JPH06303021A - Antenna system - Google Patents

Abstract

PURPOSE:To improve standby reception characteristic. CONSTITUTION:One side of a housing 1 is provided with 1st and 2nd ground type antenna elements ANT1, ANT2 arrangeed at a predetermined interval. The system is provided with an antenna changeover means selecting the antenna elements ANT1, ANT2 to be any of three kinds of antenna operating modes. In the 1st changeover mode, the antenna elements ANT1, ANT2 are operated as a two-element broad side array antenna. In the 2nd and 3rd changeover modes, the antenna elements ANT1, ANT2 act as two-element endfire array antennas whose beam direction differs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device incorporated in a stand-by reception type portable radio equipment.

[0002]

2. Description of the Related Art There are two types of usage of an antenna device used by being built in a portable wireless device. First, like a portable GPS receiver, there is a mode in which the user keeps it away from the body and holds it in a receiving state only when the user wants to use it, and second, like a paging receiver. In addition, there is a form in which the user is always in close contact with the body to maintain the standby reception state. In the former case, the user intentionally holds the receiver and operates so as to obtain the optimum reception state, so that there is no problem even if the antenna characteristics are constant.

However, in the latter case, the user is passive and the operation for optimum reception by the user cannot be expected. Therefore, it is necessary to change the antenna characteristic itself so that the optimum reception state can be obtained. Conventionally, as a device that supports this type of standby reception,
Position diversity antennas for mobile phones in the 00 MHz band are provided. FIG. 10 shows a mobile phone equipped with a position diversity antenna.

In the case of FIG. 10 (a), an antenna (so-called whip antenna) 2 that can be pulled out in a freely movable manner and an inverted F-type antenna 3 formed of a metal plate are provided in a metal housing 1 of a mobile phone. They are arranged at intervals of 0.1 wavelength (0.1λ). Further, in the case of FIG. 10B, two inverted F-type antennas 3 made of a metal plate are arranged in a metal housing 1 at intervals of 0.1 wavelength.

In either case, switching is performed to select one of the two antennas, and the antenna interval is 0.1.
Despite the narrow wavelength, the cross-correlation coefficient is about 0.2 and diversity reception is possible by devising the antenna arrangement.

[0006]

By the way, it is difficult to apply the antenna device of the mobile phone to an ultra-small and thin radio device such as a paging receiver for the following reason. First, this type of ultra-small and thin radio,
Particularly in a wireless device that is required to be thin, the number of effective component mounting surfaces is often limited to one. Therefore, unlike the above-described mobile phone, the method of mounting multiple antennas cannot be applied. Further, even if a plurality of antennas are arranged on one surface and the antennas are switched, mutual coupling is large and the correlation coefficient does not become small, so that the diversity reception effect cannot be obtained.

Secondly, since this type of wireless device is often used in a state where it is in close contact with the human body, the influence of the human body causes
Antenna gain is significantly reduced. Therefore, the antenna gain becomes low in the conventional method in which the two antennas are selectively switched and used. Thirdly, the conventional diversity method of switching between two antennas has only two switching states, and therefore cannot keep up with a rapid change in ambient environmental conditions during mobile use. Further, when the digital signal is received, if the transmission speed of the digital signal is high, the phase may suddenly change, and the optimum switching operation cannot be expected.

That is, in the case of a digital radio device, active and extremely fine (multi-state switching) antenna characteristic control is required. The present invention has been made in view of the above points, and an object of the present invention is to provide an antenna device having good standby reception characteristics.

[0009]

In order to achieve the above-mentioned object, the invention of claim 1 is to provide first and second grounded antenna elements arranged on one surface of a housing at regular intervals, and respective antenna elements. An antenna switching means for switching between three operating modes, a first switching mode for operating as a two-element broadside array antenna and a second and third switching mode for operating as a two-element endfire array antenna with different main beam directions. I have it.

Specifically, as described in claim 2, the first
In the switching mode, both the first and second antenna elements operate as a two-element broadside array antenna of equal phase and equal amplitude feeding, and in the second and third switching modes, the first and second antenna elements. It may be configured to operate as a two-element end-fire array antenna with a parasitic element in which any of the above is used as the parasitic element.

Further, as described in claim 3, in the first switching mode, both the first and second antenna elements operate as a two-element broadside array antenna of equal phase and equal amplitude feeding, and In the third switching mode, the first and second antenna elements are provided with 90 ° phase difference / equal amplitude feed
You may make it operate | move as an element end fire array antenna.

Note that, as described in claim 4, a grounding type antenna of top capacitance loading type can be used as the first and second antenna elements. Further, as described in claim 5, plate-shaped inverted F-type antennas may be used as the first and second antenna elements. Further, as a specific method of forming the first and second antenna elements, as described in claim 6, the antenna conductor portions of the first and second antenna elements are arranged at a constant interval on the first layer of the multilayer printed board. And the second layer facing the first layer may be formed as a ground layer.

In the case of claim 6, in order to reduce the occupied area of the circuit which constitutes the antenna switching means, as described in claim 7, between the antenna conductor portions of the first and second antenna elements. In addition, a partial circuit that constitutes the antenna switching means may be formed. Further, as a method for reducing the occupied area of the circuit that constitutes the antenna switching means without affecting the antenna operation as much as possible, as shown in claim 8, a multilayer printed circuit board comprising a first layer and a second layer is used. What has a third layer in between may be used, and a partial circuit which constitutes the antenna switching means may be formed in the third layer.

[0014]

According to the invention of claim 1, the above-mentioned configuration makes it possible to switch the combined directivity of the two antenna elements into three types, and in particular when applied to a digital radio device, there are three types. By switching, the rapid phase change is suppressed and a good standby reception state is obtained.

If a partial circuit forming the antenna switching means is formed between the antenna conductor portions of the first and second antenna elements, the circuit forming the antenna switching means is occupied. The area can be made as small as possible and the antenna device can be miniaturized. As described in claim 8, if a multilayer printed board having a third layer between the first layer and the second layer is used, and a partial circuit constituting the antenna switching means is formed in the third layer, It is possible to separate the antenna element portion and a part of the circuit forming the antenna switching means from each other, reduce the influence on the operation of the antenna element, and reduce the occupied area of the circuit forming the antenna switching means.

