JP5932389B2 - Communication terminal - Google Patents

Description

  The present invention relates to a communication terminal, and more particularly to a communication terminal having a charging circuit.

An example of a communication terminal having a charging circuit is disclosed in Patent Document 1. The charging system disclosed in Patent Document 1 is used in, for example, a mobile phone. In the charging system, a power supply voltage supplied from the power supply device is transformed into a charging voltage by a charging circuit. When this charging voltage is output from the charging circuit to the secondary battery, the secondary battery is charged.
JP 2007-336664 A [H02J 7/04, H02J 7/10, H01M 10/44]

  When a secondary battery is charged by a mobile phone having a charging circuit of the background art, the power supply device is connected to a charging terminal provided outside the mobile phone. The charging terminal is connected to the charging circuit by a wiring or a leaf spring provided inside the mobile phone. That is, the power supply device is connected to the charging circuit from the charging terminal through a power supply line including wiring, a leaf spring, and the like. Note that the power supply line may include only wiring and no leaf spring, or a contact other than the leaf spring may be used.

  However, due to the arrangement of the charging terminal, the power line, and the base station communication antenna, the resonance frequency of the power line from the charging terminal to the charging circuit interferes with the resonance frequency band of the base station communication antenna, and the other antennas There is a possibility that a problem of deteriorating communication performance may occur.

  To solve this problem, if the position of the charging terminal and the shape of the wiring can be changed and the distance from the base station communication antenna can be physically spoken and arranged, such a problem can be solved. However, such a measure is not a realistic solution in a mobile phone in which parts are densely packed in a compact casing.

  Therefore, a main object of the present invention is to provide a novel communication terminal.

  Another object of the present invention is to provide a communication terminal capable of reducing the interference that the power supply line from the charging terminal to the charging circuit gives to the antenna.

  The present invention employs the following configuration in order to solve the above problems. The reference numerals in parentheses, supplementary explanations, and the like indicate the corresponding relationship with the embodiments described in order to help understanding of the present invention, and do not limit the present invention.

A first invention is a charging circuit in which a charging terminal is connected through a wiring part including a wiring part on the HOT side and a wiring part on the GND side, an antenna for receiving radio waves in a predetermined frequency band, and a wiring part on the HOT side Including a first inductor connected between the charging circuit and the charging circuit, a second inductor connected between the GND-side wiring section and the charging circuit, and a capacitor connected to the second inductor. And a mitigation unit that reduces the interference given to a predetermined frequency band of the antenna by moving the resonance frequency of the unit to the high frequency side.

In the first invention, the communication terminal (10: reference numeral exemplifying a corresponding part in the embodiment, hereinafter the same) has a charging circuit (48) for charging the secondary battery (50). The communication terminal also has an antenna (34) that receives radio waves in a predetermined frequency band, and can make a call. The charging terminal (22a, 22b) connected to the power supply device is connected to the charging circuit through a wiring portion including a wiring portion (62a, 64b) on the HOT side and a wiring portion (62b, 64b) on the GND side . . In addition, the charging terminal and the wiring portion interfere with a part of the predetermined frequency band of the antenna, and deteriorate the communication performance of the antenna. Therefore, the mitigation unit (BF1, BF2, C1) mitigates this interference by moving the resonance frequency of the charging terminal and the wiring unit to the high frequency side. The first inductor (BF1) of the mitigation part is connected between the wiring part on the HOT side and the charging circuit, and the second inductor (BF2) is connected between the wiring part on the GND side and the charging circuit. (C1) is connected to the second inductor, whereby the resonance frequency of the charging terminal and the wiring portion moves to the high frequency side.

  According to the first invention, it is possible to reduce the deterioration of the communication performance of the antenna that occurs in a part of the predetermined frequency band of the antenna.

  A second invention is according to the first invention, and the mitigation unit includes an inductor (BF1, BF2) connected between the wiring unit and the charging circuit and a capacitor (C1) connected to the inductor.

  According to the second invention, it is possible to reduce the deterioration of the antenna communication performance that occurs in a part of the predetermined frequency band of the antenna with a simple circuit combining the inductor and the capacitor.

  A second invention is dependent on the first invention, and the capacitor is connected in parallel with the second inductor.

