JPH11163620A - Frequency switching antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain identical matching states at two resonance points and also to improve the matching state at two different frequencies by connecting RF signals to 1st and 2nd feeding points through switching and also controlling an impedance which is connected to one of both feeding points that remains in a non-contacted state. SOLUTION: Electrical length of a 1st feeder line 21 is set at about 1/2 wavelength of a 2nd frequency, and electrical length of a 3rd feeder line 22 is set such that the total electrical length of a 2nd radiation conductor 11 and a feeder line 22 is set at about 1/2 wavelength of a 1st frequency. When the RF signal is connected to a 1st feeding point 12 from the line 16, the impedance of the radiation conductor 11 when viewed from the feeding point 12 is almost infinite at the 1st frequency. When the RF signal is connected to a 2nd feeding point 13 from the line 16, the impedance of a 2nd feeding end 21 when viewed from the point 12 is infinite.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna used for mobile communication in a microwave band, and more particularly to an antenna used by switching between two frequency bands.

[0002]

2. Description of the Related Art In recent years, as mobile communication and satellite communication have become popular along with the development of the information society, the integration of terminals has been put into practical use by realizing a system using different frequency bands with one mobile terminal. Have been. As an antenna mounted on these terminals, a frequency switching type antenna that covers by switching a plurality of frequency bands can be considered.

FIG. 19 shows a conventional frequency switching type antenna disclosed in Japanese Utility Model Publication No. 4-8517. The frequency switching antenna of FIG. 19 includes first and second radiating conductors 131 and 132 connected in series, and first and second radiating conductors 131 and 132 connected in series.
32 whose anode terminal is connected to the connection point 133
The diode 135 and the lower end 13 of the second radiation conductor 132
4 and a DC cut capacitor 136 connected between the cathode terminal of the PIN diode 135 and a resistor 137 connected between the cathode terminal and the ground.

[0004] Frequency switching is performed by a bias superimposed on the feed line 138, and when no bias is applied, a frequency determined by the total electrical length of the first and second radiating conductors 131 and 132. Resonates at a frequency of 1.
When a HIGH bias is applied, the PIN diode 135 is turned ON, and the first and second ends 133 and 134 of the second radiation conductor 132 are short-circuited via the PIN diode 135 and the capacitor 136. Resonates at the second frequency determined by the radiation conductor 131. On this occasion,
The resistor 137 is used for controlling the bias current.

[0005]

As described above, the electrical length of the antenna can be changed by short-circuiting the element in the middle of the antenna element, and the resonance frequency thereof can be changed. Acts as an open stub, causing a shift in impedance at two resonance points before and after short-circuiting, making it difficult to achieve good matching at both frequencies. Further, in order to switch between two frequencies that are far apart from each other, it is necessary to increase the length of the element to be short-circuited. Was.

Therefore, the present invention has been made to solve such a problem, and the matching state at two resonance points is made the same, and the matching state at both frequencies is excellent even in two distant frequency bands. It is an object of the present invention to provide a frequency switching type antenna.

[0007]

According to a first aspect of the present invention, there is provided a frequency switching type antenna according to the present invention, comprising a first radiating conductor and a serially connected first radiating conductor. In a frequency switching antenna having a second radiating conductor and first and second feeding points disposed at lower ends of the first and second radiating conductors, an RF signal is supplied to the first and second feeding points. And an impedance control switching means for switching the connection to a point and controlling an impedance connected to the unconnected power supply point of the first and second power supply points.

When the RF signal is connected to the first feeding point, the impedance control switching means changes the impedance seen from the first feeding point toward the second radiation conductor to high impedance, When the second feeding point is connected, the impedance from the first feeding point to the impedance control switching means is converted to high impedance.

Further, in the frequency switching type antenna according to the present invention, the impedance control switching means switches the RF signal to the first and second power supply points and connects the RF signal to the first and second power supply points. , And a first and a second feed line connected between the switching means. The electrical length of the first feed line and the electrical length of the second radiating conductor and the second feed line The total electrical length is nλ / 2 with respect to the operating frequency.
(N = 0, 1, 2,...), And the switching means is characterized in that a non-connection terminal is opened.

[0010] When the first feeding point is connected by the switching means, the second radiation conductor and the second feeding line become a half-wavelength open stub, and the first feeding point is connected to the first feeding point from the first feeding point. The impedance seen from the second radiation conductor side is open. Similarly, when the first feeding line is connected to the second feeding point by the switching means, the first feeding line becomes a half-wavelength open stub, and the impedance viewed from the first feeding point to the switching circuit side is open. .

Further, in the frequency switching type antenna according to the third aspect, the impedance control switching means switches the RF signal to the first and second feeding points and connects the RF signal to the first and second feeding points. , And a first and a second feed line connected between the switching means. The electrical length of the first feed line and the electrical length of the second radiating conductor and the second feed line The total electrical length is (2n +
1) λ / 4 (n = 0, 1, 2,...), And the switching means is characterized in that the non-connection terminal is short-circuited.

When the first feeding point is connected by the switching means in this way, the second radiation conductor and the second feeding line become １ ／ wavelength short stubs, and the first feeding point is connected to the first feeding point from the first feeding point. The impedance seen from the second radiation conductor side is open. Similarly, when the first feeding line is connected to the second feeding point by the switching means, the first feeding line becomes a 波長 wavelength short stub, and the impedance as viewed from the first feeding point toward the switching circuit is opened. .

