NONRECIPROCAL CIRCUIT ELEMENT

Abstract

A nonreciprocal circuit element according to the present invention comprises a nonreciprocal unit provided with a ferrite, an electromagnet that applies a DC magnetic field to the ferrite, and conductors that are arranged so as to intersect with each other in an insulated state with respect to the ferrite and that have a plurality of shorted terminal ends. The nonreciprocal circuit element comprises reciprocal circuit units and a DC power supply control unit controlling DC current to be supplied to the electromagnet. The DC power supply control unit controls the DC current to be supplied to the electromagnet and controls a DC magnetic field to be applied to the electromagnet. By the control of the DC magnetic field, the center frequency of frequency characteristics of the nonreciprocal circuit element is matched with the frequency of a high-frequency signal, and insertion loss of the nonreciprocal circuit element is reduced.

Claims

1. A nonreciprocal circuit element, comprising: a nonreciprocal unit having ferrite, an electromagnet that applies a DC magnetic field to the ferrite, and a plurality of conductors arranged to intersect one another in an insulated state with respect to the ferrite and have a plurality of shorted end terminals; a reciprocal circuit unit connected between the other end terminal of each conductor and an input/output port; and a DC power source control unit that controls a DC current supplied to the electromagnet, wherein the DC power source control unit controls the DC current supplied to the electromagnet to vary intensity of the DC magnetic field applied to the ferrite, thereby controlling frequency characteristics of the nonreciprocal unit.

2. The nonreciprocal circuit element according to claim 1, wherein the DC power source control unit controls a current value of the DC current based on a quantity of supplied electricity of a high-frequency signal input from a high-frequency power source to the nonreciprocal unit to vary the intensity of the DC magnetic field, and matches a center frequency of the frequency characteristics of the nonreciprocal unit with a frequency of the high-frequency signal of the high-frequency power source.

3. The nonreciprocal circuit element according to claim 2, comprising a power supply detection unit disposed between the high-frequency power source and the reciprocal circuit unit connected to an input port for detecting the quantity of supplied electricity, wherein the quantity of supplied electricity is any one of voltage, current, electric power and reflectance.

4. The nonreciprocal circuit element according to claim 1, wherein the DC power source control unit controls the DC current based on the frequency of the high-frequency signal input from the high-frequency power source to the nonreciprocal unit to vary the intensity of the DC magnetic field, thereby matching the center frequency of the frequency characteristics of the nonreciprocal unit with the high-frequency signal of the high-frequency power source.

5. The nonreciprocal circuit element according to claim 4, comprising a frequency detection unit between the high-frequency power source and the reciprocal circuit unit connected to the input port for detecting a frequency of the high-frequency signal, wherein the DC power source control unit controls the DC current based on the frequency detected by the frequency detection unit.

6. The nonreciprocal circuit element according to claim 4, comprising a frequency control unit for controlling the frequency of the high-frequency power source, wherein the DC power source control unit controls the DC current based on a control frequency of the frequency control unit.

7. The nonreciprocal circuit element according to claim 1, wherein the reciprocal circuit unit comprises a capacitor that, together with an inductance of each conductor, forms a parallel-resonant circuit.

8. The nonreciprocal circuit element according to claim 7, comprising a constant variation unit that varies a capacitance of the capacitor of the reciprocal circuit unit, wherein the constant variation unit changes the capacitance of the capacitor of the reciprocal circuit unit based on the frequency of the high-frequency signal of the high-frequency power source, varies a resonant frequency of the parallel-resonant circuit in response to the change in the capacitance, and in response to the change in the resonant frequency, with respect to the nonreciprocal unit (a) changes the frequency characteristics for matching the center frequency with the frequency of the high-frequency signal of the high-frequency power source; and (b) performs impedance matching to match impedances between the input/output ports.

9. The nonreciprocal circuit element according to claim 1, comprising a plurality of units that includes the nonreciprocal unit, the reciprocal circuit unit and the DC power source control unit, wherein the nonreciprocal unit of each unit has frequency characteristics with a different center frequency and outputs a high-frequency signal in a different frequency band from each unit.

10. The nonreciprocal circuit element according to claim 1, wherein the DC power source control unit changes a direction of the DC current supplied to the electromagnet to switch output ports for outputting the high-frequency signal from the nonreciprocal unit.

