JP3984941B2 - Holder for portable radio - Google Patents

Description

  The present invention relates to a portable wireless device holder for holding a portable wireless device body and supplying operation power or charging a battery.

Cell phones and small handy transceivers, such as so-called portable radios, that have a built-in battery are often used in standby mode while the battery is being charged. For reasons such as making it easier to handle, portable radio holders (hereinafter also referred to as holders) for charging by holding a portable radio on a table in a standing manner are becoming widespread. There are various types of holders, such as a type placed on a table, and a wall-mounted type. However, since the mounting type is not related here, a detailed description is omitted.
Many portable wireless devices are provided with charging terminals (usually two poles on the ground side and the hot side) for receiving charging power from the outside.
The holder is provided with a spring terminal for applying a voltage to the charging terminal (not necessarily having a spring, generically called a power supply terminal) and wiring for supplying a voltage to the spring terminal. A charging circuit (hereinafter also referred to as an AC charger) for converting the voltage of the commercial power source into a voltage suitable for battery charging is provided inside this holder, but if anything, it is provided outside. In general, power is supplied through the wiring. In any case, the size of the holder is about several centimeters. On the other hand, the frequency of use of the portable wireless device is in the range of several hundred MHz to 2 GHz, and the length of the antenna attached to the portable wireless device is often several centimeters.

  The antenna performance of the portable wireless device is adjusted so as to be the best when the wireless device is used in hand. By the way, when the wireless device is set in the holder, the substrate pattern, wiring circuit, etc. inside the holder are connected to the charging terminal of the wireless device. Since at least one of the charging terminals is common to the ground side of the antenna matching circuit of the portable wireless device, when the wiring is connected to the ground side, the impedance seen from the outside of the antenna circuit of the portable wireless device changes, which affects the antenna performance. This causes adverse effects such as a decrease in standby reception sensitivity due to changes in antenna directivity and antenna gain, and a weak transmission output for connection confirmation. As a technique for removing such an influence, there is one disclosed in Patent Document 1.

In the technique described in Patent Document 1, a ferrite core, a ferrite sheet, a ferrite chip bead, or the like is arranged in the middle of the wiring between the spring terminal and the AC charger circuit where the output circuit of the AC charger is in contact with the portable wireless device. Thus, the high-frequency current flowing out from the radio main body to the AC charger side via the battery is cut off. This prevents the ground current distribution from being disturbed and the antenna gain from being lowered.
However, when this technology is put to practical use, since a DC large current for battery charging (generally several hundred mA) flows through the AC charger line, the ferrite beads used do not saturate even with a large DC current. Such a thing has the problem that an external shape is large. In other words, since the size of the holder cannot be increased unnecessarily, looking at the frequency-resistance data of commercially available ferrite bead cores that can be adopted in terms of shape, the resistance peak is about 100Ω at 1 GHz. At the above frequency, the resistance component tends to decrease. For example, as shown in FIG. 8, even if a commercially available ferrite bead core has a large size (4.5 × 1.6 × 0.9 mm), it has a resistance of about 120Ω (at a frequency of 1 GHz). The impedance is too small to sufficiently block high frequencies.
Since it is difficult to say that an impedance of about 100Ω can be sufficiently cut off at a high frequency, even if it is used, the antenna gain is actually lowered. In a system where the frequency used is higher than 1 GHz, the effect of high-frequency cutoff is reduced, and there is a problem that the performance as a radio device is lowered and the antenna gain is lowered, that is, not suitable for practical use.
JP-A-11-341126

  As described above, the conventional holder for portable radio equipment does not have sufficient high-frequency cutoff performance of the power supply terminal, and in the state where the portable radio is held for charging, the communication performance of the portable radio is higher than that of handheld use. There was a problem that it was reduced.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a holder for a portable wireless device that solves the above-described problems and does not deteriorate the communication performance of the held portable wireless device even during charging.

The portable wireless device holder of the present invention includes a storage battery, first and second charging terminals for charging the storage battery from the outside, one terminal connected to the antenna, and the other terminal connected to the second charging terminal. Holding means for holding a portable radio having a high-frequency transceiver having a high-frequency input / output terminal
First and second power supply terminals that contact the first and second charging terminals, respectively, when the portable wireless device is held;
Wiring for supplying charging current to the storage battery connected to each of the first and second power supply terminals;
It is inserted by connecting in series with each other in the middle of the wiring, provided with a plurality of different parallel resonant circuit from each other resonant frequency is tuned to one of a plurality of communication frequency bands of the portable radio device, the plurality of parallel resonance The circuit is connected in order from the highest resonance frequency to the lowest resonance frequency from the side closer to the power supply terminal to the side farther from the power supply terminal.

