JPH10107505A - Antenna coupler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an active element for transmission/reception switching form being malfunctioned by adopting a non-through resonance hole of a resonator of a dielectric filter in the antenna coupler including the active element in its circuit configuration. SOLUTION: The circuit configuration of a dielectric filter 10 includes 1st - 3rd diodes 77-79 acting like active elements to conduct transmission/reception and antenna switching, and a shield case 9 is mounted on a printed circuit board 8 so as to cover the circuit configuration provided thereto. The dielectric filter 10 has a block made of a dielectric material and two non-through resonance holes 12 formed to the block. Furthermore, the entire surface including the hole inner face is covered by a conductor except a surrounding area of a pair of input/output electrodes formed to part of a side circumferential face. Then an usual opened holes are blocked and no opening end is provided, then almost no electromagnetic wave does not leak. Since the effect of the electromagnetic wave is not caused, there is no malfunction of the diodes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna duplexer used in a mobile communication device such as a portable telephone for sharing an antenna with a transmitting / receiving circuit.

[0002]

2. Description of the Related Art Conventionally, FDD (Frequency Division Dup)
lex) as a shared antenna in a mobile communication device of the type, a band-pass filter appropriately set so that each of a transmission wave and a reception wave passes, utilizing the fact that the transmission and reception frequencies are different, or A combination of a bandpass filter and a bandstop filter has been used. However, in recent years,
There is a demand for smaller, lighter, and less expensive mobile communication devices, and smaller and less expensive antenna duplexers used for the devices. For this reason, an antenna duplexer in which transmission and reception are switched by a switch using an active element is widely used because it is small and inexpensive.

In mobile communication devices of the TDD (Time Division Duplex) system, transmission and reception frequencies are the same, and a configuration using a band-pass filter cannot be applied. Therefore, transmission and reception are generally performed by a switch using an active element. Is switched.

[0004] An antenna duplexer in which transmission and reception are switched using an active element is advantageous in realizing a compact, lightweight, and low-cost mobile communication device. However, the necessity of filtering the high-frequency signal has not been eliminated, and the transmission wave and the reception wave are connected to the transmission circuit and the reception circuit via filters set to pass the respective frequencies. Here, a device in which a switch and a filter are integrated is required, and a form of an antenna duplexer in which a switch and a filter are mounted on the same substrate and placed in a shield case is used.

FIG. 9 is a perspective view showing a conventional antenna duplexer of this type. In FIG. 9, in this antenna duplexer, a circuit configuration as an antenna duplexer having a dielectric filter 510 is provided on one circuit board 508. The circuit configuration of the dielectric filter 510 includes first to third diodes 577 to 579 as active elements for switching between transmission and reception, and first and second antenna terminals 58.
5 and 586. Further, the circuit board 50
8, so as to cover the circuit configuration provided therein,
The shield case 509 is attached.

FIG. 10 shows an example of an equivalent circuit of a switch switching type antenna duplexer. FIG. 11 is a top view showing one conventional example for realizing the circuit shown in FIG. FIG.
In this circuit, a band-pass filter (BP
F) A capacitor 2 is connected in series with 1.
Referring to FIG. 11, the circuit of FIG.
BPF1 is a dielectric filter 61
0, and the capacitor 2 is connected to the capacitor 6
20. FIGS. 12A to 12C show three views of the dielectric filter 610 in FIG. These three views show the mounting surface side of the dielectric filter 610 on the circuit board 608. Referring to FIGS. 12A to 12C, dielectric filter 610 is formed with a resonance hole 612 that penetrates a block made of a dielectric ceramic and extends to both right and left ends in the drawing. Outer conductors 613 are formed on the four side surfaces, one end surface, and the surface of the resonance hole 612 of the block. The outer conductor 613 is provided on the side surface of the block.
The input electrode 614 and the output electrode 615 are formed insulated from each other.

