JPH10285093A - Diversity device and portable radio unit using the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep a fixed gain despite the change of the peripheral condition such as a calling mode, etc., of a portable radio unit by reflecting the electric power fetched by a non-selection antenna at an open terminal of a switch means and radiating again a radio wave having the different phase from the direct wave to be sent to a selection antenna into a space. SOLUTION: A selection antenna 1 operates when a switch 5 is turned on, and the fetched electric power is supplied to a receiver 7 via a variable phase device 3 and the switch 5 and becomes effective. Meanwhile, the electric power fetched by a non-selection antenna 2 is reflected at an open part of a switch 6 after passing through a variable phase device 4 since the switch 6 is turned off. The radio waves are consumed by the device 4 but radiated again from the antenna 2 and inputted again to the antenna 1. The reflected radio waves have the the different phase from the direct wave that is sent to the antenna 1 and accordingly the radiation pattern of the antenna 1 is equal to that of a double element array antenna. Thus, a radiation pattern having high gain is obtained via the control of the device 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity device for avoiding multipath fading in wireless communication, and a portable wireless device using this device.

[0002]

2. Description of the Related Art In wireless communication, a sudden change in the reception level due to multipath fading causes deterioration in the quality of wireless communication. Accordingly, in mobile communication such as a portable wireless device, in order to avoid multipath fading, diversity (diversity: utilizing the fact that propagation variation differs in space and frequency, etc., is used, a plurality of reception branches are prepared, and the reception power in them is reduced. A method of reducing propagation fluctuations by combining or switching) reception may be performed.
There are various types of diversity reception, and among them, antenna selection diversity using a plurality of antennas. This antenna selection diversity is two (multiple)
The diversity effect is obtained by switching (selecting) the antenna having higher sensitivity among the antennas of the above. Although the diversity gain is lower than the selected diversity after detection, only one receiver is required. Is widely used as a diversity system.

[0003] However, when the antenna selection diversity is adopted, a considerable current flows to the non-selected antenna due to mutual coupling of the antennas, and power is supplied to the impedance of the feed line connected to the non-selected antenna. In the case of the antenna selection diversity, the reception power of the non-selected antenna is matched and terminated at the receiver side of the non-selected antenna without being used, and current is consumed at the termination to invalidate. As means for eliminating such wasteful power consumption, there is a conventional diversity device disclosed in Japanese Patent Application Laid-Open No. Hei 7-221681. This diversity device sets the line length of the non-selected antenna to λ / 4 of the carrier frequency so that no current flows to the non-selected antenna or the non-selected antenna does not operate as an antenna.
And λ / 2, a structure in which no current flows through the non-selected antenna itself is used to eliminate unnecessary power consumption and improve the gain of the selected antenna.

FIG. 8 is a block diagram showing a conventional diversity device disclosed in Japanese Patent Application Laid-Open No. 7-221681.
In the figure, reference numerals 1 and 2 denote antennas mounted at distant positions on the housing of the portable wireless device, and use quarter-wave monopoles. 7 is a portable radio receiver, 2
1 and 22 have one ends connected to the terminals of the antennas 1 and 2,
This is a microstrip line having an electrical length of a quarter wavelength or more.
Connects the antennas 1 and 2 to the receiver 7. 2
Reference numerals 3 and 24 denote FETs connected to the other ends of the microstrip lines 21 and 22, and reference numerals 25 and 26 are located on the microstrip lines 21 and 22 at positions separated from the terminals of the antennas 1 and 2 by a quarter of the electrical length. Connected FETs,
When the FETs 25 and 26 are on, they are short-circuited to ground.

Next, the operation will be described. The operation will be described taking an example in which the antenna 1 is selected. Antenna 1
Is selected, the FET 23 and the FET 26 are on, and the FET 24 and the FET 25 are off. Therefore, the microstrip line 22 and the receiver 7 are separated. When the microstrip line 22 is viewed from the terminal of the antenna 2, it is shorted (short-circuited) at a distance of a quarter wavelength, so that it becomes a quarter short stub, and the impedance becomes infinite. Therefore, almost no current flows through the antenna terminal of the antenna 2, and power consumption by the non-selected antenna (antenna 2) is reduced. On the other hand, the antenna 1 and the receiver 7 are connected to the FET 2
3 is ON and the FET 25 is OFF and not short-circuited, so that the impedance of the microstrip line 21 is not changed. Therefore, it is equivalent to the antenna 1 and the receiver 7 being connected by one microstrip line 21, and a loss (loss) due to mutual coupling of the antenna 2 can be prevented.

