Vehicle communication device with passive selection circuit

Abstract

The invention relates to a communication device (10) for a vehicle (2), comprising: a single communication antenna (11); a matching circuit (12) configured to match an impedance of the communication antenna (11); a high-frequency processing module (13) connected to the matching circuit (12) and configured to process a high-frequency signal received by the antenna (11); and a passive selection circuit (15) connected to the matching circuit (12) and configured to communicate with a near field communication module (14) receiving a signal via the antenna (11) so as to operate in an open state when the strength of the signal received by the antenna (11) is below a predetermined strength threshold and to operate in a closed state when the strength of said signal is above the predetermined strength threshold. A signal received by the antenna (11) is transmitted to the near field communication module (14) via the matching circuit (12).

Description

[TECHNICAL FIELD]

[0001] The present invention relates to the field of motor vehicles, more particularly to a device for transmitting high frequency signals and near field signals. [BACKGROUND]

[0002] In the field of radio frequency communication, in particular for motor vehicles, there are several types of radio frequency waves used for different applications.

[0003] One criterion for determining the type of radio frequency transmission used is the distance between the transmitter and the receiver; another is the quality required for signal reception.

[0004] For short distance applications of the order of a few meters, and in cases where the quality of the information transmitted by the signal is not very important, so-called "high frequency" radio frequencies are generally used. The high frequency (HF) range includes transmission frequencies between 3 and 30 megahertz (MHz).

[0005] For ultra-short distance applications of less than 10 centimeters, and in cases where the quality of the information transmitted is extremely important, NFC (Near Field Communication) technology is generally used. NFC operates at a frequency of 13.56 megahertz.

[0006] These two types of radio frequency signals involve the use of different types of electronic circuits in the receiver for each type of signal.

[0007] In some applications, such as in motor vehicles, it can be advantageous to equip the receiver device with the possibility of combining the two types of radio frequency signals. Thus, for a portable access device that can unlock the vehicle and activate the functions of the vehicle, it is advantageous to be able to receive high frequency signals or near field signals between the user and the vehicle.

[0008] It is then necessary to equip the same device with the circuits required for the two types of radio frequency transmission.

[0009] A first solution is to equip the device with two circuits each with a corresponding antenna, simultaneously. This solution is not advantageous because the space in a device of the type of a car key or electronic key fob is limited and the presence of two circuits so close to each other can create cross interference between the two.

[0010] Another solution is to equip a single circuit for the two types of radio frequency transmission. This solution solves the problems of space and cross interference, but the single circuit inevitably degrades the quality of the signals transmitted by the two types of radio frequency transmission.

[0011] Finally, a solution consists in equipping a common part for the two types of radiofrequency emissions, and a smart circuit able to detect the type of radiofrequency emission and to activate the corresponding components. This solution also solves the space and cross-interference problems, but the smart circuit requires a permanent power supply, which greatly shortens the life of the device, such as a vehicle key or electronic key ring.

[0012] Therefore, a simple, reliable and efficient solution that makes it possible to at least partially remedy these drawbacks would be advantageous. [SUMMARY]

[0013] To this end, one subject of the application is first of all a communication device for a motor vehicle, said device comprising: a single communication antenna; a matching circuit configured to match the impedance of said antenna; a high frequency processing module connected to said matching circuit and configured to process high frequency signals received by the antenna; and a passive selection circuit connected to the matching circuit and configured to communicate with a near field communication module, such that said near field communication module receives signals via the antenna, so as to operate in open circuit state when the strength of the signals received by the antenna is below a predetermined strength threshold, and to transmit the signals received by the antenna to the near field communication module via the matching circuit when the strength of said signals is above the predetermined strength threshold.

[0014] Thus, the device according to the application can receive radiofrequency signals of high frequency type and of near field type via a single communication antenna, and adapt the received signals according to the type of signals received, in order to redirect them to the appropriate processing module. The passive selection circuit acts as a switch, which does not require a power supply itself, since the passive selection circuit closes when the antenna receives a near field signal (which generates enough voltage in the circuit of the device), and remains open in the other cases. Thus, the circuit according to the application is self-sufficient in terms of energy. This simple circuit is therefore inexpensive and requires limited space in the device, since it does not require any additional power supply components or active management components, such as a microcontroller.