The portable wireless device holder of the present invention is tuned to a plurality of use frequency bands of the portable wireless device in series at a predetermined length of the power supply terminal that supplies power by contacting the charging terminal of the portable wireless device. A plurality of parallel resonant circuits are inserted in order from the highest frequency . Since the impedance of the parallel resonant circuit is very high, the line from this power supply terminal to the parallel resonant circuit functions as a ground line suitable for the frequency of use of the portable radio at high frequency, and the line ahead of the parallel resonant circuit is portable The effect of the long ground line is no longer applied to the antenna, the antenna characteristics are stabilized, and the change in the antenna characteristics when the portable radio is not held in the holder is reduced. It is done.

  The objective of reducing high-frequency current flowing through the wiring in the holder and reducing its adverse effects was efficiently realized with the minimum number of parts.

Embodiment 1 FIG.
The configuration of the first embodiment will be described with reference to FIGS. FIG. 1 is an explanatory diagram for explaining a use state of a holder for a portable wireless device according to the present invention, FIG. 2 is a schematic internal circuit diagram for explaining the operation thereof, and FIG. 3 shows a structure of a substrate in the holder. . In the following description, a case where the mobile wireless device is the mobile phone 1 will be described as an example. The mobile phone 1 has a storage battery 9 and a positive side 11 and a negative side 12 that are charging terminals for charging the storage battery 9. When the mobile phone 1 is inserted into the holder 2, the charging terminals (positive side 11, negative side 12) on the bottom surface of the mobile phone 1 are hot-side spring contacts (21 in FIG. 2) arranged on the holder 2, and the ground side The spring contacts 22 (both referred to as power supply terminals) are in contact. The hot-side spring contact (21 in FIG. 2) and the ground-side spring contact 22 may be simply referred to as a power supply terminal. The positive charging terminal 11 is a first charging terminal according to the present invention, and the negative charging terminal 12 is a second charging terminal according to the present invention. The hot-side spring contact (21 in FIG. 2) is a first power supply terminal referred to in the present invention, and the ground-side spring contact 22 is a second power supply terminal referred to in the present invention.
In general, the spring contacts 21 and 22 are often provided on the substrate 23 in the holder 2. The spring contacts 21 and 22 are connected to patterned lines (hot 21a and ground 22a) on the substrate 23. The line is connected to the AC charger 5 via wiring outside the holder (hot 21b, ground 22b), and receives charging power from the output of the AC charger 5 that generates a charging voltage from an AC line (not shown). The mobile phone 1 is charged by connecting the AC line to an outlet.

There are several methods for the antenna 3 of the cellular phone 1, but in the case of the most used drawer / retractable whip antenna (not shown), the antenna can be easily matched and handled as a cellular phone. From the standpoint of antenna physical length, a whip antenna (hereinafter referred to as an antenna) having a length of approximately λ / 4 is used. λ is one wavelength of the communication frequency used. Since the whip antenna is a monopole antenna, the high frequency transmitting / receiving unit 20 of the portable wireless device 1 has two high frequency input / output terminals (reception / transmission terminals) as shown in FIG. The antenna 3 is connected, and the other pole is connected to the ground, that is, to the second charging terminal 12. Depending on the model of the portable wireless device, the other end may be separated from the ground and connected to a dedicated ground line (radial) provided inside the portable wireless device to obtain an operation mode close to that of a dipole antenna. Even in such a case, since the radial is capacitively coupled to the ground of the radio and operates close to that connected to the ground, no particular distinction is made in the following description. Therefore, the ground line of the portable wireless device 1 operates as being close to the ground line of the antenna 3, that is, as a part of the antenna, and its shape and length greatly affect the characteristics of the antenna 3.
Even if not directly connected to the high-frequency circuit, the conductive material disposed in the vicinity of the antenna 3, such as a substrate inside the mobile phone 1, a shield case (not shown) that covers the mobile phone, the wiring of the holder 2, etc. However, some high-frequency current flows and affects the characteristics of the antenna 3.
Considering the influence of such proximity objects, the antenna performance of the mobile phone is adjusted including the conditions (electrical length, material, etc.) of the mobile phone ground (substrate, shield case, etc.). Since the mobile phone 1 is adjusted so as to be optimal when the mobile phone 1 is taken out, if the holder 2 holds the mobile phone 1, an unexpected cable or the like is connected to the mobile phone 1 and the adjustment is shifted, and the antenna performance changes.