[0006]

Since the conventional diversity device is configured as described above, it is equivalent to a case where one element of the selected antenna (one antenna 1) is operating. The element selection antenna is omnidirectional and has a problem that the gain of the antenna cannot be increased only in a specific direction. In particular, a portable wireless device used for mobile communication is used close to the human body or is carried around in a bag or the like, so that surrounding conditions change, so that it is necessary to provide a high gain in a specific direction (specific direction). By changing the directivity of the selected antenna, a constant gain can be maintained even when the conditions around the portable wireless device change, improving the performance of the portable wireless device. It is also possible to make it possible).

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and changes the directivity of a selective antenna so as to maintain a constant gain even when conditions around a portable wireless device change, such as during a call. It is an object of the present invention to obtain a diversity device capable of performing the above and a portable wireless device using the device.

[0008]

According to a first aspect of the present invention, there is provided a diversity apparatus having a plurality of antennas for receiving radio waves, and one end connected to each of the plurality of antennas to change the phase of power transmitted from the antenna. Variable phase means, and one end connected to each other end of the variable phase means, short-circuit the line corresponding to the selected antenna, and switch means to open the line corresponding to the antenna not selected, It is configured to include a receiver connected to a connection point at the other end of each of the switch means.

According to a second aspect of the present invention, in the diversity apparatus, the variable phase means and the switch means comprise a strip line and a switch.

According to a third aspect of the present invention, in the diversity apparatus, the variable phase means and the switch means are constituted by a lumped constant element and a switch.

According to a fourth aspect of the present invention, in the diversity apparatus, the variable phase means comprises a plurality of variable phase sections for controlling the phase of the power so as to be changeable and a switch for switching the plurality of variable phase sections. The variable phase section changes the phase of each different frequency band.

According to a fifth aspect of the present invention, there is provided a diversity apparatus which is provided with an antenna for taking in a radio wave, a receiver connected to the antenna, and a non-resonant antenna which resonates at a carrier frequency with a low correlation with the antenna. An exciting resonance element, and a variable phase means connected between the resonance element and the receiver and configured such that the line can be opened or short-circuited at the tip thereof, and the phase of the power transmitted from the resonance element is controlled so as to be changeable. It is configured to be provided.

According to a sixth aspect of the present invention, in the diversity apparatus, the variable phase means comprises a strip line and a switch.

According to a seventh aspect of the present invention, in the diversity apparatus, the variable phase means comprises a lumped constant element and a switch.

The diversity device according to the invention described in claim 8 is constructed so as to operate for the first time when the electric field is weak and when the reception level is deteriorated.

A portable wireless device according to a ninth aspect of the present invention comprises:
This is configured using the diversity device of the present application.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a configuration diagram showing a diversity device according to Embodiment 1 of the present invention.
2, a variable phase shifter (variable phase shifter) having one end connected to the terminals of antennas 1 and 2 and the other end connected to switches 5 and 6, respectively. Phase means), 5, 6 are FETs, provided between the other ends of the variable phase shifters 3, 4 and the receiver 7.
A switch (switch means) 7 composed of a diode SW or the like is a receiver of the portable wireless device. Reference numerals 8 and 9 denote control lines for variably controlling the phases of the variable phase shifters 3 and 4.
In FIG. 1, components denoted by the same reference numerals as those in FIG. 8 indicate the same or corresponding portions.

Next, the operation will be described. The operation when the antenna 1 is selected in the diversity apparatus of the antenna selection system will be described. If antenna 1 is a selected antenna and antenna 2 is a non-selected antenna, antenna 1 is connected to receiver 7 via variable phase shifter 3 and switch 5 turned on, and antenna 2 is connected to variable phase shifter 4 The switch 6 is opened (opened) with the switch 6 turned off.

When the portable radio receives radio waves, the antenna 1 operates as an antenna because the switch 5 is on, and the power taken in by the antenna 1 is transmitted to the receiver 7 via the variable phase shifter 3 and the switch 5. Is entered and becomes valid. On the other hand, since the switch 6 of the antenna 2 is off, the power taken in by the antenna 2 passes through the variable phase shifter 4 and is reflected by the open portion of the switch 6. The reflected wave (radio wave) is consumed by the variable phase shifter 4, but is re-emitted from the antenna 2 via the variable phase shifter 4. The radio wave re-emitted from the antenna 2 is re-input to the antenna 1. Since the radio wave re-emitted from the antenna 2 and the direct wave to the antenna 1 have different phases,
The radiation pattern of the antenna 1 (a radiation pattern is shown as a radiation pattern) is similar to the radiation pattern of a two-element array antenna.

