WO2006123419A1

WO2006123419A1 - Antenna apparatus and mobile communication terminal apparatus

Info

Publication number: WO2006123419A1
Application number: PCT/JP2005/009242
Authority: WO
Inventors: Yukinari Takahashi; Kenichi Satou; Satoshi Watanabe
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2005-05-20
Filing date: 2005-05-20
Publication date: 2006-11-23

Abstract

To maintain the resonance frequencies of a wide band usable in a multimode system, while allowing a diversity reception. A switching circuit (4c) located in the vicinity of a feeding part (4a) of an antenna element (402) is used to control the impedance and maintain a first resonance frequency, while switching only a second resonance frequency to a third resonance frequency. When a feeding part switching circuit (5b) is activated to switch from the feeding part to a feeding part (4d) to switch the first and second resonance frequencies to fourth and fifth resonance frequencies, the switching circuit (4c) can be used to control the impedance, while switching only the fifth resonance frequency to a sixth resonance frequency.

Description

Specification

ANTENNA DEVICE AND MOBILE COMMUNICATION TERMINAL DEVICE

Technical field

TECHNICAL FIELD [0001] The present invention relates to an antenna device that is used in a mobile communication terminal device or the like and can be switched to a wideband resonance frequency, and in particular, two resonance frequencies (which are divided into two or more and different from each other). In the built-in antenna element having the `` first resonance frequency '' and the `` second resonance frequency '', for example, the second resonance frequency of the first and second resonance frequencies is different from this. The means for switching to the “third resonance frequency” or the first and second resonance frequencies can be switched to the “fourth and fifth resonance frequencies” different from the first to third resonance frequencies. A multi-channel device having means for switching only the fifth resonance frequency to the “sixth resonance frequency” different from the first to fifth resonance frequencies while the fourth resonance frequency remains fixed when the resonance frequency is switched to this resonance frequency. Band antenna was provided It related to the mobile communication terminal unit comprising the antenna device of the antenna device and the child.

Background art

Conventionally, a resonant frequency switching type antenna used for a mobile phone includes a feed pin 103 and a feed cable 104 connected to a feed point 102 of a radiation plate 101 as shown in FIGS. 10 (A) and (B). And a switching matching circuit 105 are known. For the switching matching circuit 105, the power supply voltage Vcc is applied to the series arm consisting of the switching diode CR1 and the parallel capacitor C1, and the bias control voltage is applied to the parallel arm powered by the switching diode CR2 and the series capacitor C2. A configuration is known in which Vcont is applied and the control voltage is turned on and off to match the first and second frequency bands (see, for example, Patent Document 1).

However, with such a conventional antenna configuration, GSM (Global System for Mobile

Communication) / DCb (Digital communication bystem) / PC (Personal

When trying to support multi-mode systems such as (Communication Services) / UMTS (Universal Mobile Telecommunication System), it is difficult to secure multiple frequency bands at the same time. Also, if you try to support a multimode system, Since the frequency band is widened, the occupied volume of the antenna device is increased. From such a situation, there is a risk that the mounting space for electrical parts and electronic parts in a mobile phone or the like may be narrowed, the mounting space may be lost, or the design of the mobile phone or the like may be impaired.

[0004] The present invention has been made to solve such problems, and GSMZDCSZPCS

Ensuring a wide-band resonance frequency that can be used in a multi-mode system such as the ZUMTS system, enabling diversity reception, and securing mounting space for electrical or electronic components, and impairing design An object of the present invention is to provide an antenna device suitable for a mobile phone or the like and a mobile communication terminal device including the antenna device.

Patent Document 1: Japanese Patent Laid-Open No. 11-122037 (Page 4, FIGS. 1 and 2)

Disclosure of the invention

[0005] The antenna device of the present invention is switched to a broadband resonance frequency in which a built-in antenna element having a first resonance frequency and a second resonance frequency is provided that is divided into two or more by reactance elements. A possible antenna device, wherein the first resonance frequency remains fixed and only the second resonance frequency is different from the first and second resonance frequencies by controlling impedance. It has a configuration with a switching circuit that switches to the resonant frequency. With this configuration, by using the switching circuit, the impedance can be controlled, and only the second resonance frequency can be switched to the third resonance frequency while the first resonance frequency is fixed. It becomes possible to respond.