  Therefore, between the spring contact 22 on the ground side on the substrate 23 of the holder 2 and the patterned line (ground 22a), a parallel resonance circuit 27 constituted by a chip-shaped coil 27L and a capacitor 27C as shown in FIG. insert. The coil 27L and the capacitor 27C are selected so that the tuning frequency f0 of the parallel resonant circuit 27 is approximately the center frequency of the frequency band used by the mobile phone 1. As a result, the ground of the mobile phone 1 (minus side 12 of the charging terminal on the bottom surface of the mobile phone) is cut off at high frequency in the parallel resonance circuit 27 portion, and high-frequency current hardly flows.

  The positive side 11 of the charging terminal of the mobile phone 1 is connected to the ground by a DC smoothing capacitor (not shown) or the like. However, this type of capacitor has a certain impedance at the operating frequency of the mobile phone. The high-frequency current does not flow to the side as much as the ground side, and there is little influence on the antenna when the wiring is connected to the plus side. Still, in order to further reduce this effect, the frequency band used by the mobile phone 1 is approximately at the center frequency between the spring contact (hot side 21) and the patterned hot line 21a on the substrate 23 in the holder 2. An open stub 28 having a wavelength λ / 4 is provided. The presence of the stub 28 can considerably reduce the high frequency transmitted to the hot lines 21a, 21b, the AC charger 5 and the like connected in high frequency. When the open stub 28 is formed on the substrate 23, the wavelength is shortened due to the relative dielectric constant of the substrate, so that the actual length is shorter than λ / 4.

  With the above configuration, the connection wires 22a, 22b, 21a, and 21b on the outlet side of the spring contacts 21 and 22 of the board 23 in the holder 2 are invisible in a high frequency state (connection is not detected). When the telephone 1 is held by the holder 2, the change in antenna characteristics of the mobile telephone 1 is reduced.

  Although the parallel resonance circuit 27 may be provided on both the hot side 21 and the ground side 22, as described above, the influence of the hot side is originally small and an arrangement for avoiding mutual interference between the two coils 27L. It is provided only on the ground side for reasons such as difficulty.

In the above description, it is described that the parallel resonant circuit 27 is inserted into the ground side 22a, but more precisely, the side to which one end of the high-frequency output circuit is connected becomes the ground line referred to here, and the polarity of the storage battery 9 It doesn't matter.
By inserting the parallel resonant circuit 27, an impedance of at least about 10 KΩ can be obtained. Therefore, the high frequency current is reduced to about 1/100 compared to the case of inserting a conventional ferrite bead (only an impedance of about several hundreds of Ω can be obtained). Therefore, the antenna gain degradation cannot be measured.
In FIG. 1, the AC charger 5 is described as being provided outside the holder 2, but the same is true even if it is provided inside the holder. In FIG. 2, the storage battery 9 is illustrated such that the negative side is connected to the ground line. However, the present invention is not limited to this, and the same effect can be obtained even if the positive side is connected to the ground line.
Further, even a wireless device that does not contain a storage battery and operates by being supplied with power from the outside through a power supply line can be used as long as one side of the high-frequency circuit is connected to this power supply line.

Embodiment 2. FIG.
A second embodiment of the present invention will be described with reference to FIG. Instead of the open stub 28 on the hot line 21 side shown in FIG. 2 of the first embodiment, a ferrite bead 30 is used in FIG. The characteristics of the ferrite bead 30 itself are as described in FIG. As described above, the wiring connected to the charging terminal of the mobile phone 1 to which the high-frequency transmission / reception circuit 20 is not directly connected, that is, the power supply terminal connected to the positive side of the charging terminal (the same potential as the hot line 21 of the substrate in the holder). Is small but not zero on antenna performance. In order to reduce this influence as much as possible, the ferrite beads 30 are arranged in the hot line pattern 21b to reduce the high-frequency current flowing into the outlet side. Although the number of ferrite beads 30 is one in FIG. 4, it may be plural.