Here, when the phase of the variable phase shifter 4 is changed, the phase of the radio wave re-radiated from the antenna 2 changes,
The phase with the direct wave to the antenna 1 changes, and the directivity of the antenna changes (the direction of higher gain changes).

The TDMA system (Time Division)
When n multiple access (time division multiple access system) or the like is used, RSSI (Received Signal Str) is used in slots other than transmission / reception slots.
monitor the variable phase shifter 4 via the control line 9. And
If the optimum value of the phase of the variable phase shifter 4 is determined and the phase is used when receiving the received data by the antenna (selected antenna), the received data can always be captured with the maximum gain.

As described above, according to the first embodiment, the electric power taken into the non-selected antenna is reflected at the open end, and the radio wave having a different phase from the direct wave to the selected antenna is re-emitted into space. Because of this configuration, there is a phase difference between the re-radiated radio wave and the direct wave, so the radio wave captured by the selected antenna has a radiation pattern of a two-element array antenna, and the variable phase on the non-selected antenna side By adjusting the antenna, the radiation pattern of the two-element array antenna can have a high gain in a desired direction.
Therefore, when the diversity device according to the first embodiment is used in a portable wireless device, a constant gain can be maintained even when conditions around the portable wireless device change, and the performance of the portable wireless device can be improved. It becomes possible.

Embodiment 2 FIG. FIG. 2 is a configuration diagram showing a diversity device according to a second embodiment of the present invention. still,
In FIG. 2, the same or corresponding parts as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.
In the drawing, reference numeral 10 denotes microstrip lines (strip lines) 10a, 10b, 10c and switches 10A, 1
0B, a variable phase shifter on the antenna 1 side, 1
1 is a microstrip line (strip line) 11
This is a variable phase shifter on the antenna 2 side composed of a, 11b, 11c and switches 11A, 11B.

Next, the operation will be described. The basic operation of the diversity device is the same as that in the first embodiment, and therefore will not be described, and the operation of changing the phase of variable phase shifters 10 and 11 will be described. Variable phase shifter 10 (variable phase shifter 1
(The same applies to 1) is performed by selecting the microstrip lines 10a, 10b, and 10c by the switch 10A. That is, the microstrip lines 10a, 1
0b and 10c are formed to have different line lengths and shapes, respectively, and change the phase of electric power by the microstrip lines 10a, 10b and 10c to which the switch 10A is connected. The switch 10B of the variable phase shifter 10 (the same applies to the variable phase shifter 11) is provided in the first embodiment.
The connection and opening of the line are performed by selecting this switch 10B (opening when the microstrip lines 10a, 10b, and 10c to which the switch 10A is not connected are selected). .

As described above, according to the second embodiment, the variable phase shifters 10 and 11 are connected to the microstrip line 1.
Since it is composed of Oa, 10b and 10c and switches 10A and 10B, the degree of freedom of the variable phase is slightly reduced, but the configuration of the variable phase shifters 10 and 11 is simplified.
The configuration of the diversity device is also simplified.

Embodiment 3 FIG. FIG. 3 is a configuration diagram showing a diversity apparatus according to Embodiment 3 of the present invention. The variable phase shifters 12 and 13 in FIG. 3 use the microstrip lines 10a, 10b and 10c (or microstrip lines 11a, 11b and 11c) in FIG. 2 to simplify the variable phase shifter 10 (or the variable phase shifter 11). For,
Lumped constant elements 12a, 12 composed of lumped constants L and C
b, 12c (or lumped constant elements 13a, 13b, 1)
3c). Thus, the variable phase shifter 1
2, 13 are lumped constant elements 12a, 12b, 12c, 13
a, 13b, 13c and switches 12A, 12B, 13
A, 13B, the variable phase shifter 1
The configuration of 2 and 13 becomes simple.

Embodiment 4 FIG. 4 is a configuration diagram showing a diversity device according to a fourth embodiment of the present invention. still,
In FIG. 4, the same or corresponding parts as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.
In the figure, reference numeral 14 denotes a variable phase shifter (variable phase unit) 15, 1
6 and switches 14A and 14B, a wide-band variable phase shifter (variable phase means) on the antenna 1 side, and 17 are variable phase shifters (variable phase sections) 18, 19 and switches 17A,
17B is a wide-band variable phase shifter (variable phase means) on the antenna 2 side constituted by 17B. The variable phase shifters 15, 1
Reference numerals 6, 18, and 19 correspond to the variable phase shifters 3 and 4 shown in FIG. Thus, the variable phase shifters 15, 16
Or the wideband variable phase shifter 14 or 17 including a plurality of the phase shifters 15, 16, 18, 18, 18, 18, 19 is provided for each band of the operating frequency (reception frequency) of the portable wireless device.
19 can be selected, and the portable wireless device can use a wideband frequency.