[0016]

(Embodiment 1) 15 based on FIGS. 1 to 3
An embodiment will be described in which the present invention is applied to a portable wireless device in the 00 MHz band. In the portable wireless device of this embodiment, FIG.
As shown in (a), at the end of the metal housing 1,
The antenna element portion is configured by using the double-sided printed board 4 having copper foils on the front and back.

In the antenna element portion, the capacitive loading conductor portions 41 ₁ and 41 ₂ are formed on the front surface of the double-sided printed circuit board 4 with a copper foil pattern, and the ground conductor portion 42 is formed on the back surface with a copper foil pattern to form a capacitor. Each of the loading conductors 41 ₁ and 41 ₂ and the ground conductor 42 are connected to each other by a connecting portion 43 made of a conductor.
₁ and 43 ₂ are connected to each other, and the capacitive loading conductor portion 41 is connected.
_1, 41 ₂ is configured so as to feed from the feeding unit 44 _1, 44 ₂ made of a conductor. Here, the ground conductor portion 42 is formed of a copper foil pattern formed on almost the entire back surface of the double-sided printed circuit board 4, and the lower end portions of the power feeding portions 44 ₁ and 44 ₂ are insulated from the ground conductor portions 41 ₁ and 42 _2. I am doing it.

That is, the capacitance loading conductor portion 41 ₁ , the ground conductor portion 42, the connecting portion 43 ₁ and the power feeding portion 44 ₁ , the capacitance loading conductor portion 41 ₂ , the ground conductor portion 42, and the connecting portion 4
3 ₂ and the feeding portion 44 ₂ constitute a grounding type vertical monopole antenna of the top capacitance loading type, respectively. Therefore, in the following description, the former is the first antenna element and the latter is the second antenna element.
I will call it the antenna element.

In the present embodiment, in order to enhance the effect of switching the directivity, the interval between the feeding parts 44 ₁ and 44 ₂ is set to a quarter wavelength. Since the present embodiment is applied to a 1500 MHz band portable wireless device, the interval between the power feeding units 44 ₁ and 44 ₂ can be selected to be a quarter wavelength (λ / 4). Even if the wavelength is not one-half wavelength, it is possible to obtain the same switching effect by adjusting the phase.

FIG. 1B shows the structure of the antenna switching means.
You First and second formed by the double-sided printed circuit board 4
Antenna element ANT₁, ANT₂The received output of
Tena switch SW₁, SW₂Through the low-noise amplifier L
NA₁, LNA₂Input to the signal synthesizer COM
It is configured to be combined. Antenna switch SW₁，
SW₂Are control terminals CNT₁, CNT₂Equipped with
These control terminals CNT₁, CNT₂Control signal applied to
(High-level or low-level signal)
Element ANT₁, ANT₂Low noise amplifier LNA₁, L
AN₂As a configuration for selecting whether to connect to
It Where low-noise amplifier LNA₁, LAN₂Cut from
Antenna element ANT when separated ₁, ANT₂Out of
Force is reactance element X₁, X₂Connect to the ground via
I am supposed to continue.

In the above antenna device, by the control signal,
Three switching modes shown in Table 1 can be selected. here,
A and B in the table are antenna switches SW ₁ and SW
₂ shows the contact switching position.

[0022]

[Table 1]

In the antenna device of the present embodiment, when the first switching mode in the above table is used, the equal phase / equal amplitude feed is performed.
Operates as an element broadside array antenna,
And in the third switching mode, it operates as a two-element endfire array antenna with a parasitic element. Here, the reactance elements X ₁ and X ₂ are used as the parasitic elements (reflection elements or waveguide elements), and when reactance is not added (X = ∞) or short circuit depending on the antenna spacing and the antenna element type / shape. There is also (X = 0).

The antenna switch SW is shown in FIG.₁, SW₂
The specific circuit of is shown. FIG. 2 (a) shows an input IN and an output A,
Between B and PIN, reverse the direction of each PIN diode
D₁, D ₂And connect each diode D₁The cathode
And diode D₂Bias terminal B to each of the anodes
A voltage of 2V is always applied from IAS, and a commonly connected
Iodo D₁Anode and diode D₂The cathode
Control signal from the control terminal CNT to
It The capacitor C₁~ C_FourAre for DC cut
Yes, choke coil CH₁~ CH₃Is for high frequency blocking,
Resistance R₁Is for current limiting.

As the control signal, voltages of 5V and 0V are applied. Now, when the control signal is 5V, the diode D ₁ becomes conductive and the input IN and the output A are connected. On the contrary, when the voltage is 0 V, the diode D ₂ becomes conductive and the input IN and the output B are connected. Figure 2 (b)
Uses MOSFETs Q ₁ and Q ₂ as switching elements, and MOSFETs are respectively provided between the input IN and the outputs A and B.
It is connected to the Q _1, Q _2. Here, the commonly connected M
The bias terminals BI are connected to the drains of the OSFETs Q ₁ and Q _2.
5V is always applied from AS. MOSFET Q ₁
Then, a voltage obtained by dividing the drain voltage by the resistors R ₃ and R ₄ is applied to the gate. A control signal is applied to the gate of the MOSFET Q ₂ from the control terminal CNT. In the case of FIG. 2B, a so-called differential amplifier configuration is used. The capacitors C _{5 to} C ₇ are for DC cutting, the capacitors C ₈ and C ₉ are for high frequency bypass, the choke coils CH _{4 to} CH ₈ are for high frequency blocking, and the resistor R ₂ is MOSFETs Q ₁ and Q ₂ . It is a current limiting resistor for passing a current.

When the control signal is 0V, MO
The SFET Q ₁ is turned on, and the input IN and the output A are connected. On the contrary, when the voltage is 2V, the MOSFET Q ₂ is turned on and the input IN and the output B are connected. FIG. 3 shows the antenna directional characteristics when the mode switching shown in the above table is performed. Note that, in FIG. 3, the directional characteristics of the vertically polarized component in the horizontal plane are shown, the curved line a shown by the solid line in the figure shows the directional characteristic of the antenna device of this embodiment, and the dotted curve B shows the omnidirectional antenna. Shows the directional characteristics of. Here, the directional characteristics of the omnidirectional antenna are shown so that the gains can be compared.

