JP2007134983A - Radio communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily diagnose whether each of a plurality of antennas operates normally. <P>SOLUTION: A radio communication device is equipped with a first switch 16 which selects one of the respective antennas as a transmitting antenna and a second switch 17 which selects the antennas other than the antenna selected as the transmitting antenna as receiving antennas. A control section 11 causes the antenna selected as the transmitting antenna to radiate a radio wave of prescribed intensity for diagnosis to measure diagnostic radio wave reception levels of the antennas selected as the receiving antennas. Then failure of each of the antennas is diagnosed based on the measured diagnostic radio wave reception levels. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless communication apparatus including a plurality of antennas that radiate high-frequency signals as radio waves and convert received radio waves into high-frequency signals and output them.

  In recent years, a wireless tag (also referred to as an IC tag, an RFID tag, an electronic tag, a transponder, or the like) including an IC chip and a wireless communication device, both of which communicate data via an antenna, RFID (Radio Frequency Identification) systems that can read information on a wireless tag in a wireless communication apparatus in a non-contact manner have become widespread.

  In this RFID system, the wireless communication device continues to radiate a radio frequency signal for inquiring a wireless tag from the antenna as a radio wave. The backscatter modulation is performed by changing the reflection amount of the high-frequency signal according to the received information. Therefore, when the wireless communication device receives the backscatter modulated wave from the wireless tag by the antenna, the wireless communication device demodulates it and reads the information of the wireless tag.

  Such an RFID system can be used for communication even when a wireless tag is several centimeters to several tens of centimeters away from a wireless communication device. Therefore, the RFID system is used in various fields such as a shoplifting prevention system for goods and an entrance / exit management system for facilities. Yes.

  For example, when the RFID system is used in a shoplifting prevention system or an entrance / exit management system, normally, as shown in FIG. 7, a plurality (four in the figure) of antennas 1, 2, 3, and 4 are arranged to face each other. A gate type antenna 5 is used. In this gate type antenna 5, in order to reliably communicate with a wireless tag passing between the gates, a uniform radio wave intensity is required at each position and each direction component between the gates. For this reason, each antenna 1, 2, 3, 4 needs to form an optimal positional relationship.

  By the way, when a system is configured by a plurality of antennas such as the gate type antenna 5, even if a certain antenna is in a bad condition, the communication area is narrowed and the system operates normally. There was a problem that it was difficult to judge whether or not.

  Conventionally, in a system that performs bidirectional communication using radio waves between an interrogator equivalent to a wireless communication device and a responder equivalent to a wireless tag, whether the transmission function and reception function of the interrogator are normal. There is a technique in which a device failure can be detected by self-diagnosis (see, for example, Patent Document 1).

However, the conventional interrogator is equipped with a transmitting antenna and a receiving antenna separately. Whether the interfering radio waves transmitted from the transmitting antenna are received by the receiving antenna and demodulated to generate received data. Therefore, it can be applied to a wireless communication device in which a plurality of antennas radiate high-frequency signals as radio waves and convert received radio waves into high-frequency signals and output them. There wasn't.
JP 2004-72174 A

  As described above, in a wireless communication apparatus having a plurality of antennas that radiate high-frequency signals as radio waves and convert received radio waves into high-frequency signals and output them, it is easy to determine whether each antenna is operating normally. Could not be diagnosed.

  The present invention has been made based on such circumstances, and an object of the present invention is to provide a wireless communication apparatus that can easily diagnose whether or not each of a plurality of antennas is operating normally. To do.

  The present invention includes a transmitter that outputs a high-frequency signal, a plurality of antennas that radiate the high-frequency signal output from the transmitter as radio waves, convert the received radio waves into high-frequency signals, and output the radio signals. In a wireless communication apparatus comprising a receiving unit that inputs and processes a high-frequency signal, a transmission antenna selection unit that selects any one of the antennas as a transmission antenna, and a transmission antenna selection unit As a receiving antenna selecting means for selecting an antenna other than the selected antenna as a receiving antenna, a diagnostic radio wave emitting means for radiating diagnostic radio waves of a predetermined intensity from the antenna selected as a transmitting antenna, and a receiving antenna Receiving level measuring means for measuring the radio wave receiving level for diagnosis of the selected antenna.

  According to the present invention in which such means is taken, it is possible to provide a wireless communication apparatus that can easily diagnose whether or not each of the plurality of antennas is operating normally.