Embodiment 5 In the fifth embodiment, an operation principle similar to that of the first embodiment is applied to a portable wireless device that does not employ the antenna selection diversity having only one antenna and one receiver. FIG. 5 is a configuration diagram showing such a diversity apparatus according to the fifth embodiment of the present invention. In FIG. 5, the same or corresponding components as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted. In the figure, reference numeral 20 denotes a non-excited resonance element (small antenna with good performance) which resonates at a carrier frequency and is provided at a position where the correlation with the antenna 1 becomes low. Is connected to The tip of the line connecting the resonance element 20 and the variable phase shifter 3 is configured to be openable or short-circuitable.

Next, the operation will be described. When the portable wireless device receives a radio wave, the power taken in by the antenna 1 is directly input to the receiver 7 and becomes effective.
On the other hand, the power taken in by the resonance element 20 passes through the variable phase shifter 3 and is reflected at an open portion of the line. Although this reflected wave (radio wave) is consumed by the variable phase shifter 2, it is re-emitted from the resonance element 20 via the variable phase shifter 3. The radio wave re-emitted from the resonance element 20 is re-input to the antenna 1 as in the first embodiment. Since the radio wave re-emitted from the resonance element 20 and the direct wave to the antenna 1 have different phases, the radiation pattern of the antenna 1 (a radiation pattern whose directivity is illustrated is called a radiation pattern)
It looks like the radiation pattern of a two-element array antenna.

As described above, according to the fifth embodiment, the same effects as those of the first embodiment can be obtained with a simple configuration having only one antenna 1 and one receiver 7.

Embodiment 6 FIG. FIG. 6 is a configuration diagram showing a diversity apparatus according to Embodiment 6 of the present invention. still,
In FIG. 6, the same or corresponding components as those in FIGS. 2 and 5 are denoted by the same reference numerals. Embodiment 6
Changes the variable phase shifter 10 to the microstrip line 10a,
This configuration includes the switches 10b and 10c and the switch 10A, and has the same effects as those of the fifth embodiment. At the same time, the configuration of the variable phase shifter 10 is simplified, and the configuration of the diversity device is also simplified.

Embodiment 7 FIG. 7 is a configuration diagram showing a diversity device according to a seventh embodiment of the present invention. still,
In FIG. 7, the same or corresponding components as those in FIGS. 3 and 5 are denoted by the same reference numerals. Embodiment 7
Sets the variable phase shifter 12 to the lumped constant elements 12a, 12b, 1
This is composed of the switch 2c and the switch 12A. The same effect as that of the fifth embodiment is obtained, and the configuration of the variable phase shifter 12 is further simplified.

Embodiment 8 FIG. The diversity devices according to Embodiments 1 to 7 described above have a small effect in a strong electric field (the sensitivity of the antenna of the portable wireless device is sufficiently high in a strong electric field, so that it is necessary to use the diversity device of the present application). By monitoring the received electric field level, it is not possible to operate in the strong electric field, but to operate for the first time when the received level is degraded due to the weak electric field and the approach of the human body during a call. Can be reduced.

[0034]

As described above, according to the first aspect of the present invention, a plurality of antennas for capturing radio waves and one end thereof are connected to each of the plurality of antennas so that the phase of the power transmitted from the antenna can be changed. Variable phase means for controlling, and switch means for short-circuiting the line corresponding to the selected antenna, one end of which is connected to each other end of the variable phase means, and opening the line corresponding to the antenna not selected,
Since the receiver is connected to the connection point at the other end of each of the switch means, the power taken into the non-selected antenna (the antenna not selected) is reflected at the open end of the switch means. , By re-radiating into the space a radio wave with a different phase from the direct wave to the selected antenna (selected antenna), the radio wave captured by the selected antenna due to the phase difference between the re-radiated radio wave and the direct wave
It becomes like the radiation pattern of a two-element array antenna, and by adjusting the variable phase means on the non-selected antenna side,
There is an effect that the radiation pattern of the two-element array antenna can have a high gain in a desired direction.

According to the second aspect of the present invention, since the variable phase means and the switch means are constituted by strip lines and switches, the structure of the variable phase means is simplified, and the structure of the diversity apparatus is also simplified. There is.

