JP2001036308A - Concentrated constant type circulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable operation in plural frequency bands and to reduce insertion losses by equipping an intrinsic value adjusting circuit for mutually inverting a concentrated constant type circulator transmission direction with two necessary frequencies. SOLUTION: A same phase exciting intrinsic value adjusting circuit 42 is provided at a lower part of a circulator element 40 and an inner substrate 41. The intrinsic value adjusting circuit 42 is equipped with electrodes 42b and 42c, facing each other with a dielectric substrate 42a inbetween, an electrode 42c and a grounding electrode 42e facing each other with a dielectric substrate 42d inbetween, and a diode switch 42f. A capacity(C1) is formed by the dielectric substrate 42a and the electrodes 42b and 42c, and a capacity(C2) is formed by the dielectric substrate 42d the electrodes 42c and 42e. The device is constituted so that the capacities C1 and C2 are connected serially, the diode switch 42f is connected between the electrode 42c of the capacity C2 and the grounding electrode 42e, so that are short-circuited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lumped constant circulator, and more particularly to a lumped constant circulator used in a power amplifier output section of a two-frequency band mobile communication device such as a dual-band portable telephone terminal. .

[0002]

2. Description of the Related Art In order to satisfy the increasing demand for channels with the spread of portable telephones, the development of dual-band telephone terminals capable of handling two frequencies with the same portable telephone terminal has been active.

In general, the use of a lumped constant circulator in a portable telephone terminal has a great advantage.
That is, by inserting this kind of circulator between the transmitter and the antenna of the portable telephone terminal to match the impedance, (1) the amplifier can be operated independently of the fluctuation of the antenna impedance, (2) the QP
The following effects can be expected: a bit error rate in digital data transfer such as SK can be reduced, and (3) power saving can be achieved by optimizing load conditions by impedance matching.

As a lumped-constant circulator that operates in a dual band, a resonance capacitance that is frequency-dependent to realize an optimum capacitance at two frequencies has been proposed by the present applicant (Japanese Patent Laid-Open No. 11-1999). 97907
Publication).

FIG. 1 shows an equivalent circuit of this known three-terminal lumped constant circulator, and FIG. 2 shows an example of its transmission characteristics.

In FIG. 1, 10 is a DC magnetic field, 11 is three inductors gyromagnetically coupled, 12 is three input / output terminals, and 13 is a resonance circuit inserted between each input / output terminal 12 and ground. There, the series resonant circuit is in the attached configuration due to the capacitance C ₁ and the inductor L ₁ to the normal resonant capacitance C _2. The resonance circuit 13 operates as a frequency-dependent capacitance circuit, and as a result, a dual-band lumped-constant circulator having characteristics as shown in FIG. 2 is realized.

[0007]

However, such a conventional lumped-constant type circulator has a frequency dependent capacity by adding another resonance circuit to the main resonance circuit connected to the input / output terminals. Since the capacitance with different values is realized, when the Q value of the resonance circuit decreases,
This immediately leads to an increase in the insertion loss of the circulator. That is, the capacity of the total capacitance C ₂ is at the lower frequency of the composed, in the higher frequency, capacitance C ₁
And the capacitance is constituted by the C ₂ and the inductor L _1, out significantly less influence of the inductor L ₁ Q value,
The Q value of the obtained capacitance is reduced, and the insertion loss is increased.

Further, according to the above-mentioned conventional lumped-constant-type circulator, since the transmission characteristics of the same terminal show two-frequency characteristics, two power amplifiers are connected to this one input / output terminal. Therefore, when this circulator is used in a dual-band portable telephone terminal, a diplexer for frequency switching is required.

FIG. 3 shows an application example of a conventional lumped-constant type circulator using such a diplexer.

In FIG. 1, reference numeral 30 denotes a conventional lumped constant circulator having two frequency characteristics, 31 denotes a diplexer connected to one input / output terminal 30a, and 31a and 31b denote a low-pass filter and a high-pass filter constituting the diplexer 31. pass filters, 32 and 33 power amplifiers for frequencies _{F 1} and _{F 2} which are connected to the output terminal 30a via the diplexer 31, 34 matching resistor, 30b other input of the circulator 30 connected to an antenna Output terminal, 3
0c indicates the remaining input / output terminals of the circulator 30 connected to the matching resistors.

