JP3327048B2 - Antenna device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device mounted on a radio equipment such as a time division multiple access system (TDMA).

[0002]

2. Description of the Related Art FIG. 22 is a block diagram showing an example of the configuration of a conventional TDMA radio, which has an antenna selection diversity receiving configuration. In the figure, reference numeral 1 denotes a transmitting section TX for modulating and amplifying a transmission signal and outputting the same to an antenna; 2, a first receiving section RX1 for amplifying and demodulating an input radio wave; Units RX2 and RX4 are transmission / reception duplexers (PLXs) DPLX for connecting the output end of the transmission unit 1 and the input end of the reception unit 1 to the antennas, respectively, and 5 is a first antenna ANT for transmission and reception.
1 and 6 are the second antennas ANT2 and ANT2 for reception only, and 7 are the first antennas
This is a switch for selectively switching the outputs of the receiving unit 2 and the second receiving unit 3 to perform a so-called antenna selection diversity receiving operation.

FIG. 23 is a partially cutaway perspective view showing an example of the appearance and structure of a TDMA radio, in which reference numeral 5 denotes a first antenna shared for transmission and reception, and reference numeral 6 denotes a second antenna dedicated to reception.

Next, the operation will be described. At the time of transmission by the TDMA radio, the transmission signal is modulated and amplified by the transmission unit 1, and its output is radiated as radio waves from the first antenna 5 after removing the spurious components outside the necessary band by the duplexer 4. . On the other hand, at the time of reception, a radio wave received by the first antenna 5 is band-limited by the duplexer 4 and then input to the first receiving unit 2 to be amplified and demodulated. In addition, the radio wave received by the second antenna 6 is input to the second receiving unit 3 and is amplified and demodulated. The output selector switch 7 selects and switches an output expected to have good characteristics from the output of the first receiver 2 and the output of the second receiver 3 to perform an antenna selection diversity reception operation. At this time, there are various switching timings depending on the antenna selection diversity reception method implemented for each TDMA reception time slot, and the reception electric field strength, the line error rate, and the like are generally used as a criterion for switching selection.

FIG. 23 shows an example of the structure of a TDMA radio. The first antenna 5 for transmission and reception is a whip antenna, and the second antenna 6 for reception is a plate-shaped inverted-F antenna built in a housing. Selective diversity reception is realized. In TDMA wireless communication, which is full duplex communication, the carrier frequency is generally different between transmission and reception, so the first antenna 5 that is used for both transmission and reception needs to have a wide band covering both the transmission and reception frequency bands. However, in the whip antenna 5 shown in FIG. 23, the resonance frequency depends on the physical length and dimensions of the whip antenna itself, and has only a single resonance point. It is difficult to satisfy the best performance. The antenna performance indicates that the smaller the return loss (VSWR) value which indicates the good matching with the space or the transceiver, the better. For this reason, various antennas having a two-resonance characteristic as shown in FIG. 25 have been considered. The deviation of the resonance frequency due to the temperature change or the manufacturing variation significantly affects the deterioration of the antenna characteristics such as the radiation efficiency and the VSWR characteristic. 24 and 25 show reflection loss (VSWR) characteristics of an antenna having a single resonance point and an antenna having two resonance points, respectively.
Value, the transmission / reception frequency is plotted on the horizontal axis, fRX is the reception frequency,
fTX indicates a transmission frequency. The antenna performance is better as the VSWR value is smaller (downward in the figure).

Further, when performing antenna selection diversity reception, it is required that the first antenna 5 used for transmission / reception and the second antenna 6 dedicated to reception provided for the antenna selection diversity reception configuration have as little cross-correlation as possible. Is done. However, in a small radio as shown in FIG. 23, the first antenna 5 and the second antenna 6 have to be arranged spatially close to each other, and the cross-correlation tends to increase. Also, the radiation pattern of one antenna,
The presence of the other antenna affects the antenna characteristics such as the radiation efficiency, resulting in deterioration of the antenna characteristics.

[0007]

Since the conventional antenna device is configured as described above, it is difficult to satisfy the best characteristics in both frequency bands when the transmission and reception frequency bands are separated. . Further, when performing antenna selection diversity reception, there is a problem that a plurality of antennas for antenna selection diversity reception affect each other in a small-sized radio, and antenna characteristics are deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and can achieve the best antenna characteristics in each of TDMA transmission and reception. It is an object of the present invention to obtain an antenna device capable of improving the antenna characteristics such as the radiation efficiency and the radiation pattern, by making settings that reduce the noise or achieve a good effect.