[0006] Further, the antenna device of the present invention is a wideband including a built-in antenna element having first to sixth resonance frequencies divided by a reactance element, and a plurality of power supply portions of the antenna element. The antenna device is switched to the resonance frequency of the antenna element, and is disposed at the end of the antenna element, and the power feeding unit switching circuit that switches the power feeding unit that feeds power to the antenna element, and the power feeding unit is switched by the power feeding unit switching circuit to resonate. When the frequency is switched from the first and second resonance frequencies to the fourth and fifth resonance frequencies, the impedance is controlled, and only the fifth resonance frequency is changed while the fourth resonance frequency is fixed. It has a configuration that has a switching circuit that switches to 6 resonance frequencies. With this configuration, The power feeding unit is changed using a power feeding unit switching circuit arranged at the end of the tena element, and the first and second resonance frequencies are switched to the fourth and fifth resonance frequencies. Here, by using a switching circuit arranged in the vicinity of the power feeding unit, the impedance can be controlled, the fourth resonance frequency can be fixed, and only the fifth resonance frequency can be switched to the sixth resonance frequency. It is possible to cope with a wide frequency range.

In the antenna device of the present invention, the switching circuit includes a PIN (P Intrinsic N) diode, a FET (Field Effect Transistor) switch, a MEMS (Micro Electro Mechanical Systems) switch, and a SPDT (Single Pole Double Throw). It has either a switch, a GaAs (gallium arsenide) switch, or a solid-state switch. With such a configuration, a switching circuit can be realized using versatile electronic components.

[0008] Further, in the antenna device of the present invention, the antenna element is configured by a diversity antenna. With such a configuration, the antenna element can be controlled in the optimum directivity direction.

[0009] Further, a mobile communication terminal device of the present invention has a configuration including any one of the antenna devices described above. Therefore, when such an antenna device is used for, for example, a mobile phone, a mobile phone having a wide band and good antenna directivity can be realized. Further, by using such an antenna device for a mobile communication terminal device, the band frequency and antenna directivity of the mobile communication terminal device can be improved. Furthermore, if such a mobile communication terminal apparatus is used for wireless communication with a base station apparatus, broadband and antenna directivity communication can be performed, which is extremely convenient for users. A wireless communication system can be provided.

Brief Description of Drawings

FIG. 1 is a perspective view showing an external appearance of a mobile phone according to a first embodiment of the present invention.

[FIG. 2] (A) is a detailed configuration block diagram of an antenna portion of the antenna device provided in the mobile phone according to the first embodiment of the present invention, and (B) is a detailed circuit of the switching circuit in (A). Figure

FIG. 3 is an explanatory diagram showing a configuration of an L-shaped and inverted L-shaped antenna of the antenna device according to the first embodiment of the present invention. FIG. 4 is a block diagram showing the configuration of the antenna device according to the first embodiment of the present invention.

[FIG. 5] (A) to (C) are IL—PIL applied to the antenna device of the first embodiment of the present invention.

Explanatory drawing showing the general principle of A

[Fig. 6] Diagram showing an example of VSWR characteristics of IL PILA shown in Fig. 4.

[FIG. 7] (A) is a VSWR characteristic diagram of the antenna device when the switching circuit according to the present invention is not operated, and (B) is a VSWR characteristic diagram of the antenna device when the switching circuit is operated.

[FIG. 8] (A) is a detailed block diagram of the antenna portion of the antenna device provided in the mobile phone according to the second embodiment of the present invention, and (B) is a detailed circuit of the switching circuit in (A). Figure

[FIG. 9] (A) is a VSWR characteristic diagram of the antenna device when the switching circuit according to the second embodiment of the present invention is not operated, and (B) is a VSWR characteristic of the antenna device when the switching circuit is operated. Figure

FIG. 10 (A) is a perspective view showing the structure of a conventional mobile phone antenna, and FIG. 10 (B) is a circuit diagram showing the configuration.

Explanation of symbols

1 is the body

10 is a mobile phone (terminal device for mobile communication)

2 is flip part

21 is the LCD screen

3 is the hinge

4 is an antenna device

40A and 40B are built-in antennas (antenna devices)

41 is an antenna switching control unit

42 is the main control unit

42A is the received signal level detection circuit

43 is transmission BPF

44 is a power amplifier

45 is an isolator 46 and 47 are duplexers

48mm reception LNA

49 is receiving BPF

4A is a high-frequency element

4B is a low-frequency element

4C is the inductance component

4a and 4d are power supply units

4b is a matching circuit

4c is a switching circuit

401 is a reactance element

403 is an antenna element

404 is the ground plane

5a and 5b are power supply switching circuits

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First embodiment]

FIG. 1 shows a mobile phone (mobile communication terminal device) 10 provided with the antenna device 4 of the present invention. The mobile phone 10 includes a main body 1 having a key operation unit, a liquid crystal screen, and the like. The flip part 2 having 21 has a foldable casing structure that can be opened and closed by a hinge 3 having a rotation axis.

