JP3737768B2 - Solid state switch and power combiner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a contactless switching device and a power combiner, and is particularly effective when applied to a switching device that switches between an active system and a standby system during parallel operation of multicarrier power amplifiers in mobile communication, terrestrial digital television, and the like. Technology.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a television relay broadcasting facility or the like is generally provided with two systems, a working system and a standby system, assuming that a failure occurs in a part of the relay broadcasting facility.
For example, in the case of a power combiner, as shown in FIG. 14, four power amplifiers (PA1 to PA4) are connected in parallel, and three of these (for example, PA1 to PA3) are used as active systems, The remaining one (PA4) is used as a backup system. In this case, when a failure occurs in the power amplifier (PA2), the switches (SW21, SW22) are turned off, the power amplifier (PA2) in which the failure has occurred is removed from the active system, and the switches (SW41, SW42) ) Is turned on, and the standby power amplifier (PA4) is inserted into the active system.
[0003]
[Problems to be solved by the invention]
Conventionally, a contact-type switch is used as the switch (SW) described above. However, since switching from the active system to the standby system is performed during operation, the conventional contact-type switch is accompanied by spark discharge, which may cause an accident (or failure) such as contact fusing.
The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a contactless switching device that does not involve spark discharge and that does not cause contact fusing. It is in.
Another object of the present invention is to provide a power combiner that uses the contactless switch described above.
The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.
[0004]
[Means for Solving the Problems]
Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
That is, the present invention relates to a shield case, a first electrode disposed in the shield case, a second electrode, and a dielectric plate movably disposed on the first and second electrodes. The dielectric plate has a capacitor element formed between the first electrode and the first electrode on a surface opposite to the surface facing the first and second electrodes. A capacitance forming electrode; a second capacitance forming electrode that forms a capacitive element between the second electrode; and an inductance element that connects the first capacitance forming electrode and the second capacitance forming electrode. And changing the distance between the dielectric plate and the first and second electrodes, and conducting the first electrode and the second electrode at the frequency of the transmission signal. Or, it is characterized by being in a cut-off state.
In the present invention, at least one of the first electrode and the second electrode has a parallel circuit of a second inductance element disposed between the shield case and the second capacitance element. .
Furthermore, the present invention is a power combiner using the above-described contactless switch as the switch between the active system and the standby system.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.
[Embodiment 1]
FIG. 1 is a diagram for explaining the principle of a contactless switch according to the present invention.
As shown in FIG. 1, a series resonant circuit composed of a variable capacitance element (Cv) and an inductance element (L) is inserted into a high-frequency signal transmission path.
As is well known, the resonance frequency (fv) of this series resonance circuit is expressed by fv = 1 / 2π√ (L × Cv). At the resonance frequency (fv), the impedance of the series resonance circuit may be zero. Are known.
Therefore, now, when the resonance frequency (fv) of the series resonance circuit shown in FIG. 1 is equal to the frequency fo of the transmitted high frequency signal (fv = fo), the impedance of the series resonance circuit becomes 0, so that the high frequency signal is It is not affected by the series resonance circuit.
However, if the resonance frequency (fv) of the series resonance circuit is a frequency far away from the frequency of the high-frequency signal to be transmitted, the series resonance circuit has a high impedance, so that the high-frequency signal does not flow.
[0006]
FIG. 2 is a cross-sectional view of a main part showing a schematic configuration of the contactless switch according to Embodiment 1 of the present invention.
In FIG. 2, 1 is a shield case, 2 ₁ and 2 ₂ are inner conductors of the coaxial line, 3 ₁ and 3 ₂ are outer conductors of the coaxial line, 5 is an insulating support, and 10 is a dielectric plate. The dielectric plate 10 is made of a high dielectric constant material such as alumina.
FIG. 3 is a diagram showing a schematic configuration of the dielectric plate 10 shown in FIG.
Inner conductors of the dielectric plate 10 on the surface of the ₍₂ 1, _{2 2)} and the opposing surface opposite ₁ and the first capacitor forming electrode 11, and the second capacitor forming electrodes 11 _2, a first capacitor forming electrode 11 ₁ and the inductance element 12 connected between the second capacitor forming electrode 11 ₂ is, for example, formed by using a printing technique.
Here, the first capacitor forming electrodes 11 _1, a capacitor is formed between the inner conductor 2 _1, similarly, the second capacitor forming electrodes 11 _2, the capacitance element between the inner conductor 2 ₂ Form.
Therefore, non-contact switch of this embodiment, between the inner conductor 2 ₁ and the inner conductor 2 _2, will be provided with a series resonant circuit RS shown in FIG.
In addition, when the frequency band to be used is low, it is necessary to use a coil as the inductance element 12.
[0007]
Now, the state shown in FIG. 2, in a state in which the inner conductor ₍₂ 1, _{2 2)} the dielectric plate 10 on is placed, an inner conductor ₍₂ 1, _{2 2),} a dielectric plate 10 1 Since the dielectric plate 10 made of a high dielectric constant material such as alumina is inserted between the second capacitor forming electrodes (11 ₁ , 11 ₂ ), the internal conductors (2 ₁ , 2 ₂ ) A capacitor element (capacitor) having a large capacitance value is formed by the first and second capacitance forming electrodes (11 ₁ , 11 ₂ ) of the dielectric plate 10.