[0009]

[0010]

An antenna device according to the present invention includes a second antenna having means for switching an electrical length with a first antenna, and has a configuration for switching an electrical length of the second antenna. is there.

[0011] Also, a second antenna having means for switching the electrical length with the first antenna is provided, and the electrical length of the second antenna is switched according to the TDMA transmission / reception timing.

[0012] Further, a second antenna having means for switching the electrical length with the first antenna is provided, and the electrical length of the second antenna is switched in accordance with the presence or absence of reception selection of antenna selection diversity reception. is there.

[0013]

[0014]

[0015]

[0016]

[0017]

The antenna device according to the present invention switches the electrical length of the second antenna having means for switching the electrical length, and controls the influence of the second antenna on the first antenna.

Further, the electric length of the second antenna having a means for changing the electric length is switched according to the TDMA transmission / reception timing, and the influence of the second antenna on the first antenna is controlled.

Further, the electric length of the second antenna having a means for switching the electric length is switched in accordance with the presence or absence of the reception selection of the antenna selection diversity reception, and the influence of the second antenna on the first antenna is controlled.

[0020]

[0021]

[0022]

[0023]

【Example】

Embodiment 1 FIG. Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
Will be described. FIG. 1 is a block diagram showing the configuration of the TDMA radio of the first embodiment, and FIG. 2 is a timing chart for explaining the operation thereof. In FIG. 1, reference numeral 1 denotes a transmitting unit that modulates and amplifies a transmission signal and outputs it to an antenna, 2 denotes a receiving unit that amplifies and demodulates an input radio wave, and 4 denotes an output terminal of the transmitting unit 1 and an input terminal of the receiving unit 2 respectively. , A transmission / reception duplexer (duplexer), which is connected to the antenna, and 50, a transmission / reception shared antenna having means for switching an electrical length, and 10, an electrical length switching signal for switching the electrical length of the antenna 50. In FIG. 2, reference numeral 11 denotes a transmission time slot T in which the radio of the TDMA can emit radio waves, reference numeral 12 denotes a reception time slot R in which the radio can receive radio waves, and reference numeral 13 denotes a local station of the radio. A time frame that does not participate in transmission / reception for the channel, that is, an idle time slot I. Note that during the idle time slot 13,
In some cases, the wireless device performs a receiving operation to measure the electric field strength of the peripheral base station. Reference numeral 42 denotes a diversity switching determination period when the TDMA wireless device performs a diversity receiving operation. In addition, the electrical length switching signal 10 for switching the electrical length of the antenna 50 is such that the electrical length of the antenna 50 is set to 1T at the timing corresponding to the transmission time slot 11 and the This shows that the electrical length is switched to IR.

Next, the operation will be described. Antenna 5
0 has two types of electrical lengths IT and IR, and has means capable of switching to any electrical length by the electrical length switching signal 10. That is, the antenna 50 has an electrical length IT
, The antenna 50 resonates at the transmission frequency fTX, and when switched to the electrical length lR, the antenna 50 resonates at the reception frequency fRX. TD of this embodiment
In the MA radio, the output of the transmitting unit 1 and the input of the receiving unit 2 are connected to the antenna 50 via the duplexer 4.
The electrical length switching signal 10 is synchronized with the TDMA frame, and as shown in FIG.
The electrical length switching signal 10 switches the electrical length of the antenna 50 to 1T. The VSWR characteristic of the antenna at this time is, as shown by the solid line in FIG. 3, the antenna 50 operates as a one-resonant antenna exhibiting the best characteristic at the transmission frequency fTX. When the time advances and shifts from the transmission time slot 11 to the reception time slot 12 or the idle time slot 13, the electrical length switching signal 10
Is switched so as to be 1R. The VSWR characteristic of the antenna 50 at this time is, as shown by the dashed line in FIG. 3, the antenna 50 operates as a one-resonant antenna exhibiting the best characteristic at the reception frequency fRX. Thus, T
By switching the antenna length in accordance with the frame format of the DMA, the antenna 50 can be switched between the transmission time slot 11 and the reception time slot 12.
Also, the best antenna characteristics are realized at each frequency.

