JP2008199688A - Wireless module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve impedance characteristics and radiation characteristics, and to achieve broadbanding without causing enlargement of a terminal. <P>SOLUTION: On a circuit board 1, a conductor 6 is disposed along and in parallel with a side that generates a main radiation wave. The conductor 6 is formed L-shaped, its proximal end is electrically connected to a ground pattern 2 formed on a rear side of the circuit board 1, and its tip is made open. A position for connecting the conductor 6 to the ground pattern 2 is set to a position selected such that an effective electric length from a power feeding point BP toward an antenna 5 to the tip of the conductor is a half wavelength of a radio-frequency signal. Moreover, the full length of the conductor 6 is set to a quarter wavelength radio-frequency signal to be transmitted/received. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio module including an antenna, and more particularly to a radio module provided in a radio communication terminal used in contact with or close to a human body such as a mobile phone, a PDA (Personal Digital Assistants), a cordless phone, and a transceiver. About.

  In recent years, in mobile communication terminals typified by mobile phones, built-in antennas in which an antenna is housed in a housing have become mainstream. However, in the built-in antenna, since the antenna is close to the ground pattern of the circuit board accommodated in the housing, the impedance is lowered and the band is narrowed. In the case of a monopole antenna, there is a problem that the radiation pattern is disturbed according to the size of the ground pattern of the circuit board.

On the other hand, as a configuration for improving the radiation pattern of the antenna, for example, an L-shaped elongated plate having one end connected to this surface is provided on the ground surface of the circuit board, and this plate reduces the current flowing through the ground pattern of the circuit board. Therefore, a configuration for reducing the deterioration of directivity has been proposed (see, for example, Patent Document 1).
JP 2000-40910 A

  However, as is apparent from FIGS. 1 to 4 of this publication, this conventionally proposed configuration has an L-shaped plate placed on the surface of the circuit board close to the user's head. For this reason, since the L-shaped plate approaches the user's head, it is easily affected by the human body, and the effect of improving the antenna radiation characteristics is low. In addition, since the keypad and various circuit components are mounted with high density on the surface of the circuit board facing the user, if an L-shaped plate is installed on the same surface, the circuit board cannot be enlarged. This leads to an increase in the size and cost of the terminal, which is very undesirable.

  The present invention has been made paying attention to the above circumstances, and an object of the present invention is to provide a wireless module capable of improving impedance characteristics and radiation characteristics and widening the bandwidth without increasing the size of the terminal. is there.

  In order to achieve the above object, one aspect of the present invention includes a first surface that faces a human body during a call, a second surface that is a back surface side with respect to the first surface, and a first side And a second side orthogonal to the first side, wherein the first wireless circuit includes a circuit board on which a ground pattern is formed and the first wireless circuit is mounted. And a first antenna disposed along the first side of the circuit board and a first surface of the circuit board that is on the back side of the first surface that faces the human body during a call. A conductor disposed on the second surface or the second side along the second side and having a function of side-flowing a part of the current flowing in the ground pattern of the circuit board when the first antenna is used; Is provided. And while opening the front-end | tip part of this conductor, the effective electric length from the connection point of the said 1st radio | wireless circuit and a 1st antenna to the said front-end | tip part is transmitted and received by the said 1st antenna. The radio frequency signal is connected to the ground pattern at a position where the wavelength is approximately ½ wavelength, and the portion from the base end to the tip is further away from the connection point along the second side. It is configured to be arranged so as to face.

  With this configuration, a part of the current flowing on the ground pattern along the second side that generates the main radiated wave of the circuit board when the antenna is used is side-flowed to the conductor. For this reason, antenna radiation characteristics can be improved. The effective electrical length from the feeding point to the tip of the conductor is set to approximately ½ wavelength of the radio frequency signal. For this reason, when viewed from the feeding point, the conductor appears to be open, which makes it possible to increase the input impedance. Furthermore, a part of the current flowing on the ground pattern along the second side that generates the main radiated wave of the circuit board is caused to flow to the conductor to generate a plurality of resonance modes. This makes it possible to achieve a wider bandwidth.

  In addition, since the conductor is disposed on the surface or side opposite to the surface facing the human body when talking on the circuit board, the influence of the human body compared to the case where the conductor is installed on the surface facing the human body of the circuit board. Can be reduced. Further, the surface of the circuit board that faces the human body during a call generally has a small mounting space. However, since no conductor is disposed on this surface, an increase in the size of the terminal can be avoided.

  Therefore, according to the present invention, it is possible to provide a wireless module capable of improving impedance characteristics and radiation characteristics and increasing the bandwidth without causing an increase in the size of the terminal.