The best mode for carrying out the present invention will be described below with reference to the drawings.
In this embodiment, as shown in FIG. 7, a gate-type antenna 5 in which four antennas 1, 2, 3, and 4 are arranged so as to face each other, and information on a wireless tag is contactlessly provided. This is a case where the present invention is applied to a wireless communication device for reading.

  FIG. 1 is a schematic diagram showing an embodiment of an RFID system using a wireless communication apparatus 10 according to the present invention. The four antennas 1, 2, 3, 4 incorporated in the gate antenna 5 are connected to one wireless communication device 10 having a RFID tag reader function via communication cables 6, 7, 8, 9 respectively. Has been. The wireless communication device 10 is connected to a host device 30 such as a personal computer via a communication cable 20.

  In this RFID system, normally, when a wireless tag passes between the gate type antennas 5, the information of the wireless tag is read in a non-contact manner by data communication with any one of the antennas 1 to 4. The read information of the wireless tag is transmitted to the host device 30 via the wireless communication device 10.

  FIG. 2 is a block diagram showing a main configuration of the wireless communication apparatus 10. The wireless communication device 10 includes a control unit 11 mainly including a CPU (Central Processing Unit), a storage unit 12 of a ROM (Read Only Memory) and a RAM (Random Access Memory), and a communication unit that performs data communication with the host device 30. 13. A display unit 14 for displaying various statuses and a wireless unit 15 for performing wireless data transmission / reception are provided. Further, a first antenna selection switch 16, a second antenna selection switch 17, and a reception changeover switch 18 are provided.

  The radio unit 15 includes a PLL (Phase Locked Loop) circuit 41, a transmission unit 42, a circulator 43, a reception unit 44, and an RSSI circuit (Receive Signal Strength Indicator) 45. The PLL circuit 41 generates a high frequency sine wave signal. The transmission unit 42 modulates the digital data transmitted from the control unit 11, amplifies a signal obtained by adding the modulated signal and the high frequency signal generated by the PLL circuit 41, and outputs the amplified signal to the circulator 43. The circulator 43 outputs a signal input from the transmission unit 42 side to the antennas 1 to 4 side via the first antenna selection switch 16, and a signal input from the antennas 1 to 4 side via the reception changeover switch 18. And output to the receiving unit 44 side. The reception unit 44 amplifies the high frequency signal input via the reception changeover switch 18, and then combines the amplified high frequency signal and the high frequency signal of the PLL circuit 41 to convert it into a baseband signal. Is demodulated and converted into digital data, which is output to the control unit 11. The RSSI circuit 45 generates an analog signal indicating the level of the signal demodulated by the receiving unit 44.

  The first antenna selection switch 16 is interposed between the circulator 43 and each of the antennas 1, 2, 3, and 4, and is switched by a control signal S 1 from the control unit 11 to switch any one of the antennas. Connect to circulator 43. The second antenna selection switch 17 is interposed between the normally open terminal 18-2 of the reception changeover switch 18 and each of the antennas 1, 2, 3, 4 and performs a switching operation in response to a control signal S2 from the control unit 11. Any one antenna is connected to the normally open terminal 18-2 of the reception changeover switch 18. The reception changeover switch 18 is used for switching whether the reception unit 44 is connected to the circulator 43 or to be connected to any one of the antennas 1, 2, 3, 4 via the second antenna selection switch 17, and is a normally closed terminal. 18-1 is the circulator 43 side, and the normally open terminal 18-2 is the second switch 17 side. While the ON signal is input as the control signal S3 from the control unit 11, the contact is switched from the normally closed terminal 18-1 side to the normally open terminal 18-2 side.

  In the wireless communication apparatus 10 having such a configuration, the control signal S3 is normally in an off state, and the contact of the reception changeover switch 18 is on the side of the normally closed terminal 18-1. Thereby, the second antenna selection switch 17 is disconnected from the radio unit 15.

  In this state, when the host device 30 issues an instruction to start reading the wireless tag, the control unit 11 outputs digital data for inquiry to the wireless tag to the transmission unit 42. In addition, a control signal S1 for sequentially switching the first antenna selection switch 16 is output. As a result, the digital data is modulated, and the high-frequency signal added to the modulated signal is amplified and output to the circulator 43. The high-frequency signal output to the circulator 43 is sequentially output to each antenna 1, 2, 3, 4 by the switching operation of the first antenna selection switch 16, and is time-sequentially transmitted from each antenna 1, 2, 3, 4. Radiated as radio waves.