A third invention includes a charging circuit in which a charging terminal is connected through a wiring portion, and an antenna that receives radio waves in a predetermined frequency band. The antenna receives radio waves in a first frequency band and a second frequency band, The wiring part is included in each of the HOT side and GND side power lines including the charging terminal, and the charging circuit is connected to the charging terminal of each power line through the wiring part included in the HOT side line and the GND side power line. The interference of the secondary battery connected to the charging circuit in the power line on the HOT side and the resonance frequency of the charging terminal and the wiring portion is shifted to the high frequency side, thereby reducing interference of the antenna with the predetermined frequency. further comprising a reducing unit, reduction unit includes a first inductor provided on the power supply line of the HOT side, one end is provided between the first inductor and the secondary battery is first inductor Is connected to the motor, the other end a first capacitor connected to GND, by including a second inductor provided on the power supply line of the GND side, and a second capacitor provided in parallel with the second inductor, co the vibration frequency Before moving to the high frequency side, which is a communication terminal.

A fourth invention is according to any one of the first to third inventions, further comprising a housing and a mounting plate included in the housing, wherein the antenna is attached to the main surface of the mounting plate. The charging terminal is attached so as to be exposed to the outside of the housing, and the wiring portion is connected to the charging terminal through the inside of the attachment plate and attached in a state close to the antenna on the other surface of the attachment plate.

  According to this invention, the interference which the wiring part from a charging terminal to a charging circuit gives to an antenna can be reduced.

  The above object, other objects, features, and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

FIG. 1 is an external view showing a mobile phone according to an embodiment of the present invention. FIG. 2 is an illustrative view showing an electrical configuration of the mobile phone shown in FIG. FIG. 3 is an illustrative view showing one example of a circuit configuration around the charging terminal and the charging circuit shown in FIG. 2. FIG. 4 is an illustrative view showing an example of the relationship between the charging terminals, wirings, and circuit board mounting positions shown in FIG. FIG. 5 shows an example of an experimental result obtained by examining a change in communication performance (antenna efficiency) when the countermeasure applied to the power supply line from the charging terminal to the charging circuit is changed in the antenna for base station communication shown in FIG. FIG. 5A shows an example of antenna efficiency in a plurality of countermeasures, and FIG. 5B shows an example of a difference table showing the effect of each countermeasure. FIG. 6 is an illustrative view of a graph showing the experimental results of examining the frequency characteristics of the base station communication antenna when the present embodiment is not applied (FIG. 5: unmeasured). FIG. 7 is an illustrative view of a graph showing an experimental result of examining the frequency characteristics of the base station communication antenna when this embodiment is applied (FIG. 5: measure 3).

  Referring to FIGS. 1A and 1B, a mobile phone 10 according to an embodiment of the present invention is a feature phone as an example, and includes a vertically long flat rectangular casing 12. However, it should be pointed out in advance that the present invention is applicable to any communication terminal such as a so-called smart phone, tablet terminal, and PDA.

  One main surface (front surface) of the housing 12 is provided with a display 14 such as a liquid crystal or an organic EL that functions as a display unit. Further, a hard key 16 including a menu key, a direction input key, a confirmation key, a numeric keypad, a call key, a call end key, and the like is provided on one main surface of the housing 12. Therefore, in the mobile phone 10 of this embodiment, most input operations are performed via the hard keys 16. A speaker 18 is built in the front surface of one end of the casing 12 in the vertical direction, and a microphone 20 is built in the front surface of the other end in the vertical direction. In addition, a charging terminal 22a and a charging terminal 22b for connecting a power supply device are provided on one other surface (back surface) of the housing 12.

  For example, the user can input a telephone number by performing a key operation on the numeric keypad, and can start a voice call by operating the call key. If the end key is operated, the voice call can be terminated. Note that the user can turn on / off the power of the mobile phone 10 by pressing and holding the end call key.

  When the menu key is operated, a menu screen is displayed on the display 14. The user selects a soft key or a menu icon (both not shown) displayed on the display 14 in that state by a cursor that can be operated by a direction input key, and confirms the selection by operating a confirmation key. It can be made.

  In addition, charging is started when the mobile phone 10 is installed in a charging cradle. The charging cradle is provided with two connectors connected to the power supply device. When the two connectors of the cradle and the two charging terminals 22 of the mobile phone 10 come into contact with each other, power is supplied from the power supply device to the mobile phone 10.