FIGS. 3A to 3C correspond to switching between the second mode, the first mode and the third mode, respectively. In FIG. 3, for example, it is shown that the directional characteristics are switched between front and left and right on the front of the human body. Therefore, the antenna device of this embodiment can be used as a directional diversity antenna or a tracking reception antenna. Since the antenna device of this embodiment has an array antenna configuration, it has a good directional gain of about 3 dB in the left-right direction and about 1 dB in the front direction as compared with the omnidirectional antenna. Since the influence of the human body is ignored in FIG. 3, the directional characteristic is vertically symmetrical, but the gain on the human body side actually decreases.

(Embodiment 2) FIG. 4 shows another embodiment of the present invention. In the first embodiment described above, the grounding type vertical monopole antenna of the top capacitive loading type is used, whereas in the present embodiment, the plate-shaped inverted F type antenna is used. Is characterized by. The antenna element part of the present embodiment is also configured by using the double-sided printed circuit board 4, as shown in FIG.
(A) shows an antenna element portion provided on the upper portion of the metal housing 1, and (b) shows an antenna element portion provided on one side of the upper portion.

In the antenna element portion, the antenna element conductor portions 41 ₁ ′ and 41 ₂ ′ are formed on the front surface of the double-sided printed circuit board 4 in a copper foil pattern, and the ground conductor portion 42 is formed on the back surface in a copper foil pattern. Antenna element conductor part 4
1 ₁ ', 41 _2' Yes respectively grounded and connected to the ground conductor portion 42 at the grounding section 45 _1, 45 ₂ made of a conductor (through hole) of the antenna element conductors 41 ₁ ', 4
1 ₂ 'is a feeding portion 44 _{1 made of} a conductor (through hole),
Power is supplied from 44 ₂ . Here, the ground conductor portion 42 is composed of a copper foil pattern formed on almost the entire back surface of the double-sided printed circuit board 4, and the power feeding portions 44 ₁ , 44
₂ of the lower end portion and the ground conductors 41 _1, 42 ₂ are insulated.

That is, the antenna element conductor portion 41 ₁ ′,
Ground conductor part 42, ground part 45 ₁ and power supply part 44
₁ , antenna element conductor portion 41 ₂ ′, ground conductor portion 4
2, the grounding portion 45 ₂ and the power feeding portion 44 ₂ are respectively plate-shaped inverted F
A type antenna is configured. So, in the following explanation,
The former is called a first antenna element and the latter is called a second antenna element. The distance between the feeding points of both antenna elements is approximately one-quarter wavelength of the used frequency.

Here, the inverted F-type antenna is characterized in that it can receive both horizontal and vertical polarization components. However, the gain is reduced by about 3 dB. Therefore, even if circularly polarized waves are received,
It can be used as a directional diversity antenna or a tracking antenna. 5 (a) and 5 (b),
It is a thing which shows the directional characteristic of the antenna device of FIG. Here, the dimensions of the housing 1 are 100 × 60 × 1
5mm, the size of double-sided printed circuit board 4 is 60x15x5mm
Shows the directional characteristic at 1550 MHz when using a PPO material having a dielectric constant of 3.5. The housing 1 is not made of metal as a whole, and is experimental data when the effective ground portion is an L-shaped angle plate 1a as shown in FIG. 5 (c).

Here, FIG. 5A shows a horizontal plane when the directional characteristics are switched to the left and right when receiving the vertically polarized wave (FIG. 5A).
The directional characteristics in (XY plane of (c)) are shown by a solid line a and a dotted line b. Note that the characteristics during in-phase power supply are omitted.
The maximum gain in this case was about 1.5 dBi. Further, the directivity direction of the main beam changes ± 60 degrees with respect to the front direction (X direction).

FIG. 5B shows the directional characteristics in the horizontal plane (XY plane) when the directional characteristics are switched to the left and right when receiving the right-handed circularly polarized wave in the same configuration as FIG. 5A. And the dotted line B. In this case, the maximum gain was about -2 dBi because a loss of about 3 dB when the circularly polarized wave was received as the diagonal linearly polarized wave antenna was added. Further, the directivity direction of the main beam changes ± 75 degrees with respect to the front direction (X direction). As is apparent from FIG. 5B, the antenna device of the present embodiment has the directivity switching function effectively in the circular polarization reception.

The inverted F type antenna can receive both horizontal and vertical polarized waves and is arranged so that the ground plane is vertical.
The directional characteristic of the vertically polarized wave in the horizontal plane is almost omnidirectional as shown in FIG. Therefore, as shown in FIG. 4B, the antenna element portion can be provided on the surface of the housing 1 opposite to the surface in contact with the human body. Note that FIG. 6 (b)
Is in the upper center of the copper plate 1b of 100 × 60 × 0.5 mm,
One inverted F formed by using the double-sided printed circuit board 4 having dimensions of 15 × 15 × 5 mm and made of PPO material having a dielectric constant of 3.5.
Horizontal plane when the antenna is attached (X in Fig. 6 (a))
The vertical polarization directional characteristic in the (Y plane) is shown. The circle in the outer peripheral portion in FIG. 6B corresponds to a gain of +2 dBi. This FIG. 6 is a reference data, but it is clear that the directional characteristics can be switched to the same degree in the case of FIG. 4B because the characteristics are similar to those of the top capacitive loading type vertical antenna of the first embodiment. is there.

The structure of the antenna element portion in FIG. 4 (b) is the same as that in FIG. 4 (a). In order to arrange this antenna element portion, a space of several millimeters is provided between the wall surface of the recess 10 formed in the housing 1 and the double-sided printed circuit board 4 on which the antenna element portion is formed. By the way, in the above description, all the housings 1 have been described as being made of metal. However, in the case of a portable wireless device, the housing 1 is often made of resin.
In this case, it is the ground conductor of the printed circuit board that constitutes the wireless circuit that operates as a ground conductor at high frequencies. That is, the structure described as the housing 1 is replaced with the ground conductor made of a thin metal foil. However, also in this case, the antenna device operates similarly.

FIG. 7 shows an antenna switching means for switching the mode of the antenna device. In this Figure 7,
The outputs of the first and second antenna elements ANT ₃ and ANT ₄ amplified by the low noise amplifiers LNA ₃ and LNA ₄ ,
The antenna switching circuit 5 is used for switching, and the respective switching outputs are synthesized by using the signal synthesizer COM. That is, power is constantly supplied to both the first and second antenna elements ANT ₃ and ANT ₄ . In this case,
Low-noise amplifiers LNA ₃ and LNA without switching elements
_Since the outputs of the first and second antenna elements ANT ₃ and ANT ₄ are input to ₄ , the S / N does not deteriorate.