  Here, when the radio tag receives radio waves radiated from one of the antennas, backscatter modulation is performed on the radio tag to change the reflection amount of the high-frequency signal with information stored in the IC chip. As a result, the radio waves subjected to backscatter modulation are received by the antennas 1, 2, 3 and 4. However, since any one of the antennas is connected to the circulator 43 by the first antenna selection switch 16, the high-frequency signal of the backscatter modulated wave received by the antenna is input to the circulator 43. Thus, the high-frequency signal input to the circulator 43 is output to the receiving unit 44 via the reception changeover switch 18. In the receiving unit 44, after the input high frequency signal is amplified, the amplified high frequency signal and the high frequency signal of the PLL circuit 41 are combined and converted into a baseband signal, and the baseband signal is demodulated and wirelessly transmitted. It is output to the control unit 11 as tag information. The wireless tag information input to the control unit 11 is transmitted to the host device 30 via the communication unit 13 and processed.

  Now, the wireless communication device 10 having such a configuration has an antenna diagnosis function for diagnosing whether or not each of the antennas 1, 2, 3, and 4 is operating normally. And in order to implement | achieve this function, the reception level setting table 50 of the data structure shown in FIG.

  In FIG. 3, data ANT1 represents the first antenna 1 of the gated antenna 5, data ANT2 represents the second antenna 2, data ANT3 represents the third antenna 3, and data ANT4 represents the fourth antenna 4. Is shown. In other words, the reception level setting table 50 shows that each antenna 1, 2, 3, 4 of the gated antenna 5 has a predetermined intensity radiated from each antenna 1, 2, 3, 4 when it is normal. The standard value of the reception level when the diagnostic radio wave is received by another antenna is preset and stored in the degree of attenuation (in decibels) with respect to the diagnostic radio wave intensity.

  Further, in order to realize the above-described antenna diagnosis function, the radio communication apparatus 10 having such a configuration is used for diagnosis of a predetermined strength from each antenna 1, 2, 3, and 4 as shown in FIG. A reception level actual measurement table 60 that records reception levels of other antennas when radio waves are radiated is stored in the storage unit 12.

  Thus, when the execution of the failure diagnosis mode is instructed from the host device 30, the control unit 11 is configured to perform the processing of the procedure shown in the flowchart of FIG. 5. First, the control unit 11 turns on the control signal S3 as ST (step) 1. Thereby, the reception changeover switch 18 is switched to the normally open terminal 18-2 side.

  Next, the control unit 11 initializes the transmission antenna selection counter A to “1” as ST2. In ST3, the reception antenna selection counter B is initialized to “1”. Each of the counters A and B is formed in a memory or storage unit 12 in the control unit.

  Next, the control unit 11 compares the transmission antenna selection counter A and the reception antenna selection counter B in ST4 and determines whether or not they match. In this case, since they match, the control unit 11 increments the reception antenna selection counter B by “1” as ST5. Then, in ST6, it is determined whether or not the reception antenna selection counter B has exceeded the number n of antennas of the gate type antenna 5 (4 in the present embodiment).

  When not exceeding, the control part 11 selects the antenna corresponding to the count value of the transmission antenna selection counter A from the gate-type antenna 5 as ST7 as ST7. Here, in this embodiment, when the transmission antenna selection counter A is “1”, the antenna 1 (ANT1) is selected, when it is “2”, the antenna 2 (ANT2) is selected, and when it is “3”, the antenna 3 is selected. (ANT3) is selected, and when "4", antenna 4 (ANT4) is selected. And the control part 11 outputs control signal S1 so that the antenna selected as a transmission antenna may be connected with the circulator 43 (transmission antenna selection means).

  Further, the control unit 11 selects, as ST8, an antenna corresponding to the count value of the reception antenna selection counter B from the gated antenna 5 as a reception antenna. Here, in this embodiment, when the reception antenna selection counter B is “1”, the antenna 1 (ANT1) is selected, when it is “2”, the antenna 2 (ANT2) is selected, and when it is “3”, the antenna 3 is selected. (ANT3) is selected, and when "4", antenna 4 (ANT4) is selected. Then, the control unit 11 outputs a control signal S2 so that the antenna selected as the receiving antenna is connected to the receiving unit 44 via the reception changeover switch S3 (receiving antenna selection means).