11. The nonreciprocal circuit element according to claim 10, wherein the DC power source control unit varies the current value in addition to changing the current direction of the DC current, so as to switch the output ports and change the frequency characteristics.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0062] FIG. 1 illustrates a schematic configuration of a nonreciprocal circuit element according to the present invention;

[0063] FIG. 2 illustrates frequency characteristics of the nonreciprocal circuit element according to the present invention;

[0064] FIG. 3 is a schematic block diagram illustrating Configuration Example 1 of the nonreciprocal circuit element according to the present invention;

[0065] FIG. 4 is a schematic block diagram illustrating Configuration Example 2 of the nonreciprocal circuit element according to the present invention;

[0066] FIG. 5 is a schematic block diagram illustrating Configuration Example 3 of the nonreciprocal circuit element according to the present invention;

[0067] FIG. 6 is a schematic block diagram illustrating Configuration Example 4 of the nonreciprocal circuit element according to the present invention;

[0068] FIG. 7 is a schematic block diagram illustrating Configuration Example 5 of the nonreciprocal circuit element according to the present invention;

[0069] FIG. 8 is a schematic block diagram illustrating Configuration Example 6 of the nonreciprocal circuit element according to the present invention;

[0070] FIG. 9 is a schematic block diagram illustrating Configuration Example 7 of the nonreciprocal circuit element according to the present invention;

[0071] FIG. 10 is a schematic block diagram illustrating frequency characteristics in Configuration Example 7 of the nonreciprocal circuit element according to the present invention;

[0072] FIG. 11 shows a block diagram of a 3-port lumped constant circulator and an equivalent circuit; and

[0073] FIG. 12 illustrates narrow-band characteristics of a conventional nonreciprocal circuit element.

BEST MODE FOR CARRYING OUT THE INVENTION

[0074] In the following, a schematic configuration of a nonreciprocal circuit element of the present invention will be described by referring to FIGS. 1 and 2, and Configuration Examples 1 to 7 of the nonreciprocal circuit element of the invention will be described by referring to FIGS. 3 to 10.

[0075] Configuration Examples 1 to 4 show control on frequency characteristics of a nonreciprocal unit.

[0076] Configuration Example 1 in FIG. 3 shows control on a DC current based on a quantity of supplied electricity of a high-frequency signal input from a high-frequency power source to the nonreciprocal unit, Configuration Example 2 and Configuration Example 3 in FIGS. 4 and 5, respectively, show the control on the DC current based on a frequency of the high-frequency signal input from the high-frequency power source to the nonreciprocal unit, and Configuration Example 4 in FIG. 6 shows a change in a constant of a reciprocal circuit unit based on the frequency of the high-frequency signal input from the high-frequency power source to the nonreciprocal unit.

[0077] Configuration Examples 5 to 7 show how to use the nonreciprocal circuit element of the invention.

[0078] Configuration Example 5 in FIG. 7 shows an example that output ports are switched by switching the direction of the DC current supplied to an electromagnet, Configuration Example 6 in FIG. 8 shows an example that the output ports are switched while changing the frequency of the high-frequency signal to be output, and Configuration Example 7 in FIGS. 9 and 10 shows an example that multiple units having different frequency characteristics are provided.

Schematic Configuration of the Invention

[0079] The schematic configuration of the nonreciprocal circuit element of the invention will be described based on FIGS. 1 and 2.

[0080] FIG. 1 shows an example of providing a 3-port lumped constant circulator serving as a nonreciprocal circuit element 1 in which a high-frequency signal input to a port P1 from a high-frequency power source 8 is output to a port P2 or port P3. In FIG. 1, the nonreciprocal circuit element 1 includes a nonreciprocal unit 6 that has characteristics of transmitting a signal only in a specified direction but not in the opposite direction.

[0081] The nonreciprocal unit 6 includes ferrite 2, an electromagnet 4 that applies a DC magnetic field to the ferrite 2, and a conductor 3. In the 3-port lumped constant circulator, the conductor 3 consists of three conductors 3a, 3b and 3c which are arranged to intersect one another in an insulated state with respect to the ferrite 2, and one end of each conductor is connected on an input/output port side and the other end is connected to ground.

[0082] On both sides of the conductor 3, ferrite 2a and ferrite 2b are disposed. The ferrite 2 can be disposed on one side of the conductor 3, instead of disposing on both sides of the conductor 3.

[0083] The electromagnet 4 generates a DC magnetic field using a DC current supplied from a DC power source 7 and then applies the DC magnetic field to the ferrite 2.