FIG. 4 is a diagram showing a first specific configuration example of an antenna 50 having means for switching the electrical length provided to the antenna device of FIG. In FIG. 4, reference numeral 14 denotes a plate-shaped base material such as a printed board, 15 denotes a first antenna element made of a conductor printed and wired on the base material, and 16 denotes the base material 14 similar to the first antenna element. The second antenna element is formed on the second antenna element, but has a different length.
Are the antenna elements 15, 1 according to the electrical length switching signal 10.
6 is a changeover switch for switching the number 6. The length of the first antenna element 15 is １ ／ of the wavelength λT of the transmission frequency fTX,
The length of the second antenna element 16 is set to １ ／ of the wavelength λR of the reception frequency fRX, and the first antenna element 15
Corresponds to the electrical length lT, and the second antenna element 16 corresponds to the electrical length lR. The changeover switch 17 is generally formed of a semiconductor element such as GaAs MESFET for miniaturization, and the common connection terminal is selectively connected to either the first antenna element 15 or the second antenna element 16. In this example, the common connection terminal is connected to the duplexer 4, and the first antenna element 15 is selected in the transmission time slot 11 by the electric length switching signal 10, and the second antenna element 16 is selected in the reception time slot 12 and the idle time slot 13. Is switched to In addition, although the setting of the antenna element is based on the 例 wavelength, other examples such as 波長 wavelength and ８ wavelength are also possible.

Embodiment 2 FIG. FIG. 5 shows an antenna 50 having means for switching the electrical length provided to the antenna device of FIG.
It is a figure which shows the 2nd example of a specific structure. In FIG. 5, reference numeral 18 denotes a rod-shaped base material, 19 denotes a first antenna element formed of a conductive wire spirally wound around the base material, and 20 denotes a base material of the base material 18 similarly to the first antenna element. A second antenna element that is wound around but has a different length from the first antenna element 19. The first antenna element 19 has an electrical length of 1T, and the second antenna element 20 has an electrical length of 1R.
The lengths and intervals of the conducting wires are adjusted to correspond to the above. A common connection terminal is connected to the first antenna element 19 or the second antenna element 2 by a changeover switch 17 composed of a semiconductor element or the like.
0 is selectively connected. In this example, the common connection terminal is connected to the duplexer 4 and the electrical length switching signal 10
Is switched so that the first antenna element 19 is selected in the transmission time slot 11 and the second antenna element 20 is selected in the reception time slot 12 and the idle time slot 13, and the same effect as in the first embodiment is obtained.

Embodiment 3 FIG. FIG. 6 shows an antenna 50 having means for switching the electrical length provided to the antenna device of FIG.
It is a figure which shows the 3rd example of a specific structure. In FIG. 6, reference numerals 21a and 21b denote antenna elements made of a rod-shaped conductor or the like divided into two parts, and 22 denotes these antenna elements 21a and 21b.
A coil 23 is provided between 1b and is a switch connected to both ends of the coil and capable of ON / OFF operation. When the switch 23 is ON, the antenna elements 21a,
21b is directly connected and has an electrical length of 1T. Switch 23
Are OFF, the antenna elements 21a and 21b
2 and the electrical length is 1R. The antenna 50 shown in FIG. 6 is used as the antenna 50 shown in FIG. 1. The switch 23 is turned on in the transmission time slot 11 by the electrical length switching signal 10, the electrical length of the antenna is set to 1T, the reception time slot 12 and the idle time slot 1 are used.
In the third embodiment, the switch 23 is turned off and the electrical length is set to lR, so that the same effect as that of the first embodiment can be obtained.

Embodiment 4 FIG. FIG. 7 shows an antenna 50 having means for switching the electrical length provided to the antenna device of FIG.
It is a figure which shows the 4th example of a specific structure. FIG. 7 is similar to the antenna shown in FIG. 6, but differs in that the coil 22 is not provided. When the switch 23 is OFF, the antenna element 21
a and 21b are separated, and the electrical length as an antenna is 1T
Becomes When the switch 23 is ON, the antenna element 21a
And 21b are connected, and the electrical length as an antenna is 1R. The antenna 50 shown in FIG. 7 is used as the antenna 50 shown in FIG. 1. The switch 23 is turned off in the transmission time slot 11 by the electrical length switching signal 10 to set the electrical length of the antenna to 1 T. In the reception time slot 12 and the idle time slot 13, By turning on the switch 23 and setting the electrical length to 1R, the same effect as in the first embodiment can be obtained.

Embodiment 5 FIG. FIG. 8 shows an antenna 5 having means for switching the electrical length provided to the antenna device of FIG.
It is a figure which shows the 5th example of a specific structure of 0. An antenna 50 shown in FIG. 8 is a dipole antenna, 24 is a feed-side antenna element, 25a is a first ground-side antenna element,
b is a second ground-side antenna element, and 17 is a changeover switch. The first ground-side antenna element 25a has a transmission frequency f
1/4 of the wavelength λT of TX, second ground-side antenna element 2
5b has a length of 1/4 of the wavelength λR of the reception frequency fTX, and the electrical lengths are 1T and 1R, respectively. The antenna 5 of FIG.
0 is used as the antenna 50 in FIG. 1, the first ground-side antenna element 25a is selected in the transmission time slot 11 by the electrical length switching signal 10, and the second ground side antenna element 25a is selected in the reception time slot 12 and the idle time slot 13. By selecting the antenna element 25b, the same effect as in the first embodiment is obtained. Although the ground-side antenna element is switched in the present embodiment, the power-supply-side antenna element may be switched, or both antenna elements may be switched instead of one of the ground-side and power-supply-side antenna elements.