(First embodiment)
FIG. 1 is a perspective view showing a configuration of a wireless module for a portable terminal which is a first embodiment of a wireless module according to the present invention.
The wireless module is housed between a front cover and a rear case (both not shown) that constitute the casing of the mobile terminal. The accommodation state is set so that the side indicated as “front” in the figure is the front cover side, that is, the user's head side during a call, and the side indicated as “back” in the figure is the rear case side.

  The wireless module includes a circuit board 1. The circuit board 1 is composed of a double-sided printed wiring board in which printed wiring patterns are formed on both the front surface and the back surface, and the radio circuit 3 is mounted on the back surface. Further, on the back surface of the circuit board 1, an antenna connection terminal 41 and a signal line pattern 42 for connecting the antenna connection terminal and the radio circuit 3 are formed, respectively. Connected. As a connection method, for example, soldering or spring connection is used. The antenna 5 is formed in an L shape, and its entire length is set to an effective electrical length corresponding to ¼ (λ / 4) of the wavelength of the radio frequency signal to be transmitted and received.

  Further, on the back surface of the circuit board 1, the ground pattern 2 is formed on almost the entire surface except for the portion where the signal line pattern 42 is formed. When the circuit board 1 is a multilayer board, most of the ground pattern is formed on the second and third layers. In this case, a part of the ground pattern is formed on the back surface of the circuit board 1. In addition, a shield cap (not shown) is attached to the radio circuit 3, thereby electromagnetically shielding the inside of the radio circuit 3 from the outside.

  By the way, the conductor 6 is arranged on the circuit board 1 substantially in parallel along the side generating the main radiation wave (main polarization). The conductor 6 is formed in an L shape, and its base end is electrically connected to the ground pattern 2 formed on the back surface of the circuit board 1 and the tip is opened. As shown in FIG. 2, the conductor 6 is connected to the ground pattern 2 from the connection point of the antenna 5 to the antenna connection terminal 41, that is, from the feeding point BP. 4) It is set at a separated position. The total length of the conductor 6 is set to ¼ (λ / 4) of the wavelength of the radio frequency signal to be transmitted and received. That is, the effective electrical length from the feeding point BP of the antenna 5 to the tip of the conductor 6 is set to be ½ wavelength (λ / 2) of the radio frequency signal.

  Because of such a configuration, a high-frequency current that flows through the ground pattern 2 along the side that generates the main radiation wave of the circuit board 1 at the time of wireless transmission is partly flowing through the conductor 6. Thus, the high-frequency current flowing through the ground pattern 2 is reduced. That is, the polarization component formed by the longitudinal direction of the substrate of the radiated wave is canceled, and the radiation characteristic is less affected by the size of the circuit board 1.

  3 to 5 show the current distribution on the circuit board 1 corresponding to a plurality of resonance modes generated by providing the conductor 6, and the intensity thereof. FIG. 3 shows a series resonance mode at 1820 MHz. FIG. 4 shows a parallel resonance mode (mode 2) at 1910 MHz, and FIG. 5 shows a series resonance mode (mode 3) at 2040 MHz. As can be seen from the figure, a part of the high-frequency current flowing in the ground pattern 2 is side-flowed to the conductor 6, thereby reducing the high-frequency current flowing in the circuit board 1 and improving the radiation pattern.

  FIGS. 7A and 7B show an example of a radiation pattern when the conductor 6 is provided. FIG. 7A shows the radiation gain on the front and rear surfaces of the circuit board 1, and FIG. The radiation gains in the horizontal plane are respectively shown. As can be seen from the figure, by loading the conductor 6, the vertical polarization component formed by the longitudinal direction of the substrate is canceled and the horizontal polarization component increases. As a result, the radiation characteristics are improved as compared with the case of not loading a conductor (FIG. 8), which will be described later, whereby radiation to the human body side is suppressed and communication efficiency is improved.

  6 shows the current distribution on the circuit board 1 and its strength when the conductor 6 is not provided. The antenna 5 and the side that generates the main radiation of the circuit board 1 (in the longitudinal direction of the board) are shown. A large high-frequency current flows through the side), and the radiation pattern is affected by the high-frequency current flowing through the circuit board 1. FIGS. 8A and 8B show an example of the radiation pattern when the conductor 6 is not loaded. FIG. 8A shows the radiation gain on the front and rear surfaces of the circuit board 1, and FIG. The radiation gains in the horizontal plane are respectively shown.