Further, as shown in FIG. 2, the antenna device 4 of the cellular phone includes a switching circuit 4c in addition to the built-in antenna 40, the power feeding unit 4a, the matching circuit 4b, and the like.

[0013] The built-in antenna 40 is an L-shaped or inverted L-shaped antenna (IL PILA, which will be described later), and is located near the tip side of the main body 1 (this is referred to as “built-in antenna 40A”) and the flip section 2. It is provided on both sides of the base end (this is called “built-in antenna 40B”), but it may be installed at any one of these positions. In the present embodiment, description will be given by taking the built-in antenna 40A provided on the distal end side of the main body 1 as an example. The built-in antenna has the same configuration regardless of where it is installed. [0014] The built-in antenna 40A includes an antenna element 402 ("first resonance") divided into two (or three or more) by a reactance element 401, as shown in FIGS. Frequency fl ”; about 880 to 960 MHz) and an antenna element 403 (“ second resonance frequency f2 ”; about 1710 to 190 MHz) and a ground plane 404 serving as a ground. That is, as shown in FIG. 3, the built-in antenna 40A is divided into two parts by a reactance element 401, and has a first resonance frequency fl and a second resonance frequency f2. The impedance is controlled by using a switching circuit 4c (see Fig. 2 (B)) arranged in the vicinity of the feeding section 4a of the built-in antenna 40A. The reactance element 401 is provided in a slit (not shown) formed near the center of the two antenna elements 402 and 4003.

On the other hand, as shown in FIG. 2 (B), switching circuit 4c is connected to matching circuit 4b arranged in the vicinity of feeding portion 4a of built-in antenna 40A, and controls matching impedance. That is, the switching circuit 4c has a fixed frequency (for example, a range of about 880 MHz to 960 MHz, which is the first resonance frequency fl), and a second resonance frequency f2 (a range of about 1710 MHz to 1990 MHz). Is matched to a specific frequency different from this (for example, a range of about 1920 MHz to 2170 MHz, which is the “third resonance frequency f 3”). This realizes a multi-frequency antenna that can switch only the second resonance frequency f2 to the third resonance frequency f3 while keeping the first resonance frequency fl fixed. The switching circuit 4c is composed of a PIN diode, a FET switch, a MEMS switch, a solid state switch, and the like.

[0016] Thus, since the switching circuit 4c can appropriately switch only the second resonance frequency f2 to the third resonance frequency f3, an antenna device corresponding to a wideband multiband can be realized. That is, in the present embodiment, by controlling the impedance using the switching circuit 4c, the second resonance frequency f2 can be switched to the third resonance frequency f3 while the first resonance frequency fl is fixed. .

As shown in FIG. 4, the switching circuit 4 c is controlled by an antenna switching control unit 41, and the antenna switching control unit 41 is controlled by a main control unit 42. The main control unit 42 performs control at the time of radio unit transmission / reception. On the transmission side, the output is connected to the input of a transmission BPF (Band Pass Filter) 43. Send BP The output of F43 is connected to the input of the power amplifier 44, and the output of the power amplifier 44 is connected to the input of the isolator 45. This isolator 45 constitutes a DC input variation, and has functions such as stable operation of the amplifier and prevention of intermodulation, and each antenna for transmission and reception that requires output is provided by a single antenna. It is connected to duplexer 46, which is a component for sharing. The output of the duplexer 46 is connected to the matching circuit 4b.

On the other hand, on the reception side, the input of the duplexer 47 is connected to the output of the matching circuit 4b, and the output of the duplexer 47 is connected to a reception LNA (Low Noise Amplifier) 48. This receiving LNA 48 is connected to the input of the receiving BPF 49. The output of the reception BPF4 9 is connected to the input of the main control unit 42. The antenna switching control unit 41 via the reception signal level detection circuit 42A of the main control unit 42 controls the switching circuit 4c described above. The operation of is controlled. That is, the reception signal level detection circuit 42A in the control unit 42 selects a high frequency band of the reception electric field level, and the antenna switching control unit 41 selects and switches the band. In this embodiment, a high-performance antenna system that can maintain stable communication quality can be provided by configuring in this way.