According to the third aspect of the present invention, since the variable phase means and the switch means are composed of lumped constant elements and switches, there is an effect that the structure of the variable phase means is further simplified.

According to the fourth aspect of the present invention, the variable phase means comprises a plurality of variable phase sections for controlling the phase of the electric power so as to be changeable and a switch for switching the plurality of variable phase sections. Since each of the sections changes the phase of a different frequency band, a variable phase section can be selected for each frequency band (reception frequency) used by the portable wireless device, and the portable wireless device uses a wideband frequency. It has the effect of being able to.

According to the fifth aspect of the present invention, an antenna for receiving radio waves, a receiver connected to the antenna,
A non-excited resonance element that is provided at a position where the correlation with the antenna is low and resonates at the carrier frequency, and is connected between the resonance element and the receiver, and configured such that the line can be opened or short-circuited at its tip, A variable phase means for controlling the phase of the power transmitted from the resonance element so as to be changeable is provided, so that the same effect as that of the above-mentioned claim 1 can be obtained with a simple configuration having only one antenna and one receiver. There is an effect that can be done.

According to the sixth aspect of the present invention, since the variable phase means is composed of the strip line and the switch, the configuration of the variable phase means is simplified and the configuration of the diversity device is simplified.

According to the seventh aspect of the present invention, since the variable phase means is composed of a lumped constant element and a switch, the structure of the variable phase means is further simplified.

According to the eighth aspect of the present invention, since the operation is performed for the first time when the electric field is weak and the reception level is degraded, there is an effect that the power consumption of the diversity device can be reduced.

According to the ninth aspect of the present invention, since the diversity device of the present invention is used, a constant gain can be maintained even when conditions around the portable wireless device change. There is also an effect that the performance of the device can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a diversity device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a diversity device according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram showing a diversity device according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing a diversity device according to a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram showing a diversity device according to a fifth embodiment of the present invention.

FIG. 6 is a configuration diagram showing a diversity device according to a sixth embodiment of the present invention.

FIG. 7 is a configuration diagram showing a diversity device according to a seventh embodiment of the present invention.

FIG. 8 is a configuration diagram showing a conventional diversity device.

[Explanation of symbols]

1, 2 antenna, 3, 4 variable phase shifter (variable phase means), 5, 6 switch (switch means), 7 receiver, 10A, 10B, 11A, 11B, 12A, 12
B, 13A, 13B, 14A, 14B, 17A, 17B
Switches, 10a, 10b, 10c, 11a, 11
b, 11c microstrip line (strip line), 12a, 12b, 12c, 13a, 13b, 13
c Lumped element, 14, 17 Wideband variable phase shifter (variable phase means), 15, 16, 18, 19 Variable phase shifter (variable phase section), 20 resonance element.

Claims (9)

[Claims] 1. A plurality of antennas for receiving radio waves, one end of each of the plurality of antennas is connected to the variable phase means for controlling the phase of the power transmitted from the antenna to be changeable, and one end of the variable phase means is provided. Short-circuit the line corresponding to the selected antenna connected to each other end,
A diversity device comprising: switch means for opening a line corresponding to the antenna not selected; and a receiver connected to a connection point at the other end of each switch means. 2. The diversity device according to claim 1, wherein the variable phase means and the switch means are composed of a strip line and a switch. 3. The diversity device according to claim 1, wherein the variable phase means and the switch means are composed of a lumped constant element and a switch. 4. The variable phase means comprises a plurality of variable phase sections for controlling the phase of electric power so as to be changeable and a switch for switching between the plurality of variable phase sections, wherein the plurality of variable phase sections have different frequency bands. The diversity device according to claim 1, wherein the phase is changed. 5. An antenna for capturing a radio wave, a receiver connected to the antenna, a non-excited resonance element which is provided at a position where the correlation with the antenna is low and resonates at a carrier frequency, and the resonance element And connected between the receiver, the tip of the line can be opened or short-circuited,
A diversity device including variable phase means for controlling the phase of the power transmitted from the resonance element to be changeable. 6. The diversity apparatus according to claim 5, wherein said variable phase means comprises a strip line and a switch. 7. The diversity apparatus according to claim 5, wherein said variable phase means comprises a lumped constant element and a switch. 8. The diversity device according to claim 1, wherein the diversity device is configured to operate for the first time when the electric field is weak and when the reception level is degraded. 9. A portable wireless device using the diversity device according to any one of claims 1 to 8.