According to a fourth aspect of the present invention, there is provided a frequency switching type antenna.
The impedance control switching means switches a RF signal to the first and second power supply points for connection, and first and second power supply points connected between the first and second power supply points and the switching means. 2 feed lines, and the electrical length of the first feed line is nλ / 2 (n = 0, 1, 2,
···), and the total electric length of the second radiation conductor and the second feed line is (2n + 1) λ with respect to the working frequency.
/ 4 (n = 0, 1, 2,...), And the switching means
In a non-connection state, a terminal connected to the first power supply line is opened, and a terminal connected to the second power supply line is short-circuited.

When the first feeding point is connected by the switching means in this way, the second radiation conductor and the second feeding line become １ ／ wavelength short stubs, and the first feeding point is connected to the first feeding point from the first feeding point. The impedance seen from the second radiation conductor side is open. Similarly, when the first feeding line is connected to the second feeding point by the switching means, the first feeding line becomes a half-wavelength open stub, and the impedance viewed from the first feeding point to the switching circuit side is open. .

According to a fifth aspect of the present invention, there is provided a frequency switching type antenna.
The impedance control switching means switches a RF signal to the first and second power supply points for connection, and first and second power supply points connected between the first and second power supply points and the switching means. And the electrical length of the first feed line is (2n + 1) λ / 4 (n =
0, 1, 2,...), And the total electrical length of the second radiating conductor and the second feed line is n
λ / 2 (n = 0, 1, 2,...), and the switching means
In a non-connection state, a terminal connected to the first power supply line is short-circuited, and a terminal connected to the second power supply line is opened.

When the first feeding point is connected by the switching means in this way, the second radiation conductor and the second feeding line become a half-wavelength open stub, and the first feeding point is connected to the first feeding point from the first feeding point. The impedance seen from the second radiation conductor side is open. Similarly, when the first feeding line is connected to the second feeding point by the switching means, the first feeding line becomes a 波長 wavelength short stub, and the impedance as viewed from the first feeding point toward the switching circuit is opened. .

According to a sixth aspect of the present invention, there is provided a frequency switching type antenna.
The impedance control switching means switches a RF signal to the first and second power supply points and connects the first and second power supply points, and the first and second power supply points have arbitrary lengths connected to the first and second power supply points. It is characterized by comprising a second feed line and a reactance section, wherein the first or second feed line on the non-connection side of the switching means is connected to the reactance section.

When the first feeding point is connected by the switching means, the second radiating conductor and the second radiating conductor are connected to each other.
Is connected to the reactance, and the impedance seen from the first feeding point to the second radiation conductor side becomes high impedance. Similarly, the switching means
In this case, the first feed line is connected to the reactance section, and the impedance as viewed from the first feed point toward the first feed line becomes high impedance.

According to a seventh aspect of the present invention, there is provided a frequency switching type antenna.
The reactance value of the reactance unit is varied by a switching signal of the switching unit. When the first feeding point is connected by the switching means, the second radiation conductor and the second feeding line are connected to the second feeding line.
And the impedance when viewed from the first feeding point to the second radiation conductor side is substantially open. Similarly, when connected to the second feeding point by the switching means, the first feeding line is connected to the reactance section having the first reactance value, and the first feeding line is connected to the first feeding point from the first feeding point. The impedance seen from the feed line side is almost open.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of the frequency switching type antenna of the present invention. The frequency switching type antenna of FIG. 1 includes first and second radiating conductors 10 and 11 and first and second radiating conductors 10 and 11 connected in series, respectively.
And second feeding points 12 and 13 provided at the lower end of the
And an impedance control switching unit 14 that switches and connects an RF signal to the first and second feeding points 12 and 13 to control the impedance of a non-connected feeding point, and a switching control unit that generates a switching control signal for a used frequency. 15

First radiation conductor 10, second radiation conductor 11
Are made of a spiral conductive metal for shortening the wavelength, and the first radiation conductor 10 is set to have an electrical length that resonates at a first frequency. Also, the first and second radiation conductors 10,
The electrical length of the second radiation conductor 11 is determined so that the total electrical length of the second radiation conductor 11 resonates at the second frequency.

When the frequency switching type antenna shown in the present embodiment is used at the first frequency, the RF signal from the radio (not shown) is transmitted to the first frequency by the control signal of the switching control unit.
The impedance control switching unit 14 via the feed line 16 of
Connected to the first feeding point 12. On the other hand, the impedance connected to the second feeding point 13 which is a non-connection terminal is controlled by the impedance control switching unit 14 so that the impedance viewed from the first feeding point 12 to the second radiation conductor 11 is substantially open. High impedance. Similarly, when used at the second frequency, the RF signal from the wireless device is connected to the second power supply point 13 by the impedance control switching unit 14, and the first terminal, which is a non-connection terminal,
Is connected to an impedance which is almost opened by the impedance control switching unit 14.

As described above, while the first or second feed point 12 or 13 is switched by the impedance control switching unit 14 to form an antenna that changes the resonance frequency, the unnecessary first power point is used in each of the operating frequency bands. The impedance seen from the impedance control switching unit 14 or the second radiating conductor 11 from the feeding point 12 is opened to be electrically disconnected. Therefore,
The matching state at the two resonance points is made the same, and two
Even in one frequency band, it is possible to improve the matching state at both frequencies. In this embodiment, the first and second radiating conductors 10 and 1 are used to reduce the size of the entire antenna device.
1 is spiral, but the first and second radiation conductors 10 and 11
May be any means for providing the first and second resonances.

FIG. 2 shows a first embodiment of the impedance control switching unit 14. Components common to those in FIG. 1 are denoted by the same reference numerals. The impedance control switching unit 1 of FIG.
Reference numeral 4 denotes second and third power supply lines 21 and 22 connected to the first and second power supply points 12 and 13, and second and third power supply lines 21 and 22 based on control signals from the switching control unit 15. 22 has an SPDT (Single-pole double-throw) switch 23 composed of a diode, an FET, etc., which switches and connects an RF signal.