[0084] Between the DC power source 7 and the electromagnet 4, a DC power source control unit 9 is provided. The DC power source control unit 9 controls a DC current Idc supplied from the DC power source 7 to the electromagnet 4 to thereby control the intensity of the DC magnetic field generated around the electromagnet 4.

[0085] The terminals on the opposite side to each shorted terminal of each conductor 3 (3a, 3b, 3c) of the nonreciprocal unit 6 are connected to the ports P1 to P3 through the reciprocal circuit 5a, 5b, 5c, respectively. The high-frequency power source 8 is connected to the port 1, and a high-frequency signal of the high-frequency power source 8 is supplied through the reciprocal circuit unit 5a to the conductor 3a to thereby generate a high-frequency magnetic field.

[0086] The high-frequency magnetic field generated around the conductor 3a and the DC magnetic field generated around the electromagnet 4 are applied to the ferrite 2 (2a, 2b). The high-frequency magnetic field includes a positively circularly polarized magnetic field that rotates clockwise and a negatively circularly polarized magnetic field that rotates counterclockwise in the direction of the DC magnetic field. The intensity of the DC magnetic field is controlled to control a magnetic permeability of a positively circularly polarized wave, thereby setting the traveling direction of an electromagnetic wave at a predetermined angle. Magnetic permeability of the ferrite changes according to a frequency f of the high-frequency signal and magnetic field intensity Hdc of the DC magnetic field, so that the frequency characteristics of the nonreciprocal unit 6 shifts according to the magnetic field intensity Hdc of the DC magnetic field.

[0087] The frequency characteristics shown in FIG. 2(a) schematically indicates transmission characteristics when the high-frequency signal passes the reciprocal circuit unit 5 and the nonreciprocal unit 6. FIG. 2(a) shows a center frequency fc of the frequency characteristics when the magnetic field intensity Hdc of the DC magnetic field is a predetermined value. In this case, a frequency f1 of the high-frequency signal matches the center frequency fc, and thus the transmission characteristics is good. When the frequency f of the high-frequency signal in the above state shifts from the center frequency fc by f and changes from f1 to f2 (=fc+f), impedance mismatchings occur in the reciprocal circuit unit 5 and the nonreciprocal unit 6. These impedance mismatchings cause an insertion loss P, resulting in a decrease in strength of the high-frequency signal output from the nonreciprocal unit 6. The frequency characteristics shown in FIG. 2(b) schematically indicates the transmission characteristics when the frequency f of the high-frequency signal drifts from the center frequency fc.

[0088] When an insertion loss caused by an impedance mismatching in the reciprocal circuit unit 5 is indicated with Pre and an insertion loss caused by an impedance mismatching in the nonreciprocal unit 6 is indicated with Pire, the total insertion loss P of the reciprocal circuit unit 5 and the nonreciprocal unit 6 is expressed as P=Pre+Pire which is a sum of the insertion loss Pre of the reciprocal circuit unit 5 and the insertion loss Pire of the nonreciprocal unit 6.

[0089] In FIG. 2(b), a solid line indicates frequency characteristics before the frequency f of the high-frequency signal drifts, and a broken line indicates frequency characteristics after the frequency f of the high-frequency signal drifts. In here, the center frequency fc represents the center frequency of the frequency characteristics after the frequency f of the high-frequency signal drifts. In the frequency characteristics after the frequency f of the high-frequency signal drifts, the insertion loss P occurs in the center frequency fc due to the impedance mismatching caused by the drift of the frequency f, leading to the decrease in the high-frequency signal output. The insertion loss P is the total of the insertion loss Pre of the reciprocal circuit unit 5 and the insertion loss Pire of the nonreciprocal unit 6. Note that, it is assumed that there is no internal loss in the nonreciprocal circuit element 1.

[0090] The insertion loss Pire of the nonreciprocal unit 6 can be compensated by the impedance matching performed by matching the center frequency fc of the frequency characteristics of the nonreciprocal unit 6 with the frequency f2 of the high-frequency signal. In addition to that, the insertion loss Pre of the reciprocal circuit unit 5 can be compensated by the impedance matching performed by varying a constant of the capacitance of the reciprocal circuit unit 5.