The antenna switching circuit 5 is a MOSFET
The bias terminal BIA is configured by using Q ₃ and Q _4.
5V is applied from S, control terminals CNT ₃ and CNT ₄ are connected to the gates of the MOSFETs Q ₃ and Q _{4, respectively} , and a control signal of 0 / 2V is applied from the control terminals CNT ₃ and CNT ₄ to apply MOSFETs Q ₃ and Q 4. _It is configured to turn ₄ on and off. The capacitors C _{10 to} C ₁₅ are for DC cutting, the capacitors C _{16 to} C ₁₈ are for high frequency bypass, the choke coils CH _{10 to} CH ₁₅ are for high frequency blocking, and the resistors R ₅ and R ₆ are for current limiting. is there. Also, X ₃ and X ₄ are
It is a phase shift line (90 degree phase shift) for synthesis or inductance for obtaining endfire directivity.

In the case of this embodiment, the first and second antenna elements ANT are used as the output OUT of the signal combiner COM.
₃ , the output of ANT ₄ can be obtained by in-phase combining or 90-degree phase difference combining. (Embodiment 3) FIG. 8 shows still another embodiment of the present invention.
In this embodiment, at least a part of the peripheral circuit portion is integrally formed on the double-sided printed circuit board 4 which constitutes the antenna element portion. The peripheral circuit section includes a phase shift circuit, antenna switches SW ₁ and SW ₂ , low noise amplifiers LNA ₁ and LNA _2.
Alternatively, it is a signal synthesizer COM or the like.

In FIG. 8, the antenna switch SW ₁ , S shown in FIG. 1B is shown together with the plate-shaped inverted F-type antenna of the second embodiment.
W ₂ is integrally incorporated between the antenna element conductors 41 ₁ and 41 ₂ . Chip parts are used as the diodes D ₁ and D ₂ , the capacitors C _{1 to} C ₃ and the resistor R ₁ , and the choke coils CH _{1 to} CH ₃ are formed by a copper foil pattern. Further, the outputs A and B, the control terminal CNT, and the bias terminal BIAS are connected to the through holes 46 ₁ , 46 ₂ and 4.
7, 48 are drawn out from the back surface of the double-sided printed circuit board 4. By incorporating a part of the peripheral circuit portion in the double-sided printed circuit board 4 in this manner, the area occupied by the circuit forming the antenna switching means can be reduced.

(Embodiment 4) FIG. 9 shows still another embodiment of the present invention. In this embodiment, a laminated printed circuit board 4'having a three-layer structure is used, and a first layer (front surface layer) and a third layer (back surface layer) are used.
Is used to form the antenna element part described in Example 2,
Is obtained only choke coil CH ₁ to CH ₃ in FIG. 2 (a) formed using a copper foil pattern to the second layer (inner layer). The end portion of the choke coil CH ₁ to CH ₃ is used a through-hole 49, is led out on the back side of the printed circuit board 4 '. In this way, the choke coil CH
By forming _{1 to} CH ₃ in the inner layer, it is possible to keep away from the antenna conductor portion 41 ₁ ′ and the like, and it is possible to reduce the occupied area of the circuit constituting the antenna switching means without disturbing the antenna operation.

[0041]

As described above, the first and second grounded antenna elements arranged on one surface of the housing at regular intervals and each antenna element as a two-element broadside array antenna. 3 of the first switching mode to operate and the second and third switching modes to operate as a two-element end-fire array antenna with different main beam directions
Since there is provided an antenna switching means for switching to any of the three antenna operation modes, it is possible to switch the combined directivity of the two antenna elements into three types. , It is possible to suppress an abrupt phase change and obtain a good standby reception state.

According to the invention of claim 7, a part of the circuit which constitutes the antenna switching means is formed between the antenna conductor portions of the first and second antenna elements. The occupied area can be reduced, and the antenna device can be downsized. According to the invention of claim 8, a multilayer printed board having a third layer between the first layer and the second layer is used, and a part of the circuit forming the antenna switching means is formed in the third layer. , Keep away from the antenna element part and some circuits constituting the antenna switching means,
It is possible to reduce the influence on the operation of the antenna element and reduce the area occupied by the circuit that constitutes the antenna switching means.

[Brief description of drawings]

1A and 1B are a perspective view showing an appearance of an embodiment of the present invention and a configuration diagram of an antenna switching unit.

2A and 2B are concrete circuit diagrams of an antenna switch, respectively.

3 (a) to 3 (c) are explanatory diagrams showing antenna characteristics when switching operation modes.

4 (a) and 4 (b) are perspective views showing the appearance of another embodiment, respectively.

5 (a) and 5 (b) are explanatory views showing antenna characteristics at the time of switching operation modes, respectively, and FIG. 5 (c) is a perspective view of a device under test in which the same antenna characteristics are measured.

6A and 6B are an antenna device using an inverted F-type antenna and an antenna characteristic diagram thereof as a reference.

FIG. 7 is a configuration diagram of an antenna switching unit of the above.

FIG. 8 is a perspective view showing a configuration of an antenna element portion of still another embodiment.

FIG. 9 is a partial perspective view showing the configuration of an antenna element portion of still another embodiment.

10 (a) and 10 (b) are perspective views of an apparatus including a conventional position diversity antenna, respectively.

[Explanation of symbols]

ANT _{1 to} ANT ₄ antenna element SW ₁ , SW ₂ antenna switch LNA _{1 to} LNA ₄ low noise amplifier COM signal synthesizer X ₁ , X ₂ reactance element 1 housing 4 double-sided printed board 4'laminated printed board 5 antenna switching circuit 41 ₁ , 41 ₂ Capacitance loading conductor part 41 ₁ ', 41 ₂ ' Antenna element conductor part

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 5, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Patent application title: Antenna device

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device incorporated in a stand-by reception type portable radio equipment.

[0002]

2. Description of the Related Art There are two types of usage of an antenna device used by being built in a portable wireless device. First, like a portable GPS receiver, there is a mode in which the user keeps it away from the body and holds it in a receiving state only when the user wants to use it, and second, like a paging receiver. In addition, there is a form in which the user is always in close contact with the body to maintain the standby reception state. In the former case, the user intentionally holds the receiver and operates so as to obtain the optimum reception state, so that there is no problem even if the antenna characteristics are constant.