[0015] Advantageously, the passive selection circuit comprises a transistor comprising a collector connected to the output of the matching circuit, a base configured to communicate with the near field communication module, and an emitter connected to said collector. The operation of the transistor makes it a switch that opens as long as the voltage at the base is insufficient. When the device receives a high frequency signal, the voltage generated in the circuit is too low for the transistor, and the passive selection circuit opens. Conversely, when the device receives a near field signal, the voltage generated in the circuit is sufficient for the transistor, and the passive selection circuit closes, thus allowing the signal to be transmitted to the near field communication module.

[0016] Any type of transistor can be used in the selection circuit according to the application, for example a GaN transistor, a FET transistor, a MOSFET transistor, the connections of which have different names.

[0017] Advantageously again, the passive selection circuit comprises a transistor, a diode and a capacitor, the diode being connected by its input terminal to the output of the matching circuit, the transistor comprising a collector connected to the output of the matching circuit, an emitter connected to the capacitor and configured to communicate with the near field communication module, a base connected to a midpoint connecting the output terminal of the diode to the capacitor.

[0018] Preferably, the matching circuit comprises a plurality of, at least three, capacitors, these capacitors comprising a first capacitor connected in series with the communication antenna, a second capacitor connected to the first electrical capacitor and a third capacitor connected to the other pole of the antenna, the second capacitor being connected to the passive selection circuit, the third capacitor being connected to the other pole of the antenna, and the high frequency processing module being connected to the junction between these three capacitors. These different capacitors make it possible to match the impedance of the matching circuit according to the type of signal received. The second capacitor has a current flow only when the passive selection circuit is closed, thus modifying the impedance of the matching circuit between the reception of a high frequency signal and a near field signal.

[0019] In a first embodiment, the device according to the application comprises a near field communication module connected to the passive selection circuit. This device can thus be a key fob or a key which can receive high frequency signals and near field signals, while being compact and energy efficient.

[0020] Preferably, the near field communication module is connected to the passive selection circuit via printed circuit tracks.

[0021] In a second embodiment, the device is configured to communicate with a smartphone via a communication link. This device can then assist the smartphone, for example with a high frequency processing module which is not usually included in existing telephones.

[0022] Advantageously, in this second embodiment, the communication link is wired or wireless.

[0023] This device can thus be connected to the telephone by a cable of USB type for example.

[0024] This device can also be connected to the telephone by a wireless communication link of radio wave type for example.

[0025] According to another aspect, the application also relates to an assembly comprising a device as presented and a smartphone configured to communicate with said device via a communication link.

[0026] The communication link can be wired or wireless in nature.

[0027] Advantageously, in the presented assembly, the near field communication module is implemented in the smartphone. This scenario is the simplest to implement, as most existing smartphones already comprise a near field communication module.

[0028] According to another aspect, the invention also relates to a vehicle configured to communicate with the presented device or assembly in high frequency signals or near field signals.

[0029] According to another aspect, the invention also relates to a method of selecting the frequency between a presented vehicle and a presented device or assembly, said vehicle being configured to emit high frequency signals and near field signals, said method comprising the steps of:

[0030] - receiving a radio frequency signal via the communication antenna of the device,

[0031] - generating a voltage across the terminals of the matching circuit via the communication antenna of the device,

[0032] - configuring the passive selection circuit in a closed circuit state if the generated voltage is high enough,

[0033] - sending the signal received by the communication antenna to the near field communication module via the passive selection circuit,

[0034] - configuring the passive selection circuit in an open circuit state if the generated voltage is too low,

[0035] - sending the signal received by the communication antenna to the high frequency processing module.

[0036] According to another aspect, the invention also relates to a method for determining the distance between a presented vehicle and a device or assembly, said vehicle being configured to emit and receive high frequency signals and near field signals, said method comprising the steps of:

[0037] - emitting a radio frequency signal via the vehicle,

[0038] - receiving the emitted radio frequency signal via the device,

[0039] - generating a voltage across the terminals of the matching circuit via the communication antenna of the device,

[0040] - configuring the passive selection circuit in an open circuit state if the generated voltage is low enough,

[0041] - sending the signal received by the communication antenna to the high frequency processing module,

[0042] - processing the sent signal via the high frequency processing module and emitting a radio frequency signal,

[0043] - receiving, via the vehicle, the transmitted radio frequency signal and calculating the distance between the vehicle and the device.