[0007]

In a switch-switching type antenna duplexer, a filter used in most cases is generally a dielectric filter due to its characteristic requirements. The dielectric filter is a λ / 4 coaxial resonator having one open end, or a slightly modified form thereof. In a filter using this type of resonator, it is known that electromagnetic waves leak from the open end of the resonator. However, when a dielectric filter is used as a filter alone or as a conventional antenna duplexer that does not use a switch, the surrounding case is not affected because a shield case is provided.

However, when a dielectric filter is used in a switch switching type antenna duplexer, as shown in FIG. 9, a dielectric filter and an active element functioning as a switch are mounted on the same substrate. And it is accommodated in the same shield case. In general, it is well known that an active element is easily affected by an electromagnetic wave, and if there is an element that generates an electromagnetic wave nearby, there is a problem such as a malfunction. Even though the dielectric resonator that generates the electromagnetic wave and the active element that is easily affected by the electromagnetic wave are housed in the same shield case, a communication failure may occur in a conventional example in which no measures are taken. is there.

An object of the present invention is to provide a switch switching type antenna duplexer in which an active element does not malfunction.

In addition, in the configuration of the conventional antenna duplexer, including the example shown in FIG.
Space for mounting this and man-hours for mounting are required. Major issues in mobile communication devices include miniaturization, weight reduction, and cost reduction. For this reason, efforts have been made to reduce the number of components of the antenna duplexer as much as possible and to reduce the mounting space and the number of mounting steps.

Another object of the present invention is to provide a small, lightweight, and low-cost antenna duplexer by reducing the number of components, mounting space, and mounting man-hours of the antenna duplexer.

[0012]

According to the present invention, in an antenna duplexer in which a circuit configuration as an antenna duplexer having a dielectric filter is provided on one substrate, an active element for switching transmission and reception is provided by the circuit. An antenna duplexer included in the configuration, wherein the dielectric filter is characterized in that the resonance hole of the resonator is a non-penetrating type.

According to the present invention, there is further provided an antenna duplexer in which a circuit configuration as an antenna duplexer having a dielectric filter is provided on one substrate, wherein a capacitor connected in series to the dielectric filter is connected to the circuit configuration. Wherein the output electrode of the dielectric filter has an area equal to or greater than a predetermined size to constitute the capacitor.

According to the present invention, further, in an antenna duplexer in which a circuit configuration as an antenna duplexer having a dielectric filter is provided on one substrate, a capacitor connected in series to the dielectric filter is connected to the circuit configuration. Wherein the resonance hole of the first-stage resonator of the dielectric filter is separated from the resonance hole of the adjacent resonator by a predetermined distance, and the distance between the resonance hole and the input electrode is An antenna duplexer characterized by constituting the capacitor by being shorter than a predetermined distance is obtained.

According to the present invention, the resonance holes of the first-stage resonator of the dielectric filter are separated from the resonance holes of the adjacent resonators by a predetermined distance, and the distance between the resonance holes of the first-stage resonator and the input electrode is reduced. The antenna duplexer is characterized in that the capacitor is configured by being shorter than a predetermined distance.

According to the present invention, there is further provided an antenna duplexer including an active element for switching between transmission and reception in the circuit configuration, wherein the dielectric filter has a non-penetrating resonance hole of the resonator. The antenna duplexer characterized by the following is obtained.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an antenna duplexer according to an embodiment of the present invention will be described.

First, in the present invention, a dielectric filter which does not affect the active element by electromagnetic waves even when housed in the same shield case is used. Since the non-through-hole type dielectric filter does not have an open end, there is almost no leakage of electromagnetic waves, and the active elements do not have an influence of electromagnetic waves. That is,
An antenna duplexer in which transmission and reception are switched by an active element, wherein a non-through-hole type dielectric filter is used as a filter for filtering at least one high-frequency signal for transmission and reception. This will be specifically described in the following first and second embodiments.