The second and third power supply lines 21 and 22 are formed in a zigzag shape for miniaturization. The length of the second power supply line 21 is such that its electric length is approximately で at the second frequency. The length of the third feed line 22 is set so that the total electrical length of the second radiating conductor 11 and the third feed line 22 becomes substantially 波長 wavelength at the first frequency. Is done.

FIGS. 3A and 3B show the SPDT switch 2
3 is an operation diagram. The SPDT switch 23 shown in FIGS. 3A and 3B includes an input terminal 24 and first and second output terminals 2.
5 and 26. The input terminal 24 is connected to a first power supply line 16 connected to a wireless device (not shown), and the first and second output terminals 25 and 26 are connected to the second and third output terminals 25 and 26, respectively.
Are connected to the power supply lines 21 and 22. When the input terminal 24 is connected to the first output terminal 25, FIG.
As described above, the second output terminal 26 is opened in the SPDT switch 23. The input terminal 24 is connected to the second output terminal 26
3B, the first output terminal 25 is opened in the SPDT switch 23 as shown in FIG.

According to the control signal from the switching control unit 15, the RF signal input from the first power supply line 16 is
The switch 23 is connected to the first power supply point 12 via the second power supply line 21. At this time, the third power supply line 22
Open in the PDT switch 23, the second radiation conductor 1
The total electrical length of the first and third feed lines 22 is equal to the first electrical length.
Since the frequency is approximately 波長 wavelength, the first feed point 1
The impedance seen from the second to the second radiation conductor 11 side becomes substantially open at the first frequency. Therefore, the second radiating conductor 11 and the third feed line 22 are at the first frequency at the first frequency.
Is electrically disconnected from the radiating conductor 10 of the first feeding point 1
2 is supplied only to the first radiation conductor 11,
Only the first radiation conductor 11 resonates at the first frequency and operates as an antenna.

In accordance with the control signal from the switching control unit 15, the RF signal input from the first feed line 16
The PDT switch 23 is connected to the second power supply point 13 via the third power supply line 22. At this time, the second feed line 2
1 is opened in the SPDT switch 23, and since the electrical length of the second power supply line 21 is substantially 波長 wavelength at the second frequency, the second power supply line 21
The impedance seen from the side is almost open.

Therefore, the second feed line 21 is electrically disconnected from the first and second radiating conductors 10 and 11 at the first feed point 12 at the second frequency, and Is supplied only to the first and second radiation conductors 10, 11, and the first and second radiation conductors 10, 11 resonate at the second frequency.

As described above, when an antenna that changes the resonance point by switching the power supply point by using the SPDT switch 23 is configured, the unnecessary second power supply line 21 or the third power supply line 22, By electrically disconnecting the second radiation conductor 11, it is possible to make the matching state at two resonance points the same, and to improve the matching state at both frequencies even in two separated frequency bands. Become. still,
In the present embodiment, the total electric length of each of the second feed line 21, the second radiation conductor 11, and the third feed line 22 is substantially 波長 wavelength at the operating frequency.
It suffices if nλ / 2 (n = 0, 1, 2,...) Is almost satisfied.

In the present embodiment, the second and third feed lines 21 and 22 are formed in a zigzag shape in order to reduce the size of the entire antenna device. However, the second and third feed lines 21 and 22 are formed.
May be any configuration as long as it provides the above electrical length.

FIG. 4 shows a second embodiment of the impedance control switching unit 14. Components common to those in FIG. 1 are denoted by the same reference numerals. The impedance control switching unit 1 of FIG.
Reference numeral 4 denotes second and third power supply lines 31 and 32 connected to the first and second power supply points 12 and 13, and second and third power supply lines 31 and 32 by a control signal from the switching control unit 15. An SPDT switch 33 composed of a diode, an FET, and the like, which switches and connects an RF signal, is provided at 32.

The first and second power supply lines 31 and 32 are formed in a zigzag shape for miniaturization, and the length of the second power supply line 31 is approximately 1/4 at the second frequency. The length of the third feed line 32 is set so that the total electrical length of the second radiating conductor 11 and the third feed line 32 becomes substantially １ ／ wavelength at the first frequency. Is done.

FIGS. 5A and 5B show the SPDT switch 3
3 is an operation diagram. The SPDT switch 33 shown in FIGS. 5A and 5B has an input terminal 34 and first and second output terminals 3.
5, 36. The input terminal 34 is connected to the first power supply line 16 connected to a wireless device (not shown), and the first and second output terminals 35 and 36 are connected to the second and third output terminals 35 and 36, respectively.
Are connected to the power supply lines 31 and 32. When the input terminal 34 is connected to the first output terminal 35, FIG.
, The second output terminal 36 is short-circuited. When the input terminal 34 is connected to the second output terminal 36, the first output terminal 35 is short-circuited as shown in FIG.

When the frequency switching type antenna according to the present embodiment is used at the first frequency, the third feed line 3
2 is grounded via the SPDT switch 33, and since the total electrical length of the second radiating conductor 11 and the third feed line 32 is substantially １ ／ wavelength at the first frequency, the first feed point 2 The impedance when viewed from the side of the second radiation conductor 11 from 12 becomes substantially open at the first frequency. Similarly,
When the frequency switching type antenna according to the present embodiment is used at the second frequency, the second feed line 31 is
Since it is grounded via the switch 33 and the electrical length of the second power supply line 31 is approximately １ ／ wavelength at the second frequency,
The impedance when viewed from the first feeding point 12 toward the second feeding line 31 is substantially open at the second frequency.