When such a diplexer 31 is used, a low-pass filter 31a and a high-pass filter 31a are used.
The insertion loss due to b becomes considerably large, and further, the circuit configuration becomes complicated.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a lumped-constant circulator which can operate in a plurality of frequency bands and has a small insertion loss.

[0013]

According to the present invention, a circulator element (magnetic rotating element), a resonance capacitor connected between each input / output terminal of the circulator element and ground, a ground terminal of the circulator element and There is provided a lumped-constant-type circulator which is connected between grounds (ground terminals of a housing) and includes an eigenvalue adjusting circuit for reversing the lumped-constant-type circulator transmission directions at two required frequencies.

It should be noted that a circulator can be constructed if the eigenvalues of the circulator elements excited by the in-phase, normal-phase rotation, and anti-phase rotation eigenvectors can be adjusted at 120 ° intervals (three-terminal circulator) when the eigenvalues of the circulator element are mapped on a Smith chart. The circulator is configured by connecting an eigenvalue adjustment circuit that satisfies the circulator condition for reversing the transmission direction at the two required frequencies. Such an operation can be realized by inserting a capacitance circuit whose capacity can be switched or changed between the ground terminal of the circulator element and the ground terminal of the housing. Since a resonance circuit is not added to the main circuit on the input / output terminal side of the circulator but a capacitance circuit for adjusting the eigenvalue is connected to the ground terminal side, an increase in insertion loss cannot occur.

Further, if a circulator in which the transmission direction is reversed according to the frequency and the power amplifiers of the two-frequency terminal are connected to separate input / output terminals and used as described above,
A switching circuit such as a diplexer is not required, so that an increase in insertion loss and a complicated circuit configuration can be avoided.

Preferably, the eigenvalue adjustment circuit is a circuit for adjusting the eigenvalue of the in-phase excitation.

More preferably, the eigenvalue adjusting circuit is a capacitance circuit whose capacitance value is switched.

It is preferable that the capacitance circuit includes a plurality of capacitances and a switch for switching the capacitance. In this case, the capacitance circuit may include two capacitors connected in series and a diode switch capable of short-circuiting one of the capacitors.

It is also preferable that the eigenvalue adjusting circuit is a frequency-dependent capacitance circuit.

It is more preferable that the frequency-dependent capacitance circuit is a two-terminal resonance circuit having two resonance frequencies. This frequency-dependent capacitance circuit may be a series-parallel resonance circuit.

[0021]

FIG. 4A is an exploded perspective view schematically showing an entire structure of a dual-band lumped-constant-type circulator according to an embodiment of the present invention, and FIG. 4B is a structure of an eigenvalue adjusting circuit thereof. FIG.

In these figures, reference numeral 40 denotes a circulator element (magnetic rotating element). The circulator elements 40 are insulated from each other and 12
Three drive lines formed so as to be three-fold symmetrical with an angle of 0 °, a magnetic (ferrite) block in which these drive lines are provided and integrated, and an outside of the magnetic block This is a well-known element mainly composed of a shield electrode, a ground electrode, and an input / output terminal formed on the surface.

The circulator element 40 includes an internal substrate 41
Is configured to be incorporated in the through hole. Inside the substrate 41, resonant capacitor C ₀ is connected between the ground terminal of the input-output terminal and the ground i.e. the housing of the circulator element 40 is provided. The inner substrate 41 is formed of a dielectric material, the electrode 41a of the resonant capacitor C ₀ on the surface, and 41b and 41c are formed, the ground electrode is formed opposite to the back surface .

Circulator element 40 and internal substrate 41
On the lower side, an in-phase excitation eigenvalue adjustment circuit 42 is provided. In the present embodiment, the eigenvalue adjustment circuit 42
As shown in FIG. 3B, electrodes 42b and 42c facing each other with a dielectric substrate 42a interposed therebetween, and a dielectric substrate 42
electrode 42c and ground electrode 42 facing each other with d
e and a diode switch 42f. The capacitance C is determined by the dielectric substrate 42a and the electrodes 42b and 42c.
₁ is formed, the capacitance _{C 2} is formed by a dielectric substrate 42d and the electrode 42c and 42e. Capacitance _{C 1} and _{C 2} are connected in series, a diode switch 42f
It is connected between the electrodes 42c and the ground electrode 42e capacitor C _2, and is configured to short-circuit them.

In FIG. 4, reference numeral 43 denotes a permanent magnet for applying a DC magnetic field in the thickness direction of the circulator element 40, 44 denotes an upper yoke, 45 denotes a lower yoke, and 46 denotes a terminal block.