However, in the latter case, the user is passive and the operation for optimum reception by the user cannot be expected. Therefore, it is necessary to change the antenna characteristic itself so that the optimum reception state can be obtained. Conventionally, as a device that supports this type of standby reception,
Position diversity antennas for mobile phones in the 00 MHz band are provided. FIG. 10 shows a mobile phone equipped with a position diversity antenna.

In the case of FIG. 10 (a), an antenna (so-called whip antenna) 2 that can be pulled out in a freely movable manner and an inverted F-type antenna 3 formed of a metal plate are provided in a metal housing 1 of a mobile phone. They are arranged at intervals of 0.1 wavelength (0.1λ). Further, in the case of FIG. 10B, two inverted F-type antennas 3 made of a metal plate are arranged in a metal housing 1 at intervals of 0.1 wavelength.

In either case, switching is performed to select one of the two antennas, and the antenna interval is 0.1.
Despite the narrow wavelength, the cross-correlation coefficient is about 0.2 and diversity reception is possible by devising the antenna arrangement.

[0006]

By the way, it is difficult to apply the antenna device of the mobile phone to an ultra-small and thin radio device such as a paging receiver for the following reason. First, this type of ultra-small and thin radio,
Particularly in a wireless device that is required to be thin, the number of effective component mounting surfaces is often limited to one. Therefore, unlike the above-described mobile phone, the method of mounting multiple antennas cannot be applied. Further, even if a plurality of antennas are arranged on one surface and the antennas are switched, mutual coupling is large and the correlation coefficient does not become small, so that the diversity reception effect cannot be obtained.

Secondly, since this type of wireless device is often used in a state where it is in close contact with the human body, the influence of the human body causes
Antenna gain is significantly reduced. Therefore, the antenna gain becomes low in the conventional method in which the two antennas are selectively switched and used. Thirdly, the conventional diversity method of switching between two antennas has only two switching states, and therefore cannot keep up with a rapid change in ambient environmental conditions during mobile use. Further, when the digital signal is received, if the transmission speed of the digital signal is high, the phase may suddenly change, and the optimum switching operation cannot be expected.

That is, in the case of a digital radio device, it is required to control the antenna characteristics which are active and capable of fine switching . The present invention has been made in view of the above points, and an object of the present invention is to provide an antenna device having good standby reception characteristics.

[0009]

In order to achieve the above-mentioned object, the invention of claim 1 is to provide first and second grounded antenna elements arranged on one surface of a housing at regular intervals, and respective antenna elements. An antenna switching means for switching between three operating modes, a first switching mode for operating as a two-element broadside array antenna and a second and third switching mode for operating as a two-element endfire array antenna with different main beam directions. I have it.

Specifically, as described in claim 2, the first
In the switching mode, both the first and second antenna elements operate as a two-element broadside array antenna of equal phase and equal amplitude feeding, and in the second and third switching modes, the first and second antenna elements. It may be configured to operate as a two-element end-fire array antenna with a parasitic element in which any of the above is used as the parasitic element.

As described in claim 3 , a grounding antenna of top capacitance loading type can be used as the first and second antenna elements. Further, as described in claim 4 , plate-shaped inverted F-type antennas may be used as the first and second antenna elements. Further, as a specific method of forming the first and second antenna elements, as described in claim 5 , the antenna conductor portions of the first and second antenna elements are arranged at a constant interval on the first layer of the multilayer printed board. And the ground layer may be formed by the second layer facing the first layer.

In the case of claim 5 , in order to reduce the occupied area of the circuit which constitutes the antenna switching means, as described in claim 6 , between the antenna conductor portions of the first and second antenna elements. In addition, a partial circuit that constitutes the antenna switching means may be formed. Further, as a method for reducing the occupied area of the circuit that constitutes the antenna switching means without affecting the antenna operation as much as possible, as shown in claim 7 , a multilayer printed circuit board comprising a first layer and a second layer is provided. What has a third layer in between may be used, and a partial circuit which constitutes the antenna switching means may be formed in the third layer.

[0013]

According to the invention of claim 1, the above-mentioned configuration makes it possible to switch the combined directivity of the two antenna elements into three types, and in particular when applied to a digital radio device, there are three types. By switching, the rapid phase change is suppressed and a good standby reception state is obtained.

[0014] As shown in claim 6, between the antenna conductor of the first and second antenna elements, by forming a part circuit constituting the antenna switching means, occupation of circuits included in the antenna switching means The area can be made as small as possible and the antenna device can be miniaturized. As described in claim 7 , when a multi-layer printed circuit board having a third layer between the first layer and the second layer is used, and a partial circuit constituting the antenna switching means is formed in the third layer, It is possible to separate the antenna element portion and a part of the circuit forming the antenna switching means from each other, reduce the influence on the operation of the antenna element, and reduce the occupied area of the circuit forming the antenna switching means.

[0015]

(Embodiment 1) 15 based on FIGS. 1 to 3
An embodiment will be described in which the present invention is applied to a portable wireless device in the 00 MHz band. In the portable wireless device of this embodiment, FIG.
As shown in (a), at the end of the metal housing 1,
The antenna element portion is configured by using the double-sided printed board 4 having copper foils on the front and back.

In the antenna element portion, the capacitance loading conductor portions 41 ₁ and 41 ₂ are formed on the front surface of the double-sided printed circuit board 4 with a copper foil pattern, and the ground conductor portion 42 is formed on the back surface with a copper foil pattern to form a capacitor. Each of the loading conductors 41 ₁ and 41 ₂ and the ground conductor 42 are connected to each other by a connecting portion 43 made of a conductor.
₁ and 43 ₂ are connected to each other, and the capacitive loading conductor portion 41 is connected.
_1, 41 ₂ is configured so as to feed from the feeding unit 44 _1, 44 ₂ made of a conductor. Here, the ground conductor portion 42 is formed of a copper foil pattern formed on almost the entire back surface of the double-sided printed circuit board 4, and the lower end portions of the power feeding portions 44 ₁ and 44 ₂ are insulated from the ground conductor portions 41 ₁ and 42 _2. I am doing it.