Accordingly, similarly to the above-described first embodiment of the impedance control switching section 14, the unnecessary second feeder line 31 or third feeder line 32 and the second radiation conductor 11 in each frequency band are used. By electrically disconnecting, 2
It is possible to make the matching state at one resonance point the same, and to make the matching state at both frequencies good even in two separated frequency bands.

Further, the impedance control switching unit 14 according to the present embodiment includes the impedance control switching unit 1 described above.
4, the first and second power supply lines 31,
Since the length of the antenna 32 is reduced, the antenna system can be further reduced in size. In the present embodiment, the second feed line 31, the second radiation conductor 11, and the third feed line 32
Is approximately 1/4 wavelength at the used frequency, but approximately (2n-1) λ / 4 (n =
1, 2, ...). In the present embodiment, the second and third feed lines 31 and 32 are formed in a zigzag shape in order to reduce the size of the entire antenna device, but the second and third feed lines 31 and 32 have the above-described electrical length. Any configuration may be provided as long as it is given.

FIG. 6 shows a third embodiment of the impedance control switching unit 14. Components common to those in FIG. 1 are denoted by the same reference numerals. The impedance control switching unit 1 of FIG.
Reference numeral 4 denotes second and third power supply lines 41 and 42 connected to the first and second power supply points 12 and 13, and second and third power supply lines 41 and 42 by a control signal from the switching control unit 15. Reference numeral 42 denotes an SPDT switch 43 composed of a diode, an FET, and the like for switching and connecting an RF signal.

The first and second power supply lines 41 and 42 are formed in a zigzag shape for miniaturization, and the length of the second power supply line 41 is such that its electric length is approximately で at the second frequency. The length of the third feed line 42 is set so that the total electrical length of the second radiating conductor 11 and the third feed line 42 becomes approximately ４ wavelength at the first frequency. Is done.

FIGS. 7A and 7B show the SPDT switch 4.
3 is an operation diagram. The SPDT switch 43 shown in FIGS. 7A and 7B includes an input terminal 44 and first and second output terminals 4.
5 and 46. The input terminal 44 is connected to the first power supply line 16 connected to a wireless device (not shown), and the first and second output terminals 45 and 46 are connected to the second and third terminals, respectively.
Are connected to the power supply lines 41 and 42. When the input terminal 44 is connected to the first output terminal 45, the second output terminal 46 is short-circuited as shown in FIG. 7 when the input terminal 44 is connected to the second output terminal 46.
The first output terminal 45 is connected to the SPDT switch 4 as shown in FIG.
Open within 3.

When the frequency switching type antenna according to the present embodiment is used at the first frequency, the third feed line 4
2 is grounded via the SPDT switch 43, and since the total electrical length of the second radiating conductor 11 and the third feed line 42 is approximately 波長 wavelength at the first frequency, the first feed point 2 The impedance when viewed from the side of the second radiation conductor 11 from 12 becomes substantially open at the first frequency. Similarly,
When the frequency switching antenna according to the present embodiment is used at the second frequency, the second feed line 41 is
Since the second power supply line 41 is opened in the switch 43 and the electrical length of the second power supply line 41 is substantially 波長 wavelength at the second frequency, the impedance as viewed from the first power supply point 12 to the second power supply line 41 side is reduced. It becomes almost open at the second frequency.

Therefore, similarly to the first embodiment of the impedance control switching unit 14, the unnecessary second feed line 41 or third feed line 42 and the second radiation conductor 11 in each frequency band are used. By electrically disconnecting, 2
It is possible to make the matching state at one resonance point the same, and to make the matching state at both frequencies good even in two separated frequency bands. In the present embodiment, the electrical length of the second power supply line 41 is 波長 wavelength at the operating frequency, but may be approximately nλ / 2 (n = 0, 1, 2,...). The total electrical length of the radiating conductor 11 and the third feed line 42 is approximately １ ／ wavelength at the operating frequency, but is approximately (2n−1) λ / 4 (n = 1, 2,
・) In the present embodiment, the second and third feed lines 4 are used to reduce the size of the entire antenna device.
Although the first and second feed lines 41 and 42 are formed in a zigzag shape, the second and third feed lines 41 and 42 may be of any configuration as long as they provide the above-described electrical length.

FIG. 8 shows a fourth embodiment of the impedance control switching unit 14. Components common to those in FIG. 1 are denoted by the same reference numerals. The impedance control switching unit 1 of FIG.
Reference numeral 4 denotes second and third power supply lines 51 and 52 connected to the first and second power supply points 12 and 13, and second and third power supply lines 51 and 52 by a control signal from the switching control unit 15. 52 has an SPDT switch 53 composed of a diode, an FET, etc., which switches and connects the RF signal.

The first and second power supply lines 51 and 52 are formed in a zigzag for miniaturization, and the length of the second power supply line 51 is such that its electric length is approximately 1/4 at the second frequency. The length of the third feed line 52 is set so that the total electrical length of the second radiating conductor 11 and the third feed line 52 becomes substantially 波長 wavelength at the first frequency. Is done.

FIGS. 9A and 9B show the SPDT switch 5.
3 is an operation diagram. The SPDT switch 53 shown in FIGS. 9A and 9B includes an input terminal 54 and first and second output terminals 5.
5 and 56. The input terminal 54 is connected to the first power supply line 16 connected to a wireless device (not shown), and the first and second output terminals 55 and 56 are connected to the second and third terminals, respectively.
Are connected to the power supply lines 51 and 52. When the input terminal 54 is connected to the first output terminal 55, the second output terminal 56 is opened in the SPDT switch 53 as shown in FIG. When the input terminal 54 is connected to the second output terminal 56, the first output terminal 55 is short-circuited as shown in FIG.