Second, in the present invention, a capacitor connected in series with the filter is taken into the filter. However,
Rather than increasing the number of capacitors on the filter side, an independent capacitor is eliminated without changing the circuit configuration on the filter side, thereby reducing the size and cost. That is, the present antenna duplexer is an antenna duplexer in which a dielectric filter and other circuit components are housed on the same substrate, and a capacitor is connected in series with the dielectric filter.
The dielectric filter is a surface mount type dielectric filter in which a pair of input / output electrodes is formed electrically insulated from the outer conductor, and the pair of input / output electrodes of the surface mount type dielectric filter has an asymmetric shape. What it does. In a surface mount type dielectric filter in which an input electrode and an output electrode are formed so as to be electrically insulated from an outer conductor, the first stage and the last stage resonator and the input / output electrode are capacitively coupled. Focusing attention here, by incorporating a capacitor connected in series with the dielectric filter in this capacitive coupling portion, the capacitor can be taken in and eliminated without changing the filter circuit itself. Referring to the equivalent circuit shown in FIG. 10, in order to obtain both the capacitance of the series capacitor and the coupling capacitance between the resonator and the input electrode to which the series capacitor 2 is connected, It is formed larger than. Since there is almost no circuit in which a capacitor having the same capacitance value is connected in series on the input side and the output side, the input electrode and the output electrode are always formed in an asymmetric shape.

According to another aspect of the present invention, there is provided an antenna duplexer in which a dielectric filter and other circuit components are provided on the same substrate, and a capacitor is connected in series with the dielectric filter. Dielectric filter,
A surface-mounted dielectric filter in which a pair of input / output electrodes are formed electrically insulated from the outer conductor, and the resonance holes of the first-stage or last-stage resonator of the surface-mounted dielectric filter have another resonance hole. An antenna duplexer having a shape different from a shape of a resonance hole of a resonator is provided. Referring to FIG. 10, in order to obtain both the capacitance of the series capacitor 2 and the coupling capacitance between the resonators, for example, a first-stage resonance hole is formed closer to the input electrode side. Simply bringing the resonance hole close to the input electrode reduces the coupling capacitance between adjacent resonators, and changes the filter characteristics. For this reason, the resonator hole is formed in a shape different from other resonance holes so as to increase the coupling capacitance with the input electrode without changing the coupling capacitance between adjacent resonators.

These inventions are described in the following third to sixth embodiments.
Now, a specific description will be given.

[First Embodiment] FIG. 1 is a perspective view showing a configuration of an antenna duplexer according to a first embodiment of the present invention. FIG. 2 is an equivalent circuit diagram thereof. Referring to FIG. 1 and FIG. 2 together, this antenna duplexer is an example applied to a diversity system, and performs switching between the first and second antennas as well as switching between transmission and reception. The duplexer is a two-element monolithic dielectric filter 1.
A circuit configuration as an antenna duplexer having 0 is provided on one circuit board 8. In the circuit configuration of the dielectric filter 10, first to third diodes 77 to 79 as active elements for performing transmission / reception and switching between antennas,
It includes first and second antenna terminals 85 and 86 to which the first and second antennas 95 and 96 are connected. Further, a shield case 9 is attached to the circuit board 8 so as to cover a circuit configuration provided thereon.

The dielectric filter 10 is made of TiO ₂ −
It has a block made of a BaO-based dielectric material of ε _r = 95, and two non-penetrating resonance holes 12 formed in this block. Except for a region around a pair of input / output electrodes formed on a part of the side peripheral surface, the entire surface including the inner surface of the hole is covered with the conductor by baking silver. Then, the hole is closed where it hits the normal open end and has no open end, so there is almost no electromagnetic leakage from this filter. Since there is no influence by the electromagnetic wave, in the antenna duplexer of the present invention, there is no fear of malfunction of the diode.