[0044] Advantageously, in the presented method, the device is configured to communicate with the vehicle through a Bluetooth® Low Energy (BLE) radio frequency link, the vehicle being configured to calculate the distance between the vehicle and the device on the basis of the exchange of Bluetooth® Low Energy (BLE) signals, and wherein, after the step of receiving, via the vehicle, the transmitted high frequency signal and calculating the distance between the vehicle and the device, there is a step of comparing the distance calculated on the basis of the exchange of high frequency signals with the distance calculated on the basis of the exchange of Bluetooth® Low Energy signals, and a step of verifying the measured distance if the two distances are equal. [SUMMARY]

[0045] Further features and advantages of the present invention will become more apparent upon reading the following description. This description is purely illustrative and should be read in conjunction with the attached drawings, in which:

[0046] [ Figure 1 ] Figure 1 An assembly comprising a device according to the present invention is schematically illustrated.

[0047] [ Figure 2 ] Figure 2 A first embodiment of a device according to the present invention is schematically illustrated.

[0048] [ Figure 3 ] Figure 3 A second embodiment of a device according to the present invention connected to a smartphone is schematically illustrated.

[0049] [ Figure 4 ] Figure 4 A frequency selection method according to the present invention is illustrated.

[0050] [ Figure 5 ] Figure 5 A distance measurement verification method according to the present invention is illustrated. [DETAILED DESCRIPTION]

[0051] As shown in Figure 1, an assembly 1 comprising a device 10 according to the present invention communicates with a vehicle 2. Figure 1

[0052] Assembly 1 In the first embodiment shown in Figures 2 and 3, the assembly 1 comprises a communication device 10.

[0053] Figure 1 and Figure 2 In the first embodiment shown in Figures 2 and 3, the assembly 1 comprises a communication device 10.

[0054] In​​​​Figure 3 In the second embodiment shown, the assembly 1 comprises a communication device 10 and a smartphone 20.

[0055] Communication device 10

[0056] As shown, the device 10 comprises an antenna 11, a matching circuit 12, a high frequency processing module 13, a near field communication module 14 and a passive selection circuit 15. Figure 2

[0057] In the embodiment shown, the device 10 further comprises a communication link 16. In this embodiment, the device 10 is an accessory, such as a case or an additional device, connected to the smartphone 20 via the communication link 16. Figure 3 In another embodiment, not shown in the figures, the device 10 is the smartphone 20, which comprises the antenna 11, the matching circuit 12, the high frequency processing module 13, the near field communication module 14 and the passive selection circuit 15.

[0058]

[0059] Communication antenna 11

[0060] The antenna 11 is an antenna configured to receive high frequency radio signals between 3 MHz and 30 MHz and near field signals at the precise frequency of 13.56 MHz.

[0061] When the antenna 11 receives a high frequency signal, the antenna generates a voltage across its terminals.

[0062] Matching circuit 12

[0063] The matching circuit 12 is connected to the antenna 11, the high frequency processing module 13 and the passive selection circuit 15.

[0064] The matching circuit 12 comprises a first capacitor 12A, a second capacitor 12B and a third capacitor 12C.

[0065] As shown, the first capacitor 12A is connected to one pole of the antenna 11. The second capacitor 12B is connected to the first capacitor 12A and the other pole of the antenna 11. Figure 2

[0066] The third capacitor 12C is connected to the first capacitor 12A and the passive selection circuit 15.

[0067] The first capacitor 12A and the second capacitor 12B are configured to form a loop circuit when the antenna 11 receives a high frequency signal from a long distance and to make the resonant frequency of this circuit match the frequency of the received high frequency signal.

[0068] ​​​The first capacitor 12A, the second capacitor 12B and the third capacitor 12C are configured to form a loop circuit with the passive selection circuit 15 and the near field communication module 14 when the antenna 11 receives a near field signal from a short distance (lower than 10 cm).

[0069] The resonant frequency of the loop circuit thus formed matches the frequency of the received NFC signal at 13.56 MHz.

[0070] High frequency processing module 13

[0071] The high frequency processing module 13 is electrically connected to the matching circuit 12.

[0072] The high frequency processing module 13 is configured to pick up voltage variations in the matching circuit 12 and to process these variations in order to extract therefrom high frequency signals received by the antenna 11 of the device 10.

[0073] The processing of high frequency signals is known per se.