When the frequency switching type antenna according to the present embodiment is used at the first frequency, the third feed line 5
2 is opened in the SPDT switch 53, and since the total electric length of the second radiating conductor 11 and the third feed line 52 is substantially 波長 wavelength at the first frequency, the first feed point 2 is provided. The impedance when viewed from the side of the second radiation conductor 11 from 12 becomes substantially open at the first frequency. Similarly, when the frequency switching type antenna according to the present embodiment is used at the second frequency, the second power supply line 51 is short-circuited via the SPDT switch 53, and the electrical length of the second power supply line 51 is reduced. Since the wavelength is approximately １ ／ wavelength at the second frequency, the impedance seen from the first power supply point 12 toward the second power supply line 51 becomes substantially open at the second frequency.

Therefore, similarly to the above-described first embodiment of the impedance control switching unit 14, the unnecessary second feed line 51 or the third feed line 52 and the second radiation conductor 11 in each frequency band are used. By electrically disconnecting, 2
It is possible to make the matching state at one resonance point the same, and to make the matching state at both frequencies good even in two separated frequency bands. In the present embodiment, the electrical length of the second power supply line 51 is substantially ほ ぼ wavelength at the operating frequency, but is approximately (2n−1) λ / 4 (n = 1, 2,...).
The total electrical length of the second radiation conductor 11 and the third feed line 52 may be substantially nλ / 2 (n = 0, 1, 2,...) At the operating frequency. In the present embodiment, the second and third feed lines 51 and 52 are formed in a zigzag shape in order to reduce the size of the entire antenna device.
The second and third power supply lines 51 and 52 may have any configuration as long as the configuration provides the above-described electrical length.

FIG. 10 shows a fifth embodiment of the impedance control switching unit 14. Components common to those in FIG. 1 are denoted by the same reference numerals. The impedance control switching unit 14 in FIG. 10 is configured to control the second and third power supply lines 61 and 62 connected to the first and second power supply points 12 and 13 and the second and third power supply lines 61 and 62 based on control signals from the switching control unit 15. Third power supply lines 61 and 62
, FE for switching and connecting RF signal to
It has an SPDT switch 63 composed of T or the like, and an impedance control reactance 64 connected to the SPDT switch 63.

FIGS. 11A and 11B show the operation of the SPDT switch 63. FIG. SPDT of FIGS. 11A and 11B
The switch 63 has an input terminal 65 and first and second output terminals 66 and 67. The input terminal 65 is connected to the first power supply line 16 connected to a wireless device (not shown),
The first and second output terminals 66 and 67 are connected to the second and third power supply lines 61 and 62, respectively. When the input terminal 65 is connected to the first output terminal 66, FIG.
As described above, the second output terminal 67 is connected to the impedance control reactance 64 via the SPDT switch 63. When the input terminal 65 is connected to the second output terminal 67, as shown in FIG.
6 is connected to an impedance control reactance 64 via an SPDT switch 63.

Hereinafter, the first and second power supply lines 61 and the second radiation conductor 11 viewed from the first power supply point 12 when the connection is disconnected by the SPDT switch 63 will be described.
Is described.

FIG. 12 shows the respective impedances from the first feeding point 12 to the second feeding line 61 and the second radiating conductor 11. Black points 71 and 72 in the figure are white points 7 when there is no impedance control reactance 64.
Squares 72 and 74 show cases where inductances are used as reactances 64 for impedance control.
5 shows the case where the side looks at the second power supply line 61 side, and the case where the circles 71 and 73 look at the side of the second radiation conductor 11.

When there is no impedance control reactance 64, the first impedance as viewed from the first feeding point 12 to the second feeding line 61 is the second impedance of the second feeding line 6.
Reference numeral 1 denotes an open stub, which has the first capacitance, and indicates the impedance of the black square 72 in FIG. The second impedance of the second radiating conductor 11 as viewed from the first feeding point 12 is the second radiating conductor 11 and the third feeding line 6.
Reference numeral 2 denotes an open stub, which has the second capacitance, and indicates the impedance of the black circle 71 in FIG.

According to the present embodiment, when an inductance is inserted as the impedance control reactance 64 so as to cancel the first and second capacitances, the first and second impedances are respectively represented by white squares 74 and white circles in FIG. 7
It is almost open like 3.

Therefore, the impedance control switching unit 1
Similarly to the first embodiment of FIG. 4, unnecessary second power supply lines 61 or third power supply lines 62 and second radiation conductors 11 in each frequency band can be almost electrically disconnected,
The matching state at the two resonance points is made the same, and two
Even in one frequency band, it is possible to improve the matching state at both frequencies. In addition, the second and third power supply lines 61 and 6
2. Since there is no restriction on the length, the degree of freedom of design is improved, and the antenna device itself is downsized. In this embodiment, an inductance is used as the impedance control reactance 64. However, a capacitance that makes the first and second impedances substantially open may be used. Also,
The impedance control reactance 64 may be formed of a distributed constant line such as an open stub and a short stub. In addition, the second and third power supply lines 61 and 62 may have any length and may not be provided.

FIG. 13 shows a sixth embodiment of the impedance control switching unit 14. Components common to those in FIG. 1 are denoted by the same reference numerals. The impedance control switching unit 14 in FIG. 13 is configured to control the second and third power supply lines 81 and 82 connected to the first and second power supply points 12 and , The third power supply lines 81, 8
2, a diode for switching and connecting an RF signal to F
An SPDT switch 83 composed of an ET or the like;
It has a variable reactance 66 for impedance control, which is connected to the switch 83 and whose reactance changes according to the signal of the switching control unit 15.