Embodiment 6 FIG. Another embodiment of the present invention will be described with reference to FIGS. FIG. 9 shows a TDMA according to the sixth embodiment.
FIG. 10 is a timing chart for explaining the operation of the wireless device. In this embodiment of FIG. 9, an antenna selection diversity reception configuration is used to improve reception characteristics, and a changeover switch that switches between the second antenna 60, the second reception unit 3, and the reception unit for performing antenna selection diversity reception 7 have been added to FIG. The antenna that switches the electrical length by the electrical length switching signal 10 is not the first antenna 5 but the second antenna 60. That is, the second antenna 60
There are means that have different types of electrical lengths l1 and l2 and can be switched to any one of the electrical lengths by the electrical length switching signal 10. In FIG. 10, reference numeral 11 denotes a transmission time slot in which the radio equipment of TDMA can radiate radio waves;
Reference numeral 2 denotes a reception time slot in which the wireless device can receive a radio wave, and reference numeral 13 denotes an idle time slot, which is a time frame in which the wireless device does not participate in transmission / reception regarding its own channel. The electrical length switching signal 10 for switching the electrical length of the antenna 60 indicates that the electrical length of the antenna 60 is 11 at the timing corresponding to the transmission time slot 11 and the electrical length of the antenna 60 at the timing other than the transmission time slot 11 such as the reception time slot 12. Indicates switching to l2. That is, the antenna 60 is connected to the reception time slot 12
Or the electrical length l in the idle time slot 13 or the like.
When the frequency is switched to 2, the antenna 60 is set to resonate at the reception frequency fRX, and operates as an antenna device that obtains the best antenna characteristics at the reception frequency.

On the other hand, in the transmission time slot 11, since the transmission is performed using the first antenna 5, the second antenna 60 does not normally participate. However,
As described in the conventional example, in a small wireless device,
Since the first antenna 5 and the second antenna 60 are spatially close to each other, they affect each other. That is, the antenna characteristics such as the resonance frequency, the radiation efficiency, and the radiation pattern of the second antenna 60 influence the antenna characteristics of the first antenna 5 in the transmission time slot 11 and thus the wireless device. However, in the conventional example, the second antenna 6 of FIG. 22 is designed in consideration of only the antenna characteristics at the time of reception. For example, since the electric length is fixed to a value corresponding to l2, the transmission time slot There is a great possibility that the antenna 5 transmitting at 11 will be adversely affected.
In order to improve this, in the present embodiment, as shown in FIG. 10, in the transmission time slot 11, the electrical length of the second antenna 60 is switched to l1. Here, the electric length l1 is equal to the first length of the second antenna 60 during transmission.
Is set so as to reduce the influence on the antenna or to positively influence the antenna. By the above operation, in the antenna selection diversity reception configuration of TDMA, the antenna characteristics can be improved for both transmission and reception.

FIG. 11 shows a second antenna 60 having means for switching the electrical length provided to the antenna device of FIG.
FIG. 3 is a diagram showing a first specific configuration example of FIG. The present antenna 60 shown in FIG.
Is a radiation plate, 27 is a ground plane, 28 is a ground conductor connecting the radiation plate and the ground plane, 29 is a first feeding point on the radiation plate 26, 30 is a second feeding point on the radiation plate 26, and 17 is a feeding point Is a changeover switch for switching the position of. The antenna 60 can switch between two types of electrical lengths l1 and l2 depending on which of the first feeding point 29 and the second feeding point 30 is selected. The antenna 60 is used as the second antenna 60 in FIG. 9, and switches the feeding point of the radiation plate 26 in the transmission time slot 11, the reception time slot 12, and the idle time slot 13 so that the TDMA
In the antenna selection diversity receiving configuration described above, antenna characteristics can be improved for both transmission and reception. In addition,
In the plate-shaped inverted-F antenna, the closer the ground conductor 28 and the feeding point are, the lower the resonance frequency is. Therefore, in the embodiment shown in FIG. 11, the electric length becomes longer when the feeding point 29 is selected.