  Although not shown in FIGS. 1A and 1B, a USB connector is provided on the upper side surface of the mobile phone 10. When a USB cable is connected to the USB connector, data communication can be performed with an external terminal. When the USB cable is connected to a power source, power is supplied to the mobile phone 10 from the power source.

  Referring to FIG. 2, the mobile phone 10 of the embodiment shown in FIG. 1 includes a processor 30 called a computer or CPU. The processor 30 is connected to a wireless communication circuit 32, an A / D converter 36, a D / A converter 38, an input device 40, a display driver 42, a flash memory 44, a RAM 46, a charging circuit 48, and the like.

  The processor 30 controls the entire mobile phone 10. All or part of the program preset in the flash memory 44 is expanded in the RAM 46 when used, and the processor 30 operates according to the program on the RAM 46. The RAM 46 is further used as a working area or a buffer area for the processor 30.

  The input device 40 includes the hard key 16 shown in FIG. 1 and constitutes an operation unit or an input unit. Information on the keys operated by the user (key data) is input to the processor 30.

  The wireless communication circuit 32 is a circuit for transmitting and receiving radio waves for voice calls and mails through the base station communication antenna 34. In the embodiment, the wireless communication circuit 32 is a circuit for performing wireless communication by the CDMA method. For example, when the user operates the hard key 16 to instruct a telephone call (calling), the radio communication circuit 32 executes a telephone call process under the instruction of the processor 30 and via the base station communication antenna 34. Outputs a telephone call signal. The telephone call signal is transmitted to the other party's telephone through the base station and the communication network. When an incoming call process is performed at the other party's telephone, a communicable state is established, and the processor 30 executes a call process.

  The normal call processing will be specifically described. The modulated voice signal transmitted from the other party's telephone is received by the base station communication antenna 34. The received modulated audio signal is demodulated and decoded by the wireless communication circuit 32. The received voice signal obtained by these processes is converted to a voice signal by the D / A converter 38 and then output from the speaker 18. On the other hand, the transmission voice signal captured through the microphone 20 is converted into voice data by the A / D converter 36 and then given to the processor 30. The audio data is subjected to encoding processing and modulation processing by the wireless communication circuit 32 under the instruction of the processor 30 and is output via the base station communication antenna 34. Therefore, the modulated voice signal is transmitted to the other party's telephone through the base station and the communication network.

  When a telephone call signal from the other party's telephone is received by the base station communication antenna 34, the radio communication circuit 32 notifies the processor 30 of an incoming call (incoming call). In response to this, the processor 30 controls the display driver 42 to display caller information (such as a telephone number) described in the incoming call notification on the display 14. In addition, the processor 30 causes the speaker 18 to output a ring tone (sometimes called a ringing melody or a ringing voice) from the speaker 18.

  When the user performs a response operation using the call key included in the input device 40, the wireless communication circuit 32 executes the incoming call process under the instruction of the processor 30. Further, a communicable state is established, and the processor 30 executes the above-described call processing.

  In addition, when a call end operation is performed by the end key included in the input device 40 after the transition to the call ready state, the processor 30 controls the wireless communication circuit 32 to transmit a call end signal to the other party. Then, after transmitting the call end signal, the processor 30 ends the call process. The processor 30 also ends the call process when a call end signal is received from the other party first. Furthermore, the processor 30 also ends the call process when a call end signal is received from the mobile communication network regardless of the call partner.

  The wireless communication circuit 32 according to the present embodiment can process a signal in the first frequency band from 816 MHz to 894 MHz and a signal in the second frequency band from 1851 MHz to 1988 MHz. The base station communication antenna 34 can transmit and receive radio waves in the first frequency band and the second frequency band, respectively.

  The microphone 20 shown in FIG. 1 is connected to the A / D converter 36, and the audio signal from the microphone 20 is connected to the digital audio data by the A / D converter 36 and input to the processor 30 as described above. The The speaker 18 is connected to the D / A converter 38. The D / A converter 38 converts digital audio data into an audio signal and supplies the audio signal to the speaker 18 through an amplifier. Therefore, the sound data is output from the speaker 18.

  The processor 30 adjusts the volume of the sound output from the speaker 18 by controlling the amplification factor of the amplifier connected to the D / A converter 38, for example, in response to the volume operation by the user. I can do it.