FIGS. 14A and 14B are diagrams showing the operation of the SPDT switch 83. FIG. SPDT in FIGS. 14A and 14B
The switch 83 has an input terminal 85 and first and second output terminals 86 and 87. The input terminal 85 is connected to the first power supply line 16 connected to a wireless device (not shown),
The first and second output terminals 86 and 87 are connected to the second and third power supply lines 81 and 82, respectively. When the input terminal 85 is connected to the first output terminal 86, FIG.
As described above, the second output terminal 87 is connected to the variable reactance 84 for impedance control via the SPDT switch 83. When the input terminal 85 is connected to the second output terminal 87, the first output terminal 86 is connected to the variable reactance 84 for impedance control via the SPDT switch 83 as shown in FIG. .

Variable reactance 8 for impedance control
Reference numeral 4 denotes a first inductance value when operating at the first frequency and a second inductance value when operating at the second frequency in response to a signal from the switching control unit 15. The first and second inductance values are set to values that cancel the first and second capacitances described in the third embodiment of the impedance switching control unit 14 described above.

Therefore, the degree of freedom in design and the size of the antenna device itself can be improved, and the SPDT switch 83 can be used regardless of the electrical length of the second and third feed lines 81 and 82 or the switching frequency interval. From the unconnected first feed point 12 to the second feed line 81 side and the second
The first and second impedances as viewed from the radiation conductor 11 side can be completely opened.

In this embodiment, a variable inductance is used as the variable reactance 84 for impedance control. However, a variable capacitor that opens the first and second impedances may be used. Further, the second and third power supply lines 81 and 82 may be of any length and may not be provided.

FIG. 15 shows a first embodiment of the variable reactance 84 for impedance control in the fifth embodiment of the impedance control switching section. The variable reactance 84 for impedance control in FIG. 15 is used to switch between first and second reactances 92 and 93, one side of which is grounded, and the first and second reactances whose input terminals are connected to the SPDT switch 83. It has a reactance switch 91. When used at the first frequency according to a control signal signal from the switching control unit 15, the reactance switch 91 connects the first reactance 92. Similarly, when using at the second frequency, the reactance switch 91 connects the second reactance. Therefore, the reactance connected to the SPDT switch can be changed according to the frequency used by the control signal from the switching control unit 15.

FIG. 16 shows a second embodiment of the variable reactance 84 for impedance control in the fifth embodiment of the impedance control switching section. The variable reactance 84 for impedance control in FIG. 16 has one side grounded and the other connected to an SPDT switch 83, and an inductance 102 connected in parallel and a variable capacitor 101 whose capacity can be varied by a control signal from a switching control unit. Having. By changing the capacitance of the variable capacitance 101 according to a control signal signal from the switching control unit 15, the SPDT
The reactance connected to the switch 83 can be changed.

In this embodiment, the inductance 102
Although the variable capacitor 101 and the variable capacitor 101 are connected in parallel, they may be formed by an arbitrary lumped constant circuit such as a resistor such as a serial connection. Further, it may be constituted by a distributed constant line such as an open stub and a short stub.

FIG. 17 is a view showing a second embodiment of the frequency switching type antenna according to the present invention. The frequency switching type antenna shown in FIG. 17 is a case where an antenna unit and an impedance control switching unit are integrally formed on a dielectric substrate.
First and second radiation conductor patterns 1 formed in a zigzag pattern on the surface by etching or the like and connected in series, respectively.
11, 112, a ground pattern 113 formed in a portion of the back surface of the dielectric substrate 110 which does not overlap the first and second radiating conductor patterns 111, 112, and lower ends of the first and second radiating conductor patterns 111, 112 , And first and second feed points 119a and 119b connected to the first and second feed points 119a and 119b, respectively.
, And an SPDT switch 116 composed of a diode and an FET for switching and connecting an RF signal to the first and second strip lines 114 and 115, and the first and second strip lines 114 and 115.
15 and the first and second matching capacitors 11
8a and 118b and a third strip line 117 connected to the input terminal of the SPDT switch 116.

The first radiating conductor pattern 111 is set to have an electrical length that resonates at a first frequency.
The total electrical length of the radiation conductor patterns 111 and 112 is set to resonate at the second frequency.

The first matching capacitor 118a
Represents matching of the antenna formed only by the first radiation conductor pattern 111, and the second matching capacitor 118b represents
The first and second radiating conductor patterns 111 and 112 are inserted to match the antenna formed as a whole.

When the frequency switching type antenna according to the present embodiment is used at the first frequency, the second strip line 115 is used in response to a signal from a switching control unit (not shown).
Is grounded via the SPDT switch 116, and the second radiating conductor pattern 112 and the second strip line 11
5 and the second matching capacitor 118b such that the total electric length of the second matching capacitor 118b becomes approximately ほ ぼ wavelength at the first frequency.
The electrical length of the strip line 115 is set, and the impedance from the first feeding point 119a toward the second radiation conducting pattern 112 becomes substantially open at the first frequency.

On the other hand, the RF signal from the third strip line 117 is passed through the SPDT switch 116, the first strip line 114, and the first matching capacitor 118a to the first radiating conductor pattern 1 from the first feeding point 119a.
11, only the first radiation conductor pattern 111 operates as an antenna. Similarly, when the frequency switching type antenna according to the present embodiment is used at the second frequency, the first strip line 114 is grounded via the SPDT switch 116 by a signal from a switching control unit (not shown). And the first strip line 114 and the first
The electrical length of the first strip line 114 is set so that the total electrical length of the matching capacitor 118a becomes approximately ス ト リ ッ プ wavelength at the second frequency.
The impedance when viewed from the side of the first strip line 114 from 19a becomes substantially open at the second frequency.