In this antenna duplexer, at the time of transmission, the first diode 77 connected in series with the transmission line is turned on, the second diode 78 connected in parallel is turned off, and the second antenna 96 is connected in series. The third diode 79 connected to is turned off, and transmission is performed from the first antenna 95. When receiving using the first antenna 95, the first antenna
Is turned off, the second diode 78 is turned on, and the third diode 79 is turned off. After the reception wave is filtered by the dielectric filter 10, it is transmitted to the reception circuit. When receiving using the second antenna 96, the first
Is turned off, the second diode 78 is turned off, and the third diode 79 is turned on. The received wave is filtered by the dielectric filter 10 and then transmitted to the receiving circuit. With such an operation, the present duplexer performs transmission / reception and switching between the first and second antennas.

In the present embodiment, a non-through-hole type dielectric filter is used only for the filter on the receiving side, and a filter is formed using discrete inductors and capacitors on the transmitting side. A through-hole type dielectric filter may be used.

Further, although a diode is used in the changeover switch circuit, a transistor may be used, and the number and method used are not limited to the embodiment. When switching diversity antennas separately,
The second antenna and the switch circuit associated therewith may be eliminated.

[Embodiment 2] Embodiment 2 of the present invention
Is another example of a dielectric filter.

In the second embodiment, a dielectric filter 10 'shown in FIG. 3 is used instead of the monolithic dielectric filter 10 in the antenna duplexer according to the first embodiment. The dielectric filter 10 'is a single-hole type resonator 10a'.
And 10b 'are connected by connecting windows 17a' and 17b 'and the like. Each of the resonators 10a 'and 10b' has a non-through hole type resonance hole 12 '. An input electrode 14 'is formed on the resonator 10a', and an input electrode 14b 'is formed.
Is formed with an output electrode 15 '. Also in the second embodiment, since the hole is closed at a position corresponding to a normal open end and has no open end, there is almost no electromagnetic leakage from this filter. Since there is no influence by the electromagnetic wave, in the antenna duplexer of the present invention, there is no fear of malfunction of the diode.

[Third Embodiment] FIG. 4 is a top view showing an antenna duplexer according to a third embodiment of the present invention. FIG.
(A)-(c) is a three-view drawing of the dielectric filter in FIG. These three views show the mounting surface side of the dielectric filter on the circuit board.

Referring to FIG. 4, the present antenna duplexer realizes the antenna shared circuit shown in FIG.
On the circuit board 38, the dielectric filter 20 functioning as both the BPF 1 and the capacitor 2 in FIG.
have. Referring to FIGS. 5A to 5C, dielectric filter 20 has non-penetrating resonance holes 22 extending to the left and right ends in the drawing in a block made of a TiO ₂ —BaO-based dielectric ceramic. ing. An outer conductor 23 is formed on the surface of the block including the end surface and the inner surface of the resonance hole. An input electrode 24 and an output electrode 25 are formed on the side surface of the block insulated from the outer conductor 23.

In the third embodiment, the capacitance of the capacitor 2 (FIG. 10) connected in series to the BPF 1 is obtained by setting the area of the input electrode 24 of the dielectric filter 20 large. Regarding the area of the input electrode 24, for example, if the capacitance value of the capacitor 2 in FIG. 10 is 8.5 pF, the input electrode 24 at this time needs to be 2.5 mm × 3 mm. Incidentally, the size of the output electrode 25 that does not include a series capacitor is 1 mm × 3 mm. In addition, since the electrode itself is formed of a conductive film, when the capacitance needs to be adjusted, it can be easily adjusted by trimming the electrode. Therefore, it is also possible to increase the degree of freedom in manufacturing by forming the electrodes in advance and trimming them appropriately.

Since the dielectric filter 20 has the non-through hole type resonance hole 22 and does not leak electromagnetic waves, there is no possibility of malfunction even in a configuration in which active elements are arranged on the same circuit board.

