JP3425349B2 - Portable wireless devices - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile radio device such as a mobile phone or a personal digital assistant which is composed of a plurality of dielectric substrates, and more particularly to an antenna generated on a radio section substrate due to a board connector. The present invention relates to a portable wireless device configured to suppress the generation of leakage current.

[0002]

2. Description of the Related Art Generally, in a mobile wireless device such as a mobile phone or a personal digital assistant, a high frequency current generated in a wireless unit appears as noise in a control unit including a baseband circuit. Often the sub-boards are configured separately.

FIG. 12 shows an example of a conventional portable radio apparatus in which a radio section board and a control section board are separately constructed. This portable wireless device 101 includes a substrate 103 on which a control circuit 102 mainly composed of an integrated circuit is mounted and a wireless circuit 10.
4 is mounted, and the antenna 106 for transmitting and receiving is connected to the wireless circuit 104.

The board 103 and the board 105 are connected by a connector 107. The connector 107 is used for signal transmission and power supply between the control circuit 102 and the wireless circuit 104. The connector 107 is connected to the part farthest from the antenna 106. This is because TX (transmitter), VCO, etc. in the wireless circuit 104 are caused by the current leaked from the antenna 106 to the substrate 105.
There is a case where the performance of the (voltage controlled oscillator) or the like is deteriorated (deterioration of the modulation accuracy, etc.), and the component which is weak against the interference is directly received by the current generated on the antenna 106.
It was said that it was better to separate it as much as possible. Along with this, a connector 107 for transmitting signals and supplying electric power to these parts is also provided at a position far from the antenna 106. However, simply separating these parts from the antenna does not provide a countermeasure against the performance deterioration.
It was necessary to shield 4 with a metal not shown. This is an obstacle to downsizing, weight saving, and price reduction of the portable wireless device.

FIG. 13 shows a simulation model of the high frequency current generated on the portable radio apparatus 101 of FIG. Since mobile wireless devices such as mobile phones and PHSs have been downsized to the same wavelength as the frequency used, the length of the wireless device is 1 wavelength and the width is approximately 1/5 wavelength. As for the antenna, a 1/4 wavelength monopole antenna is used. All of these are made of perfect conductors.

FIG. 14 shows the amplitude of the current distribution between the substrate 103 and the back plate 105 analyzed by the simulation model of FIG. From FIG. 14, the antenna 1 is attached to the connector 107.
It can be seen that a current larger than the maximum value on 06 is generated. From this, the wireless circuit 104 is connected to the antenna 10
Even if it is separated from 6, the effect is small.
It can be seen that a leakage current from the antenna 106 is generated above.

[0007]

As described above, the conventional portable radio device relates to a portable radio device such as a mobile phone or a personal digital assistant which is composed of a plurality of dielectric substrates, and in particular, a radio due to the presence of a substrate connector. There is a problem that leakage current from the antenna is generated on the circuit board and the characteristics of the wireless circuit are deteriorated.

An object of the present invention is to provide a portable radio apparatus which solves such problems and can suppress the generation of leakage current from an antenna.

[0009]

According to the present invention, there is provided a first dielectric substrate provided with a radio circuit section, and a second dielectric substrate provided in parallel with the first dielectric board and provided with a control circuit section. A dielectric substrate, a connector connecting the first and second dielectric substrates, and an antenna connected to the first dielectric substrate, the connector being the first dielectric substrate and the antenna. A portable wireless device arranged at the end portion of the second dielectric substrate at a connection point with.

Further, as a method of positively eliminating the leakage current from the antenna, the length of the first dielectric substrate in the extension direction of the antenna is set to a quarter wavelength of the frequency used in the portable radio device. Has been done.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of a portable radio apparatus according to the first embodiment of the present invention. The mobile wireless device 11 includes a wireless circuit board 15 on which a wireless circuit module (wireless circuit unit) 14 is mounted and a control circuit module (control circuit unit).
A control circuit board 13 on which 12 is mounted is configured in parallel, these boards are connected by a connector 17, and an antenna 16 is connected to a wireless circuit board 15. The connector 17 is used for signal transmission and power supply between the control circuit module 12 and the wireless circuit module 14, and has a control circuit board slot 17a at one end and a wireless circuit board slot 17b at the other end. , The control circuit board 13 and the wireless circuit board 15 are inserted into the slots 17a and 17b, respectively, to connect the two boards to each other. The connector 17 is provided at the end of the control circuit board 13 where the wireless circuit board 15 and the antenna 16 are connected. Specifically, the antenna 16 is connected to the board 15 at the terminal connection terminal portion 15a of the wireless circuit board 15, and the connector 17 is connected to the connection point between the board 15 and the antenna 16 and the terminal connection terminal portion 13a of the control circuit board 15. Are arranged to connect the substrates 13 and 15 to each other. That is, the connector 17 connects the control circuit board 13 and the wireless circuit board 15 at the position closest to the antenna 16. In addition,
As the antenna 16, for example, a linear monopole antenna may be used.