Embodiment 7 FIG. FIG. 12 is a diagram showing a second specific configuration example of the second antenna 60 having means for switching the electrical length provided to the antenna device of FIG. FIG.
In the example of FIG. 1, the feeding point is switched.
Switch the grounding point of No. 6. 31 is a first ground point on the radiation plate 26, 32 is a second ground point on the radiation plate 26, 33 is a feed point, and 34 is a switch for switching the ground point by performing ON / OFF operation complementarily. is there. That is, when the first switch 34a in the switch 34 is ON, the second switch 34b is OFF, and conversely, the first switch 3a
When 4a is OFF, the second switch 34b is ON. Note that ON corresponds to closing and OFF corresponds to opening. Using this switch 34, the first ground point 3 on the radiation plate 26 is
By selecting which one of the first and second ground points 32 on the radiation plate 26 is grounded, the two types of electrical lengths l1 and l2 can be switched in the second antenna 60 which is a plate-shaped inverted F antenna. It is possible. The antenna 60 is used as the second antenna 60 in FIG. 9, and switches the ground point of the radiation plate 26 in the transmission time slot 11, the reception time slot 12, and the idle time slot 13, thereby providing the same effect as in the sixth embodiment. Play.

Embodiment 8 FIG. FIG. 13 is a diagram showing a third specific configuration example of the second antenna 60 having means for switching the electrical length provided to the antenna device of FIG. FIG.
At 35, 35 is a second ground point on the radiation plate 26, 36
Is a switch for performing ON / OFF operation. Depending on whether or not the second ground point 35 provided separately from the normal ground conductor 28 is grounded by turning on / off the switch 36,
In the second antenna 60 which is a plate-shaped inverted F antenna, 2
The types of electrical lengths l1 and l2 are switched. Antenna 60
Is used as the second antenna 60 in FIG. 9. For example, by turning off the switch 36 in the reception time slot 12 and the idle time slot 13 and turning on the switch 36 in the transmission time slot, the same effect as in the sixth embodiment can be obtained. Play.

Embodiment 9 FIG. Another embodiment of the present invention will be described with reference to FIGS. FIG. 14 shows the TD of the ninth embodiment.
FIG. 15 is a timing chart for explaining the operation of the MA radio in the same manner. In FIG. 14, reference numeral 37 denotes a termination impedance ZL for terminating the second antenna 6, and reference numeral 38 denotes a changeover switch for selectively switching between the second antenna 6 and the termination impedance 37 or the second receiving unit 3. Also, 39 is synchronized with the TDMA frame as shown in FIG.
Or the reception time slot 12 and the idle time slot 13, the switching signal of the switch 38 for switching the connection destination of the antenna 6.

In the sixth to eighth embodiments, in the configuration of the antenna selection diversity reception of TDMA, in order to reduce the influence of the second antenna 60 on the first antenna 5 in the transmission time slot 11 or to use the antenna for improving the performance, Although the electrical length of the second antenna 60 is switched, FIG.
4, in the present example shown in FIG.
The characteristic of the second antenna 6 is switched by switching the terminal impedance 37 of the second antenna 6 at. That is, as shown in FIG.
In the reception time slot 12 and the idle time slot 13, the second antenna 6 is connected to the second reception unit 3, and in the transmission time slot 11, the second antenna 6 is connected to the terminal impedance 37. The changeover switch 38 is operated. The value of the terminating impedance 37 is set so that the adverse effect of the second antenna 6 on the first antenna 5 is reduced or a favorable effect is exerted during transmission. According to the above operation, in the TDMA antenna selection diversity reception configuration, the first antenna 5 that performs transmission is not affected or favorably affected by the second antenna 6, thereby improving the antenna characteristics.

Embodiment 10 FIG. FIG. 16 shows another embodiment of the present invention.
17 will be described. FIG. 16 is a block diagram showing the configuration of the TDMA radio of the tenth embodiment, and FIG. 17 is a timing chart for explaining the operation thereof. In this embodiment, an antenna selection diversity reception configuration is used to improve the reception characteristics.
1 is a first transmission / reception system having means for switching an electrical length.
Antenna and its operation state, 61 is a second reception-only antenna having means for switching the electrical length and its operation state, and 40 is whether the reception antenna is the first antenna 51 or the second antenna 61. An antenna changeover switch to be switched and its operation state, and 41 indicates a diversity changeover signal for selecting a reception antenna in the case of the antenna selection diversity reception configuration and its operation state, respectively. Reference numeral 42 denotes a diversity switching determination period.