  4, components such as the wiring on the outlet side from the spring contacts 21/22 (feeding terminals) on the substrate 23 in the holder 2 are not visible in high frequency. Antenna characteristics can be obtained.

Embodiment 3 FIG.
Embodiment 3 will be described with reference to FIG. In recent years, mobile phones (or mobile radio devices in general) do not use only one frequency band but often use a plurality of frequencies. In such a cellular phone, when only one parallel resonant circuit is used as shown in FIGS. 2, 3, and 4, the circuit on the outlet side is cut off at a high frequency from the spring contact in the holder only in one frequency band. Therefore, a plurality of parallel resonant circuits having different frequencies according to the width of the used frequency band are connected in series. FIG. 5 shows an example in which the second parallel resonant circuit 270 is provided and two circuits are provided. With this configuration, the wiring on the outlet side of the spring contacts 21 and 22 of the substrate 23 in the holder 2 is invisible in high frequency in a wide frequency band, so that the antenna characteristics of the mobile phone as designed can be obtained. It becomes possible.
In FIG. 5, a ferrite bead 30 is used on the hot side, but an open stub 28 may be used as in FIG.

Embodiment 4 FIG.
A fourth embodiment will be described with reference to FIG. Although the length of the case of the mobile phone 1 is determined in consideration of the characteristics of the antenna, it should be determined without giving sufficient consideration to the characteristics of the antenna according to the design concept of the external design of the product and the technology at the time of development. There is also. However, especially when an antenna corresponding to λ / 4 is used, as described above, the ground portion in the casing is electrically operated as a part of the antenna. Therefore, when the length of the ground portion is changed from an appropriate value when held by the holder 2, the radiation efficiency of the antenna is considerably reduced. In addition, since the average value (averaged gain) in the plane orthogonal to the antenna is also affected by the ground portion (unnecessary directivity is generated, etc.), there is a possibility that the sensitivity will decrease more than the efficiency deterioration. The holder of the present embodiment optimizes the electrical length of the ground portion by adjusting the length of 99 parts in FIG. 6 (the length from the ground-side power supply terminal 22 to the first parallel resonant circuit 27). The optimal antenna efficiency and horizontal plane averaging gain are obtained. FIG. 7 shows a change example of the antenna radiation efficiency when the value of 99 parts in FIG. 6 is changed. This example is an example of a frequency of 1 GHz, but the maximum degradation is about 40% compared to the efficiency at the optimum value (about 70 mm).

In addition, as shown in FIG. 5 of the third embodiment, when a plurality of parallel resonant circuits 27 having different frequencies are connected, the size of 99 parts is different for each frequency. Accordingly, the 99-part dimension is selected to be an optimum value for each frequency.
For example, when the case length is 75 mm and the mobile phone operates in the 1 GHz band, the parallel resonance circuit 27 is provided near the spring contact of 75 mm (λ / 4), so that the lines after the parallel resonance circuit 27 are high-frequency. Can be blocked. Similarly, if the case length is 75 mm and the mobile phone operates in the 800 MHz band, λ / 4 is about 94 mm. Therefore, by providing a parallel resonance circuit in the desktop holder wiring about 19 mm from the spring contact, The same effect can be obtained. Therefore, when using a plurality of parallel resonant circuits, the parallel resonant circuits are connected in order from the one with the highest frequency from the side close to the contact.
In addition, when the casing length is 75 mm as described above, if the mobile phone operates in the 2 GHz band, the optimal cutoff point is inside the mobile phone, and when a parallel resonant circuit is arranged in the holder wiring, The position is about 114 mm from the lower end of the housing. This is because the high frequency short / open characteristics are repeated every half wavelength. In this case, the parallel resonant circuit for the high frequency is arranged farther from the spring contact than the parallel resonant circuit for the low frequency.

Embodiment 5 FIG.
The capacitor 27C of the parallel resonance circuit 27 in FIG. 3 of the first embodiment is a varicap (variable capacitance diode), and the capacitance is changed in accordance with the switching of the frequency used by the mobile phone 1, thereby making one set of parallel resonance. The circuit 27 can correspond to a wide frequency.

Embodiment 6 FIG.
In FIG. 6 of the fourth embodiment, the dimension from the ground-side spring terminal 22 to the optimum position of the parallel resonant circuit 27 becomes negative, that is, as the dimension 99 is increased, the antenna efficiency decreases and the optimum position is obtained. There may not be. In such a case, since the ground line inside the mobile phone 1 is originally too long, the parallel resonance circuit 27 may be attached inside the mobile phone 1.