In this state, the resonant frequency of the series resonance circuit RS shown in FIG. 4 (fv) is the set to be equal to the frequency (fo) of the high-frequency signal to be transmitted between the inner conductor 2 ₁ and the inner conductor 2 _2, The impedance of the series resonant circuit RS becomes 0, and the contactless switch according to the present embodiment is turned on.
Next, as shown in FIG. 5, when the support body 5 is lifted and the dielectric plate 10 is lifted upward, the inner conductor (2 ₁ , 2 ₂ ) and the first and second capacitance forming electrodes of the dielectric plate 10 Since air enters between (11 ₁ , 11 ₂ ), the inner conductor (2 ₁ , 2 ₂ ) and the first and second capacitance forming electrodes (11 ₁ , 11 ₂ ) of the dielectric plate 10 The formed capacitive element has a small capacitance value.
Therefore, in the state shown in FIG. 5, the series resonant circuit RS of the resonance frequency (fv) is made higher than the frequency of the high-frequency signal to be transmitted between the inner conductor 2 ₁ and the inner conductor 2 ₂ (fo) Therefore, the series resonant circuit is in a high impedance state, and a large amount of attenuation is obtained, so that the contactless switch according to the present embodiment is turned off.
[0008]
[Embodiment 2]
FIG. 6 is a cross-sectional view of an essential part showing a schematic configuration of the contactless switch according to Embodiment 2 of the present invention.
In FIG. 6, 6 is an inductance element composed of a conductive wire, 7 is a high dielectric constant material such as alumina, and the other symbols are the same as those in FIG.
FIG. 7 is a circuit diagram showing an equivalent circuit of the contactless switch according to the present embodiment. As shown in FIG. 7, non-contact switch of this embodiment is constituted by adding a parallel resonance circuit RP1 to the inner conductor 2 _1, the parallel resonance circuit RP1 is the inductance device 6 shown in FIG. 6, It is composed of an inner conductor 2 ₁ , an outer conductor 3 ₁ , and a capacitive element formed by a material 7 having a high dielectric constant such as alumina inserted therebetween.
The contactless switching device of the first embodiment has a disadvantage that the usable frequency band is narrow because a single series resonance circuit is used. However, as in this embodiment, the series resonance circuit is used. By adding the parallel resonant circuit RP1 to the circuit RS, the usable frequency band can be expanded.
In this case, the resonance frequency of the parallel resonant circuit RP1 is a frequency near the frequency of the high-frequency signal to be transmitted between the inner conductor 2 ₁ and the inner conductor 2 _2.
[0009]
[Embodiment 3]
FIG. 8 is a cross-sectional view of an essential part showing a schematic configuration of the contactless switch according to Embodiment 3 of the present invention.
In FIG. 8, 61 is an inductance element composed of a conducting wire, 71 is a high dielectric constant material such as alumina, and the other symbols are the same as those in FIG.
FIG. 9 is a circuit diagram showing an equivalent circuit of the contactless switch according to the present embodiment. As shown in FIG. 9, the contactless switch of this embodiment, which has also added a parallel resonant circuit RP2 to the inner conductor 2 _2, the parallel resonant circuit RP2 includes an inductance element 61 shown in FIG. 8 , An inner conductor 2 ₂ , an outer conductor 3 ₂ , and a capacitive element formed of a high dielectric constant material 71 such as alumina inserted therebetween.
In the contactless switch according to the present embodiment, since two parallel resonant circuits (RP1, RP2) are added to the series resonant circuit RS, it is possible to expand the usable frequency band.
In this case, the resonance frequency of the parallel resonant circuit RP2 is a frequency near the frequency of the high-frequency signal to be transmitted between the inner conductor 2 ₁ and the inner conductor 2 _2.
[0010]
Hereinafter, an example of a power combiner using the contactless switch of the present invention will be described with reference to FIG.
As shown in the figure, the high-frequency signal is distributed by the distributor 30 and input to the power amplifiers (PA1 to PA4) via the circulators (31 _{1 to} 31 ₄ ). The high frequency signals amplified by the power amplifiers (PA1 to PA4) are synthesized by the synthesizer 32 and then output via the transformer 33.
The transformer 33 is provided for impedance matching. In FIG. 10, R is a non-reflection terminator, and λo is the wavelength of the high-frequency signal to be amplified.
In FIG. _10, 35 1 to 35 ₄ are non-contact switch of the first embodiment described above, among the non-contact switch ₍₃₅ 1 to 35 _4), a single three is on, the remaining Is turned off, three power amplifiers (for example, PA1 to PA3) are used as the active system, and the remaining one (for example, PA4) is used as the standby system.
In this case, when a failure etc. occurs in the power amplifier (PA2), as a clear non-contact switch 35 _2, remove the power amplifier in which the failure occurs and (PA2) from the working, non-contact switch 35 ₄ is turned on, and the standby power amplifier (PA4) is inserted into the active system.