In the first to ninth embodiments, the TDMA transmission time slot 11 and the reception time slot 12 are distinguished from each other.
Although the electrical length or terminal impedance of the antenna is switched, in this example, the electrical length of the antenna is switched in accordance with the antenna selection diversity reception operation.
In general, when performing antenna selection diversity reception in TDMA, a determination period 42 provided immediately before the reception time slot 12 is used, and antenna selection is performed during this period. First, in the period 42a, the first antenna 51 is connected to the receiver 2, and the electric field strength is measured. Subsequently, the second antenna 61 is connected to the receiving unit 2 in the period 42b upon receiving the diversity switching signal 41, and the electric field strength is measured again. The former and latter electric field strengths are compared, and the antenna having the larger electric field strength value is received in time slot 1
It is determined to use in 2. In FIG. 17, the result is
The case where the first antenna 51 is selected is shown. There are various types of setting of the determination period 42, the frequency of the determination, and the like depending on the antenna selection diversity reception method.
As a criterion, an error rate or the like may be used in addition to the electric field strength.

The first antenna 51 has two types of electrical lengths l1 and l2. The electrical length is an electrical length suitable for the first antenna 51 itself for transmission and reception to perform transmission and reception. The electrical length l2 is an influence of the first antenna 51 when performing reception using the second antenna 61. It is an electrical length that reduces or favorably affects. In addition, the second for reception only
Antenna 61 has two types of electrical lengths l3 and l4. The electrical length l3 is an electrical length suitable for the second antenna 61 itself to perform reception, and the electrical length l4 reduces the effect of the second antenna 61 when transmitting and receiving using the first antenna 51. Or an electrical length that gives a good effect.

As shown in FIG. 17, the switching of the electrical length between the antenna changeover switch 40 and the two antennas 51 and 61 during the antenna selection diversity reception is performed by the diversity changeover signal 41 as shown in FIG.
Controlled in conjunction. That is, 11, 1 in FIG.
As shown in the period of 2, 42a, the changeover switch 40 is
When the antenna 51 and the receiving unit 2 are connected, the electrical length of the first antenna 51 is selected to be 11 and the electrical length of the second antenna 61 is selected to be 14. At this time, the two antennas 51 and 61
Both have characteristics suitable for reception using the first antenna 51. As shown in a period 42b in FIG. 17, when the changeover switch 40 connects the second antenna 61 and the receiving unit 2, the electric length of the first antenna 51 is l2, and the electric length of the second antenna 61 is As the length, l3 is selected. By these two switching operations, the two antennas 51 and 61 are both selected so as to have characteristics suitable for reception using the second antenna 61.

As described above, in the antenna selection diversity reception operation, by switching the electrical length of the non-selection side reception antenna, the influence of the non-selection side transmission / reception or reception antenna is reduced or actively utilized. The antenna characteristics of the antenna on the selection side can be improved. In the present embodiment, an example of the antenna selection diversity receiving configuration in the TDMA radio has been described.
The present invention can also be applied to an antenna selection diversity reception configuration of a wireless device other than A.

As the first antenna 51, for example, the antennas shown in FIGS. 4 to 8 and the second antenna 61, for example, the antennas shown in FIGS. 11 to 13 can be used.

Embodiment 11 FIG. FIG. 18 shows another embodiment of the present invention.
FIG. 19 will be described. FIG. 18 is a block diagram showing the configuration of the TDMA radio of the eleventh embodiment, and FIG. 19 is a timing chart for explaining the same operation. In this embodiment, an antenna selection diversity reception configuration is used to improve reception characteristics.
Is an antenna changeover switch that switches between the first antenna 5 and the second antenna 6 as the reception antenna and its operation state, 41 is a diversity changeover signal for selecting a reception antenna in the case of the antenna selection diversity reception configuration, and This is the operating state. Reference numeral 43 denotes a first termination switch connected to the first antenna 5 for transmission and reception and its operation state, and reference numeral 44 denotes a second termination switch connected to the second antenna 6 for reception only and its operation state. And 45 is the first terminating impedance Z
Reference numerals 1 and 46 are second terminating impedances Z2.

In the tenth embodiment, the electrical length of the non-selection antenna at the time of antenna selection diversity reception is switched. In this embodiment, the termination impedance of the non-selection antenna is switched. When the first terminal impedance 45 is connected to the first antenna 5, the first terminal impedance 45 is a value that can reduce the effect of the first antenna 5 or give a good effect upon reception using the second antenna 6. Set to. When connected to the second antenna 6, the second terminating impedance 46 can reduce the effect of the second antenna 6 or give a favorable effect upon reception using the first antenna 5. Set to a value.