[0091] The frequency characteristics in FIG. 2(c) show a state that the frequency characteristics of the nonreciprocal unit 6 and the capacitance of the reciprocal circuit unit 5 are adjusted to thereby prevent the insertion loss P due to the impedance mismatching. The prevention of the insertion loss P is achieved in such a way that during the shift of the frequency characteristics, the impedance matching of the nonreciprocal unit 6 is conducted by matching the center frequency fc of the frequency characteristics of the nonreciprocal unit 6 with the frequency f2 of the high-frequency signal, varying the constant of the capacitance of the reciprocal circuit unit 5, and thereby performing the impedance matching of the reciprocal circuit unit 5.

[0092] The DC power source control unit 9 controls the DC current supplied to the electromagnet 4 so as to vary the magnetic field intensity Hdc of the DC magnetic field applied to the ferrite 2, thereby controlling the frequency characteristics of the nonreciprocal unit 6.

[0093] When the frequency of the high-frequency signal of the high-frequency power source 8 is varied within a variable frequency range, the magnetic field intensity Hdc of the DC magnetic field is controlled to control the frequency characteristics of the nonreciprocal unit 6, so that the intensity of the high-frequency signal output from the nonreciprocal circuit element 1 can be made uniform.

[0094] In a case where the frequency of the high-frequency power source 8 fluctuates around a predetermined frequency, the magnetic field intensity Hdc of the DC magnetic field is controlled to control the frequency characteristics of the nonreciprocal unit 6, thereby preventing the intensity fluctuation of the high-frequency signal output from the nonreciprocal circuit element 1.

[0095] Now, Configuration Examples 1 to 7 of the present invention will be described. It is assumed that there is no internal loss in the nonreciprocal circuit element 1 in Configuration Examples 1 to 7.

Configuration Example 1

[0096] Configuration Example 1 of the nonreciprocal circuit element of the invention will be described by referring to FIG. 3.

[0097] Configuration Example 1 is an example that the control of the DC current is executed by the DC power source control unit 9 based on the quantity of supplied electricity which is supplied from the high-frequency power source 8 to the nonreciprocal unit 6. Configuration Example 1 includes a power supply detection unit 10 arranged between the high-frequency power source 8 and a reciprocal circuit unit 5a in the schematic configuration shown in FIG. 1. The power supply detection unit 10 is configured to detect the quantity of supplied electricity supplied from the high-frequency power source 8 to the nonreciprocal unit 6.

[0098] The insertion losses in the reciprocal circuit unit 5 and the nonreciprocal unit 6 due to the impedance mismatching causes the decrease in the voltage, the current and the power, and thus the reflectance increases. The power supply detection unit 10 detects the fluctuation of the voltage, the current, the power or the reflectance caused by the insertion losses in the reciprocal circuit unit 5 and the nonreciprocal unit 6 due to the impedance mismatching as the quantity of supplied electricity, and feeds back the detection result to the DC power source control unit 9. Configuration Example 1 detects the quantity of supplied electricity to detect the amount of change due to a reverse power loss or a forward power loss, thereby feeding back the detected amount of change to the DC power source control unit 9.

[0099] The DC power source control unit 9 controls the DC current supplied from the DC power source 7 to the electromagnet 4 based on the quantity of supplied electricity fed back, and controls the DC magnetic field generated by the electromagnet 4 to thereby control the frequency characteristics of the nonreciprocal unit 6. The DC power source control unit 9 compares the detected quantity of supplied electricity with a reference value, and conducts the control such that a difference acquired by the comparison is small. As the reference value, for example, a quantity of supplied electricity can be used when the reverse power loss or forward power loss is a predetermined value.

[0100] In Configuration Example 1, the frequency control unit 11 may be used to vary a frequency fRF of the high-frequency signal output from the high-frequency power source 8. The frequency control unit 11 controls the frequency fRF of the high-frequency signal output from the high-frequency power source 8 within the variable frequency range.

Configuration Example 2

[0101] Configuration Example 2 of the nonreciprocal circuit element of the present invention will be described by referring to FIG. 4.

[0102] Configuration Example 2 is an example that the control of the DC current is executed by the DC power source control unit 9 based on the frequency fRF of the high-frequency signal input from the high-frequency power source 8 to the nonreciprocal unit 6.

[0103] Configuration Example 2 includes a frequency detection unit 12 that detects the frequency of the high-frequency signal. The frequency detection unit 12 transmits the detected frequency fRF of the high-frequency signal to the DC power source control unit 9. The DC power source control unit 9 controls the DC current supplied from the DC power source 7 to the electromagnet 4 based on the transmitted frequency fRF of the high-frequency signal, so as to control the DC magnetic field generated by the electromagnet 4.