  The display driver 42 is connected to the display 14 and the processor 30 and stores image data output from the processor 30 in the VRAM. Then, the display driver 42 displays an image corresponding to the VRAM data on the display 14. That is, the display driver 42 controls display on the display 14 connected to the display driver 42 under the instruction of the processor 30. The display 14 is provided with a backlight using, for example, an LED as a light source, and the display driver 42 controls the brightness of the backlight and lighting / extinguishing according to an instruction from the processor 30.

  The charging circuit 48 is a power management IC that functions as a charging unit, and is connected to a secondary battery 50 that is a lithium ion battery, a charging terminal 22a, a charging terminal 22b, and the like. Further, the charging circuit 48 measures the remaining battery level of the secondary battery 50 and outputs it to the processor 30. Further, the charging circuit 48 supplies power based on the voltage of the secondary battery 50 to the entire system. Here, when the charging circuit 48 supplies power to the entire system, it is referred to as a power-on state. On the other hand, when the charging circuit 48 is not supplying power to the entire system, it is referred to as a power-off state. However, since it is necessary to receive key data from the input device 40 even when the power is off, the processor 30 is always supplied with power. The charging circuit 48 is activated when a power-on operation is performed by the input device 40 in the power-off state, and is stopped when a power-off operation is performed by the input device 40 in the power-on state. Further, even when the power is off, the charging circuit 48 is activated when the power supply device is connected to the charging terminals 22 a and 22 b and power is supplied (charged) to the secondary battery 50. It stops when the state of charge is detected.

  When the power supply is an AC power supply, a DC power converted by an AC-DC adapter or the like is connected to the charging terminal 22a and the charging terminal 22b.

  Here, “charging” refers to storing electric energy in the secondary battery 50 by receiving power from the power supply device via the charging terminal 22 a and the charging terminal 22 b. Then, the processor 30 detects the fully charged state based on the voltage value measured by the charging circuit 48.

  FIG. 3 is a circuit diagram showing a peripheral circuit configuration of each of the charging terminals 22a and 22b and the charging circuit 48. Referring to FIG. 3, a charging terminal 22a on the HOT side and a charging terminal 22b on the GND side are provided on one side of the housing 12, that is, the front side. Further, on the back side of the housing 12, wiring 62 a and wiring 62 b for connecting the charging terminal 22 a and the charging terminal 22 b to the circuit board 60 are provided.

  In the circuit board 60, a leaf spring 64a and a bead filter BF1 are provided on the HOT side. In addition, a detection circuit 66, a state notification circuit 68, a capacitor C2, and the like are connected between the bead filter BF1 and the secondary battery 50. On the other hand, a leaf spring 64b and a bead filter BF2 are provided on the GND side. Further, a capacitor C1 is connected in parallel with the bead filter BF2 at a contact point between the bead filter BF2 and the leaf spring 64b.

  Note that the detection circuit 66 and the state notification circuit 68 are included in the charging circuit 48. On the HOT side, the path from the charging terminal 22a to the secondary battery 50 may be referred to as a “HOT-side power line”. Further, on the GND side, the path from the charging terminal 22b to the GND may be referred to as “GND-side power line”. The wiring 62 and the leaf spring 64 on the HOT side and the GND side may be referred to as wiring portions.

  In the power line on the HOT side, the leaf spring 64a contacts the wiring 62a. Further, a bead filter BF1 is provided between the wiring portion on the HOT side and the detection circuit 66 (charging circuit 48). On the other hand, in the power line on the GND side, the leaf spring 64b is in contact with the wiring 62b. Further, a bead filter BF2 is provided between the GND-side wiring portion and GND.

The bead filter BF1 may be called a first inductor, and the bead filter BF2 may be called a second inductor. The capacitor C1 may be called a second capacitor, and the capacitor C2 may be called a first capacitor.

  Further, since the bead filters BF1 and BF2 have a rated current value larger than that of a normal coil, they can be provided on a power supply line through which a large current (for example, 1A) flows.

  First, in the power line on the HOT side, the capacitor C2 is grounded to GND. Thereby, the noise flowing through the power line on the HOT side falls to GND.

  The detection circuit 66 is a circuit for detecting that the power supply device is connected to the charging terminals 22a and 22b. The detection circuit 66 is a general-purpose IC, and includes a resistor R1, a resistor R2, and a transistor T. Therefore, the detection circuit 66 is provided with ports corresponding to B (base), C (collector), and E (emitter) of the transistor T. The B port of the detection circuit 66 is connected to the power line on the HOT side, the E port is connected to GND, and the C port is connected to the processor 30.