That is, the capacitance loading conductor portion 41 ₁ , the ground conductor portion 42, the connecting portion 43 ₁ and the power feeding portion 44 ₁ , the capacitance loading conductor portion 41 ₂ , the ground conductor portion 42, and the connecting portion 4
3 ₂ and the feeding portion 44 ₂ constitute a grounding type vertical monopole antenna of the top capacitance loading type, respectively. Therefore, in the following description, the former is the first antenna element and the latter is the second antenna element.
I will call it the antenna element.

In the present embodiment, in order to enhance the effect of switching the directivity, the interval between the feeding parts 44 ₁ and 44 ₂ is set to a quarter wavelength. Since the present embodiment is applied to a 1500 MHz band portable wireless device, the interval between the power feeding units 44 ₁ and 44 ₂ can be selected to be a quarter wavelength (λ / 4). Even if the wavelength is not one-half wavelength, it is possible to obtain the same switching effect by adjusting the phase.

FIG. 1B shows the structure of the antenna switching means.
You First and second formed by the double-sided printed circuit board 4
Antenna element ANT₁, ANT₂The received output of
Tena switch SW₁, SW₂Through the low-noise amplifier L
NA₁, LNA₂Input to the signal synthesizer COM
It is configured to be combined. Antenna switch SW₁，
SW₂Are control terminals CNT₁, CNT₂Equipped with
These control terminals CNT₁, CNT₂Control signal applied to
(High-level or low-level signal)
Element ANT₁, ANT₂Low noise amplifier LNA₁，L
NA ₂ As a configuration for selecting whether to connect to
It Where low-noise amplifier LNA₁，LNA ₂ Cut from
Antenna element ANT when separated ₁, ANT₂Out of
Force is reactance element X₁, X₂Connect to the ground via
I am supposed to continue.

In the above antenna device, by the control signal,
Three switching modes shown in Table 1 can be selected. here,
A and B in the table are antenna switches SW ₁ and SW
₂ shows the contact switching position.

[0021]

[Table 1]

In the antenna device according to the present embodiment, when the first switching mode in the above table is used, the equal phase and equal amplitude feeding is performed.
Operates as an element broadside array antenna,
And in the third switching mode, it operates as a two-element endfire array antenna with a parasitic element. Here, the reactance elements X ₁ and X ₂ are used as the parasitic elements (reflection elements or waveguide elements), and when reactance is not added (X = ∞) or short circuit depending on the antenna spacing and the antenna element type / shape. There is also (X = 0).

The antenna switch SW is shown in FIG.₁, SW₂
The specific circuit of is shown. FIG. 2 (a) shows an input IN and an output A,
Between B and PIN, reverse the direction of each PIN diode
D₁, D ₂And connect each diode D₁The cathode
And diode D₂Bias terminal B to each of the anodes
A voltage of 2V is always applied from IAS, and a commonly connected
Iodo D₁Anode and diode D₂The cathode
Control signal from the control terminal CNT to
It The capacitor C₁~ C_FourAre for DC cut
Yes, choke coil CH₁~ CH₃Is for high frequency blocking,
Resistance R₁Is for current limiting.

As the control signal, voltages of 5V and 0V are applied. Now, when the control signal is 5V, the diode D ₁ becomes conductive and the input IN and the output A are connected. On the contrary, when the voltage is 0 V, the diode D ₂ becomes conductive and the input IN and the output B are connected. Figure 2 (b)
Uses FETs Q ₁ and Q ₂ as switching elements.
FETs Q ₁ and Q ₂ are connected between the input IN and the outputs A and B, respectively. Here, the commonly connected FETs Q ₁ and Q
The drain of ₂ is constantly applied with 5 V from the bias terminal BIAS. In FET Q ₁ , the drain voltage is changed to the resistance R
_The voltage divided by ₃ and R ₄ is applied to the gate. A control signal is applied to the gate of the FET Q ₂ from the control terminal CNT. In the case of FIG. 2B, a so-called differential amplifier configuration is used. The capacitors C _{5 to} C ₇ are for DC cutting, the capacitors C ₈ and C ₉ are for high frequency bypass, and the choke coil CH _{4 is used.}
~ CH ₈ is for high frequency blocking, resistor R ₂ is FET Q ₁ , Q ₂
It is a current limiting resistor for supplying a constant current to.

When the control signal is 0V, FE
T Q ₁ turns on, and the input IN and the output A are connected. On the contrary, when the voltage is 2V, the FET Q ₂ turns on and the input I
N and output B are connected. FIG. 3 shows the antenna directional characteristics when the mode switching shown in the above table is performed. Figure 3
Shows the directional characteristic of the vertically polarized component in the horizontal plane, the curve a shown by the solid line in the figure shows the directional characteristic of the antenna device of this embodiment, and the dotted curve B shows the directional characteristic of the omnidirectional antenna. Indicates. Here, the directional characteristics of the omnidirectional antenna are shown so that the gains can be compared.

FIGS. 3A to 3C correspond to switching between the second mode, the first mode and the third mode, respectively. In FIG. 3, for example, it is shown that the directional characteristics are switched between front and left and right on the front of the human body. Therefore, the antenna device of this embodiment can be used as a directional diversity antenna or a tracking reception antenna. Since the antenna device of this embodiment has an array antenna configuration, it has a good directional gain of about 3 dB in the left-right direction and about 1 dB in the front direction as compared with the omnidirectional antenna. Since the influence of the human body is ignored in FIG. 3, the directional characteristic is vertically symmetrical, but the gain on the human body side actually decreases.

(Embodiment 2) FIG. 4 shows another embodiment of the present invention. In the first embodiment described above, the grounding type vertical monopole antenna of the top capacitive loading type is used, whereas in the present embodiment, the plate-shaped inverted F type antenna is used. Is characterized by. The antenna element part of the present embodiment is also configured by using the double-sided printed circuit board 4, as shown in FIG.
(A) shows an antenna element portion provided on the upper portion of the metal housing 1, and (b) shows an antenna element portion provided on one side of the upper portion.