  Further, since the conductor 6 operates as a stub when viewed from the feeding point, the impedance viewed from the feeding point BP is increased. FIG. 9 shows an example of a change in impedance with respect to frequency. As shown in the figure, when the conductor 6 is loaded (1 PCB-Pa-Re, 1 PCB-Pa-Im), compared to the case where the conductor 6 is not loaded (1 PCB-Re, 1 PCB-Im), Impedance characteristics are improved.

  Furthermore, by loading the conductor 6, for example, as shown in 1PCB-Pa-Im of FIG. 9, a plurality of resonance modes (in the example of the figure, a series resonance mode at 1820MHz, a parallel resonance mode at 1910MHz, a series at 2040MHz) Resonance mode) occurs. That is, it is possible to increase the bandwidth of the antenna. FIG. 10 shows an example of a change in voltage standing wave ratio (VSWR) with respect to frequency. As is clear from the figure, when the conductor 6 is loaded (solid line in the figure), VSWR is improved over a wider frequency band than when the conductor 6 is not loaded (broken line in the figure). I understand that.

  In addition, in the first embodiment, the conductor 6 is connected to the ground pattern 2 at a position on the side of the circuit board 2 that generates the main radiated wave and spaced from the feeding point BP by a quarter wavelength of the radio frequency signal. is doing. That is, as shown in FIGS. 11 and 12, the conductor 6 is connected to the ground pattern 2 at a position where the current value is the largest on the ground pattern 2. For this reason, it becomes possible to flow the high-frequency current flowing on the ground pattern 2 along the side of the circuit board 2 that generates the main radiated wave most efficiently to the conductor 6, thereby easily generating a plurality of resonance modes. Thus, the band of the antenna can be broadened more effectively.

  In addition, the length from the feeding point BP to the tip of the conductor 6 is set to be a half wavelength of the radio frequency signal. Here, the position of ½ wavelength from the feeding point BP is the position where the high-frequency current is minimized as is apparent from FIG. For this reason, the impedance when viewed from the feeding point is maximized, and thereby the impedance characteristics can be most effectively improved.

Further, the conductor 6 is disposed on the side of the substrate along the side of the circuit board 1 that generates the main radiation wave, and the base end portion of the conductor 6 is connected to the ground pattern 2 on the back side of the circuit board 1. . That is, the conductor 6 is disposed on the surface opposite to the surface facing the human body when the circuit board 1 is talking. For this reason, the influence by a human body can be reduced compared with the case where the conductor 6 is installed in the surface facing the human body of the circuit board 1. The surface of the circuit board 1 that faces the human body during a call generally has a small mounting space. However, by not arranging the conductor 6 on the circuit component mounting surface, it is possible to avoid an increase in the size of the terminal.
That is, the impedance characteristics and radiation characteristics can be improved and the bandwidth can be increased most efficiently without increasing the size of the terminal.

(Second Embodiment)
According to a second embodiment of the present invention, a radio circuit and an antenna are arranged in a radio module in which two circuit board units are connected by a flexible cable or a thin coaxial cable, like a radio module provided in a foldable portable terminal. The conductor is grounded on the side of the circuit board unit that generates the main radiated wave and on the extension of the installation position of the cable connector as viewed from the feeding point.

  FIG. 13 is a perspective view showing the configuration of a wireless module according to the second embodiment of the present invention. In the figure, the same parts as those in FIG. In the wireless module of this embodiment, a first circuit board 1 housed in a lower housing and a second circuit board 7 housed in an upper housing are connected via a cable 11 and its connectors 9 and 10. The connector 9 is arranged on the side of the circuit board 1 that generates the main radiated wave. In addition, in the rigid board | substrate with which the board | substrate and the flexible cable were integrated, a connector is not provided but a cable is directly connected to a board | substrate.

  By the way, also in this 2nd Embodiment, the conductor 6 is arrange | positioned in parallel along the edge | side which produces | generates the main radiation wave (main polarization) of the circuit board 1. FIG. The conductor 6 is formed in an L shape, and its base end is electrically connected to the ground pattern 2 formed on the back surface of the circuit board 1 and the tip is opened. The connection position of the conductor 6 to the ground pattern 2 is an extension of the connection position of the connector 9 of the cable 11 when viewed from the connection point of the antenna 5 to the antenna connection terminal 41, that is, the feeding point, and It is set at a position that is a quarter wavelength (λ / 4) of the radio frequency signal with respect to the feeding point. The total length of the conductor 6 is set to ¼ (λ / 4) of the wavelength of the radio frequency signal to be transmitted and received.

  Because of such a configuration, when the antenna is used, a part of the high-frequency current flowing through the ground pattern 2 along the side that generates the main radiation wave of the circuit board 1 flows through the conductor 6 in the prior art. Thus, the high-frequency current flowing through the ground pattern 2 of the circuit board 1 is reduced. At the same time, the high-frequency current flowing from the ground pattern 2 of the circuit board 1 to the ground pattern of the circuit board 7 via the connector 9 and the cable 11 is also reduced.