On the other hand, the RF signal from the third strip line 117 is passed through the SPDT switch 116, the second strip line 115, and the second matching capacitor 118b to the second radiating conductor pattern from the second feeding point 119b. 112, the first and second radiating conductor patterns 11
1, 112 operate as antennas.

Therefore, similarly to the above-described first embodiment,
Unnecessary first or second stripline 114, 115, second radiation conductor pattern 11 in each frequency band
2. First and second matching capacitors 118a, 118b
Is electrically disconnected, it is possible to independently optimize and control the matching state at the two resonance points. In addition, it is possible to improve the matching state at both frequencies even in two separated frequency bands, and to integrally form the antenna unit and the impedance control switching unit on the dielectric substrate 110. Note that, in the present embodiment, the second impedance control switching unit is used as the impedance control switching unit.
Although the embodiment is used, the first, third, fourth, fifth, and sixth embodiments of the impedance control switching unit may be followed.

FIG. 18 is a view showing a third embodiment of the frequency switching type antenna according to the present invention. The frequency switching type antenna of FIG. 18 is a case where an antenna unit and an impedance control switching unit are integrally formed on a dielectric substrate, and is an embodiment in which two relatively close frequencies are switched and used. A first and a second radiating conductor patterns 121 and 122 formed zigzag on the surface of the dielectric substrate 120 by etching or the like and connected in series, respectively;
20, the first and second radiation conductor patterns 121 and 12 on the back surface
Ground pattern 12 formed in a portion not overlapping with 2
3 and first and second feed points 129 provided at the lower end portions of the first and second radiation conductor patterns 121 and 122, respectively.
a, 129b and the first and second feeding points 129a, 129
b, the first and second striplines 124 connected to
125 and the first and second strip lines 124 and 12
5, an SPDT switch 126 composed of a diode and an FET for switching and connecting an RF signal, a third strip line 127 connected to an input terminal of the SPDT switch 126, and a third strip line 127 connected to the third strip line 127. Matching capacitor 128 and SPDT switch 12
The impedance control reactance 13 connected to 6
Has zero.

The first radiation conductor 121 is set to have an electrical length that resonates at a first frequency, and the total electrical length of the first and second radiation conductors 121 and 122 resonates at a second frequency. It is set as follows. The matching capacitor 128 has a relatively small impedance between the antenna formed by the first radiating conductor pattern 121 alone and the antenna formed by the first and second radiating conductor patterns 121 and 122 in total. Commonly used because of close proximity.

As in the above-described third embodiment of the impedance control switching unit, the first strip line 124 or the second strip line
Radiating conductor pattern 122 of the second strip line 1
Reference numeral 25 denotes a first power supply point 129a, the former has a first capacitance, and the latter has a second capacitance, and the impedance control reactance 130 has an inductance inserted to cancel the first capacitance and the second capacitance. Is done.

Therefore, similarly to the above-described second embodiment,
The first or second strip line 1 which is integrally formed on the dielectric substrate 120 and is unnecessary in each frequency band.
24, 125, and the second radiating conductor pattern 122 are electrically cut to make the matching state at two resonance points the same, and to make the matching state at both frequencies good even in two separated frequency bands. It becomes possible. In the present embodiment, the fifth embodiment of the impedance control switching unit is used as the impedance control switching unit. However, the sixth embodiment of the impedance control switching unit may be used.

[0074]

As described above, in the frequency switching type antenna according to the present invention, while the first or second feeding point is switched by the impedance control switching unit to change the resonance frequency, each of the operating frequencies is changed. Unnecessary first feeding point or second feeding point and second radiation conductor in the band are electrically disconnected to make the matching state at the two resonance points the same, and to provide two separated frequencies Even in the band, it is possible to improve the matching state at both frequencies.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a frequency switching type antenna according to the present invention.

FIG. 2 is a diagram illustrating a first embodiment of an impedance control switching unit in the frequency switching antenna.

FIG. 3A is an SPD of a first embodiment of the impedance control switching unit in the frequency switching antenna according to the present invention;
It is an operation | movement diagram of a T switch, (b) is an operation | movement diagram of the SPDT switch of 1st Embodiment of the impedance control switching part in a frequency switching type antenna.

FIG. 4 is a diagram illustrating a second embodiment of the impedance control switching unit in the frequency switching antenna.

FIG. 5A is an SPD of a second embodiment of the impedance control switching unit in the frequency switching antenna according to the present invention;
It is an operation | movement diagram of a T switch, (b) is an operation | movement diagram of the SPDT switch of 2nd Embodiment of the impedance control switching part in a frequency switching type antenna.

FIG. 6 is a diagram illustrating a third embodiment of the impedance control switching unit in the frequency switching antenna.

FIG. 7A is an SPD of a third embodiment of the impedance control switching unit in the frequency switching antenna according to the present invention.
It is an operation | movement diagram of a T switch, (b) is an operation | movement diagram of the SPDT switch of 3rd Embodiment of the impedance control switching part in a frequency switching type antenna.

FIG. 8 is a diagram illustrating a fourth embodiment of the impedance control switching unit in the frequency switching antenna.

FIG. 9A shows an SPD according to a fourth embodiment of the impedance control switching unit in the frequency switching antenna according to the present invention;
It is an operation | movement diagram of a T switch, (b) is an operation | movement diagram of the SPDT switch of 4th Embodiment of the impedance control switching part in a frequency switching type antenna.

FIG. 10 is a diagram illustrating a fifth embodiment of the impedance control switching unit in the frequency switching antenna.

FIG. 11A shows an SP of a fifth embodiment of the impedance control switching unit in the frequency switching antenna according to the present invention.
It is an operation | movement diagram of a DT switch, (b) is an operation | movement diagram of the SPDT switch of 5th Embodiment of the impedance control switching part in a frequency switching type antenna.