  The resistor R1 is provided between the ports of the transistors T and B. The resistor R2 is provided between the resistor R1 and the port of E. In the transistor T, C is connected to the C port, E is connected to the E port, and B is connected to the resistor R1 (B port).

  The C port of the detection circuit 66 is supplied with power from the processor 30 through the resistor R3. A processor 30 is connected to a contact between the resistor R3 and the port of C. That is, the voltage value input to the port C is input to the processor 30 as the detection signal.

  A voltage is applied to C of the transistor T. However, if no power supply device is connected, no voltage is applied to B of the transistor T, so that no current flows from C to E (GND) of the transistor T. When the power supply device is connected to the charging terminals 22a and 22b in this state, a voltage is applied to the power line on the HOT side. At this time, since a voltage is also applied to the port B of the detection circuit 66, a current flows from C to E of the transistor T. Then, since the voltage value between the port C and the resistor R3 varies, the state of the detection signal changes. Then, the processor 30 detects that the power supply device is connected to the charging terminals 22a and 22b based on the change in the state of the detection signal.

  The state detection circuit 68 is a circuit for notifying the state of charge by the power supply device. The state detection circuit 68 includes a first port connected to the GND, a second port connected to the power line on the HOT side, and a third port that outputs a state signal.

  When a voltage is applied to the power line on the HOT side, a current flows through the second port. At this time, since the state signal output from the third port changes, the state of charge by the power supply device is notified. Here, although not shown in FIG. 3, the circuit board 60 is provided with a circuit for notifying the state of charge by the USB connector. When the USB connector is connected to the power supply device via the USB cable, this circuit outputs a signal notifying the state.

  And if the charge state by a power supply device is notified, a power supply line will be switched so that the voltage of a power supply device may be applied with respect to the secondary battery 50. FIG. On the other hand, if the state of charge by the USB connector is notified, the power line is switched so that the voltage supplied from the USB cable is applied to the secondary battery 50.

  FIG. 4 is an illustrative view showing a relationship among mounting positions of the charging terminal 22 on the GND side, the circuit board 60, and the wiring 62. Since there is almost no difference in the relationship between the mounting positions on the HOT side and the GND side, alphabetic suffixes are omitted in FIG.

  Referring to FIG. 4, the housing 12 includes a mounting plate SB and a circuit board 60. The charging terminal 22 is attached to the main surface of the attachment plate SB so as to be exposed to the outside of the housing 12. A base station communication antenna 34 is also attached to the main surface of the attachment plate SB. On the other hand, wiring 62 is attached to the other surface of the attachment plate SB. Further, one end of the wiring 62 is connected to the charging terminal 22 through the inside of the attachment plate SB. The other end of the wiring 62 is in contact with a leaf spring 64 provided on the main surface of the circuit board 60.

  Here, as can be seen from FIG. 4, the wiring portion from the charging terminal 22 to the charging circuit 48 provided on the circuit board 60 and the base station communication antenna 34 are arranged close to each other. The circuit connected to the charging terminal 22 and the wiring portion includes a capacitor component and an inductor component, and resonates at a predetermined frequency. Since the predetermined frequency is included in the first frequency band, the charging terminal 22 and the wiring unit function as an antenna and receive a part of the radio waves in the first frequency band.

  At this time, if no countermeasure is taken, the resonance frequency of the power line from the charging terminal 22 to the leaf spring 64, that is, the charging terminal 22 and the wiring part, interferes with the resonance frequency band of the base station communication antenna 34. The communication performance deteriorates in part of the first frequency band (816 MHz to 894 MHz) of the base station communication antenna 34.

  For example, in the state where the base station communication antenna 34 and the power supply line are close to each other, when a first frequency band signal is received, the first frequency band signal is received. In this case, a signal received by the base station communication antenna 34 is input to the wireless communication circuit 32, but a signal received by the power supply line is not input to the wireless communication circuit 32. Therefore, the communication performance when receiving a signal in the first frequency band deteriorates.

  On the other hand, when a signal in the first frequency band is transmitted from the base station communication antenna 34, a part of the signal is absorbed (received) by the power supply line. Therefore, the communication performance when transmitting a signal in the first frequency band is degraded.