  Thereafter, the control unit 11 supplies digital data to the transmission unit 42 and the PLL circuit 41 so that a diagnostic radio wave having a predetermined intensity is radiated from the antenna in ST9. As a result, a high-frequency signal corresponding to the diagnostic radio wave is generated by the action of the transmitter 42 and the PLL circuit 41. The high-frequency signal is output to the antenna selected as the transmitting antenna by the first antenna selection switch 16 via the circulator 43, and a diagnostic radio wave having a predetermined intensity is radiated from the antenna (diagnostic radio wave radiating means). ).

  Thus, the diagnostic radio waves radiated from the transmitting antenna are received by the antennas 1, 2, 3, and 4, respectively. However, the high-frequency signal corresponding to the radio wave received by the transmitting antenna is not input to the receiving unit 44 because the reception selector switch 18 is switched to the normally open side. The high-frequency signal input to the receiving unit corresponds to the radio wave received by any one antenna selected as the receiving antenna by the second antenna selection switch 17. The high frequency signal input to the receiving unit is demodulated and output to the control unit 11.

  Therefore, after transmitting diagnostic radio waves from the transmitting antenna, the control unit 11 waits for reception of diagnostic radio waves at the receiving antenna as ST10. If received, ST11 measures the reception level based on the high-frequency signal data demodulated by the receiving unit 44 based on the analog signal from the RSSI circuit 45 in the degree of attenuation (in decibels) with respect to the strength of the diagnostic radio wave. (Reception level measurement means), and records this measurement value in the reception level area corresponding to the transmission antenna and reception antenna of the reception level actual measurement table 60.

  Next, the control unit 11 increments the reception antenna selection counter B by “1” in ST13. Then, in ST14, it is determined whether or not the reception antenna selection counter B exceeds the number of antennas n of the gate type antenna 5. If not, the transmission antenna selection counter A and the reception antenna selection counter B are compared in ST15 to determine whether or not they match. If they match, the process returns to ST13 and the reception antenna selection counter B is further incremented by “1”.

  When the transmission antenna selection counter A and the reception antenna selection counter B do not match in ST15, the control unit 11 returns to ST7 and executes the processes after ST7 again.

  On the other hand, when the reception antenna selection counter B exceeds the number of antennas n of the gated antenna 5 in ST6 or ST14, the control unit 11 counts up the transmission antenna selection counter A by “1” as ST17. Then, in ST18, it is determined whether or not the transmission antenna selection counter A exceeds the number of antennas n of the gate type antenna 5. If not, the process returns to ST3, the reception antenna selection counter B is returned to "1", and the transmission antenna selection counter A and the reception antenna selection counter B are compared to determine whether or not they match as ST4. To do. If they do not match, the process proceeds to ST7.

  When the transmission antenna selection counter A exceeds the number of antennas n of the gated antenna 5 in ST18, the control unit 11 is based on the data of the reception level setting table 50 and the data of the reception level actual measurement table 60 as ST19. The failure diagnosis of each antenna 1, 2, 3, 4 is performed. Specifically, the reference value set in the reception level setting table 50 is compared with the value of the reception level recorded in the reception level actual measurement table 60. If all the reception levels when the radio waves transmitted from one transmission antenna are received by all other reception antennas are below the reference value, the transmission antenna is diagnosed as having an abnormality. Alternatively, if there is a receiving antenna whose receiving level is lower than the reference value when receiving the diagnostic radio wave transmitted from each transmitting antenna, this receiving antenna is diagnosed as having an abnormality (antenna diagnosis means ).

  When the failure diagnosis is completed, the control unit 11 causes the display unit 14 to display the diagnosis result as ST20. Thereafter, the control signal S3 is turned off as ST21. As a result, the reception changeover switch 18 is switched to the normally closed terminal 18-1 side, and thus this processing is terminated.

  As described above, in the wireless communication apparatus 10 according to the present embodiment, when the execution of the failure diagnosis mode is instructed from the host device 30, first, the reception changeover switch 18 is switched from the normally closed terminal 18-1 side to the normally open terminal 18-. Switch to 2 side. Next, both the transmission antenna selection counter A and the reception antenna selection counter B are initialized to “1”. In this case, since the transmission antenna selection counter A and the reception antenna selection counter B are equal, the reception antenna selection counter B is counted up. Therefore, the first antenna 1 (ANT1) is selected as the transmitting antenna, and the second antenna 2 (ANT2) is selected as the receiving antenna. A diagnostic radio wave having a predetermined intensity is radiated from the first antenna 1. Then, a high frequency signal corresponding to the diagnostic radio wave received by the second antenna 2 is input to the control unit 11 via the receiving unit 44. Thus, the reception level at the second antenna 2 is measured and recorded in the (ANT1, ANT2) area of the reception level actual measurement table 60.