FIG. 12 is a characteristic diagram illustrating impedance characteristics of a fifth embodiment of the impedance control switching unit as viewed from a first feeding point.

FIG. 13 is a diagram illustrating a sixth embodiment of the impedance control switching unit in the frequency switching antenna.

FIG. 14A shows an SP of a sixth embodiment of the impedance control switching unit in the frequency switching antenna according to the present invention.
It is an operation | movement diagram of a DT switch, (b) is an operation | movement diagram of the SPDT switch of 6th Embodiment of the impedance control switching part in a frequency switching type antenna.

FIG. 15 is a diagram illustrating a first embodiment of a reactance varying unit of a sixth embodiment of the impedance control switching unit in the frequency switching antenna.

FIG. 16 is a diagram illustrating a second embodiment of the reactance varying means of the sixth embodiment of the impedance control switching unit in the frequency switching antenna.

FIG. 17 is a diagram showing a second embodiment of the frequency switching type antenna according to the present invention.

FIG. 18 is a diagram showing a third embodiment of the frequency switching type antenna according to the present invention.

FIG. 19 is a diagram showing a conventional frequency switching type antenna.

[Explanation of symbols]

10, 131 First radiating conductor 11, 132 Second radiating conductor 12, 119a, 129a, 133 First feeding point 13, 119b, 129b, 134 Second feeding point 14 Impedance control switching unit 15 Switching control unit 16 First power supply line 21, 31, 41, 51, 61, 81 Second power supply line 22, 32, 42, 52, 62, 82 Third power supply line 23, 33, 43, 53, 63, 83, 116 SPD
T switch 24, 34, 44, 54, 65, 85 Input terminal of SPDT switch 25, 35, 45, 55, 66, 86 First output terminal of SPDT switch 26, 36, 46, 56, 67, 87 SPDT switch The second output terminal 64, 130 The impedance control reactance 71 The impedance when the second radiation conductor side is viewed from the first feed point when there is no impedance control reactance 72 The first power supply when there is no impedance control reactance Impedance viewed from the second feed line side from the point 73 Impedance viewed from the first feed point when there is an impedance control reactance 74 From the first feed point when the second radiation conductor side is present 74 Impedance looking at the second feed line side 84 in Variable reactance for dance control 91 reactance changeover switch 92 first reactance 93 second reactance 101 variable capacitance 102 inductance 110, 120 dielectric substrate 111, 121 first radiating conductor pattern 112, 122 second radiating conductor pattern 113, 123 Ground pattern 114, 124 First strip line 115, 125 Second strip line 117, 127 Third strip line 118a First matching capacitor 118b Second matching capacitor 128 Matching capacitor 135 PIN diode 136 DC Cutting capacitor 137 Resistance 138 Feeding line

Claims (7)

[Claims] 1. A first radiation conductor, a second radiation conductor connected in series to the first radiation conductor, and a first radiation conductor disposed at a lower end of the first and second radiation conductors. In a frequency switching type antenna having a second feeding point, an RF signal is switched to the first and second feeding points to be connected, and to a non-connected feeding point among the first and second feeding points. A frequency switching type antenna having impedance control switching means for controlling an impedance to be connected. 2. The method according to claim 1, wherein the impedance control switching means includes
Switching means for switching the F signal to the first and second feeding points for connection, and first and second feeding lines connected between the first and second feeding points and the switching means. The electrical length of the first feed line and the total electrical length of the second radiating conductor and the second feed line are expressed by n
λ / 2 (n = 0, 1, 2,...), and the switching means
The frequency switching type antenna according to claim 1, wherein the non-connection terminal is opened. 3. The impedance control switching means according to claim 1, wherein
Switching means for switching the F signal to the first and second feeding points for connection, and first and second feeding lines connected between the first and second feeding points and the switching means. The electric length of the first feed line and the total electric length of the second radiating conductor and the second feed line are expressed as (2n + 1) λ / 4 (n = 0, 1, 2, 2. The frequency switching antenna according to claim 1, wherein a non-connection terminal of the switching unit is short-circuited. 3. 4. The impedance control switching means according to claim 1, wherein
Switching means for switching the F signal to the first and second feeding points for connection, and first and second feeding lines connected between the first and second feeding points and the switching means. And the electrical length of the first feed line is nλ / 2 (n
= 0, 1, 2,...), And the total electric length of the second radiating conductor and the second feed line is (2n + 1) λ / 4 (n = 0, 1, 2,. .), The switch means that, when not connected, the terminal connected to the first power supply line side is opened and the terminal connected to the second power supply line side is short-circuited. The frequency switching antenna according to claim 1, wherein: 5. An impedance control switching means, comprising:
Switching means for switching the F signal to the first and second feeding points for connection, and first and second feeding lines connected between the first and second feeding points and the switching means. And the electrical length of the first feed line is (2n + 1) with respect to the working frequency.
.lamda. / 4 (n = 0, 1, 2,...), and the total electric length of the second radiation conductor and the second feed line is expressed as nλ / 2 (n = 0, 1,. When the switching means is not connected, the terminal connected to the first power supply line is short-circuited and the terminal connected to the second power supply line is opened. The frequency switching type antenna according to claim 1, wherein: 6. An impedance control switching means, comprising:
Switching means for switching the F signal to the first and second feeding points for connection; first and second feeding lines of arbitrary lengths connected to the first and second feeding points; and a reactance And the first or the second on the non-connection side of the switching means.
The frequency switching type antenna according to claim 1, wherein the feeding line is connected to the reactance section. 7. The frequency switching type antenna according to claim 6, wherein a reactance value of said reactance section is varied by a switching signal of said switching means.