FIG. 5 shows an equivalent circuit of the embodiment of FIG.

In the figure, 50 is a DC magnetic field, 51 is a gyromagnetically coupled three inductor L ₀ , 52 constituted by a drive line, and three are input / output terminals. The resonance capacitance _C0 is inserted between each input / output terminal 52 and the ground, and the eigenvalue adjustment circuit 42 is inserted between the ground terminal of the circulator element and the ground.

Here, the basic operation of the lumped-constant-type circulator will be described by eigenvalue theory.

Generally, an input signal a applied to each input / output terminal of the three-hole circuit and an output signal b coming out of each terminal are related by a scattering matrix S shown below.

[0030]

(Equation 1)

Now, when a special combination of input signals a ₁ , a ₂ and a ₃ are added to each terminal of the symmetrical three-hole circuit having the same terminal impedance, the input / output terminals give the following equations. An output signal having an equal amplitude appears.

[0032]

(Equation 2)

An input signal that satisfies this condition is called an eigenvector.

[Outside 1] And these can be expressed as follows:

[0034]

(Equation 3)

Of the eigenvectors,

[Outside 2] Is called in-phase excitation because the phases of the signals applied to all terminals are equal,

[Outside 3] Are called positive-phase excitation and negative-phase excitation, respectively, because the phase of the signal applied to each terminal corresponds to three-phase alternating current of forward rotation and reverse rotation. Reflection coefficient when excited by eigenvector
(Amplitude ratio between the traveling wave and the reflected wave) is called an eigenvalue, which also corresponds to the eigenvector and has three independent eigenvalues s ₁ and s _2.
And there is _{s 3.} Now, the case where a signal is applied only to the terminal 1 is represented by an eigenvector as follows.

[0036]

(Equation 4)

At this time, the output signal appearing from each terminal is:
Expressions (2) and (3) can be expressed as follows from the principle of superposition.

[0038]

(Equation 5)

If each eigenvalue can be adjusted as follows:

[0040]

(Equation 6) The output signal obtained from each terminal is expressed as follows using the eigenvalue. If each eigenvalue is considered as a vector on the complex plane, these are vectors that are separated from each other by 120 °.

[0041]

(Equation 7)

The output signal at terminal 2 is the result of the input to terminal 1 appearing at terminal 2 due to the action of the circulator.
That is, all inputs to terminal 1 appear at terminal 2 and do not appear at terminal 3. The output signal of the terminal 1 being O indicates that the circulator is in the matching state. Since this input / output relationship is established even if the subscripts are exchanged, the input to the terminal 2 appears at the terminal 3 and does not appear at the terminal 1, and the input to the terminal 3 appears at the terminal 1 and does not appear at the terminal 2. . Since the input / output relationship between the terminals is thus given cyclically, this element is called a circulator.

The eigenvalue relationship as shown in equation (6) is
It can be realized in a circuit containing a substance exhibiting tensor permeability such as magnetized ferrite. Now, when the subscripts 2 and 3 in the equation (6) are exchanged and the relationship of the eigenvalues is exchanged, the input to the terminal 1 appears at the terminal 3,
It will be obvious that the direction of the circulation shown above is reversed.

As described above, a general lumped-constant circulator is composed of an irreversible coupling inductance including a ferrite exhibiting tensor permeability and a capacitor for adjusting an eigenvalue.

FIG. 6 shows a specific structure of such a general circulator element, and FIG. 7 shows an equivalent circuit thereof.

In these figures, 60 is a magnetic plate, 6
Reference numeral 1 denotes three drive lines integrated with the magnetic plate 60;
Represents three resonance capacitors C, 63 represents a shield electrode, 64 represents a ground electrode plate, 70 represents a DC magnetic field, 71 represents three inductors L constituted by the drive line 61 and magnetically coupled, and 72 represents three terminals. I have. The resonance capacitors 62 are inserted between each input / output terminal 72 and the ground electrode plate 64.

Assuming that admittances when each terminal of the circulator is excited by the eigenvector are y ₁ , y ₂ and y ₃ , the relationship between the eigen value and the admittance is given by the following equation.

[0048]

(Equation 8) Here, i = 1, 2, 3, and y _c indicates the characteristic admittance of the circuit.