[0011]
11 is a cross-sectional view of a main part showing a schematic configuration of the contactless switch shown in FIG. 10, and FIG. 12 is a view showing the dielectric plate shown in FIG.
As shown in FIGS. 11 and 12, a large-area internal conductor ₂₅ is disposed in the center of the shield case 1. The inner conductor ₂₅ also serves as a transformer section.
Then, around the inner conductor _{2 5,} it is arranged an inner conductor having a small area ₍₂₁ to _24), between these inner conductors ₍₂₁ to _24), an inner conductor _{2 5,} dielectric Body plates (10 ₁ to 10 ₄ ) are arranged so as to be movable. On the surface opposite to the surface facing the inner conductor (2 ₁ to 2 ₅ ) of the dielectric plate (10 ₁ to 10 ₄ ), the first capacitance forming electrode, the second capacitance forming electrode, and An inductance element is formed to connect between the first capacitance forming electrode and the second capacitance forming electrode.
FIG. 13 is a diagram illustrating another example of a power combiner using the contactless switch according to the present invention. The power combiner shown in FIG. 13 is different from the power combiner shown in FIG. 10 in that the non-contact switchers (35 _{1 to} 35 ₄ ) are constituted by series-parallel circuits. Since the circuit configuration is the same as that of FIG.
[0012]
Thus, in the contactless switching device of the present invention, even when switching from the active system to the standby system is performed during operation, spark discharge does not occur unlike the conventional contact type switch, and the contact Accidents (or failures) such as fusing will not occur.
On the other hand, in digital television using an OFDM modulated wave, it is assumed that relay broadcasting is performed by using a MCPA (multi-carrier power amplifier) to simultaneously amplify a multi-channel television signal having a bandwidth of about 100 MHz. . The contactless switch of the present invention is most suitable for such applications.
Although the invention made by the present inventor has been specifically described based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. Of course.
[0013]
【The invention's effect】
The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.
ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the non-contact-type switch which does not accompany a spark discharge and does not produce a fusing of a contact.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining the principle of a contactless switch according to the present invention.
FIG. 2 is a cross-sectional view of a main part showing a schematic configuration of a contactless switch according to Embodiment 1 of the present invention.
3 is a diagram showing a schematic configuration of a dielectric plate shown in FIG. 2. FIG.
FIG. 4 is a circuit diagram showing an equivalent circuit of the contactless switch according to the first embodiment of the present invention.
FIG. 5 is a diagram illustrating a state in which the contactless switch according to the first embodiment of the present invention is off.
FIG. 6 is a cross-sectional view of a main part showing a schematic configuration of a contactless switch according to a second embodiment of the present invention.
FIG. 7 is a circuit diagram showing an equivalent circuit of a contactless switch according to Embodiment 2 of the present invention.
FIG. 8 is a cross-sectional view of a main part showing a schematic configuration of a contactless switch according to Embodiment 3 of the present invention.
FIG. 9 is a circuit diagram showing an equivalent circuit of a contactless switch according to Embodiment 3 of the present invention.
FIG. 10 is a diagram showing an example of a power combiner using the contactless switch according to the present invention.
FIG. 11 is a cross-sectional view of a principal part showing a schematic configuration of the contactless switch shown in FIG. 10;
12 is a view showing the dielectric plate shown in FIG. 11. FIG.
FIG. 13 is a diagram showing another example of a power combiner using the contactless switch according to the present invention.
FIG. 14 is a circuit diagram showing a conventional power combiner.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Shield case, 2 _{1 to} 2 ₅ ... Inner conductor of coaxial line, 3 _{1 to} 3 ₅ ... Outer conductor of coaxial line, 5 ... Insulator support, 6, 12, 61, L ... Inductance element, 7, 71 ... high dielectric constant material, 10, 10 ₁ to 10 ₄ ... dielectric plate, 11 ₁ , 11 ₂ ... capacitance forming electrode, 30 ... distributor, 31 _{1 to} 31 ₄ ... circulator, 32 ... synthesizer, 33 ... Transformer, 35 _{1 to} 35 ₄ ... Non-contact switching device, Cv... Capacitive element, PA1 to PA4... Power amplifier, SW11 to SW41, SW12 to SW42.

Claims (2)

A shield case,
A first electrode and a second electrode disposed in the shield case ;
A contactless switch comprising a dielectric plate movably disposed on the first and second electrodes,
The dielectric plate has a first capacitance forming electrode that forms a capacitive element with the first electrode on a surface opposite to a surface facing the first and second electrodes, and the second A second capacitance forming electrode that forms a capacitive element with the first electrode, and an inductance element that connects the first capacitive forming electrode and the second capacitive forming electrode,
At least one of the first electrode and the second electrode has a parallel circuit of a second inductance element arranged between the shield case and a second capacitance element ,
By changing the distance between the dielectric plate and the first and second electrodes, the first electrode and the second electrode are in a conductive state or a cut-off state at the frequency of the transmission signal. A contactless switch characterized by that. A power combiner using the non-contact switch according to claim 1 as a switch between an active system and a standby system.

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