[0074] In the embodiment illustrated in the figures, the high frequency processing module 13 is connected to the smartphone 20 via a communication link 16. Figure 3

[0075] The high frequency processing module 13 can transmit to the smartphone 20 the high frequency signals received by the antenna 11 and processed by the device 10.

[0076] Preferably, the communication link 16 comprises a processing module for converting the signals before sending them to the smartphone 20. This processing module is not illustrated in the figures for the sake of clarity.

[0077] Near field communication module 14

[0078] In the embodiment illustrated in the figures, the near field communication module 14 is integrated into the same circuit as the matching circuit 12 via the passive selection circuit 15.

[0079] When the passive selection circuit 15 is closed, the near field communication module 14 is configured to pick up voltage variations in the matching circuit 12 and to process these variations in order to extract therefrom near field signals received by the antenna 11 of the device 10.

[0080] The processing of near field signals is known per se.

[0081] In the embodiment illustrated in the figures, the near field communication module 14 is connected to the smartphone 20 via a communication link 16. Figure 3

[0082] The near field communication module 14 can transmit to the smartphone 20 the near field signals received by the antenna 11 and processed by the device 10. ​​

[0083] Preferably, the communication link 16 comprises a processing module for converting the signals before sending them to the smartphone 20. This processing module is not shown in the figures for the sake of clarity.

[0084] Passive selection circuit 15

[0085] The passive selection circuit 15 is electrically connected to the matching circuit 12 and to the near field communication module 14.

[0086] The passive selection circuit 15 is configured to act as an open switch when the signals received by the device 10 are high frequency signals, the source of which is more than 10 cm away from the device 10, and as a closed switch when the signals received by the device 10 are near field communication signals, that is to say, signals at 13.56 MHz, the source of which is less than 10 cm away.

[0087] As shown in Figure 2 The passive selection circuit 15 comprises a transistor 151, a diode 152 and a capacitor 153.

[0088] The transistor 151 is advantageously a bipolar transistor comprising a collector C, a base B and an emitter E.

[0089] The transistor 151 is configured to allow a current to flow between the collector C and the emitter E only if the base B is supplied with sufficient current.

[0090] The collector C is connected to the matching circuit 12, the emitter E is connected to the input of the near field communication module 14, and the base B is connected to the midpoint of the capacitor 153 connecting the output terminal of the diode 152.

[0091] The diode 152 comprises an input terminal and an output terminal. A current can flow from the input terminal to the output terminal of the diode 152, but not the other way around.

[0092] The input terminal of the diode 152 is connected to the collector C of the transistor 151.

[0093] The output terminal of the diode 152 is connected to the base B of the transistor 151.

[0094] The diode 152 only allows a current to flow from its input terminal to its output terminal, thus ensuring that a current flows from the matching circuit 12 to the base B of the transistor 151.

[0095] The capacitor 153 is connected to the base B and to the emitter E of the transistor 151.

[0096] The capacitor 153 makes it possible to adjust the voltage at the base B of the transistor 151.

[0097] Communication link 16

[0098] In Figure 3 In the embodiment illustrated, the device 10 comprises a communication link 16 which makes it possible to communicate with the smartphone 20.

[0099] The communication link 16 can be wired (for example via a USB connection) or wireless (for example via BLE low power).

[0100] The communication link 16 allows the high-frequency processing module 13 and the near-field communication module 14 to communicate directly with the smartphone 20 without passing through the antenna 11.

[0101] In the case where the communication link 16 is a wireless communication link, the device 10 can communicate directly with the vehicle 2 via the communication link 16.

[0102] In particular, if the communication link 16 belongs to the low power type, the device 10 can communicate with the vehicle 2 using low power.

[0103] Smartphone 20

[0104] The smartphone 20 is the smartphone of the user of the vehicle 2.

[0105] In Figure 3 the embodiment illustrated, the smartphone 20 is connected to the device 10 via the communication link 16.

[0106] In this embodiment, the device 10 is an accessory of the smartphone 20 and can be included in an external case which plugs in the smartphone 20 or in an additional device which is connected to the smartphone 20.

[0107] The smartphone 20 can communicate with the vehicle 2 via radiofrequency signals.

[0108] Vehicle 2

[0109] The vehicle 2 comprises means for emitting radiofrequency signals, in particular high-frequency signals and near-field communication signals.

[0110] Advantageously, the vehicle 2 also comprises at least one BLE low power) transmission and reception means.