FIG. 2 shows a schematic configuration of a portable radio apparatus according to the second embodiment of the present invention.

In the portable radio device 11, a radio circuit board 15 on which the radio circuit module 14 is mounted and a control circuit board 13 on which the control circuit module 12 is mounted are arranged in parallel and connected to each other by a connector 17, and the radio circuit board is connected. An antenna 16 is connected to 15. Antenna 1
The length of the wireless circuit board 15 in the extension direction of 6 is set to a quarter wavelength of the frequency used in the portable wireless device 11, and the connector 17 connects the wireless circuit board 15 and the antenna 16 as in the first embodiment. It is arranged at the end of the control circuit board 13 at the connection point.

FIG. 3 shows a simulation model of the portable wireless device according to the embodiment of the present invention. Similar to the simulation model of the portable wireless device of the conventional example shown in FIG. 13, the portable wireless device such as a mobile phone and PHS is downsized to the same wavelength as the frequency to be used. The length of the machine is one wavelength and the width is about 1 /
The wavelength is set to 5 and the antenna is a 1/4 wavelength monopole antenna. All of these are composed of perfect conductors. Here, the difference from the conventional example is that the connector is located near the antenna feeding point.

FIG. 4 shows the amplitude of the current distribution between the control unit substrate 13 and the radio unit substrate 15. From this figure, the current on the antenna 16 hardly changes, and the control unit substrate 1
It can be seen that the leakage current from the antenna is suppressed between 3 and the radio section substrate 15.

The reason why the leakage current from the antenna generated on the radio section substrate can be suppressed by disposing the connector as described above in the present invention will be described below.

In the conventional example, the current generated on the antenna 16 was flowing between the control unit substrate 13 and the radio unit substrate 15, but the connector 17 as in the first embodiment.
By arranging, the current flows along the path as shown in FIG. 5, and the control unit substrate 13 and the wireless unit substrate 1 are
It is considered that the current between the two and 5 decreases.

In the second embodiment, the length of the radio circuit board is set to one quarter wavelength of the frequency used.
In this case, it is considered that the current between the control circuit board 13 and the wireless circuit board 15 is generated in the route of ~ as shown in FIG. An equivalent circuit constructed based on this route is shown in FIG. In the path, the current amplitude is maximum at the feeding point. Here, since the portion shown as an open portion between the control circuit board 13 and the wireless circuit board 15 is away from the feeding point of the antenna by a quarter wavelength, it becomes a node of radio waves and the current is reduced.

Further, paths are formed in this portion so as to have a high impedance value, and it becomes difficult for current to flow into these paths. A description of this mechanism is shown in FIG. According to the figure. In the parallel two lines, the voltage becomes 0 at the short-circuited portion (x = 1), and the current becomes 0 near x = 0. Voltage (V)
Can be assumed to be V∞cos (kx) (where k = 2π / λ, λ: wavelength), and the current (I) can be assumed to be I∞sin (kx). The impedance is Z = V / I∞1 / tan (kx)
Can be assumed, and when l = λ / 4, impedance Z → ∞ (infinity). Thereby, the leakage current from the antenna, which is generated between the control circuit board 13 and the wireless circuit board 15, can be reduced. Here, the length of the path does not affect the present invention and may be arbitrary.

FIG. 9 shows a result of simulating the maximum value of the leakage current from the antenna generated between the control circuit board 13 and the radio circuit board 15 when the position of the connector 17 is changed. Here, the numerical value of the leakage current from the antenna is standardized by the maximum value of the current generated on each antenna. In the case of l = λ / 4, a current is generated between the substrates more than the current generated on the antenna, and as l approaches 0,
It can be seen that the leakage current from the antenna generated between the substrates is reduced, and finally the current value is ⅕ of that in the case of λ / 4.

Here, the operation of the wireless device will be briefly described taking the case of a portable wireless device as an example. First, at the time of transmission, the user's voice input via a transmitter (not shown) is supplied to the wireless circuit module 14 via the control circuit module 12, modulated into a high frequency signal of a predetermined frequency, and then transmitted from the antenna 16. Emitted as radio waves. On the other hand, when receiving,
The signal received by the antenna 16 is the wireless circuit module 1
After being converted to a predetermined intermediate frequency in 4, it is supplied to the control circuit module 12 and output as a voice from a receiver (not shown).

As described above, in the wireless device of the present embodiment, the current leaking from the antenna 16 to the substrate 15 is suppressed, so that the TX which is particularly vulnerable to the interference due to the leakage current from the antenna 16 in the wireless circuit module 14.
(Transmission unit), VCO (Voltage Controlled Oscillator), etc. are placed away from the connector provided near the antenna feeding point, and placed at the farthest place that is a quarter wavelength away from the antenna to reduce the effect of leakage current from the antenna. It becomes possible. Furthermore,
Depending on the specifications of the wireless device, the need for the metal shield is eliminated, and the portable wireless device can be downsized, weighed, and reduced in price.