Equation (8) is called a bilinear transformation, and is a transformation equation for mapping the entire complex admittance space inside a circle.
A diagram obtained by mapping admittance by the expression (8) is called an admittance Smith chart. Eigenvalue is (6)
When the admittance satisfying the relation of the formula is shown on the Smith chart, it is proved that y ₁ , y ₂ and y ₃ also open at an interval of 120 ° from each other. If the admittance is lossless, y
_1, it indicates the adjusted element always circulator characteristics as y ₂ and y ₃ is 120 ° intervals from one another,
This is called a circulator condition.

Now, considering the case where the circulator is excited with each eigenvector, the total current flowing into each terminal is as shown in equation (9).

[0051]

(Equation 9)

According to this equation, in the in-phase excitation, current flows from all terminals, so that the current returns to the signal source as ground current. On the other hand, in the positive-phase excitation and the negative-phase excitation, a current equal to the current that flows in flows out of each terminal, so that no ground current flows. Therefore, it can be seen that when an admittance element is inserted between the ground terminal of the circulator element and the ground, only the eigenvalue of the in-phase excitation can be changed without affecting the eigenvalues of the positive-phase excitation and the negative-phase excitation.

As described above, according to the equations (7) and (8), the characteristics of the lumped-constant-type circulator include the real number and the imaginary number of the inductance eigenvalues with respect to the applied magnetic field and frequency.
If (loss) is known, it can be predicted without actually assembling the element. When constructing a practical circulator, the circulator cannot be constructed in a range where the loss of the inductance eigenvalue is large, so it is not necessary to find the eigenvalue with a complex number. Can design a circulator.

With respect to an actual circulator element, an inductance eigenvalue is measured under a constant applied magnetic field, and an admittance is calculated by connecting a capacitor satisfying the circulator condition. FIG. 8 shows the angular components of y ₁ , y ₂ and y ₃ calculated by applying a DC magnetic field of 1250 Oe to a closed magnetic circuit type inductance element having an effective diameter of 2.5 mm and connecting a resonance capacitance of 7 pF as a function of frequency. Show.

If the angle difference between y ₂ and y ₃ is ± 120 °
And the eigenvalue of y ₁ is also 120 ° with respect to y ₂ and y ₃ .
If the angle can be adjusted so as to satisfy the above condition, the circulator condition is satisfied at that frequency. y ₂ and y ₃
FIG. 9 shows the calculation result of the difference between the angle components of FIG.

[0056] From the figure, while the angle difference of _{y 2} and _{y 3} are -120 ° in 840 MHz, 1680M
It turns out that it is 120 degrees in Hz. Therefore, if adjusting the angle of y ₁ to y _'1 as shown in FIG. 10, and thus there is a possibility of constituting a circulator operating at these frequencies. Furthermore, since the circulating directions of y ₁ , y ₂ and y ₃ at these frequencies are interchanged, this circulator is a circulator whose transmission direction is reversed depending on the frequency.

[0057] As described above, it admittance eigenvalues of y ₁ is to be set independently without affecting the y ₂ and y ₃ by inserting the admittance element between a ground terminal of the circulator element ground and it can. In the admittance eigenvalue measurement of the circulator element, y
₁ changes as shown in FIG. Therefore, in order to configure the circulator as described above, it is necessary to insert an appropriate admittance element between the ground terminal of the element and the ground to move the admittance of common-mode excitation, and simultaneously satisfy the circulator conditions at two frequencies. .

[0058] angle values of _{y 1} obtained from the calculation results, 84
At 0 MHz and 1680 MHz, 17
1.3 ° and 143.4 °. This element is 840
To operate as a circulator in MHz and 1680MHz, the angle value _{y 1,} respectively -14
Since the angle must be 3.8 ° and −158.8 °, the distance between the ground terminal of the circulator element and the ground is 8 °.
At 40 MHz and 1680 MHz, respectively.
Admittances having angle values of 9 ° and 57.8 ° may be inserted. This value is 20m each
S and 12.6 mS. Table 1 summarizes the results of these calculations.

[0059]

[Table 1]

In order to clarify this operation, the relationship between the respective admittances at the two frequencies is plotted on a Smith chart as shown in FIGS. 11A and 11B, respectively. If the characteristic impedance of the line is 50Ω, these admittances are 840 MHz and 1680 MHz.
In Hz, they correspond to capacitance values of 3.8 pF and 1.2 pF, respectively.

Since the value of the insertion element differs depending on the frequency, the admittance described above cannot be realized with a single element. Therefore, when the frequency is changed by switching the switch by separately providing the power amplifiers of the two frequencies, the ground capacitance may be switched in conjunction with the switch.