[0111] Examples of embodiments

[0112] First embodiment

[0113] As Figure 1 and Figure 2As shown, in the first embodiment, the assembly 1 comprises only the device 10.

[0114] In a preliminary step, the vehicle 2 emits a radio frequency signal.

[0115] In a first step E1, the device 10 receives the radio frequency signal emitted by the vehicle 2.

[0116] When the radio frequency signal reaches the antenna 11 of the device 10, the device 10 of the assembly 1 receives said radio frequency signal.

[0117] In a second step E2, the antenna 11 generates an oscillating voltage from the received radio frequency signal.

[0118] This voltage makes an electric charge flow through the terminals of the antenna 11.

[0119] The amplitude of the generated voltage depends on the strength of the received radio frequency signal. This strength decreases as the distance between the vehicle 2 and the device 10 increases.

[0120] If the radio frequency signal emitted by the vehicle 2 belongs to the near field communication type, the device 10 will only capture the signal when it is very close to the vehicle 2 (within 10 cm).

[0121] The radio frequency signal received by the device 10 is then very strong, and the amplitude of the generated voltage is also high.

[0122] The voltage at the base B of the transistor 151 of the passive selection circuit 15 is therefore high, and the transistor 151 works like a closed switch, causing a current to flow to the near field communication module 14 in step E3.

[0123] In step E4, the near field communication module 14 receives and processes the signal.

[0124] The capacitances of the capacitors 12A, 12B and 12C are matched to the expected frequency of the near field communication signal at 13.56 MHz. The matching circuit 12 thus makes it possible to adjust the voltage oscillations in one step to a signal usable by the near field communication module 14.

[0125] If the radio frequency signal emitted by the vehicle 2 belongs to the high frequency communication type, the device 10 can capture the signal at a greater distance from the vehicle 2 (of the order of several meters).

[0126] The radio frequency signal received by the device 10 is then not so strong, and the amplitude of the generated voltage is also not so high.

[0127] The voltage at the base B of the transistor 151 of the passive selection circuit 15 is therefore no longer sufficient, and the transistor 151 works like an open switch, preventing a current from reaching the near field communication module 14.

[0128] The capacitor 12C of the matching circuit 12 is no longer powered, and the signal is then captured in step E3* by the high-frequency processing module 13.

[0129] In step E4*, the high-frequency processing module 13 receives the signal and processes it.

[0130] The matching circuit 12, with the capacitors 12A, 12B, thus makes it possible to adjust the voltage oscillations in one step into a signal that can be used by the high-frequency processing module 13.

[0131] Second embodiment

[0132] In Figure 3 In the second embodiment illustrated, in which the device 10 is an accessory connected to the smartphone 20 via the communication link 16, the method proceeds in the same way.

[0133] This embodiment is therefore advantageous for a smartphone 20 that does not comprise a high-frequency processing module 13.

[0134] This embodiment thus allows the assembly 1 to implement a method for determining the distance between the vehicle 2 and the assembly 1 comprising the device 10 and the smartphone 20.

[0135] In step Fl, the vehicle 2 emits a high-frequency signal.

[0136] In step F2, the device 10 receives the high-frequency signal sent by the vehicle 2.

[0137] Due to the high frequency, the voltage generated by these signals received by the antenna 11 is not sufficient to close the passive selection circuit 15; thus, in step F3, the high-frequency signal is transmitted to the high-frequency processing module 13 via the matching circuit 12.

[0138] The high-frequency processing module 13 receives the signal sent by the vehicle 2 in step F4 and detects that the user carrying the assembly 1 is located in the vicinity of the vehicle 2.

[0139] In step F5, the high-frequency processing module 13 generates a response signal that is sent to the smartphone 20 via the communication link 16 and then to the vehicle 2 via the smartphone 20 in step F6.

[0140] As a variant, when the communication link 16 is a wireless link, in particular a low-power consumption link, the device 10 can send a signal directly to the vehicle 2 via the wireless communication link 16.

[0141] The signal sent to the vehicle 2 via the smartphone 20 is preferably a low-power consumption signal.

[0142] In step F7, vehicle 2 receives a response signal and calculates the distance between vehicle 2 and the user carrying assembly 1.

[0143] Distance can be based on RSSI (Received Signal Strength Indicator), that is, in It can be calculated by measuring the strength of the received signal under low-power signal conditions, or by measuring the amplitude of the received signal under high-frequency signal conditions.