[Fourth Embodiment] In the fourth embodiment, a through-hole type filter having one open end shown in FIG. 3 is used instead of the non-through-hole type dielectric filter 20 in the antenna duplexer according to the third embodiment. Is used. If the antenna shared circuit is not a switch switching type including active elements, there is no problem with a through-hole type dielectric filter. The dielectric filter 20 'includes a block made of a dielectric ceramic, a through-hole type resonance hole 22', an outer conductor 23 ', an input electrode 24', and an output electrode 25 '. The input electrode 24 'has a predetermined area or more.

[Fifth Embodiment] In a fifth embodiment, a dielectric filter 20 "shown in FIG. 7 is used instead of the monolithic dielectric filter 10 in the antenna duplexer according to the third embodiment. The dielectric filter 20 '' includes single-hole resonators 20a '' and 20b '' connected to the coupling window 2 ''.
7a '' and 27b ''. Resonator 2
Both 0a '' and 20b '' have non-through-hole type resonance holes 22 ''. Further, an input electrode 24 '' is formed on the resonator 20a '', and an output electrode 25 '' is formed on 20b ''. The input electrode 24 '' has an area larger than a predetermined area. Also in Embodiment 4,
Since the hole is closed at the normal open end and has no open end, there is almost no electromagnetic leakage from this filter. Since there is no influence by the electromagnetic wave, in the antenna duplexer of the present invention, there is no fear of malfunction of the diode. In this embodiment, each single-hole resonator is of a non-through-hole type, but may be a combination of through-hole type single-hole resonators. In this case, no coupling window is required.

[Embodiment 6] Embodiment 6 is an example of a dielectric filter having a different structure and effects similar to those of Embodiments 3 to 5.

FIG. 8A shows a sixth embodiment of the present invention. FIG. 8A is an end view of the dielectric filter 30 viewed from the short-circuit end surface side. In order to realize the shared antenna circuit shown in FIG.
The distance to the input electrode is reduced without changing the distance to
The capacitance of the capacitor 2 (FIG. 10) connected in series to F1 is obtained. The dielectric filter 30 is a non-through-hole type monolithic dielectric filter as in the third embodiment. The resonance hole 32a of the resonator on the input electrode side (first stage side)
It has a long hole shape, and the distance from the input electrode is reduced while maintaining the same distance from the resonance hole 32b of the last stage resonator, so that a large capacitance can be obtained.

FIG. 8B is an end view of a conventional dielectric filter 50 as a comparative example. In the dielectric filter 50, for example, the diameter φ of the last-stage resonance hole 32b is 0.9 m.
m, the interval a between the resonance holes is 1.2 mm, and the resonance hole 32b at the last stage
The distance b between the electrode and the output electrode is 0.5 mm. Usually, since the shape is symmetrical, the diameter of the first-stage resonance hole 32a is equal to the diameter of the last-stage resonance hole 32b. Also, the first-stage resonance hole 3
The distance between 2a and the input electrode is equal to the distance between the last-stage resonance hole 32b and the output electrode.

On the other hand, in the dielectric filter 30 according to the present embodiment, the capacitance of the capacitor 2 (FIG. 10) is 12
When pF, major axis phi _L of the resonance holes 32a is 1.1 mm, short diameter phi _S is 0.9 mm. The distance c between the resonance hole 32a and the input electrode is 0.3 mm.

Even in the case where the distance between the resonance hole and the input electrode is reduced as in this embodiment, a capacitor having a larger capacitance can be formed by increasing the area of the input electrode to a predetermined size or more. It can be substantially included in the filter. Specifically, for example, Embodiments 3 to 5
The first stage resonance hole of each dielectric filter is formed in a cross-sectional shape as in the present embodiment, and a required capacitance is obtained.

[0040]

The antenna duplexer according to the present invention is an antenna duplexer including an active element for switching between transmission and reception in a circuit configuration. Since the resonance hole of the dielectric filter resonator is non-penetrating, Active elements do not malfunction.