Next, the operation principle of the present embodiment will be described in detail with reference to FIGS. 5 and 6. FIG. 5 is a schematic configuration diagram of IL-PILA (described later) applied to the present invention. FIG. 6 is a diagram showing an example of the VSWR characteristic of IL-PILA shown in FIG. In the present embodiment, reactance elements 401 are divided and loaded on linear or plate-like antenna elements 402 and 403 having an L-shape or an inverted L-shape. Accordingly, each of the divided antenna elements 402 and 403 is a wideband multi-frequency antenna that resonates in two or more frequency bands (that is, the first resonance frequency fl and the second resonance frequency f2). Realized. Such a multi-frequency antenna is called an inductance-loaded plate-type inverted L antenna (commonly known as IL-PILA).

[0020] As shown in Fig. 5 (A), the IL PILA constituting the antenna elements 402, 403 (see Fig. 2 (A) or Fig. 3) is divided into two elements (that is, high-frequency element elements). An inductance component 4C is loaded between 4A and the low-frequency element 4B). And high lap In the wave number band (for example, about 1710 MHz to 1990 MHz, which is the second resonance frequency f2), the portion after loading the inductance component 4C (that is, the portion of the low-frequency element element 4B) is regarded as open. Also, in the low frequency band (for example, about 880 MHz to 960 MHz, which is the first resonance frequency fl), the portion after the inductance component 4C is loaded (the portion of the low frequency element element 4B) also flows so that current flows. Determine the constant. In other words, the inductance component 4C uses a characteristic of flowing a low-frequency current but not a high-frequency current. In the high-frequency band, as shown in Fig. 5 (B), only the high-frequency element element 4A is configured. In the low frequency band, as shown in FIG. 5C, a configuration is realized in which the high frequency element element 4A and the low frequency element element 4B are connected in series. The antenna elements 412 and 4 13 can achieve a VSWR characteristic as shown in Fig. 6 and realize a triple-band dual-resonance antenna by adopting such an IL-PILA configuration.

Next, FIG. 7 shows the case where the switching circuit 4c arranged in the vicinity of the feeding portion 4a of the antenna elements 402 and 403 is not operated in the antenna configuration shown in FIG. 2, and the VSW R characteristics when the switching circuit 4c is operated. It is a figure which shows an example. 7A shows a case where the switching circuit 4c is not operated, and FIG. 7B shows a case where the switching circuit 4c is operated. In both cases, the horizontal axis represents frequency, and the vertical axis represents VSWR (Voltage Standing Wave Ratio).

These characteristics shown in Fig. 7 show an example of VSWR characteristics at 880MHz to 2170MHz. When VSWR is 3 or less, the switching circuit 4c is not operated.In Fig. 7 (A), the first resonance frequency f1 from about 880MHz to 960MHz appears first, and then from about 1710MHz to 1990MHz. The second resonance frequency f2 appears. However, when the impedance is controlled by operating the switching circuit 4c arranged in the vicinity of the feeding part 4a of the antenna elements 402 and 403, as shown in FIG. The resonance frequency up to (resonance frequency fl) is still fixed, and only the resonance frequency up to about 1710 MHz to l 990 MHz (second resonance frequency f2) is about 1920 MHz to 2170 MHz (third resonance frequency f3). It is switched to the resonance frequency. As a result, a multi-frequency antenna that resonates in three frequency bands fl to f3 can be realized.

[0022] [Second Embodiment]

Hereinafter, the second embodiment of the present invention will be described in detail with reference to FIGS. 8 and 9. To do. In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals to avoid redundant description.

FIG. 8 shows an antenna device provided in a mobile communication terminal device according to the second embodiment of the present invention. Unlike the first embodiment, the antenna device of the present embodiment is an antenna element. Power supply unit switching circuits 5a and 5b for changing the power supply state are provided at each end of 402 and 403, respectively.