  Therefore, in this embodiment, the bead filters BF1 and BF2 and the capacitor C1 are provided on the HOT side and the GND side in order to reduce such deterioration in communication performance. Thereby, the frequency characteristic of the power supply line from the charging terminal 22 to the leaf | plate spring 64 can be changed. And if a frequency characteristic changes, the interference to the base station communication antenna 34 which adjoins the power source line from the charging terminal 22 to the leaf | plate spring 64 will reduce.

  The bead filter BF1 and the bead filter BF2 are the same component, and have an impedance of about 215 to 230Ω with respect to a signal in the first frequency band (816 MHz to 894 MHz). Therefore, the power supply line from the charging terminal 22 to the leaf spring 64 is electrically disconnected from the circuit board 60 in the first frequency band. For this reason, the antenna function of the charging terminal 22 and the wiring portion is reduced, and the frequency characteristic of the power supply line changes. Further, in the power line on the GND side, the frequency characteristic is further changed by adding a capacitor C1 (for example, 1.5 pF).

  Thereby, the deterioration of the communication performance that occurs in a part of the first frequency band of the base station communication antenna 34 is reduced. In particular, in this embodiment, a simple circuit combining the bead filter BF and the capacitor C can reduce deterioration in communication performance that occurs in a part of the first frequency band of the base station communication antenna 34. Therefore, the bead filter BF1, the second bead filter BF2, and the capacitor C1 may be referred to as a mitigation unit or an attenuation unit.

  FIG. 5A is a table showing experimental results of examining changes in communication performance (antenna efficiency) in the first frequency band and the second frequency band in a plurality of countermeasures, and FIG. 5B shows the effect of each countermeasure. It is a difference table shown.

  Referring to FIG. 5 (A), this table includes a row of “unmeasured” for which no measures are taken, a row of “measure 1” in which a bead filter BF2 is provided on the GND power line, the HOT side, and GND. The “Countermeasure 2” row in which the bead filter BF1 and the bead filter BF2 are provided on the power line on the side, the bead filter BF1 and the bead filter BF2 are provided in the HOT and GND power lines, and the capacitor C1 is provided in the GND power line. The line of “Countermeasure 3 (this embodiment)” is included.

  In the first frequency band, the antenna efficiency of “816 HMz”, “824 HMz”, “836 HMz”, “848 HMz”, “861 HMz”, “870 HMz”, “882 HMz” and “894 HMz” is recorded for each measure. . In the second frequency band, the antenna efficiencies of “1851 HMz”, “1880 HMz”, “1908 HMz”, “1930 HMz”, “1960 HMz”, and “1988 HMz” are recorded for each measure.

  Referring to FIG. 5B, in this table, the row of “difference 1” in which the difference between the antenna efficiency of “Countermeasure 1” and the antenna efficiency of “Unmeasured” is recorded, and the antenna of “Countermeasure 2” The “difference 2” row in which the difference between the efficiency and the “unmeasured” antenna efficiency is recorded, and the “difference 3” row in which the difference between the antenna efficiency of “measure 3” and the “unmeasured” antenna efficiency is recorded. Is included. Each column in FIG. 5B corresponds to the frequency in FIG.

  When the bead filter BF2 is provided on the GND side in “Countermeasure 1”, as can be seen from the row of “Difference 1” in this table, deterioration in antenna efficiency of the first frequency band of the base station communication antenna 34 can be suppressed. However, the antenna efficiency of the second frequency band deteriorates as a whole due to the influence of suppressing the deterioration of the antenna efficiency of the first frequency band of the base station communication antenna 34.

  Next, in the case of “Countermeasure 2”, when the bead filter BF1 is also provided in the power line on the HOT side, the deterioration of the antenna efficiency of the first frequency band of the base station communication antenna 34 is further suppressed, but the second frequency band Antenna efficiency is further degraded.

  Therefore, if the capacitor C1 is further provided in the power line on the GND side in “Countermeasure 3”, the deterioration of the antenna efficiency in the first frequency band is most suppressed, and the deterioration of the antenna efficiency in the second frequency band is also suppressed. In other words, with the circuit configuration shown in FIG. 3, it is possible to reduce the influence on the second frequency band while reducing the deterioration of the antenna efficiency in the first frequency band.