When the antenna changeover switch 40 for switching the receiving antenna connects the system of the first antenna 5 and the receiving section 2, the first termination changeover switch 43 is turned on as shown in periods 11, 12, and 42a in FIG. , First antenna 5
And the duplexer 4 and the second termination switch 4
4 is controlled so as to connect the second antenna 6 and the second terminating impedance 46. By this operation, the effect of the second antenna 6 can be reduced or positively utilized to improve the antenna characteristics of the first antenna 5. When the antenna changeover switch 40 connects the system of the second antenna 6 and the receiving unit 2, 42 in FIG.
As shown in the period b, the first termination switch 43 is
The first antenna 5 is connected to the first terminal impedance 45, and the second terminal switch 44 is controlled to connect the second antenna 6 to the receiver 2 via the antenna switch 40. By this operation, the effect of the first antenna 5 can be reduced or positively utilized to improve the antenna characteristics of the second antenna 6.

As described above, in the antenna selection diversity receiving operation, by switching the terminating impedance of the non-selection side antenna, the influence of the non-selection side antenna can be reduced or actively used. The antenna characteristics of the antenna can be improved. In the present embodiment, an example of the antenna selection diversity receiving configuration in the TDMA radio has been described.
The present invention can also be applied to an antenna selection diversity reception configuration of a wireless device other than A.

Embodiment 12 FIG. FIG. 20 is a block diagram showing another embodiment of the present invention. In the figure, reference numeral 47 denotes a dummy antenna ANT having means for switching the electrical length, which does not directly perform transmission / reception operations but has a favorable effect on the first antenna.
−D, which corresponds to the second antenna.

The dummy antenna 47 and the first antenna 5 are arranged spatially close to each other so as to affect each other.
The dummy antenna 47 has two types of electrical lengths l1 and l2, where l1 is an electrical length capable of improving the characteristics of the first antenna 5 in the transmission frequency band, and l2 is the characteristic of the first antenna 5 in the reception frequency band. Is set to an electrical length that can improve the electrical length. Two electrical lengths l1 and l2
Is switched by the switching signal 10 synchronized with the TDMA frame, as in the first or sixth embodiment. That is, in the transmission time slot 11, the electrical length 11 of the dummy antenna is set, and in the reception time slot 12 and the idle time slot 13, the dummy antenna 4
7, the first antenna 5 can improve the antenna characteristics for both transmission and reception. In addition,
In this example, the first antenna has been described as an example of a transmission / reception shared antenna in a TDMA radio, but the present invention can also be applied to a case of a radio other than TDMA or a configuration of an antenna for transmission / reception.

Embodiment 13 FIG. FIG. 21 is a block diagram showing another embodiment of the present invention. In the figure, reference numeral 48 denotes a dummy antenna which has means for switching the connection to the first and second terminal impedances that are the connection destinations and does not directly perform the transmission / reception operation but has a favorable effect on the first antenna. 2
Antenna. 49 is a termination switch, 38
0 is the first terminal impedance ZT, and 381 is the second terminal impedance ZR.

[0050] The first terminating impedance 380 is connected to the dummy antenna 48, and in the transmission frequency band,
A value that can improve the characteristics of the first antenna 5,
The second terminal impedance 381 is the dummy antenna 4
8 is set to a value that can improve the characteristics of the first antenna 5 in the reception frequency band. TD
In the transmission time slot 11, the first terminal impedance 3
At 80, the reception time slot 12 and the idle time slot 13, the termination changeover switch 49 operates so that the second termination impedance 381 is connected to the dummy antenna 48, respectively, and the first antenna 5 improves the antenna characteristics for both transmission and reception. Can be done. In this example, the first antenna has been described as an example of a transmission / reception shared antenna in a TDMA wireless device. However, the first antenna can be applied to a wireless device other than TDMA or an antenna configuration for transmission / reception.

In the above embodiments, the selection of the electrical length of the antenna has been described on the assumption that the frequency allocation transmission frequency fTX is higher than the reception frequency fRX. Needless to say, the selection of the electrical length of the antenna is opposite to that described above.

In the idle time slot 13, switching to the electrical length lR or l2 has been described. However, switching to the electrical length lT or l1 may occur depending on how the idle time slot 13 of the applied TDMA radio communication system is used. Further, switching of the electrical length may occur during the idle time slot 13.

[0053]

[0054]

The antenna device according to the present invention switches the electrical length of the second antenna having means for switching the electrical length, and controls the influence of the second antenna on the first antenna. The antenna performance of the antenna is improved.

Further, by switching the electrical length of the second antenna having means for switching the electrical length in accordance with the TDMA transmission / reception timing and controlling the influence of the second antenna on the first antenna, Antenna performance is improved.