[0104] The DC power source control unit 9 predefines the relationship between the center frequency fc and the DC current Idc within the variable frequency range. The DC power source control unit 9 uses the detected frequency fRF of the high-frequency signal as the center frequency fc of the frequency characteristics of the nonreciprocal unit 6, determines the DC current Idc from the center frequency fc corresponding to the detected frequency fRF of the high-frequency signal based on the predefined relationship between the center frequency fc and the DC current Idc, and supplies the DC current Idc to the electromagnet 4 to control the DC magnetic field, thereby controlling the frequency characteristics of the nonreciprocal unit 6.

[0105] In Configuration Example 2, as with Configuration Example 1, the frequency control unit 11 may be configured to vary the frequency fRF of the high-frequency signal output from the high-frequency power source 8. The frequency control unit 11 controls the frequency fRF of the high-frequency signal output from the high-frequency power source 8 within the variable frequency range.

Configuration Example 3

[0106] Configuration Example 3 of the nonreciprocal circuit element of the present invention will be described based on FIG. 5.

[0107] Configuration Example 3 is an example that the control of the DC current is executed by the DC power source control unit 9 based on the frequency fRF of the high-frequency signal input from the high-frequency power source 8 to the nonreciprocal unit 6, as with Configuration Example 2. Configuration Example 2 acquires the frequency fRF of the high-frequency signal from the detection signal detected by the frequency detection unit 12, whereas Configuration Example 3 acquires the frequency fRF of the high-frequency signal from the frequency control unit 11 which controls the frequency fRF of the high-frequency signal output from the high-frequency power source 8.

[0108] Configuration Example 3 includes the frequency control unit 11, the frequency control unit 11 controlling the frequency fRF of the high-frequency signal output from the high-frequency power source 8. The frequency control unit 11 transmits the frequency fRF of the high-frequency signal to the DC power source control unit 9. The DC power source control unit 9 controls the DC current supplied from the DC power source 7 to the electromagnet 4 based on the transmitted frequency fRF of the high-frequency signal to control the DC magnetic field generated by the electromagnet 4, thereby controlling the frequency characteristics of the nonreciprocal unit 6.

[0109] The DC power source control unit 9 predefines, as with Configuration Example 2, the relationship between the center frequency fc and the DC current Idc within the variable frequency range. The DC power source control unit 9 uses the detected frequency fRF of the high-frequency signal as the center frequency fc of the frequency characteristics of the nonreciprocal unit 6, determines the DC current Idc from the center frequency fc corresponding to the detected frequency fRF of the high-frequency signal based on the predefined relationship between the center frequency fc and the DC current Idc, and supplies the determined DC current Idc to the electromagnet 4 to thereby generate the DC magnetic field.

Configuration Example 4

[0110] Configuration Example 4 of the nonreciprocal circuit element of the present invention will be described based on FIG. 6.

[0111] Configuration Example 4 includes, as with Configuration Example 1, a control system that feeds back the quantity of supplied electricity detected by the power supply detection unit 10 to the DC power source control unit 9 to control a DC current, and controls the DC magnetic field generated by the electromagnet 4 based on the DC current Idc obtained by controlling the DC current, so as to control the frequency characteristics of the nonreciprocal unit 6.

[0112] In addition to the control system for controlling the frequency characteristics of the nonreciprocal unit 6 by controlling the DC current by the DC power source control unit 9, Configuration Example 4 includes another control system that controls the frequency characteristics of the nonreciprocal unit 6 by varying a constant of the capacitance of the capacitor included in the reciprocal circuit unit 5a.

[0113] Configuration Example 4 includes a constant variation unit 13, the constant variation unit 13 varying the constant Cp of the capacitance of the capacitor included in the reciprocal circuit unit 5a. The constant variation unit 13 acquires the frequency fRF of the high-frequency signal from the frequency control unit 11, determines the constant Cp of the capacitance based on the relationship expressed by Formula (2), and varies the constant of the capacitance of the reciprocal circuit unit 5a based on the determined constant Cp. Consequently, the reciprocal circuit unit 5a can match the center frequency fc of the frequency characteristics of the nonreciprocal unit 6 with the frequency fRF of the high-frequency signal of the high-frequency power source 8.