[0062] In the eigenvalues adjusting circuit 42 in the present embodiment, therefore, as shown in FIG. 5, a capacitor _{C 1} having a capacitance value of 3.8PF, capacitor C having a capacitance value of 1.8pF
₂ are connected in series, and the diode switch 42f
There has been configured to short-circuit the capacitor C _2. As a result, a capacitance value of 3.8 pF is obtained when the switch 42f is on, and a capacitance value of 1.2 pF is obtained when the switch 42f is off.

FIG. 12A is an exploded perspective view schematically showing the entire structure of a dual-band lumped-constant-type circulator as another embodiment of the present invention, and FIG. 12B is a schematic view of the structure of an eigenvalue adjusting circuit thereof. It is an exploded perspective view shown in FIG. In this embodiment, as a characteristic value adjusting circuit, a capacitance circuit having frequency dependency is configured without using a switch by a resonance circuit.

In these figures, reference numeral 120 denotes a circulator element (magnetic rotating element). The circulator element 120 is insulated from each other and formed three drive lines formed so as to be three-fold symmetrical while maintaining an angle of 120 ° with each other, and these drive lines are provided inside and integrated. A magnetic (ferrite) block;
A shield electrode formed on the outer surface of the magnetic block,
This is a well-known element mainly composed of a ground electrode and an input / output terminal.

The circulator element 120 is connected to the internal substrate 1
It is configured to be incorporated into the through hole 21.
Inside the substrate 121, the resonant capacitor C ₀ is connected between the ground terminal of the input-output terminal and the ground i.e. the housing of the circulator element 120 is provided. This internal substrate 12
1 is formed of a dielectric material, the electrode 121a of the resonant capacitor C ₀ on the surface, and 121b and 121c are formed, the ground electrode opposite thereto is formed on the back surface.

Circulator element 120 and internal substrate 1
An in-phase excitation eigenvalue adjustment circuit 122 is provided below 21. In this embodiment, the eigenvalue adjustment circuit 1
Reference numeral 22 denotes a dielectric substrate 122a as shown in FIG.
122b and 12 facing each other at the center with
2c, an electrode 122e and a ground electrode 122f facing each other across the dielectric substrates 122a and 122d, and a coil conductor 122g formed on the dielectric substrate 122d. Capacitance _{C 1} is formed by a dielectric substrate 122a and electrodes 122b and 122c, the dielectric substrate 12
2a and 122d and electrode 122e and ground electrode 12
Capacitance _{C 2} is formed by 2f, further coil conductor 12
Inductor _{L 1} is formed by 2g. Capacity C
₁ and the inductor L ₁ is connected in series, to which has capacitance C ₂ is connected in parallel, whereby a series-parallel resonant circuit is constituted.

FIG. 13 shows an equivalent circuit of the embodiment of FIG.

In the figure, 130 is a DC magnetic field, 131
Is a gyromagnetically coupled 3 composed of drive lines
Two inductors L ₀ and 132 indicate three input / output terminals, respectively. The resonance capacitance C ₀ is inserted between each input / output terminal 132 and the ground, and
2 is inserted between the ground terminal of the circulator element and the ground.

[0069] In forming such a series-parallel resonant circuit, if the series resonance frequency and F _S, the parallel resonant frequency F _P, as shown in FIG. 14, capacitive at frequencies below F _S, F _S inductive between F _P, the capacitive in F _P more frequencies. By choosing the _{F S} and _{F P} appropriately between the lower circulator center frequency _{(F L)} and the upper circulator center frequency _{(F H),} 2
A capacitance circuit that satisfies the circulator condition at one operating frequency can be configured.

[0070] Since the number of circuit elements is a is an equivalent circuit constants need 3 is 2, one of the F _S and F _P can freely selected. However, if these frequencies are close to each other, the frequency dependence of the equivalent circuit constant increases and the operating frequency range is narrowed. Such to eliminate _{problems, F} L, F S, it is desirable that the relationship F _P and F _H is the approximate geometric series. _{F L: 840MHz, F H:} 1
At 680 MHz, F _S : 1008 MHz,
F _P : 1207 MHz is selected, and the result is used to calculate F _P
When constants indicating admittances of 20 mS and 12.6 mS are obtained at _L and F _H , L ₁ = 36.5 nH and C ₁ = O. 68pF, _{C 2} = O. 4
8 pF.