In the antenna element portion, the antenna element conductor portions 41 ₁ ′ and 41 ₂ ′ are formed on the front surface of the double-sided printed circuit board 4 in a copper foil pattern, and the ground conductor portion 42 is formed on the back surface in a copper foil pattern. Antenna element conductor part 4
1 ₁ ', 41 _2' Yes respectively grounded and connected to the ground conductor portion 42 at the grounding section 45 _1, 45 ₂ made of a conductor (through hole) of the antenna element conductors 41 ₁ ', 4
1 ₂ 'is a feeding portion 44 _{1 made of} a conductor (through hole),
Power is supplied from 44 ₂ . Here, the ground conductor portion 42 is composed of a copper foil pattern formed on almost the entire back surface of the double-sided printed circuit board 4, and the power feeding portions 44 ₁ , 44
₂ of the lower end portion and the ground conductors 41 _1, 42 ₂ are insulated.

That is, the antenna element conductor portion 41 ₁ ′,
Ground conductor part 42, ground part 45 ₁ and power supply part 44
₁ , antenna element conductor portion 41 ₂ ′, ground conductor portion 4
2, the grounding portion 45 ₂ and the power feeding portion 44 ₂ are respectively plate-shaped inverted F
A type antenna is configured. So, in the following explanation,
The former is called a first antenna element and the latter is called a second antenna element. The distance between the feeding points of both antenna elements is approximately one-quarter wavelength of the used frequency.

Here, the inverted F-type antenna is characterized in that it can receive both horizontal and vertical polarization components. However, yen
The gain is reduced by about 3 dB because it is not a polarized wave receiving antenna, but it can be used as a directional diversity antenna or a tracking antenna even when used for circular polarized wave reception . 5A and 5B show the directional characteristics of the antenna device of FIG. 4A. Where housing 1
Dimensions are 100 x 60 x 15 mm, double-sided printed circuit board 4
Has a size of 60 × 15 × 5 mm and a dielectric constant of 3.5.
A directional characteristic at 1550 MHz is shown when a material made of a material is used. The housing 1 is not made of metal as a whole, and is experimental data when the effective ground portion is an L-shaped angle plate 1a as shown in FIG. 5 (c).

Here, FIG. 5A shows a horizontal plane when the directional characteristics are switched to the left and right when receiving vertically polarized waves (see FIG. 5).
The directional characteristics in (XY plane of (c)) are shown by a solid line a and a dotted line b. Note that the characteristics during in-phase power supply are omitted.
The maximum gain in this case was about 1.5 dBi. Further, the directivity direction of the main beam changes ± 60 degrees with respect to the front direction (X direction).

FIG. 5B shows the directional characteristics in the horizontal plane (XY plane) when the directional characteristics are switched to the left and right when the right-handed circularly polarized wave is received in the same configuration as that of FIG. And the dotted line B. In this case, the maximum gain was about -2 dBi because a loss of about 3 dB when the circularly polarized wave was received as the diagonal linearly polarized wave antenna was added. Further, the directivity direction of the main beam changes ± 75 degrees with respect to the front direction (X direction). As is apparent from FIG. 5B, the antenna device of the present embodiment has the directivity switching function effectively in the circular polarization reception.

The inverted F-type antenna can receive both horizontal and vertical polarized waves and is arranged such that the ground plane is vertical.
The directional characteristic of the vertically polarized wave in the horizontal plane is almost omnidirectional as shown in FIG. Therefore, as shown in FIG. 4B, the antenna element portion can be provided on the surface of the housing 1 opposite to the surface in contact with the human body. Note that FIG. 6 (b)
Is in the upper center of the copper plate 1b of 100 × 60 × 0.5 mm,
One inverted F formed by using the double-sided printed circuit board 4 having dimensions of 15 × 15 × 5 mm and made of PPO material having a dielectric constant of 3.5.
Horizontal plane when the antenna is attached (X in Fig. 6 (a))
The vertical polarization directional characteristic in the (Y plane) is shown. The circle in the outer peripheral portion in FIG. 6B corresponds to a gain of +2 dBi. This FIG. 6 is a reference data, but it is clear that the directional characteristics can be switched to the same degree in the case of FIG. 4B because the characteristics are similar to those of the top capacitive loading type vertical antenna of the first embodiment. is there.

The structure of the antenna element portion in FIG. 4 (b) is the same as that in FIG. 4 (a). In order to arrange this antenna element portion, a space of several millimeters is provided between the wall surface of the recess 10 formed in the housing 1 and the double-sided printed circuit board 4 on which the antenna element portion is formed. By the way, in the above description, all the housings 1 have been described as being made of metal. However, in the case of a portable wireless device, the housing 1 is often made of resin.
In this case, it is the ground conductor of the printed circuit board that constitutes the wireless circuit that operates as a ground conductor at high frequencies. That is, the structure described as the housing 1 is replaced with the ground conductor made of a thin metal foil. However, also in this case, the antenna device operates similarly.

FIG. 7 shows an antenna switching means for switching the mode of the antenna device. In this Figure 7,
The outputs of the first and second antenna elements ANT ₃ and ANT ₄ amplified by the low noise amplifiers LNA ₃ and LNA ₄ ,
The antenna switching circuit 5 is used for switching, and the respective switching outputs are synthesized by using the signal synthesizer COM. That is, power is constantly supplied to both the first and second antenna elements ANT ₃ and ANT ₄ . In this case,
Low-noise amplifiers LNA ₃ and LNA without switching elements
_Since the outputs of the first and second antenna elements ANT ₃ and ANT ₄ are input to ₄ , the S / N does not deteriorate.

The antenna switching circuit 5 includes FETs Q ₃ and Q ₄
5V from the bias terminal BIAS.
It was applied to connect the control terminal CNT _3, CNT ₄ to the gate of each FET Q _3, Q _4, the control terminal CNT _3, CN
Applying a control signal of 0 / 2V from T ₄ to FETs Q ₃ and Q
_It is configured to turn ₄ on and off. It should be noted that the capacitors C _{10 to} C ₁₅ are for cutting DC, and the capacitor C ₁₆
~ C ₁₈ is for high frequency bypass, choke coil CH ₁₀ ~ C
H ₁₅ is for high frequency blocking, and resistors R ₅ and R ₆ are for current limiting. Further, X ₃ and X ₄ are phase shift lines (90 ° phase shift) for synthesis for obtaining endfire directivity or inductances.

In the case of this embodiment, the first and second antenna elements ANT are used as the output OUT of the signal combiner COM.
₃ , the output of ANT ₄ can be obtained by in-phase combining or 90-degree phase difference combining. (Embodiment 3) FIG. 8 shows still another embodiment of the present invention.
In this embodiment, at least a part of the peripheral circuit portion is integrally formed on the double-sided printed circuit board 4 which constitutes the antenna element portion. The peripheral circuit section includes a phase shift circuit, antenna switches SW ₁ and SW ₂ , low noise amplifiers LNA ₁ and LNA _2.
Alternatively, it is a signal synthesizer COM or the like.