Configuration Example 5

[0114] Configuration Example 5 of the nonreciprocal circuit element of the present invention will be described based on FIG. 7.

[0115] Configuration Example 5 is an example that switches the output ports of the nonreciprocal unit 6. Although the switching of the output ports can be performed in any of Configuration Examples 1 to 4, the following description takes Configuration Example 1 as an example.

[0116] The output ports of the nonreciprocal unit 6 are switched by changing the direction of the DC magnetic field generated by changing the direction of the DC current Idc supplied to the electromagnet 4. The direction of the DC current Idc is changed by controlling the DC power source control unit 9 by a control unit 14. FIG. 7(a) shows that the port P2 is switched to the output port, and FIG. 7(b) shows that the port P3 is switched to the output port.

Configuration Example 6

[0117] Configuration Example 6 of the nonreciprocal circuit element of the present invention will be described based on FIG. 8.

[0118] Configuration Example 6 is an example that switches the output ports of the nonreciprocal unit 6 as with Configuration Example 5, and changes the frequency of the high-frequency signal output from the output port at the same time as the switching.

[0119] The switching of the output ports of the nonreciprocal unit 6 and the change of the frequency are performed by changing the direction of the DC current Idc supplied to the electromagnet 4 concurrently with the change of the frequency of the high-frequency output from the high-frequency power source 8.

[0120] Configuration Example 6 includes the control unit 14, and the control unit 14 performs current process control for changing the direction of the DC current Idc and frequency control for changing the frequency of the high-frequency signal output from the high-frequency power source 8.

[0121] The control unit 14 controls the DC power source control unit 9 to change the direction of the DC current Idc, thereby reversing the direction of the DC magnetic field generated due to the change in the current direction. In addition to that, the control unit 14 controls the high-frequency power source 8 to change the frequency of the high-frequency signal.

[0122] FIG. 8(a) shows that the port P2 is switched to the output port to thereby output the high-frequency signal at the frequency f1 from the port P2, and FIG. 8(b) shows that the port P3 is switched to the output port to thereby output the high-frequency signal at the frequency f2 from the port P3. The frequencies f1 and f2 of the high-frequency signals output from the ports P2 and P3, respectively, can be set freely within the variable frequency range of the high-frequency power source.

Configuration Example 7

[0123] Configuration Example 7 of the nonreciprocal circuit element of the present invention will be described based on FIGS. 9 and 10.

[0124] Configuration Example 7 includes a plurality of units having different frequency characteristics, and outputs the high-frequency signal from a nonreciprocal circuit element of the unit that has frequency characteristics suitable for the frequency of a high-frequency signal input from the high-frequency power source.

[0125] There is a limit in the variable frequency range of the variable frequency characteristics defined by changing the DC magnetic field, and when the variable frequency range of the high-frequency power source is wide, it is difficult to make an adjustment to the entire variable frequency range by one nonreciprocal circuit element. Configuration Example 7 uses the plurality of units having the frequency characteristics, of which frequency ranges to be separated are different, to separate high-frequency signals at frequencies in different frequency ranges for each unit, so as to be able to separate signals for the entire variable frequency range of the high-frequency power source.

[0126] Each unit 20 includes the nonreciprocal unit 6, the reciprocal circuit unit 5 and the DC power source control unit 9. Configuration Example 7 shows a configuration having three units 20A, 20B and 20C as a plurality of units 20.

[0127] The reciprocal circuit units 5 included in the unit 20A, 20B and 20C set constants corresponding to respective frequency ranges. The nonreciprocal unit 6 of each of the units 20A, 20B, 20C shifts the frequency characteristics of the center frequency defined by the reciprocal circuit unit 5 by controlling the DC magnetic field of the electromagnet 4, so as to broaden the frequency range to be separated.

[0128] By shifting the frequency range to be separated by each of the units 20A, 20B, 20C, the total frequency range of the nonreciprocal circuit element becomes a combination of the frequency ranges of the units, and thereby the frequency range can be broadened.

[0129] FIG. 10 schematically shows that the frequency characteristics of the nonreciprocal circuit element is implemented by the plurality of units according to Configuration Example 7. FIG. 10 is an example in which an entire frequency bandwidth BW of the nonreciprocal circuit element is configured by combining three frequency widths, namely a frequency width BW1, a frequency width BW2 and a frequency width BW3. In this configuration example, the frequency characteristics of the units 20A, 20B and 20C are set by setting frequencies fc1, fc2 and fc3 as center frequencies, and the frequency widths BW1, BW2 and BW3 are set.