  FIG. 14 shows the current distribution and its strength in the circuit boards 1 and 7 when the conductor 6 is provided. This figure shows a state where the resonance frequency is 1950 MHz. FIG. 15 shows the current distribution and the intensity when the conductor 6 is not provided. As can be seen from the figure, when the conductor 6 is provided, not only the current distribution in the circuit board 1 but also the current distribution to the circuit board 7 is suppressed as compared with the case where the conductor 6 is not provided. The

  When the conductor 6 is loaded, the polarization component formed by the longitudinal direction of the circuit board 1 is canceled out by the current generated in the conductor 6, thereby preventing the deterioration of the radiation characteristics due to the size of the circuit board 1. . In addition, since the horizontal polarization components of the antenna 5 and the circuit board 1 are opposite to each other in the thickness direction of the circuit board, the radiation gain in the forward direction is reduced. Therefore, radiation toward the user is reduced, and a decrease in antenna gain by the user during a call is suppressed. Incidentally, when the conductor 6 is not provided, the main radiated wave depends on the current flowing on the side of the circuit board 1 opposite to the feeding point, so that the vertical polarization component becomes the main component.

  FIG. 16 shows an example of the radiation pattern when the conductor 6 is provided. (A) shows the radiation gain on the front and rear surfaces of the circuit board 1, and (b) shows the radiation gain on the horizontal plane of the circuit board 1. Respectively. FIG. 17 shows a radiation pattern when the conductor 6 is not provided. As can be seen from the figure, when the conductor 6 is provided, the radiation gain in the forward direction of the circuit board 1 is suppressed, and the radiation gain in the upward direction is increased.

  Even when there are two circuit boards 1, 7, the conductor 6 is in an open state when viewed from the feeding point, so that the impedance viewed from the feeding point is high. FIG. 18 shows an example of a change in impedance with respect to frequency. As shown in the figure, when the conductor 6 is loaded (2PCB-Pa-Re, 2PCB-Pa-Im), compared to when the conductor 6 is not loaded (2PCB-Re, 2PCB-Im), Impedance characteristics are improved.

  Furthermore, loading of the conductor 6 causes a multi-resonance mode, thereby broadening the antenna. FIG. 19 shows an example of a change in voltage standing wave ratio (VSWR) with respect to frequency. As is clear from the figure, when the conductor 6 is loaded (solid line in the figure), VSWR is improved over a wider frequency band than when the conductor 6 is not loaded (broken line in the figure). I understand that.

  Moreover, also in the second embodiment, the conductor 6 is placed on the ground pattern 2 at a position on the side of the circuit board 2 where the main radiated wave is generated and separated from the feeding point by a quarter wavelength of the radio frequency signal. Connected. For this reason, it becomes possible to flow the high-frequency current flowing on the ground pattern 2 along the side of the circuit board 2 that generates the main radiated wave most efficiently to the conductor 6, thereby making it easy to generate a multi-resonance mode. The band of the antenna can be broadened more effectively. In addition, the improvement effect of a radiation pattern becomes high when the distance between the conductor 6 and the connector 9 is short.

  Further, also in the second embodiment, the conductor 6 is arranged on the side surface of the circuit board 1 along the side generating the main radiation wave of the circuit board 1, and the base end portion of the conductor 6 is the back side of the circuit board 1. Is connected to the ground pattern 2. For this reason, the conductor 6 is disposed on the surface opposite to the surface facing the human body during a call on the circuit board 1. When the conductor 6 is installed on the surface facing the human body of the circuit board 1. In comparison, the influence of the human body can be reduced. Further, by not arranging the conductor 6 on the circuit component mounting surface, it is possible to avoid an increase in the size of the terminal 1.

(Third embodiment)
In the third embodiment of the present invention, when the conductor 6 is grounded to the ground pattern 2, it is grounded via an impedance adjustment circuit.
FIG. 20 is a perspective view showing a configuration of a wireless module according to the third embodiment of the present invention. In the figure, the same parts as those in FIG. An impedance adjustment circuit 12 is mounted on the side of the circuit board 1 on which the main radiated wave is generated and at a position separated from the feeding point by a quarter wavelength of the radio frequency signal. The parasitic dielectric element 6 is connected to the ground pattern 2 via the impedance adjustment circuit 12.

(1) Example 1
The impedance adjustment circuit 12 is configured by an inductor L1, for example, as shown at 12a in FIG. When the conductor 6 is connected to the ground pattern 2 via the inductor L1 in this way, the effective electrical length from the feeding point to the tip of the conductor 6 can be equivalently shortened. Specifically, the element length of the conductor 6 can be shortened, thereby reducing the installation space of the conductor 6 and reducing the size of the wireless module accordingly.

In addition, as the impedance adjustment circuit 12, a capacitor or a variable reactance element can be used. In particular, when a variable reactance element is used, the frequency range that can be matched can be further widened.
Instead of inserting a variable reactance element between the conductor 6 and the ground pattern 2, the intermediate portion of the antenna 5 is grounded to the ground pattern 2 via the variable reactance element 22 as shown in FIG. May be. Even with this configuration, the frequency range where matching can be achieved can be further widened.

(2) Example 2
The impedance adjustment circuit 12 can also be configured by a switch SW1, for example, as shown at 12b in FIG. The switch SW1 includes a MEMS, PIN diode, MESFET (Metal Semiconductor FET), and the like, and is turned on / off by a switching control signal SW1 output from a control circuit (not shown) of the portable terminal.

  The control circuit outputs the switching control signal SWC1 according to the operation mode of the mobile terminal. For example, during a period in which the mobile terminal is operating in the call mode, the switch control signal SWC1 for turning on the switch SW1 is output, while in a period in which the mobile terminal is operating in a data communication mode such as mail transmission / reception or web access, A switching control signal SWC1 for turning off the switch SW1 is output.

  With such a configuration, when the portable terminal is operating in the call mode, the switch SW1 is turned on and the conductor 6 is connected to the ground pattern 2. For this reason, as described in the first embodiment, the gain in the front direction of the radiation pattern is suppressed. Therefore, even if the user's head is in contact with or close to the portable terminal for a call, the influence of the radiation gain due to the user's head is reduced.

  On the other hand, when the mobile terminal is in a data communication mode in which the wireless module is not in contact with or close to the user's head, such as sending / receiving mail or web access, the switch SW1 is turned off and the conductor 6 is turned off. Is separated from the ground pattern 2. That is, the portable terminal operates without the conductor 6. For this reason, more direct radiation can be realized by making the directivity of the radiation pattern uniform.

(Fourth embodiment)
In the fourth embodiment of the present invention, when a plurality of radio circuits and antennas are provided on the circuit board 1, one of these antennas can be used as a conductor.
FIG. 23 is a perspective view showing a configuration of a wireless module according to the fourth embodiment of the present invention. In the figure, the same parts as those in FIG. In addition to the first radio circuit 3 and its antenna 5, a second radio circuit 13 is provided on the back surface of the circuit board 1. A connection circuit 15 is connected to the second wireless circuit 13 via a signal line pattern 14, and a second antenna 16 is connected to the connection circuit 15.

(1) Example 1
The first embodiment shows a configuration when the first antenna 5 and the second antenna 16 are used for different wireless systems.
The second antenna 16 is on the side that generates the main radiated wave when wireless transmission is performed using the first antenna 5, and is a quarter wavelength away from the feeding point for the first antenna 5. Installed in a different position. The connection circuit 15 includes a variable reactance element RC as shown by 15a in FIG.

  With this configuration, for example, in the reception period of the mobile terminal, the second antenna 16 operates as an antenna for diversity reception of radio frequency signals to the second radio circuit 13, and the first antenna 5 in the transmission period. It operates as the conductor 6 for improving the radiation characteristics and the like. That is, the second antenna 16 is also used as the conductor 6. Therefore, the effect of the present invention can be obtained without providing a separate conductor 6. Further, the frequency range in which matching can be achieved can be further widened by inserting a variable reactance element RC or a matching circuit.

  As shown in FIG. 34, a predetermined intermediate position of the second antenna 16 is connected to the feeding point BP2 by the second radio circuit 13, and the base end portion of the second antenna 16 is connected to the ground pattern of the circuit board 1. 2 may be grounded. With this configuration, the second antenna 16 can also be used as the conductor 6.

(2) Example 2
In the second embodiment, the first wireless circuit 3 and its antenna 5 are used for mobile communication, while the second wireless circuit 13 and its antenna 16 are used for wireless LAN (Local Area Network), Bluetooth (registered trademark), etc. This shows a configuration when used for short-range data communication.

  The second antenna 16 is on the side that generates the main radiated wave when wireless transmission is performed using the first antenna 5, and the radio frequency signal of the second antenna 16 is supplied from the feeding point to the first antenna 5. Installed at a position one quarter wavelength away. As shown in 15b of FIG. 25, the connection circuit 15 includes a changeover switch SW2 and an inductor L2. The change-over switch SW2 is composed of a semiconductor switch or the like, and a base end portion of the second switch element 16 is connected to the second radio circuit 13 and the ground pattern according to a change-over control signal SWC2 output from a control circuit (not shown) of the portable terminal. Selectively connect to 2. The inductor L2 is interposed between the base end portion and the ground pattern 2 when the second switch element 16 is grounded.

  The control circuit outputs a switching control signal SWC2 for connecting the changeover switch SW2 to the second wireless circuit 13 during the short-range data communication period according to the operation mode of the mobile terminal, and during the transmission period of the mobile communication Outputs a switch control signal SWC2 for connecting the switch SW2 to the ground pattern.

  Because of such a configuration, for example, during a short distance data communication for transmitting audio data to an earphone unit (not shown), the changeover switch SW2 is switched to the second wireless circuit 13 side and Connected to the second radio circuit 13. Therefore, the transmission signal for short-range data communication output from the second wireless circuit 13 is wirelessly transmitted via the second antenna 16.

  On the other hand, during a period in which a call is being made by mobile communication, the changeover switch SW2 is switched to the ground pattern 2 side and connected to the ground pattern 2 via the inductor L2. At this time, the grounding position of the second switch element 16 is set to be a position away from the feeding point of the first antenna 5 by a quarter wavelength of the radio frequency signal for mobile communication. For this reason, as described in the first embodiment and the like, a part of the current flowing in the ground pattern 2 flows in the second antenna 16, thereby reducing the current flowing in the ground pattern 2. Radiation gain in the front direction (the direction of the user's head) is suppressed.

Therefore, even if the user's head is in contact with or close to the portable terminal for a call, the influence of the radiation gain due to the user's head is reduced. In addition, as in the first embodiment, the impedance characteristics can be improved and the bandwidth can be increased. Furthermore, since the second antenna 16 is grounded via the inductor L2, the impedance of the second antenna 16 can be adjusted to an optimum value.
That is, the second antenna 16 provided for near field data communication can also be used as the conductor 6 when performing mobile communication. In addition, since the second antenna 16 is also used as the conductor 6, it is not necessary to provide a separate conductor, thereby preventing an increase in the size of the wireless module and hence the portable terminal.

(Fifth embodiment)
The fifth embodiment of the present invention is a wireless module in which two circuit board units are connected by a flexible cable or a thin coaxial cable, such as a wireless module provided in a foldable portable terminal. A set of wireless circuits and their antennas are provided, and one of these antennas can be used as a conductor.

FIG. 26 is a perspective view showing the configuration of a wireless module according to the fifth embodiment of the present invention. In the figure, the same parts as those in FIG. 1 and FIG.
In the wireless module of this embodiment, a flexible cable 19 and its second circuit board 7 are accommodated between the first circuit board 1 accommodated in the lower casing of the mobile terminal and the second circuit board 7 accommodated in the upper casing. They are connected via connectors 17 and 18. In addition to the first radio circuit 3 and its antenna 5, a second radio circuit 13 is provided on the back surface of the first circuit board 1 among the circuit boards 1 and 7. A connection circuit 15 is connected to the second wireless circuit 13 via a signal line pattern 14, and a second antenna 16 is connected to the connection circuit 15.

  As described in the fourth embodiment, the connection circuit 15 has a configuration in which the second antenna 16 is connected to the second radio circuit 13 using a variable reactance element RC, an inductor, a capacitor, or the like. By using the switch SW2, there is one that selectively connects the second antenna 16 to the second radio circuit 13 and the ground pattern 2 according to the communication mode of the mobile terminal.

  According to this embodiment, in the wireless module composed of two circuit board units, the second antenna 16 functions as the conductor 6 in the same manner as the fourth embodiment. In addition to being able to improve the bandwidth, the second antenna 16 can also be used as the conductor 6, so that it is not necessary to provide a separate conductor. Increase in size can be prevented.

(Other embodiments)
Various modifications of the configuration, grounding position, and grounding structure of the conductor 6 can be considered. For example, as shown in FIG. 27, it is preferable to provide a cutout portion 20 in the circuit board 1 and accommodate the conductor 6 in the cutout portion 20. In this way, the conductor 6 can be prevented from protruding from the side surface portion of the circuit board 1.

  In addition, as shown in FIG. 28, a magnetic member 21 is interposed between the conductor 6 and the circuit board 1. In this way, the conductor 6 can be downsized. By using a conductive material or a magnetic material having a high magnetic permeability, there is no need to set a large gap between the conductive material 6 and the circuit board 1, and this enables downsizing of the wireless module. It is also possible to provide a dielectric member instead of the magnetic member 21.

  On the other hand, the grounding position of the conductor may be set to a side close to the feeding point BP1 of the antenna 5, as shown in FIGS. 29, 30 or 31a, 6a, 6b, and 6c. As such, it may be provided on the back surface of the circuit board 1. As for the configuration of the conductor 6, for example, as shown in 6a of FIG. 29, all or part of the conductor 6 may be bent in a crank shape. If comprised in this way, even when a long conductor cannot be installed on account of installation space, required effective electrical length can be ensured. For example, when it is necessary to provide a long conductor according to the antenna 5a formed in a crank shape as shown in FIG. 32, the length of the side where the conductor 6d is installed like the circuit board 1d. Is sufficiently long, the long conductor 6d may be installed as it is along the side of the circuit board 1d.

  Further, the grounding position of the conductor 6 on the circuit board 1 is not limited to a position that is separated from the feeding point BP by a quarter wavelength of the radio frequency signal. Good. Further, the effective electrical length from the feeding point BP to the tip of the conductor 6 is not limited to ½ wavelength of the radio frequency signal, and may be set to any length as long as the value is close thereto. .

In addition, the shape and size of the circuit board, the configuration and installation position of the conductor, the radio frequency signal frequency transmitted and received by the radio module, the type of the portable terminal, and the like can be variously modified without departing from the gist of the present invention.
In short, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in each embodiment. Furthermore, you may combine suitably the component covering different embodiment.

It is a perspective view which shows the structure of the radio | wireless module concerning 1st Embodiment of this invention. It is a figure for demonstrating the grounding position of the conductor in the radio | wireless module shown in FIG. 1, and the length of a radio | wireless module. In the wireless module shown in FIG. 1, it is a figure which shows the 1st example of the distribution of the electric current on a circuit board when the series resonance mode generate | occur | produces at 1820 MHz, and its intensity | strength. In the wireless module shown in FIG. 1, it is a figure which shows the 1st example of distribution of the electric current on a circuit board when the parallel resonance mode generate | occur | produces at 1910 MHz, and its intensity | strength. FIG. 4 is a diagram illustrating a first example of current distribution and intensity on a circuit board when a series resonance mode occurs at 2040 MHz in the wireless module illustrated in FIG. 1. It is the figure which showed an example of distribution of the electric current on a circuit board when not providing a conductor, and its intensity | strength. It is a figure which shows an example of the radiation pattern which generate | occur | produces in the radio | wireless module shown in FIG. It is a figure which shows an example of the radiation pattern in case a conductor is not loaded. It is the figure which showed an example of the impedance characteristic in the radio | wireless module shown in FIG. It is the figure which showed an example of the VSWR characteristic in the radio | wireless module shown in FIG. The figure which shows the electric current value on the edge | side where the main radiation wave of a circuit board generate | occur | produces in the radio | wireless module shown in FIG. The figure which shows the electric current value on the edge | side where the main radiation wave of a circuit board generate | occur | produces in the radio | wireless module shown in FIG. It is a perspective view which shows the structure of the radio | wireless module concerning 2nd Embodiment of this invention. It is a figure which shows the example of distribution and the intensity | strength of the electric current which generate | occur | produce on a circuit board in the radio | wireless module shown in FIG. It is the figure which showed an example of distribution of the electric current on a circuit board when not providing a conductor, and its intensity | strength. It is a figure which shows an example of the radiation pattern which generate | occur | produces in the radio | wireless module shown in FIG. It is a figure which shows an example of the radiation pattern in case a conductor is not loaded. It is the figure which showed an example of the impedance characteristic in the radio | wireless module shown in FIG. It is the figure which showed an example of the VSWR characteristic in the radio | wireless module shown in FIG. It is a perspective view which shows the structure of the radio | wireless module concerning the 3rd Embodiment of this invention. FIG. 21 is a circuit diagram showing a configuration of a first embodiment of the wireless module shown in FIG. 20. FIG. 21 is a circuit diagram showing a configuration of a second embodiment of the wireless module shown in FIG. 20. It is a perspective view which shows the structure of the radio | wireless module concerning 4th Embodiment of this invention. FIG. 24 is a circuit diagram showing a configuration of a first example of the wireless module shown in FIG. 23; FIG. 24 is a circuit diagram showing a configuration of a second embodiment of the wireless module shown in FIG. 23; It is a perspective view which shows the structure of the radio | wireless module concerning 5th Embodiment of this invention. It is a figure which shows the 1st example of the radio | wireless module concerning other embodiment of this invention. It is a figure which shows the 2nd example of the radio | wireless module concerning other embodiment of this invention. It is a figure which shows the 3rd example of the radio | wireless module concerning other embodiment of this invention. It is a figure which shows the 4th example of the radio | wireless module concerning other embodiment of this invention. It is a figure which shows the 5th example of the radio | wireless module concerning other embodiment of this invention. It is a figure which shows the 6th example of the radio | wireless module concerning other embodiment of this invention. It is a figure which shows the modification of the radio | wireless module concerning the 3rd Embodiment of this invention. It is a figure which shows the modification of the radio | wireless module concerning 4th Embodiment of this invention. It is a figure which shows the 7th example of the radio | wireless module concerning other embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Circuit board (1st circuit board), 2, 8 ... Ground pattern, 3 ... Wireless circuit (1st radio circuit), 41 ... Antenna connection terminal (feeding terminal), 42, 14 ... Signal line pattern, 5 ... Antenna (first antenna), 6 ... Conductor, 7 ... Second circuit board, 9, 10, 17, 18 ... Connector, 11, 19 ... Flexible cable, 12 ... Impedance adjustment circuit, 13 ... Second Radio circuit, 15 ... connection circuit, 16 ... second antenna, 20 ... notch, 21 ... magnetic member.

Claims (9)

A first surface that faces the human body during a call, a second surface that is the back side of the first surface, a first side, and a second surface that is orthogonal to the first side And a circuit board on which the ground pattern is formed and the first wireless circuit is mounted;
A first antenna connected to the first radio circuit and disposed along a first side of the circuit board;
A function that is arranged along the second side or the second side of the circuit board along the second side, and that partly flows a current flowing in the ground pattern of the circuit board when the first antenna is used. And a conductor having
The electric conductor has an open front end, and a base end has an effective electrical length from a connection point between the first radio circuit and the first antenna to the front end. Connected to the ground pattern at a position where the radio frequency signal is approximately ½ wavelength, and further, a portion from the base end to the tip is directed in a direction away from the connection point along the second side. A wireless module comprising:   The base end of the conductor has an effective electrical length from the connection point between the first radio circuit and the first antenna to the tip of the radio frequency signal transmitted and received by the first antenna. 2. The wireless module according to claim 1, wherein the wireless module is connected to the ground pattern at a position where the wavelength is / 2 wavelength and at a distance of approximately ¼ wavelength of the radio frequency signal from the connection point. An impedance adjusting unit that is disposed between a base end portion of the conductor and a ground pattern of the circuit board and adjusts the impedance of the conductor as viewed from a connection point between the first wireless circuit and the first antenna. Further comprising
The wireless module according to claim 1, wherein the impedance adjustment unit includes an inductor, a capacitor, or a variable reactance element.   A state in which the conductor is connected to the ground pattern according to an operation mode that is inserted between the base end portion of the conductor and the ground pattern of the circuit board and is required for the wireless module, and the ground The wireless module according to claim 1, further comprising a switch that switches a state in which the conductor is separated from the pattern. A second wireless circuit mounted on the circuit board and operating in a second period different from the first period in which the first wireless circuit operates;
The switch connects the conductor to the second radio circuit during the second period, and connects the conductor to the first radio circuit and the first antenna during the first period. 5. The wireless module according to claim 4, wherein the wireless module is connected to the ground pattern at a position that is separated by approximately ¼ wavelength of a radio frequency signal transmitted and received by the first antenna. The first antenna has a portion extending from a base end portion to a tip end portion arranged along the first side of the circuit board, the tip end portion is opened, and the base end portion is connected to the circuit board. Connected to the first radio circuit at a first side;
The portion of the conductor that extends from the base end portion to the tip end portion is located on the side of the second side that is close to the connection point between the base end portion of the first antenna and the first wireless circuit. And the base end portion is connected to the ground pattern at a position separated from the connection point by approximately ¼ wavelength of the radio frequency signal transmitted and received by the first antenna. The wireless module according to claim 1, wherein When the circuit board is rectangular,
The first antenna has a portion extending from the base end portion to the tip end portion along the short side of the circuit board,
Of the two long sides where the portion from the base end portion to the tip end portion is in contact with the short side of the circuit board, the conductor is a connection point between the first antenna and the first radio circuit. 2. The wireless module according to claim 1, wherein the wireless module is disposed so as to face in a direction away from the connection point along a long side closer to 2.   2. The wireless module according to claim 1, wherein the first antenna is connected to the first wireless circuit at a base end portion at a corner portion where the first side is in contact with the second side. .   The wireless module according to claim 1, wherein the conductor is configured by bending all or part of a portion from the base end portion to the tip end portion in a crank shape.

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