In FIG. 8, the antenna switch SW ₁ , S shown in FIG. 1B is shown together with the plate-like inverted F-type antenna of the second embodiment.
W ₂ is integrally incorporated between the antenna element conductors 41 ₁ and 41 ₂ . Chip parts are used as the diodes D ₁ and D ₂ , the capacitors C _{1 to} C ₃ and the resistor R ₁ , and the choke coils CH _{1 to} CH ₃ are formed by a copper foil pattern. Further, the outputs A and B, the control terminal CNT, and the bias terminal BIAS are connected to the through holes 46 ₁ , 46 ₂ and 4.
7, 48 are drawn out from the back surface of the double-sided printed circuit board 4. By incorporating a part of the peripheral circuit portion in the double-sided printed circuit board 4 in this manner, the area occupied by the circuit forming the antenna switching means can be reduced.

(Embodiment 4) FIG. 9 shows still another embodiment of the present invention. In this embodiment, a laminated printed circuit board 4'having a three-layer structure is used, and a first layer (front surface layer) and a third layer (back surface layer) are used.
Is used to form the antenna element part described in Example 2,
Is obtained only choke coil CH ₁ to CH ₃ in FIG. 2 (a) formed using a copper foil pattern to the second layer (inner layer). The end portion of the choke coil CH ₁ to CH ₃ is used a through-hole 49, is led out on the back side of the printed circuit board 4 '. In this way, the choke coil CH
By forming _{1 to} CH ₃ in the inner layer, it is possible to keep away from the antenna conductor portion 41 ₁ ′ and the like, and it is possible to reduce the occupied area of the circuit constituting the antenna switching means without disturbing the antenna operation.

[0040]

As described above, the first and second grounded antenna elements arranged on one surface of the housing at regular intervals and each antenna element as a two-element broadside array antenna. 3 of the first switching mode to operate and the second and third switching modes to operate as a two-element end-fire array antenna with different main beam directions
Since there is provided an antenna switching means for switching to any of the three antenna operation modes, it is possible to switch the combined directivity of the two antenna elements into three types. , It is possible to suppress an abrupt phase change and obtain a good standby reception state.

According to the sixth aspect of the invention, since a part of the circuit which constitutes the antenna switching means is formed between the antenna conductor portions of the first and second antenna elements, the circuit which constitutes the antenna switching means is formed. The occupied area can be reduced, and the antenna device can be downsized. According to the invention of claim 7 , a multilayer printed circuit board having a third layer between the first layer and the second layer is used, and a part of the circuit forming the antenna switching means is formed in the third layer. , Keep away from the antenna element part and some circuits constituting the antenna switching means,
To reduce the influence on the operation of the antenna element, it is Ru can <br/> to reduce the area occupied by the circuit constituting the antenna switching means.

[Brief description of drawings]

1A and 1B are a perspective view showing an appearance of an embodiment of the present invention and a configuration diagram of an antenna switching unit.

2A and 2B are concrete circuit diagrams of an antenna switch, respectively.

3 (a) to 3 (c) are explanatory diagrams showing antenna characteristics when switching operation modes.

4 (a) and 4 (b) are perspective views showing the appearance of another embodiment, respectively.

5 (a) and 5 (b) are explanatory views showing antenna characteristics at the time of switching operation modes, respectively, and FIG. 5 (c) is a perspective view of a device under test in which the same antenna characteristics are measured.

6A and 6B are an antenna device using an inverted F-type antenna and an antenna characteristic diagram thereof as a reference.

FIG. 7 is a configuration diagram of an antenna switching unit of the above.

FIG. 8 is a perspective view showing a configuration of an antenna element portion of still another embodiment.

FIG. 9 is a partial perspective view showing the configuration of an antenna element portion of still another embodiment.

10 (a) and 10 (b) are perspective views of an apparatus including a conventional position diversity antenna, respectively.

[Explanation of symbols] ANT _{1 to} ANT ₄ antenna element SW ₁ and SW ₂ antenna switch LNA _{1 to} LNA ₄ low noise amplifier COM signal synthesizer X ₁ and X ₂ reactance element 1 housing 4 double-sided printed board 4 ′ laminated printed board 5 Antenna switching circuit 41 ₁ , 41 ₂ Capacitance loading conductor part 41 ₁ ', 41 ₂ ' Antenna element conductor part

Claims (8)

[Claims] 1. A first and a second grounded antenna element arranged on a surface of a housing at regular intervals, and a first switching mode for operating each antenna element as a two-element broadside array antenna in a main beam direction. An antenna device comprising: an antenna switching means for switching between three different antenna operation modes, a second and a third switching mode, for operating as different two-element end-fire array antennas. 2. In the first switching mode, both the first and second antenna elements operate as a two-element broadside array antenna of equal phase and equal amplitude feeding, and in the second and third switching modes, The antenna device according to claim 1, wherein the antenna device operates as a two-element end-fire array antenna with a parasitic element in which one of the first antenna element and the second antenna element is a parasitic element. 3. In the first switching mode, both the first and second antenna elements operate as a two-element broadside array antenna of equal phase and equal amplitude feeding, and in the second and third switching modes, The first and second antenna elements are 90
The antenna device according to claim 1, wherein the antenna device operates as a two-element end-fire array antenna of a phase difference / equal amplitude feed. 4. The antenna device according to claim 1, wherein the first and second antenna elements are ground-capacity antennas with top capacitance loading. 5. The antenna device according to claim 1, wherein plate-shaped inverted F-type antennas are used as the first and second antenna elements. 6. A multi-layer printed circuit board, wherein antenna conductor portions of the first and second antenna elements are formed at regular intervals on a first layer, and a second layer facing the first layer is formed as a ground layer. The antenna device according to claim 1, wherein: 7. The antenna device according to claim 6, wherein a partial circuit that constitutes an antenna switching means is formed between the antenna conductor portions of the first and second antenna elements. 8. A multi-layer printed circuit board having a third layer between a first layer and a second layer is used, and a partial circuit constituting an antenna switching means is formed on the third layer. The antenna device described.