[0130] FIG. 10(a) shows the frequency width BW1 in the unit 20A that is acquired by varying the DC magnetic field of the electromagnet and thus shifting the frequency characteristics which has the frequency fc1 as the center frequency. The frequency width BW1 is set by shifting the frequency characteristics.

[0131] FIG. 10(b) shows the frequency width BW2 of the frequency characteristics that defines the frequency fc2 as a center frequency in the unit 20B. FIG. 10(c) shows the frequency width BW3 of the frequency characteristics that defines the frequency fc3 as a center frequency in the unit 20C.

[0132] The frequency width for shifting the frequency characteristics can be set by a variation width for the frequency characteristics which can be varied due to the change in the DC magnetic field of the electromagnet, based on the relationship between the variation width for the DC magnetic field of the electromagnet and the variation width for the frequency characteristics.

[0133] FIG. 10(d) shows that the total frequency bandwidth BW of the nonreciprocal circuit element is formed by combining the frequency width BW1, BW2 and BW3 of the unit 20A, 20B and 20C.

[0134] According to Configuration Example 7, even when the frequency bandwidth of the frequency characteristics adjustable by each unit is narrow, the combination of multiple units having the frequency characteristics of the different center frequencies can broaden the total frequency bandwidth BW of the nonreciprocal circuit element, thereby achieving wider bandwidth.

[0135] In each configuration example, a reverse direction loss (isolation) which is a power loss portion due to a return of reflection generated at the output port of the circulator can be detected by adding power supply detection units to the port P2 and the port P3, in addition to the power supply detection unit provided to the port P1.

[0136] In a case where the circulator is used for transmitting the high-frequency current from the port P1 to a load of the port P2, from the load of the port P2 to a load of the port P3, and from the load of the port P3 to the port P1, the power supply detection unit provided to the port P2 detects a quantity of electricity reflected from a load connected to an output part of the circulator, and the power supply detection unit provided to the port P3 detects a quantity of electricity reflected from the load and input to the circulator.

[0137] The reverse direction loss can be obtained by an adding operation of the quantity of electricity detected by these power supply detection units. The detected quantity of electricity is fed back to the DC power source control unit so as to be able to apply control to reduce the reverse direction loss.

[0138] The above-described embodiments and variations are some examples of the nonreciprocal circuit element of the invention, and the invention is not limited to these embodiments. The present invention can be varied based on the gist of the invention, and such variations will not be excluded from the scope of the invention.

INDUSTRIAL APPLICABILITY

[0139] The nonreciprocal circuit element of the present invention can be applied to, for example, a power source (RF generator) for outputting a high frequency that is used for semiconductor manufacturing equipment, liquid crystal panel manufacturing equipment and others.

REFERENCE SIGNS LIST

[0140] 1 Nonreciprocal Circuit Element [0141] 2, 2a, 2b Ferrite [0142] 3, 3a, 3b Conductor [0143] 4 Electromagnet [0144] 5,5a, 5b, 5c Reciprocal Circuit Unit [0145] 6 Nonreciprocal Unit [0146] 7 DC Power Source [0147] 8 High-Frequency Power Source [0148] 9 DC Power Source Control Unit [0149] 10 Power Supply Detection Unit [0150] 11 Frequency Control Unit [0151] 12 Frequency Detection Unit [0152] 13 Constant Variation Unit [0153] 14 Control Unit [0154] 20, 20A, 20B, 20C Unit [0155] 100 Ideal Circulator [0156] 101 Lumped Constant Circulator [0157] 102 Ferrite [0158] 103, 103a, 103b, 103c Conductor [0159] 104, 104a, 104b Permanent Magnet [0160] 105, 105a, 105b, 105c Capacitor [0161] 106, 106a, 106b, 106c Parallel-Resonant Circuit [0162] BW Frequency Bandwidth [0163] BW1, BW1, BW2 Frequency Width [0164] Cp Capacitance Constant [0165] Hdc Magnetic Field Intensity of DC Magnetic Field [0166] Idc DC Current [0167] Lp Inductor [0168] P1, P2, P3 Port [0169] P Insertion Loss [0170] Pre Insertion Loss [0171] Pire Insertion Loss [0172] Ps Insertion Loss [0173] fc, fc1, fc2, fc3 Center Frequency [0174] Nonreciprocal Index