Also, by changing the electrical length of the second antenna having means for switching the electrical length in accordance with the presence or absence of the reception selection of the antenna selection diversity reception, the influence of the second antenna on the first antenna is controlled. The antenna performance of the first antenna is improved.

[0057]

[0058]

[0059]

[Brief description of the drawings]

FIG. 1 is a block diagram of a TDMA radio using an antenna device according to an embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the TDMA radio shown in FIG. 1;

FIG. 3 is a diagram showing VSWR characteristics of a transmission / reception shared antenna used in FIG. 1;

4 is a configuration diagram showing a specific configuration example of an antenna provided in the antenna device of FIG. 1;

5 is a configuration diagram illustrating another specific configuration example of the antenna provided in the antenna device of FIG. 1;

FIG. 6 is a configuration diagram showing another specific configuration example of the antenna provided in the antenna device of FIG. 1;

7 is a configuration diagram illustrating another specific configuration example of the antenna provided in the antenna device of FIG. 1;

FIG. 8 is a configuration diagram showing another specific configuration example of the antenna provided in the antenna device of FIG. 1;

FIG. 9 is a block diagram of a TDMA radio using an antenna device according to another embodiment of the present invention.

FIG. 10 is a timing chart for explaining the operation of the TDMA radio shown in FIG. 9;

11 is a configuration diagram showing a specific configuration example of an antenna provided for the antenna device of FIG. 9;

FIG. 12 is a configuration diagram showing another specific configuration example of the antenna provided in the antenna device of FIG. 9;

FIG. 13 is a configuration diagram showing another specific configuration example of the antenna provided in the antenna device of FIG. 9;

FIG. 14 is a block diagram of a TDMA radio using an antenna apparatus according to another embodiment of the present invention.

FIG. 15 is a timing chart illustrating an operation of the TDMA radio device shown in FIG.

FIG. 16 is a block diagram of a TDMA radio using an antenna device according to another embodiment of the present invention.

FIG. 17 is a timing chart illustrating the operation of the TDMA radio device shown in FIG.

FIG. 18 is a block diagram of a TDMA radio using an antenna device according to another embodiment of the present invention.

FIG. 19 is a timing chart illustrating the operation of the TDMA radio device shown in FIG.

FIG. 20 is a block diagram of a TDMA radio using an antenna apparatus according to another embodiment of the present invention.

FIG. 21 is a block diagram of a TDMA radio using an antenna device according to another embodiment of the present invention.

FIG. 22 is a block diagram showing a TDMA radio using a conventional antenna device.

FIG. 23 is a perspective view showing the external appearance and structure of a conventional portable wireless device, partially cut away.

FIG. 24 is a diagram showing VSWR characteristics of a conventional one-resonant antenna.

FIG. 25 is a diagram showing VSWR characteristics of a conventional two-resonance antenna.

[Explanation of symbols]

5, transmission / reception shared antenna 6, reception-only antenna 7, reception unit changeover switch 10, electric length changeover signal 11, transmission time slot 12, reception time slot 13, idle time slot 38, 43, 44, 49, termination changeover switch 37, 45, 46, 380, 381, terminal impedance 39, connection destination switching signal 40, antenna switching switch 41, diversity switching signal 42, diversity reception determination period 47, dummy antenna 48 having means for switching electrical length, dummy antennas 50, 51 , 60, 61, antenna having means for switching electrical length

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-213907 (JP, A) JP-A-7-7462 (JP, A) JP-A-7-202774 (JP, A) JP-A-7-202 JP 111674 (JP, A) JP-A-58-111371 (JP, A) JP-A-58-186066 (JP, A) JP-A-8-181527 (JP, A) JP-A-63-60628 (JP, A) JP-A-8-78949 (JP, A) JP-A-59-178194 (JP, U) JP-A-5-29994 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01Q 3/00-11/20 H01Q 21/00-25/04 H04B 7/12

Claims (3)

(57) [Claims] An antenna device used for a wireless device includes a first antenna and a second antenna having means for switching an electrical length, wherein the electrical length of the second antenna is switched, and a correlation with the first antenna is provided. An antenna device characterized by optimizing the antenna . 2. An antenna device used for a TDMA radio, comprising: a first antenna and a second antenna having means for switching an electrical length, wherein an electrical length of the second antenna is set according to a TDMA transmission timing. Switch, first
Antenna apparatus characterized by optimizing the correlation between the first antenna. 3. An antenna device used for a radio device, comprising: a first antenna and a second antenna having means for switching an electrical length, wherein the electrical length of the second antenna is determined by whether or not reception of antenna selection diversity reception is selected. Characterized in that the switching is performed in accordance with the first and second antennas to optimize the correlation with the first antenna .