Embodiment 7 FIG.
In the description of the embodiment in which a plurality of parallel resonance circuits are inserted into the ground line side 22a in the holder 2 in FIG. 5 of the third embodiment, it has been described that the ferrite beads 30 are inserted into the hot line side 21a. It is also possible to use the stub 28 of the first form. Needless to say, the embodiment in which the capacitor of the parallel resonance circuit according to the fifth embodiment is a varicap is applicable to the case where the number of parallel resonance circuits 27 is plural.
The cellular phone 1 described in the above embodiment is a portable radio device according to the present invention.

  The present invention can be used not only for a cellular phone but also for a transceiver, a portable radio, or a portable modem for a wireless LAN.

It is explanatory drawing explaining the use condition of the holder for portable radio | wireless machines by Embodiment 1 of this invention. It is an internal circuit diagram for demonstrating the operation | movement of FIG. It is detailed explanatory drawing inside the holder of FIG. FIG. 5 is an internal detailed explanatory diagram of a portable wireless device holder according to a second embodiment. FIG. 10 is an internal detailed explanatory diagram of a portable wireless device holder according to a third embodiment. FIG. 10 is an internal detailed explanatory diagram of a portable wireless device holder according to a fourth embodiment. It is a characteristic explanatory view explaining the effect of FIG. It is a characteristic view of the ferrite bead used for this invention.

Explanation of symbols

1 mobile phone, 2 holder, 3 antenna, 4 power line,
5 AC charger, 20 high frequency transmitter / receiver circuit,
11 first charging terminal, 12 second charging terminal,
21 Hot-side spring contact (first power supply terminal),
21a pattern, 21b (hot side) wiring,
22 ground side spring contact (second power supply terminal),
22a pattern, 22b (ground side) wiring,
23 substrate, 27 parallel resonant circuit, 27L coil,
27C capacitor, 28 open stub, 30 ferrite beads,
99 Distance between the ground-side spring contact and the parallel resonant circuit,
270 Second parallel resonant circuit.

Claims (5)

High-frequency transmission / reception having a storage battery and first and second charging terminals for charging the storage battery from the outside, a high-frequency input / output terminal having one terminal connected to the antenna and the other terminal connected to the second charging terminal Holding means for holding a portable wireless device having a portion,
First and second power supply terminals that contact the first and second charging terminals, respectively, when the portable wireless device is held;
Wiring for supplying charging current to the storage battery connected to each of the first and second power supply terminals;
It is inserted by connecting in series with each other in the middle of the wiring, provided with a plurality of different parallel resonant circuit from each other resonant frequency is tuned to one of a plurality of communication frequency bands of the portable radio device, the plurality of parallel resonance The holder for a portable radio device , wherein the circuit is connected in order from the highest resonance frequency to the lowest resonance frequency from the side closer to the power supply terminal to the side farther from the power feeding terminal . The plurality of parallel resonant circuits are inserted in the middle of the wiring connected to the second power supply terminal on one side of the first and second power supply terminals to which one of the high-frequency input / output terminals is connected. The portable radio holder according to claim 1, wherein   The connection position of the plurality of parallel resonance circuits is connected to a position where the radiation efficiency of the antenna is substantially maximum at each resonance frequency when the portable wireless device is held by the holding means. The holder for portable radios according to claim 1 or 2. High-frequency transmission / reception having a storage battery and first and second charging terminals for charging the storage battery from the outside, a high-frequency input / output terminal having one terminal connected to the antenna and the other terminal connected to the second charging terminal Holding means for holding a portable wireless device having a portion,
First and second power supply terminals that contact the first and second charging terminals, respectively, when the portable wireless device is held;
Wiring for supplying charging current to the storage battery connected to each of the first and second power supply terminals;
A coil having a predetermined inductance inserted in the middle of the wiring and a variable capacitance diode connected in parallel to the coil, and provided with a parallel resonance circuit that tunes to a plurality of communication frequency bands of the portable radio device. A holder for a portable radio. The parallel resonant circuit configured by the coil having a predetermined inductance and a variable capacitance diode connected in parallel to the coil and tuned to the plurality of communication frequency bands is used by connecting a plurality of sets in series with each other. The portable radio holder according to claim 4, wherein

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