[0144] This distance calculation can be used to activate the proximity function of vehicle 2, for example, to unlock or turn on the air conditioning when the user is close enough to vehicle 2.

[0145] This method of determining distance via high-frequency signals allows for the limitation of risks associated with the location of the smartphone 20 relative to the user, which could be affected by interference with the signal due to organic tissue or metallic components.

[0146] In addition to being transmitted by the smartphone 20 itself In addition to the distance determination method performed by low-power signals, this method of determining distance via high-frequency signals can also be performed to confirm the determined distance.

[0147] Specifically, Low-power signals are more likely to be interfered with by human tissue and metal components, which could distort distance measurements if the smartphone 20 is carried, for example, in the back pocket of the user's pants or near metal components (such as keys).

[0148] The antenna 11 of the device 10 can also capture near-field signals when the user is close enough to the vehicle 2, and ensure redundancy with the antenna of the smartphone 20 if the near-field signals are blocked by part of the user's body or metal components.

Claims

1. A communication device (10) for a motor vehicle (2), the device (10) comprising: A single communication antenna (11); a matching circuit (12) configured to match the impedance of the communication antenna (11); a high-frequency processing module (13) connected to the matching circuit (12) and configured to process high-frequency signals received by the antenna (11); and a passive selection circuit (15) connected to the matching circuit (12) and configured to communicate with a near-field communication module (14) such that the near-field communication module (14) receives signals via the antenna (11), the communication device (10) being configured such that when it receives a high-frequency signal with an intensity lower than a predetermined intensity threshold via the antenna (11), the passive selection circuit (15) operates in an open-circuit state, and when it receives a near-field signal with an intensity higher than the predetermined intensity threshold via the antenna (11), the passive selection circuit (15) operates in a closed-circuit state and transmits the signal to the near-field communication module (14) via the matching circuit (12).

2. The device (10) as claimed in claim 1, wherein, The passive selection circuit (15) includes a transistor (151) having a collector (C), a base (B), and an emitter (E). The collector (C) is connected to the output of the matching circuit (12), the emitter (E) is configured to communicate with the near-field communication module (14), and the base (B) is connected to the collector (C).

3. The device (10) as claimed in the preceding claim, wherein, The matching circuit (12) includes multiple capacitors, at least three capacitors (12A, 12B, 12C), including a first capacitor (12A) connected in series with one pole of the antenna (11), a second capacitor (12B) connected to the first capacitor (12A), and a third capacitor (12C). The second capacitor (12B) is connected to the passive selection circuit (15), and the third capacitor (12C) is connected to the other pole of the antenna (11). The high-frequency processing module (13) is connected to the connection point between the three capacitors (12A, 12B, 12C).

4. The device (10) as claimed in any of the preceding claims, the device (10) comprising the near-field communication module (14) connected to the passive selection circuit (15).

5. The device (10) as claimed in the preceding claim, wherein the device (10) is configured to communicate with a smartphone (20) via a communication link (16).

6. The device (10) as claimed in the preceding claim, wherein, The communication link (16) can be wired or wireless.

7. An assembly (1) comprising a device (10) as described in any of the preceding claims and a smartphone (20) configured to communicate with the device (10) via a communication link (16).

8. The assembly (1) as described in the preceding claim, wherein, The near-field communication module (14) is implemented in the smartphone (20).

9. A vehicle (2) configured to communicate with a device (10) as claimed in any one of claims 1 to 6 or an assembly (1) as claimed in any one of claims 7 and 8 using high-frequency signals or near-field signals.

10. A method for selecting a signal between a vehicle and a communication device (10) as claimed in any one of claims 1 to 6, wherein the transmitter is configured to transmit a high-frequency signal and a near-field signal, the method comprising the steps of: -Receive (E1) radio frequency signals via the antenna (11) of the device (10), - The antenna (11) of the device (10) generates an (E2) voltage across the terminals of the matching circuit (12). -If the generated voltage is high enough, the passive selection circuit (15) is configured (E3) to be in a closed circuit state. -The signal received by the antenna (11) is transmitted (E4) to the near-field communication module (14) via the passive selection circuit (15) and the matching circuit (12). -If the generated voltage is too low, the passive selection circuit (15) is configured (E3*) to be in an open circuit state. - The signal received by the antenna (11) is transmitted (E4*) to the high-frequency processing module (13) via the matching circuit (12).

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