According to the present embodiment, since there is no need to provide a switch in the eigenvalue adjustment circuit, the circuit configuration and its operation are simplified. The other configurations, functions and effects of the present embodiment are the same as those of the embodiment of FIG.

FIG. 15 shows the results of actually measuring the transmission characteristics of the dual-band lumped-element circulator of the embodiment shown in FIG.

[0073] As apparent from the figure, the circulator, the lower circulator center frequency (F ₁ channel) and the upper circulator center frequency (F ₂ channels)
The transmission direction of the signal is different between the circulator and the circulator whose transmission direction depends on the frequency. As described in detail above, (1) the required operating frequency is selected, and (2) the resonance capacity at which the angular difference of the admittance eigenvalue in the rotational excitation is 120 ° and −120 ° at the selected frequency is determined. (3) A circulator that operates in two frequencies with different transmission directions at the required frequency is determined by determining a capacitance circuit that satisfies the circulator condition at the operating frequency and inserting it between the ground terminal of the circulator element and the ground. be able to.

FIG. 16 shows an example in which the lumped constant circulator of the present invention is applied to a two-frequency power amplifier.

In the figure, reference numeral 160 denotes a lumped constant type circulator described in each embodiment, 161 denotes a switch connected to one input / output terminal 160a, and 162 denotes a switch connected to another input / output terminal 160b of the circulator. Switches 163 and 164 are switches 161 and 16
2, 165 and 166 are switches which can be connected to the input / output terminals 160a and 160b via the switch 16 respectively.
1 and 162 can be connected to the input and output terminals 160a and 160b via respective frequencies _{F 1} and _{F 2} for the power amplifier, 160c indicates the remaining output terminals of the circulator 160 is connected to the antenna, respectively.

As described above, the power amplifiers 165 and 166 operating at two different frequencies are connected to the two input / output terminals 160a and 160b of the circulator 160,
The remaining input / output terminal 160c of circulator 160 is connected to the antenna. In this circuit, one of the amplifiers 1
When the switch 65 is operating, the terminal 160 b to which the other amplifier 166 is connected is connected to the matching resistor 164 by the switch 162. In the case of the embodiment of FIG. 4, the switches of the eigenvalue adjustment circuit 42 in the circulator 160 are also operated in conjunction. This allows
A two-frequency power amplifier can be stabilized without using a frequency division filter. Therefore, not only the insertion loss due to the diplexer is eliminated, but also the circuit configuration is greatly simplified. Since the switch on the matching resistor side is not inserted in the transmission path, it does not contribute to transmission power loss.

FIG. 17 shows another example in which the lumped constant circulator of the present invention is applied to a two-frequency power amplifier.

[0078] In the figure, 170 lumped circulators described in each embodiment, 175 that one directly connected frequencies F ₁ for the power amplifier to the input-output terminal 170a, 176 is of one of the other circulator directly connected frequency _{F 2} for the power amplifier to the input-output terminal 170b,
170c is a circulator 1 connected to the antenna
The remaining 70 input / output terminals are shown.

As described above, the power amplifiers 175 and 176 operating at two different frequencies are directly connected to the two input / output terminals 170a and 170b of the circulator 170, and the remaining input / output terminals 17a and 170b of the circulator 170 are connected.
0c is connected to the antenna. However, the configuration is such that the impedance of the amplifier on the cool-down side becomes the matching impedance. Thus, the switch as in the example of FIG. 16 is not required, and the circuit configuration is further simplified.

The embodiments described above all show the present invention by way of example and not by way of limitation, and the present invention can be embodied in various other modified forms and modified forms. Therefore, the scope of the present invention is defined only by the appended claims and their equivalents.

[0081]

As described above in detail, according to the present invention, a circulator element (magnetic rotating element), a resonance capacitor connected between each input / output terminal of the circulator element and ground, and a circulator element It is connected between a ground terminal and a ground (ground terminal of the housing), and has a characteristic value adjusting circuit for reversing the transmission directions of the lumped constant type circulator at two required frequencies.

A circulator is configured by connecting an eigenvalue adjusting circuit that satisfies a circulator condition for reversing the transmission direction at two required frequencies. Such an operation can be realized by inserting a capacitance circuit whose capacity can be switched or changed between the ground terminal of the circulator element and the ground terminal of the housing. Since a resonance circuit is not added to the main circuit on the input / output terminal side of the circulator but a capacitance circuit for adjusting the eigenvalue is connected to the ground terminal side, an increase in insertion loss cannot occur. In this way, if a circulator in which the transmission direction is reversed according to the frequency is configured and the power amplifier of the dual-frequency terminal is connected to separate input / output terminals and used, a switching circuit such as a diplexer becomes unnecessary, and the insertion loss is reduced. And the complexity of the circuit configuration can be avoided.