An antenna duplexer according to the present invention is an antenna duplexer including a capacitor connected in series with a dielectric filter in a circuit configuration, wherein an output electrode of the dielectric filter has an area larger than a predetermined size. Alternatively, the resonance hole of the first-stage resonator of the dielectric filter is separated from the resonance hole of the adjacent resonator by a predetermined distance and the distance between the input electrode and the resonance hole is equal to or less than the predetermined distance. Therefore, the number of parts, mounting space, and mounting man-hours can be reduced, and the size, weight, and cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an antenna duplexer according to Embodiment 1 of the present invention.

FIG. 2 is an equivalent circuit diagram of the antenna duplexer shown in FIG.

FIG. 3 is a perspective view showing a dielectric filter used in an antenna duplexer according to a second embodiment of the present invention.

FIG. 4 is a top view showing an antenna duplexer according to a third embodiment of the present invention.

FIGS. 5A to 5C are diagrams showing a dielectric filter used in the antenna duplexer shown in FIG. 4;

FIG. 6 is a perspective view showing a dielectric filter used in an antenna duplexer according to a fourth embodiment of the present invention.

FIG. 7 is a perspective view showing a dielectric filter used in an antenna duplexer according to a fifth embodiment of the present invention.

FIG. 8 is a diagram for explaining a dielectric filter used in an antenna duplexer according to a sixth embodiment of the present invention;
(A) shows the end face of the dielectric filter of the invention, and (b) shows the end face of the dielectric filter of the comparative example.

FIG. 9 is a perspective view showing a conventional antenna duplexer.

FIG. 10 is an equivalent circuit diagram of an antenna duplexer according to the present invention and a conventional example.

FIG. 11 is a top view showing a conventional antenna duplexer.

FIGS. 12A to 12C are diagrams showing a dielectric filter used for the antenna duplexer shown in FIG.

[Explanation of symbols]

1 BPF 2 Capacitor 8, 38, 508, 608 Circuit board 9, 509 Shield case 10, 10 ', 20, 20', 20 ", 510, 61
0 Dielectric filter 12, 12 ', 22, 22', 22 ", 612 Resonant hole 14 ', 24, 24', 24", 614 Input electrode 15 ', 25, 25', 25 ", 615 Output Electrode 17a ', 17b', 27a ', 27b' Coupling window 23, 23 ', 23 ", 613 Outer conductor 32a, 32b, 52a, 52b Resonant hole 77, 577 First diode 78, 578 Second diode 79 579 third diode 85 first antenna terminal 86 second antenna terminal

Claims (5)

[Claims] 1. An antenna duplexer in which a circuit configuration as an antenna duplexer having a dielectric filter is provided on one substrate, wherein an active element for switching between transmission and reception is included in the circuit configuration. An antenna duplexer, wherein the dielectric filter has a non-penetrating resonance hole of the resonator. 2. An antenna duplexer in which a circuit configuration as an antenna duplexer having a dielectric filter is provided on one substrate, wherein an antenna shared in the circuit configuration includes a capacitor connected in series with the dielectric filter. An antenna duplexer, wherein the output electrode of the dielectric filter has an area larger than a predetermined size to constitute the capacitor. 3. An antenna duplexer in which a circuit configuration as an antenna duplexer having a dielectric filter is provided on one substrate, wherein an antenna shared including a capacitor connected in series to the dielectric filter is included in the circuit configuration. Wherein the resonance hole of the first-stage resonator of the dielectric filter is separated from the resonance hole of an adjacent resonator by a predetermined distance, and the distance from the input electrode is not more than a predetermined distance. An antenna duplexer characterized by comprising the above-mentioned capacitor. 4. A resonance hole of a first-stage resonator of the dielectric filter is separated from a resonance hole of an adjacent resonator by a predetermined distance, and a distance from an input electrode is not more than a predetermined distance. 3. The antenna duplexer according to claim 2, wherein the capacitor is configured by the following. 5. An antenna duplexer including an active element for switching between transmission and reception in the circuit configuration, wherein the dielectric filter has a non-penetrating resonance hole of the resonator. Item 5. The antenna duplexer according to any one of Items 2 to 4.