  FIG. 6 is a graph showing an experimental result of examining the frequency characteristics of the base station communication antenna 34 in a state where no countermeasure is taken, and FIG. 7 is a graph showing the frequency characteristics of the base station communication antenna 34 in a state where countermeasure 3 is taken. It is a graph which shows an experimental result. The graphs of FIGS. 6 and 7 show the VSWR (voltage standing wave ratio) of the base station communication antenna 34. In these graphs, the vertical axis indicates the value of VSWR, and the horizontal axis indicates the frequency (MHz).

  Further, Δ (marker) in these graphs is identified by “M” and a numerical suffix. M1 indicates 816 MHz, M2 indicates 894 MHz, M3 indicates 1851 MHz, and M4 indicates 1988 MHz.

  As can be seen from FIG. 6, it can be seen that the waveform around M1-M2 is wavy when it is not taken measures. There are two valleys between M2 and M3. On the other hand, as shown in FIG. 7, in the case of measure 3, the waveform of M1-M2 is not wavy and there is only one valley between M2-M3. It turns out that it has moved to the high frequency side rather than the case of 6. FIG.

  This is because the complicated resonance frequency that the charging terminal 22 and the wiring portion had interfered over a wide range of 800 MHz to 1500 MHz moved to a higher frequency side by implementing the measure 3. As a result, it can be seen that interference with the frequency band between M1 and M2 is reduced. In other words, this is an indication that the frequency characteristic of the base station communication antenna 34 has been changed by implementing measure 3.

  Note that only the wiring 62 may be provided in the power supply line. The power supply line may have no leaf spring, or a contact other than the leaf spring may be used.

  In the above-described embodiments, the base station communication antenna 34 is described as an example of an antenna that can reduce the deterioration in communication performance. However, in other embodiments, other antennas such as a GPS antenna and a TV antenna are used. It may be.

  In addition, the specific numerical values given in this specification are merely examples, and can be appropriately changed according to a change in product specifications.

DESCRIPTION OF SYMBOLS 10 ... Mobile phone 14 ... Display 22a, 22b ... Charging terminal 30 ... Processor 34 ... Base station communication antenna 40 ... Input device 44 ... Flash memory 46 ... RAM
48 ... Charging circuit 50 ... Secondary battery 62a, 62b ... Wiring 64a, 64b ... Leaf spring BF1, BF2 ... Bead filter C1, C2 ... Capacitor

Claims (4)

A charging circuit in which a charging terminal is connected through a wiring portion including a wiring portion on the HOT side and a wiring portion on the GND side ;
An antenna for receiving radio waves in a predetermined frequency band;
The first inductor connected between the wiring portion on the HOT side and the charging circuit, the second inductor connected between the wiring portion on the GND side and the charging circuit, and the second inductor. by including a capacitor, and a relief portion for said resonant frequency charging terminal and the wiring portion has moved to the high frequency side, to reduce the interference given to the predetermined frequency band of the previous SL antenna, communication terminal. The capacitor, the second being connected in parallel with the inductor, the communication terminal according to claim 1. A charging circuit in which a charging terminal is connected through a wiring portion;
An antenna for receiving radio waves of a predetermined frequency band,
The antenna receives radio waves in a first frequency band and a second frequency band,
The wiring portion is included in each of a power line on the HOT side and the GND side including the charging terminal,
The charging circuit is connected to a charging terminal of each power supply line through a wiring portion included in the HOT side line and the GND side power supply line,
A secondary battery connected to the charging circuit in the power line on the HOT side, and
Further comprising a mitigation unit that reduces interference given to the predetermined frequency of the antenna by moving a resonance frequency of the charging terminal and the wiring unit to a high frequency side ,
The mitigation unit is provided between a first inductor provided on the power line on the HOT side, the first inductor and the secondary battery, one end connected to the first inductor, and the other end to GND. a first capacitor connected, and a second inductor provided on the power supply line of the GND side, by including a second capacitor provided in parallel with the second inductor, the pre-Symbol co-oscillating frequency to the high frequency side Ru was moved, communications terminal. A housing,
A mounting plate included in the housing;
The antenna is attached to the main surface of the mounting plate,
The charging terminal is attached so as to be exposed to the outside of the housing,
The wiring portion, which is connected through the interior of the mounting plate and the charge terminal, and the attached in close proximity to the antenna in the other surface of the mounting plate, the communication terminal according to any one of claims 1 to 3.

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