  Next, the reception antenna selection counter B is counted up. Therefore, the third antenna 3 (ANT3) is selected as the receiving antenna. A diagnostic radio wave having a predetermined intensity is radiated from the first antenna 1. Thus, the reception level at the third antenna 3 is measured and recorded in the (ANT1, ANT3) area of the reception level actual measurement table 60.

  Next, only the reception antenna selection counter B is counted up. Therefore, the fourth antenna 4 (ANT4) is selected as the receiving antenna. A diagnostic radio wave having a predetermined intensity is radiated from the first antenna 1. As a result, the reception level at the fourth antenna 4 is measured and recorded in the (ANT1, ANT4) area of the reception level actual measurement table 60.

  Next, the reception antenna selection counter B is counted up. However, since the number of antennas exceeds n, the transmission antenna selection counter A is counted up and the reception antenna selection counter B returns to “1”. Therefore, the second antenna 2 (ANT2) is selected as the transmitting antenna, and the first antenna 1 (ANT1) is selected as the receiving antenna. Then, a diagnostic radio wave having a predetermined intensity is radiated from the second antenna 2. Then, a high frequency signal corresponding to the diagnostic radio wave received by the first antenna 1 is input to the control unit 11 via the receiving unit 44. Thus, the reception level at the first antenna 1 is measured and recorded in the (ANT2, ANT1) area of the reception level actual measurement table 60.

  Next, the reception antenna selection counter B is counted up. At this time, since the reception antenna selection counter B becomes equal to the transmission antenna selection counter A, the reception antenna selection counter B is further counted up. Therefore, the third antenna 3 (ANT3) is selected as the receiving antenna. Then, a diagnostic radio wave having a predetermined intensity is radiated from the second antenna 2. Thus, the reception level at the third antenna 3 is measured and recorded in the (ANT2, ANT3) area of the reception level actual measurement table 60.

  Next, only the reception antenna selection counter B is counted up. Therefore, the fourth antenna 4 (ANT4) is selected as the receiving antenna. Then, a diagnostic radio wave having a predetermined intensity is radiated from the second antenna 2. Thus, the reception level at the fourth antenna 4 is measured and recorded in the (ANT2, ANT4) area of the reception level actual measurement table 60.

  Next, the reception antenna selection counter B is counted up. However, since the number of antennas exceeds n, the transmission antenna selection counter A is counted up and the reception antenna selection counter B returns to “1”. Therefore, the third antenna 3 (ANT3) is selected as the transmitting antenna, and the first antenna 1 (ANT1) is selected as the receiving antenna. A diagnostic radio wave having a predetermined intensity is radiated from the third antenna 3. Then, a high frequency signal corresponding to the diagnostic radio wave received by the first antenna 1 is input to the control unit 11 via the receiving unit 44. Thus, the reception level at the first antenna 1 is measured and recorded in the (ANT3, ANT1) area of the reception level actual measurement table 60.

  Thereafter, when the third antenna 3 is selected as the transmitting antenna in the same manner, the second antenna 2 and the fourth antenna 4 are sequentially selected as the receiving antennas, and the reception level is the reception level actual measurement table 60. Are recorded in the (ANT3, ANT2) area and (ANT3, ANT4) area.

  Next, the fourth antenna 4 is selected as a transmitting antenna, and the first to third antennas 1, 2, and 3 are sequentially selected as receiving antennas. The reception level is recorded in the (ANT4, ANT1) area, (ANT4, ANT2) area, and (ANT4, ANT3) area of the reception level actual measurement table 60.

  Now, when the reference value is set in the reception level setting table 50 as shown in FIG. 3, as a result of executing the failure diagnosis mode, the reception level is recorded in the decibel unit in the reception level actual measurement table 60 as shown in FIG. Suppose. In this case, since the reception levels when the radio waves transmitted from the transmission antenna ANT2 are received by all other reception antennas ANT1, ANT3, and ANT4 are all below the reference value, the transmission antenna ANT2, that is, the first 2 antenna 2 is diagnosed as being abnormal.