[Brief description of the drawings]

FIG. 1 is an equivalent circuit diagram of a known three-terminal lumped constant type circulator.

FIG. 2 is a transmission characteristic diagram of the conventional lumped constant circulator of FIG.

FIG. 3 is a circuit diagram showing an application example of a conventional lumped constant circulator using a diplexer.

FIG. 4 is an exploded perspective view schematically showing an entire structure of a dual-band lumped-constant-type circulator as one embodiment of the present invention, and an exploded perspective view schematically showing a structure of an eigenvalue adjusting circuit thereof.

FIG. 5 is an equivalent circuit diagram of the embodiment of FIG.

FIG. 6 is a perspective view showing a specific structure of a general circulator element.

7 is an equivalent circuit diagram of the circulator element of FIG.

FIG. 8 is a frequency characteristic diagram of a circulator eigenvalue angle component.

FIG. 9 is a frequency characteristic diagram of a difference between circulator eigenvalue angle components.

10 is a diagram showing a method of designing a lumped-constant circulator in the embodiment of FIG. 4 from difference data of circulator eigenvalue angle components.

FIG. 11 is a Smith chart at the center frequency of the lumped constant circulator in the embodiment of FIG. 4;

FIG. 12 is an exploded perspective view schematically showing an entire structure of a dual-band lumped-constant-type circulator as another embodiment of the present invention, and an exploded perspective view schematically showing a structure of an eigenvalue adjusting circuit thereof.

FIG. 13 is an equivalent circuit diagram of the embodiment of FIG.

14 is an admittance frequency characteristic diagram of the eigenvalue adjustment circuit of the embodiment in FIG.

FIG. 15 is a transmission characteristic diagram showing a result of actually measuring transmission characteristics of the dual-band lumped-constant-type circulator of the embodiment in FIG. 12;

FIG. 16 is a circuit diagram showing an example in which the lumped constant circulator of the present invention is applied to a two-frequency power amplifier.

FIG. 17 is a circuit diagram showing another example in which the lumped constant circulator of the present invention is applied to a two-frequency power amplifier.

[Explanation of symbols]

40, 120 circulator elements 41, 121 internal substrates 41a, 41b, 41c, 42b, 42c, 121a,
121b, 121c, 122b, 122c, 122e
Electrodes 42, 122 In-phase excitation eigenvalue adjustment circuit 42a, 42d, 122a, 122d Dielectric substrate 42e, 122f Ground electrode 42f Diode switch 43, 123 Permanent magnet 44, 124 Upper yoke 45, 125 Lower yoke 46, 126 Terminal block 50, 130 DC magnetic field 51, 131 Inductor 52, 132 Input / output terminal 122g Coil conductor

Claims (8)

[Claims] A circulator element, a resonance capacitor connected between each input / output terminal of the circulator element and ground, and a resonance capacitor connected between a ground terminal of the circulator element and the ground. A lumped-constant-type circulator, comprising: an eigenvalue adjusting circuit for reversing the transmission directions of the lumped-constant-type circulator. 2. The lumped constant circulator according to claim 1, wherein the eigenvalue adjusting circuit is a circuit for adjusting an eigenvalue of the in-phase excitation. 3. The lumped-constant circulator according to claim 1, wherein the eigenvalue adjustment circuit is a capacitance circuit that switches a capacitance value. 4. The lumped constant circulator according to claim 3, wherein said capacitance circuit includes a plurality of capacitances and a switch for switching the capacitance. 5. The lumped-constant circulator according to claim 4, wherein the capacitance circuit includes two capacitors connected in series and a diode switch capable of short-circuiting one of the capacitors. 6. The lumped-constant circulator according to claim 1, wherein the eigenvalue adjusting circuit is a frequency-dependent capacitance circuit. 7. The lumped constant circulator according to claim 6, wherein the frequency-dependent capacitance circuit is a two-terminal resonance circuit having two resonance frequencies. 8. The lumped-constant circulator according to claim 6, wherein the frequency-dependent capacitance circuit is a series-parallel resonance circuit.