The power feeding unit switching circuits 5a and 5b switch the power feeding state to the antenna elements 402 and 403 to one of them. For example, by switching the feeding point from the feeding unit 4a to the feeding unit 4d, the antenna element 402 can be changed from the first and second resonance frequencies to the fourth and fifth resonance frequencies (specifically for any co-frequency). It is configured to switch to an appropriate frequency value (to be described later). In this case, the switching circuit 4c controls the impedance, so that the fourth resonance frequency f4 remains fixed and only the fifth resonance frequency f5 is changed to the sixth resonance frequency f6 (also in this case, the frequency A multi-frequency antenna that switches the value to (described later) is realized. Here, the “fourth resonance frequency f4” is in the range of about 830 to 960 MHz, the “fifth resonance frequency f5” is in the range of about 1710 to 1880 MHz, and the “sixth resonance frequency f6” is in the range of about 1850 to 1990 MHz. is there.

Next, FIG. 9 shows a case where, in the antenna configuration shown in FIG. 8, for example, the feeder switching circuit 5a disposed at the end of the antenna element 402 is operated to switch the feeder 4a to the feeder 4d. FIG. 6 is a diagram showing an example of VSWR characteristics when the switching circuit 4c arranged in the vicinity of the power feeding unit 4d of the antenna element 403 is not operated and when it is operated. 9A shows the case where the switching circuit 4c is not operated, and FIG. 9B shows the case where the switching circuit 4c is operated. In both cases, the horizontal axis represents frequency and the vertical axis represents VSWR.

[0025] These characteristic diagrams shown in Fig. 9 show an example of VSWR characteristics in the range of 830MHz to 1990MHz. When VSWR is 3 or less, what was the first and second resonance frequencies 1S When switching circuit 4c in Fig. 9 (A) is not operated, first, about 830 MHz to 960 MHz (fourth resonance frequency f4 ) Appears, followed by a resonance frequency of about 1710 MHz to 1880 MHz (fifth resonance frequency f 5). Here, by operating the switching circuit 4c arranged in the vicinity of the feeding portion 4d of the antenna element 403, about 830 The resonance frequency from MHz to 960 MHz (fourth resonance frequency f4) remains fixed, and only the resonance frequency from approximately 1710 MHz to 1880 MHz (fifth resonance frequency f5) is approximately 1850 MHz to 1990 MHz (sixth resonance frequency). Switch to the resonance frequency up to f6). As a result, a multi-frequency antenna that resonates in the six frequency bands fl to f6 can be realized.

[0026] Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. is there.

Industrial applicability

[0027] As explained above, there are many small antenna devices built in mobile phones that support tri-bands such as GSM systems, and so on, so that they tried to make them compatible with multi-mode systems such as GSMZDCSZPCS ZUMTS. In some cases, the conventional antenna device occupies a large occupied volume, impairs the design of a mobile phone or the like, or it is difficult to mount electrical components. On the other hand, the antenna device of the present invention solves the above-mentioned conventional problems, and can provide a built-in small antenna suitable for a mobile phone that can be used in a wide band compatible with a multi-mode system. Furthermore, antenna directivity can be further improved by making the antenna device a diversity antenna configuration.

The antenna device of the present invention can be used not only for a mobile phone but also for any mobile communication terminal device.

Claims

The scope of the claims

[1] An antenna device that is divided into two or more by a reactance element and is provided with a built-in antenna element having a first resonance frequency and a second resonance frequency, and is switchable to a broadband resonance frequency,

A switching circuit that switches only the second resonance frequency to a third resonance frequency different from the first and second resonance frequencies while controlling the impedance while the first resonance frequency remains fixed. Antenna device.

[2] An antenna device that switches to a wideband resonance frequency having a built-in antenna element having first to sixth resonance frequencies divided by a reactance element and a plurality of feeding portions of the antenna element. And

A power feeding unit switching circuit that is disposed at the end of the antenna element and switches the power feeding unit that feeds power to the antenna element;

When the power feeding unit is switched by the power feeding unit switching circuit and the resonance frequency is switched from the first and second resonance frequencies to the fourth and fifth resonance frequencies, the impedance is controlled, and the fourth resonance frequency Is an antenna device having a switching circuit that switches only the fifth resonance frequency to the sixth resonance frequency while maintaining a fixed value.

[3] The antenna device according to claim 1 or 2, wherein the switching circuit includes any one of a PIN diode, a FET switch, a MEMS switch, an SPDT switch, a GaAs switch, and a solid-state switch.

[4] The antenna device according to any one of claims 1 to 3, wherein the antenna element is configured by a diversity antenna.

[5] A mobile communication terminal device comprising the antenna device according to any one of claims 1 to 4.