  Alternatively, the reception antenna ANT2 has a reception level that is lower than the reference value when each of the other antennas ANT1, ANT3, and ANT4 is selected as a transmission antenna. Therefore, the reception antenna ANT2, that is, the second antenna 2 is diagnosed as abnormal.

  Thus, according to the present embodiment, it is possible to automatically diagnose in a short time whether or not each of the plurality of antennas 1, 2, 3, 4 constituting the gated antenna 5 is operating normally. .

  The present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage.

  For example, in the above-described embodiment, the case of diagnosing a plurality of antennas constituting a gate type antenna has been shown. However, the present invention is not limited to the diagnosis technique of a plurality of antennas arranged to face each other like a gate type antenna, for example, on one plane. The present invention can also be applied to a wireless communication device that includes a plurality of antennas arranged in series or in parallel and reads data of a wireless tag by sequentially switching the antennas.

  Also, the number of antennas is not limited to four, and if it is three or more, it is possible to easily diagnose which antenna has failed by the present invention. In addition, even when there are two antennas, when there is an abnormality in one or both, according to the present invention, it is possible to easily determine whether there is an abnormality.

  In the above embodiment, the control unit 11 of the wireless communication apparatus 10 diagnoses the failure of each of the antennas 1, 2, 3, and 4. However, the host device 30 has the data of the reception level setting table 50, and FIG. 6, when the transmission antenna selection counter A exceeds the number of antennas n in the process of ST18, the host device performs failure diagnosis by transferring the data of the reception level actual measurement table 60 to the host device 30. The result may be output to the output device of the host device.

  Further, the data of the reception level setting table 50 and the data of the reception level actual measurement table 60 may be output from the display unit 14 or the output device of the host device 30, and the operator may determine whether there is an abnormality by looking at the output result. Even in this case, it is possible to easily diagnose whether or not each antenna has a failure.

  In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements over different embodiments may be combined.

1 is an overall configuration diagram of an RFID system according to an embodiment of the present invention. The block diagram which shows the principal part structure of the radio | wireless communication apparatus in the embodiment. The schematic diagram which shows the data structure of the reception level setting table used in the embodiment. The schematic diagram which shows the data structure of the reception level actual measurement table used in the embodiment. 6 is a flowchart showing a main procedure of failure diagnosis mode processing executed by the control unit of the wireless communication apparatus in the embodiment. The schematic diagram which shows the example of 1 data of a reception level actual measurement table. The perspective view which shows an example of a gate type antenna.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1-4 ... Antenna, 5 ... Gate type antenna, 10 ... Wireless communication apparatus, 11 ... Control part, 12 ... Memory | storage part, 13 ... Communication part, 14 ... Display part, 15 ... Wireless part, 16 ... 1st antenna selection Switch, 17 second antenna selection switch, 18 reception switch, 30 host device, 50 reception level setting table, 60 reception level actual measurement table.

Claims (4)

A transmitter that outputs a high-frequency signal, a plurality of antennas that radiate the high-frequency signal output from the transmitter as radio waves, convert the received radio wave to a high-frequency signal, and output the high-frequency signal; In a wireless communication device comprising a receiving unit for inputting and processing,
A transmitting antenna selecting means for selecting any one of the antennas as a transmitting antenna;
A receiving antenna selecting means for selecting an antenna other than the antenna selected by the transmitting antenna selecting means as a receiving antenna;
Diagnostic radio wave radiation means for radiating diagnostic radio waves of a predetermined intensity from the antenna selected as the transmitting antenna;
A reception level measuring means for measuring the diagnostic radio wave reception level of the antenna selected as the reception antenna;
A wireless communication apparatus comprising: Antenna diagnosis means for diagnosing a failure of each antenna based on the diagnostic radio wave reception level measured by the reception level measurement means;
The wireless communication apparatus according to claim 1, further comprising: In the case where there are three or more antennas,
The antenna diagnosis means diagnoses a failure of the antenna selected as the transmitting antenna when all diagnostic radio wave reception levels of the plurality of antennas selected as the receiving antenna are lower than a set value. The wireless communication apparatus according to claim 2. In the case where there are three or more antennas,
The antenna diagnostic means has a diagnostic radio wave reception level as a set value when there is an antenna whose diagnostic radio wave reception level is not less than a set value and an antenna that is less than a set value among a plurality of antennas selected as the reception antenna. 3. The wireless communication apparatus according to claim 2, wherein an antenna that does not satisfy the condition is diagnosed as a failure.

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