The present invention is not limited to the above embodiment, but can be variously modified as follows. For example, although the monopole antenna is used as the antenna in the above-described embodiment, a whip antenna, a loop antenna, an inverted F-type antenna, or the like can be used, and the shape and form thereof are not particularly limited.

Further, in the above embodiment, the dielectric substrate is 2
Although it is composed of a single board, as shown in FIGS. 10 (a) and 10 (b), it is possible to use a plurality of dielectric boards of 3 or more maki, and the position of the connector is located near the antenna feeding part. can do. FIG. 10A shows an example in which a low frequency transmission module and a high frequency reception module are separately provided on the left and right sides. FIG. 10B shows an example in which the transmission module and the reception module are arranged above and below the control circuit board.

In the above embodiment, the shape of the dielectric substrate is a rectangle long in the antenna direction, but it may be a rectangle short in the antenna direction as shown in FIG.

[0027]

As described above, according to the present invention, the wireless circuit module is provided on the first dielectric substrate, and the control circuit module is provided on the second dielectric substrate.
In a dielectric wireless device in which a second dielectric substrate is configured in parallel, a connector for connecting the first and second dielectric substrates is provided, and an antenna is connected to the first dielectric substrate, the position of the connector is It is possible to provide a portable wireless device characterized in that it is arranged at the end of the second dielectric substrate at the location where the first dielectric substrate and the antenna are connected.

Further, in order to positively reduce the leakage current from the antenna, the length of the first dielectric substrate in the extension direction of the antenna is set to a quarter wavelength of the frequency used in the portable radio device. A portable wireless device characterized in that it can be applied.

As a result, among the radio circuits, TX (transmitting section), VC, which is particularly vulnerable to interference due to leakage current from the antenna,
It is possible to reduce the influence of leakage current from the antenna by arranging O (voltage-controlled oscillator) away from the connector provided near the antenna feeding point and arranging it at the farthest place that is a quarter wavelength away from the antenna. Further, depending on the specifications of the wireless device, the need for the metal shield is eliminated and unnecessary.
This makes it possible to reduce the size, weight and cost of the portable wireless device.

[Brief description of drawings]

FIG. 1 is a perspective view of an internal configuration of a mobile wireless device according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a schematic internal configuration of a mobile wireless device according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a model in the second embodiment.

FIG. 4 is a view showing a distribution of current amplitudes on a substrate and an antenna according to the second embodiment.

FIG. 5 is a diagram showing an operating principle of a leakage current from an antenna generated in the mobile wireless device of the first embodiment.

FIG. 6 is a diagram showing an operating principle of a leakage current from an antenna generated in the mobile wireless device of the second embodiment.

FIG. 7 is a diagram showing an equivalent circuit of a leakage current from an antenna generated in the mobile wireless device of the present invention.

FIG. 8 is a diagram showing impedance between a wireless board and a control board of the portable wireless device of the present invention.

FIG. 9 is a diagram illustrating a change in a current value on a board when the position of a connector is changed.

FIG. 10 is a schematic configuration diagram of a mobile wireless device according to another embodiment of the present invention.

FIG. 11 is a schematic configuration diagram of a mobile wireless device according to another embodiment of the present invention.

FIG. 12 is a perspective view showing a schematic configuration of a conventional portable wireless device.

FIG. 13 is a diagram showing an analysis model in a conventional portable wireless device.

FIG. 14 is a diagram showing a distribution of amplitudes of currents on a substrate and an antenna in a conventional portable wireless device.

[Explanation of symbols]

11 ... Portable wireless device 12 ... Control circuit module 13 ... Control circuit board 14 ... Wireless circuit module 15 ... Wireless circuit board 16 ... Antenna 17 ... Connector

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-9-83233 (JP, A) JP-A-3-285425 (JP, A) JP-A-5-327527 (JP, A) JP-A-9- 270728 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04B 1/38-1/58 H01Q 1/00-1/52

Claims (3)

(57) [Claims] 1. A first dielectric substrate provided with a wireless circuit unit, a second dielectric substrate arranged in parallel with the first dielectric substrate and provided with a control circuit unit, said first dielectric substrate, a connector for connecting first and the second dielectric substrate being connected to said first dielectric substrate, the connector viewed from
And an antenna provided on the side opposite to the first dielectric substrate, and the length of the first dielectric substrate is used in the wireless circuit unit.
The portable wireless device is set to a quarter wavelength of the frequency, and the connector is arranged at the end of the second dielectric substrate at the connection point between the first dielectric substrate and the antenna. 2. The portable wireless device according to claim 1 , wherein the first dielectric substrate is composed of a pair of dielectric substrates on which a transmission module and a reception module are mounted. Wherein said antenna is portable radio apparatus according to claim 1 or 2, wherein a linear antenna.