short sides of the substrate to the other long side. The antenna module according to any one of claims 1 to 4 is provided.
An IC card characterized by: