JP4853368B2 - Wireless communication device - Google Patents

Description

  The present invention relates to a foldable wireless communication device in which a circuit board is housed in a pair of housings.

Conventionally, in this type of wireless communication device, for example, as disclosed in Patent Literature 1 and Patent Literature 2, a good antenna gain can be maintained in a state where a pair of housings are opened. The structure is adopted.
FIG. 15 is a schematic cross-sectional view showing a wireless communication device according to the first conventional example, and FIG. 16 is a perspective view showing a main part of the wireless communication device according to the second conventional example.
In the wireless communication device 100 disclosed in Patent Document 1, as shown in FIG. 15, the antenna power supply unit 101 is fixed to the first housing 102, the helical coil 104 is conducted to the antenna power supply unit 101, and the element 105 is built in the second housing 103.
Thereby, in the folded state, the helical coil 104 built in the first housing 102 is fed from the antenna feeding unit 101 and operates as an antenna. In the open state, the element 105 incorporated in the second casing 103 is capacitively coupled to the helical coil 104 fed by the first casing 102 to operate as an antenna. ing.

  On the other hand, in the wireless communication device disclosed in Patent Document 2, as shown in FIG. 16, the upper case 201 and the lower case 202 are rotatably connected at the hinge portion 203, and the plate-like conductor 204 and the plate-like conductor 205 are connected. The upper case 201 is disposed along the surface of the case. Then, the ground plate 206 is configured by a ground pattern of a circuit board disposed inside the lower case 202, and either the plate-like conductor 204 or the plate-like conductor 205 is selected by the high-frequency switch 214, and the power supply unit 215 A dipole antenna is configured by connecting to one end and connecting the other end of the power feeding unit 215 to the ground plate 206.

JP 2001-284933 A JP 2004-056426 A

However, the above-described conventional wireless communication device has the following problems.
First, in the wireless communication device shown in FIG. 15, in addition to the helical coil 104, the element 105 is further required to capacitively couple the element 105 with the helical coil 104 to operate as an antenna. For this reason, the number of parts increases correspondingly, leading to an increase in the cost of the product. Further, although the element 105 is capacitively coupled to the helical coil 104, a desired capacity cannot be obtained depending on the terminal design, and an expected antenna gain cannot be obtained.

  Next, in the wireless communication device shown in FIG. 16, a high frequency switch 214 for selectively connecting one of the plate conductors 204 and 205 to one end of the power feeding unit 215 is specially required. The number of points increases, leading to increased product costs. In addition, the two plate-like conductors 204 and 205 interfere with each other, and currents in opposite phases to each other are induced in the plate-like conductors 204 and 205, which may deteriorate the antenna performance.

  The present invention has been made to solve the above-described problems, and can reduce the product cost. In addition, two circuit boards respectively housed in a pair of housings are connected to a radiating element of a dipole antenna. An object of the present invention is to provide a wireless communication device that can be used as a wireless communication device.

In order to solve the above-mentioned problems, the invention of claim 1 includes a first housing that houses a first circuit board having a power feeding portion, a second housing that houses a second circuit board, A balun transformer that includes a hinge unit that connects a case and a second case so as to be freely opened and closed, and that converts an unbalanced current from a power feeding unit into a pair of balanced currents and outputs the pair of balanced currents The pair of output terminals of the balun transformer are connected to the first ground electrode of the first circuit board and the second ground electrode of the second circuit board, respectively, and separated from the first ground electrode. In this state, the third ground electrode is provided on the first circuit board, the power feeding unit is disposed on the third ground electrode, and the input / output unit of the power feeding unit and the second circuit board A power feeding unit input / output line that functions as a first inductor by connecting the two ground electrodes, and a third group A first capacitor between the first electrode and the second ground electrode, a second capacitor between the input / output unit of the power supply unit and the first ground electrode, a third ground electrode, A balun transformer was configured by the second inductor provided between the ground electrode.
With this configuration, when the first housing and the second housing are opened and the power feeding unit is operated, the unbalanced current from the power feeding unit is converted into a pair of balanced currents by the balun transformer and output. Since the pair of output terminals of the balun transformer are connected to the first ground electrode of the first circuit board and the second ground electrode of the second circuit board, respectively, the output is output from the balun transformer. The balanced current is input to each of the first ground electrode and the second ground electrode. As a result, the first and second ground electrodes are excited by a balanced current having a predetermined frequency and function as a radiating element of the dipole antenna.
Specifically, a bridge-type balun transformer is configured by the power supply unit input / output line functioning as the first inductor, the first capacitor, the second capacitor, and the second inductor, and one of the balanced currents is fed. The other balanced current, that is, the balanced current that has the same magnitude as that of the one balanced current and flows in the opposite direction, is output from the input / output unit of the unit to the second ground electrode through the first inductor. Or output to the first ground electrode through the second capacitor. As a result, an equilibrium current flows from the first ground electrode toward the second ground electrode, and these first and second ground electrodes function as a radiating element of the dipole antenna.

According to a second aspect of the present invention, in the wireless communication device according to the first aspect, the electrical length of the dipole antenna composed of the power feeding unit and the first to third ground electrodes is set to a half of the wavelength with respect to the frequency of 470 MHz to 770 MHz. The configuration is set to 1.
With this configuration, even a frequency band having a long wavelength such as D-TV (Digital-Television) can be received.

According to a third aspect of the present invention, in the wireless communication device according to the first or second aspect, the power supply unit and the third ground electrode are provided on an LTCC (Low Temperature Co-fire Ceramic) substrate. .
With this configuration, the power feeding unit can be made compact. Here, the power feeding unit is an input unit such as a D-TV module.

According to a fourth aspect of the present invention, in the wireless communication device according to any one of the first to third aspects, the third ground electrode is disposed on one end of the first circuit board, and the first When the second housing is in the open state, the end of the third ground electrode on the first circuit board overlaps the end of the second ground electrode on the second circuit board in a projection view, A high dielectric for adjusting the first capacitance by connecting the first and second housings by the hinge portion so that the first capacitance is generated between the second ground electrode and the third ground electrode. The body is arranged between the overlapping portions of the third ground electrode and the second ground electrode.
With this configuration, since the high dielectric is located between the overlapping portion of the third ground electrode and the second ground electrode when the first and second housings are in the open state, the third ground electrode The first capacitor between the first and second ground electrodes can be easily adjusted with a high dielectric.

According to a fifth aspect of the present invention, in the wireless communication device according to the fourth aspect, the metal member is provided inside the high dielectric.
With this configuration, the high dielectric body having the metal member therein is located between the overlapping portion of the third ground electrode and the second ground electrode, so that the third ground electrode and the second ground electrode The size of the first capacitor can be further increased.

As described above in detail, according to the wireless communication device of the present invention, the first and second ground electrodes are connected to the dipole antenna by the balun transformer interposed between the power feeding unit and the first and second ground electrodes. Therefore, unlike the above-described conventional wireless communication device, a balanced current can be reliably supplied to the first and second ground electrodes without the need for a special antenna element. As a result, there is an excellent effect that a good antenna gain can be obtained.
In particular, since the balun transformer is configured by the power supply unit input / output line, the first capacitor, the second capacitor, and the second inductor, a load element such as a high-frequency switch required by a conventional wireless communication device is not required. As a result, an increase in the number of parts can be suppressed, and the size of the wireless communication device can be reduced.

According to the second aspect of the present invention, since a dipole antenna having the maximum antenna size can be formed, even a frequency band with a long wavelength such as D-TV can be received with high sensitivity. As a result, the lengths of the first and second circuit boards can be given a margin, and various terminal designs can be supported.

According to the invention of claim 4, since the magnitude of the first capacitance between the third ground electrode and the second ground electrode can be easily adjusted by the high dielectric, The coupling capacitance between the second ground electrodes can be easily controlled.
Further, according to the invention of claim 5, since the size of the first capacitance between the third ground electrode and the second ground electrode can be further increased, the third and second ground electrodes The coupling capacity between them can be further increased.

  The best mode of the present invention will be described below with reference to the drawings.

  FIG. 1 is a perspective view showing a wireless communication apparatus according to a first embodiment of the present invention, and FIG. 2 is a perspective view showing the wireless communication apparatus of FIG. 3 is a sectional view of the wireless communication device showing a folded state, and FIG. 4 is a sectional view of the wireless communication device showing an opened state.

  As shown in FIG. 1, the wireless communication device of this embodiment is a foldable mobile phone, and a case 1 as a first case and a case 2 as a second case have a hinge portion. 3 are connected via a switch 3.

The housing 1 is a case for use as an operation unit of a wireless communication device, and is formed of a synthetic resin such as plastic.
A keyboard 11, a microphone 12, and the like are attached to the housing 1, and a circuit board 4 as a first circuit board is accommodated therein as indicated by a broken line.
As shown in FIG. 2, this circuit board 4 is a normal dielectric substrate, and has a module 6 as a power feeding unit on the back surface (surface on the front surface side in FIG. 2). Specifically, on the circuit boards 4 and 5, a ground electrode 41 as a first ground electrode, a non-ground region 42, and a ground as a third ground electrode provided in a state separated from the ground electrode 41. An electrode 61 is formed. The main antenna unit 40 is surface-mounted on the non-ground region 42, and the module 6 is mounted on the ground electrode 61.
The module 6 includes a transmission / reception unit and the like, and is grounded to the ground electrode 61.

On the other hand, the housing 2 is a case for use as a display unit of a wireless communication device, and is formed of a synthetic resin such as plastic like the housing 1, but is set shorter than the housing 1. In this embodiment, the casings 1 and 2 are formed of a synthetic resin such as plastic, but these can also be formed of a metal such as a magnesium alloy.
As shown in FIG. 1, a liquid crystal panel 21, a speaker 22, and the like are attached to the housing 2, and a circuit board 5 as a second circuit board is accommodated in the housing 2 as indicated by a broken line. ing.
As shown in FIG. 2, this circuit board 5 is also a normal dielectric substrate, and has ground electrodes 51 and 51 as second ground electrodes on both surfaces thereof. Various circuits for operating the liquid crystal panel 21, the speaker 22 and the like are provided on the ground electrode 51 on the front side. For ease of understanding, these circuits are provided as shown in FIG. Is shown as one circuit 52.

As shown in FIG. 2, the module 6 provided on the ground electrode 61 of the circuit board 4 and the ground electrode 51 of the circuit board 5 are electrically connected by a module input / output line 7 as a power feeding section input / output line. ing.
Specifically, the module input / output line 7 drawn from the input / output unit (not shown) of the module 6 passes through the hinge unit 3 as shown in FIG. The electrode 51 is electrically connected. Therefore, equivalently, the inductor L1 as the first inductor by the module input / output line 7 extends from the input / output portion of the module 6 and is connected to the ground electrode 51 of the circuit board 5.
The ground electrodes 41 and 51 of the circuit boards 4 and 5 and the circuit 52 and the circuit board 4 of the circuit board 5 are connected by signal lines and control lines, but are not shown.

The hinge portion 3 is a portion that connects the housing 1 and the housing 2 so as to be openable and closable, and connects a portion inside the housing 1 and an end portion of the housing 2.
FIG. 5 is a partial enlarged cross-sectional view for explaining the formation position of the hinge portion 3, and FIG. 6 is a partial enlarged cross-sectional view for explaining an overlapping portion of the housings 1 and 2.
As shown in FIG. 5, the hinge portion 3 is connected to the end 2 a of the housing 2 on one side, and on the other side to the portion 1 b that is closer to the inner side (right side in FIG. 5) than the end 1 a of the housing 1. It is connected.
Thereby, the housing | casing 2 can be rotated centering on the hinge part 3 with respect to the housing | casing 1, and the housing | casing 1 and 2 can be made into the open state, as shown in FIG.
In this way, when the housings 1 and 2 are opened, the hinge portion 3 is connected to the portion 1b of the housing 1, so that the end 2a side of the housing 2 as shown in FIG. Part D2 of the casing 1 overlaps with the part D1 from the part 1b of the housing 1 to the end part 1a in a projection view. As a result, the end of the ground electrode 51 of the circuit board 5 overlaps with the end of the ground electrode 61 of the circuit board 4 in a projection view, and as shown by the broken line, the capacitor C1 as the first capacitor is in this overlapping portion. appear.

In this embodiment, as shown in FIG. 2, a balun transformer 8 is provided in order to make such circuit boards 4 and 5 function as a radiating element of a dipole antenna.
7 is a plan view showing the back side of the circuit boards 4 and 5, FIG. 8 is a schematic diagram showing the configuration of the balun transformer 8, and FIG. 9 is an equivalent circuit diagram of the balun transformer 8 of FIG. is there.
In FIG. 2, a balun transformer 8 is a transformer that converts an unbalanced current from the module 6 serving as a power feeding unit into a pair of balanced currents and outputs the balanced current to the ground electrodes 41 and 51 of the circuit boards 4 and 5. As shown in FIG. 8, the inductor L <b> 1 that is the module input / output line 7, the capacitance C <b> 1 between the ground electrodes 61 and 51, and a second electrode provided between the input / output unit of the module 6 and the ground electrode 41. A capacitor C2 as a capacitor and an inductor L2 as a second inductor provided between the ground electrodes 61 and 41 are configured.
As shown in FIG. 9, the balun transformer 8 having such a configuration is a bridge-type balun transformer. As shown in FIG. 8, the input / output unit of the module 6 is used as an input terminal P0 for an unbalanced current, and the inductor A connection portion between L1 and the capacitor C1 is an output terminal P1 that outputs one balanced current, and a connection portion between the inductor L2 and the capacitor C2 is an output terminal P2 that outputs the other balanced current. These output terminals P2 and P1 are connected to the ground electrodes 41 and 51 of the circuit boards 4 and 5, respectively. Thus, a dipole antenna having the ground electrodes 41 and 51 as radiating elements is configured in the wireless communication device of this embodiment.

FIG. 10 is a schematic diagram showing a dipole antenna.
That is, as shown in FIG. 10, the input / output part of the module 6 grounded to the ground electrode 61 is connected to the input terminal P0 of the balun transformer 8, and the output terminals P2, P1 of the balun transformer 8 are connected to the ground electrodes 41, 51. It is connected. As a result, the unbalanced current I ′ from the module 6 is converted into a pair of balanced currents I and −I by the balun transformer 8, and these balanced currents I and −I are output to the ground electrodes 51 and 41, respectively. As a result, the balanced currents I and -I having the same amplitude and the opposite phases, that is, the balanced currents I and -I having the same magnitude and opposite directions flow through the ground electrodes 51 and 41, so that the current I is the tip of the ground electrode 41. Thus, the ground electrode 41, 51 functions as a radiating element of the dipole antenna.
In this embodiment, the electrical length of the dipole antenna, that is, the electrical length between the tips 41a and 51a of the ground electrodes 41 and 51 is set to one half of the wavelength with respect to the frequency of 470 MHz to 770 MHz, and broadcasting such as D-TV is performed. Can be sent and received.

As described above, according to the wireless communication device of this embodiment, the ground electrodes 41 and 51 function as the radiating elements of the dipole antenna, and the balanced current can be surely passed through these electrodes. Gain and antenna characteristics can be obtained.
Further, in this embodiment, since it is possible to transmit and receive using radio waves having a long wavelength such as D-TV, the circuit boards 4 and 5 can be given a sufficient length. It is possible to give a margin to the design of 4, 5 and the hinge portion 3 and the like.

Next explained is the second embodiment of the invention.
FIG. 11 is a partial enlarged cross-sectional view showing the main part of the wireless communication apparatus according to the second embodiment of the present invention, and FIG.
As shown in FIG. 11, this embodiment is different from the first embodiment in that the high dielectric 9 is disposed in the overlapping portion of the ground electrode 61 and the ground electrode 51.
The high dielectric 9 is a dielectric having a relative dielectric constant in the range of 5 to 1000, for example, and is a trapezoidal member for adjusting the capacitance C1 between the ground electrodes 61 and 51 of the circuit boards 4 and 5. It is. As shown in FIG. 12, the high dielectric 9 is bonded onto the portion D1 from the part 1b to the end 1a of the housing 1 and when the housings 1 and 2 are opened, as shown in FIG. The high dielectric 9 is set so as to be positioned between the overlapping portions of the ground electrodes 61 and 51. The high dielectric 9 can also be bonded onto the portion D2 on the end 2a side of the housing 2.
Thereby, when the housings 1 and 2 are opened, the high dielectric 9 is interposed in the capacitor C1 formed by the ground electrodes 61 and 51.
Therefore, the size of the capacitance C1 between the ground electrode 61 and the ground electrode 51 can be easily adjusted by changing the relative dielectric constant of the high dielectric 9. As a result, the coupling capacitance between the ground electrodes 61 and 51 can be easily controlled.
Since other configurations, operations, and effects are the same as those in the first embodiment, description thereof is omitted.

Next explained is the third embodiment of the invention.
FIG. 13 is a partial enlarged cross-sectional view showing a main part of a wireless communication apparatus according to the third embodiment of the present invention, and FIG. 14 is a partial enlarged cross-sectional view showing a state where the housings 1 and 2 are opened.
This embodiment differs from the second embodiment in that a metal member is provided on a high dielectric material.
Specifically, as shown in FIG. 13, a high dielectric 9 ′ having a rectangular cross section is also provided on the end 2 a side of the housing 2, and the metal member 91 is connected to the inside of the high dielectric 9 ′ and the housing. Provided inside the high dielectric 9 on the body 1 side.
Then, the metal members 91 and 91 in the high dielectrics 9 and 9 ′ were electrically connected to the ground electrodes 61 and 51 through the metal lines 92 and 93.
As a result, as shown in FIG. 14, the metal members 91, 91 are interposed in the pair of high dielectrics 9, 9 ′ by opening the casings 1, 2. By adjusting the size, the size of the capacitor C1 between the ground electrodes 61 and 51 can be easily controlled.
Other configurations, operations, and effects are the same as those in the first and second embodiments, and thus description thereof is omitted.

In addition, this invention is not limited to the said Example, A various deformation | transformation and change are possible within the range of the summary of invention.
For example, in the above embodiment, a normal dielectric substrate is applied as the circuit boards 4 and 5. However, the circuit boards 4 and 5 may be formed using a so-called LTCC substrate. That is, at least, the module 6 can be made compact by forming the module 6 and the ground electrode 61 on the LTCC substrate.

1 is a perspective view showing a wireless communication device according to a first embodiment of the present invention. FIG. 2 is a perspective view illustrating the wireless communication device of FIG. 1 with a circuit board seen through from the back side. It is sectional drawing of the radio | wireless communication apparatus which shows the state folded. It is sectional drawing of the radio | wireless communication apparatus which shows the open state. It is a partial expanded sectional view for demonstrating the formation position of a hinge part. It is a partial expanded sectional view for demonstrating the overlapping part of a housing | casing. It is a top view which shows the back surface side of a circuit board. It is the schematic which shows the structure of a balun transformer. FIG. 9 is an equivalent circuit diagram of the balun transformer in FIG. 8. It is the schematic which shows a dipole antenna. It is a partial expanded sectional view which shows the principal part of the radio | wireless communication apparatus which concerns on 2nd Example of this invention. It is a partial expanded sectional view which shows the state which closed the housing | casing. It is a partial expanded sectional view which shows the principal part of the radio | wireless communication apparatus which concerns on 3rd Example of this invention. It is a partial expanded sectional view which shows the state which opened the housing | casing. It is a schematic sectional drawing which shows the radio | wireless communication apparatus which concerns on a 1st prior art example. It is a perspective view seeing through and showing the principal part of the radio communication equipment concerning the 2nd conventional example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 2 ... Housing | casing, 1a, 2a ... End part, 1b ... Area | region, 3 ... Hinge part, 4, 5 ... Circuit board, 6 ... Module, 7 ... Module input / output line, 8 ... Balun transformer, 9, 9 ' ... high dielectric material, 40 ... main antenna part, 41, 51, 61 ... ground electrode, 41a, 51a ... tip, 42 ... non-ground region, 91 ... metal member, 92, 93 ... metal line, C1, C2 ... capacitance, I ′: unbalanced current, I, −I: balanced current, L1, L2: inductor.

Claims (5)

A first housing containing a first circuit board having a power feeding unit;
A second housing containing a second circuit board;
A wireless communication device comprising: a hinge portion that connects the first housing and the second housing so as to be openable and closable,
A balun transformer is provided that converts the unbalanced current from the power feeding unit into a pair of balanced currents and outputs the pair, and the pair of output terminals of the balun transformer are connected to the first ground electrode of the first circuit board and the first balun transformer. Connected to the second ground electrode of each of the two circuit boards,
In a state separated from the first ground electrode, a third ground electrode is provided on the first circuit board, and the power feeding unit is disposed on the third ground electrode.
A power supply unit input / output line that functions as a first inductor by connecting the input / output unit of the power supply unit and the second ground electrode of the second circuit board, the third ground electrode, and the second ground electrode A first capacitor between the ground electrode, a second capacitor between the input / output unit of the power feeding unit and the first ground electrode, and between the third ground electrode and the first ground electrode. The balun transformer is configured by a second inductor provided in
A wireless communication device. The electrical length of the dipole antenna composed of the power feeding unit and the first to third ground electrodes is set to one half of the wavelength with respect to the frequency of 470 MHz to 770 MHz.
The wireless communication device according to claim 1 . The power feeding unit and the third ground electrode are provided on the LTCC substrate.
The wireless communication device according to claim 1, wherein the wireless communication device is a wireless communication device. The third ground electrode is disposed on one end of the first circuit board;
When the first and second housings are open, the end of the third ground electrode on the first circuit board is projected onto the end of the second ground electrode on the second circuit board. The first and second housings are connected by the hinge portion so that the first capacitance is generated between the second ground electrode and the third ground electrode.
A high dielectric for adjusting the first capacitance is disposed between overlapping portions of the third ground electrode and the second ground electrode.
The wireless communication device according to claim 1 , wherein the wireless communication device is a wireless communication device. A metal member is provided inside the high dielectric,
The wireless communication device according to claim 4 .

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