Irreversible circuit element

Abstract

The irreversible circuit element of this invention is a circuit element with an irreversible transmission direction characteristic that transmits signals only in a specific direction and not in the opposite direction. The irreversible section is composed of ferrite, an electromagnet applying a DC magnetic field to the ferrite, and multiple conductors with short-circuited terminals arranged in an insulated state relative to the ferrite. The irreversible circuit element includes a reversible circuit section connected between the input / output port and the other end of the short-circuited conductor, ensuring no deviation in the transmission direction, and a DC power supply control section that controls the DC current supplied to the electromagnet. The DC power supply control section controls both the DC current supplied to the electromagnet and the DC magnetic field applied to the electromagnet. By controlling the DC magnetic field, the center frequency of the irreversible circuit element's frequency characteristics is matched to the frequency of the high-frequency signal, reducing the insertion loss of the irreversible circuit element.

Description

Technical Field

[0001] This invention relates to irreversible circuit elements of ferrite devices such as isolators and circulators, and more particularly to irreversible circuit elements composed of lumped constant elements. Prior Technology

[0002] Utilizing the Faraday effect of ferrite as an irreversible circuit element, it is known to absorb reflected waves from the load, stabilizing the operation of oscillators and amplifiers, and to act as a circulator for unidirectional transmission of high-frequency signals to two-terminal components. A circulator is a basic ferrite device based on isolating one end by terminating it with a resistor.

[0003] As a lumped constant type circulator with three ports, it is known to consist of a permanent magnet, a ferrite in which a DC magnetic field is applied by the permanent magnet, three center conductors arranged in a cross manner in an electrically insulating state on the ferrite, and a matching capacitor electrically connected to the center conductors. The operating frequency is adjusted according to the capacitance value of the capacitor connected in parallel to the three center conductors (Patent Document 1, Patent Document 2).

[0004] Figure 11(a) shows the construction diagram of a 3-port lumped constant type circulator, and Figure 11(b) shows the equivalent circuit. In Figure 11(a), the lumped constant type circulator 101 includes ferrite 102 (102a, 102b), a permanent magnet 104 that applies a DC magnetic field to the ferrite 102, conductors 103 (103a~103c) disposed in an electrically insulated state in the ferrite 102, and capacitors 105 (105a~105c) connected in parallel to the conductors 103. The conductors 103 are three conductors of the first conductor 103a, the second conductor 103b, and the third conductor 103c, which are crossed at 120° intervals and disposed in an insulated state from each other. One end of each conductor 103a~103c is connected to the first port P1, the second port P2, and the third port P3, respectively, and the other end is short-circuited by the terminal. Furthermore, capacitors 105a to 105c are connected in parallel to each conductor 103a to 103c, and a parallel resonant circuit is formed by the inductive component of the conductor and the capacitive component of the capacitor.

[0005] Figure 11(b) shows the equivalent circuit of a parallel resonant lumped constant circulator, which is composed of an ideal circulator 100 and parallel resonant circuits 106 (106a~106c). Each parallel resonant circuit 106 (106a~106c) is composed of lumped constant elements consisting of inductors Lp (Lp1, Lp2, Lp3) and constants Cp (Cp1, Cp2, Cp3) ​​of the capacitance component. The frequency characteristics of the lumped constant circulator are determined by the lumped constant elements.

[0006] In a lumped constant type circulator with 3 ports, the high-frequency signal input from port 1 P1 is output from port 3 P3, the high-frequency signal input from port 3 P3 is output from port 2 P2, and the high-frequency signal input from port 2 P2 is output from port 1 P1. [Previous Technical Documents] [Patent Literature]

[0007] [Patent Document 1] International Publication No. 2011 / 052803 [Patent Document 2] International Publication No. 2016 / 158044 Summary of the Invention

[0008] [The problem that the invention aims to solve]

[0009] As items for evaluating the characteristics of irreversible circuit elements, the insertion loss of forward loss and the isolation of reverse loss are well known. Furthermore, the insertion loss of forward loss is evaluated as a pass-through characteristic, while the reverse loss characteristic of a circulator is evaluated by the isolation when a terminating resistor is connected at one end.

[0010] Previous irreversible circuit elements operated in a narrow frequency band, thus failing to meet the variable frequency range of high-frequency power supplies.

[0011] The characteristics of irreversible circuit elements are determined by the capacitance value of the matching capacitor in a parallel resonant circuit. The frequency band in which effective frequency characteristics can be obtained depends on the circuit characteristics of the parallel resonant circuit. The operating frequency range of irreversible circuit elements is a narrow band, and it is impossible to obtain a wide operating frequency range. Therefore, it is difficult to make the variable frequency range of a high-frequency power supply operate effectively in a single parallel resonant circuit.

[0012] Figure 12 is a diagram used to illustrate the narrow frequency band characteristics of the aforementioned irreversible circuit element, representing the frequency characteristics of the circulator as a function of frequency transmission. Furthermore, the frequency characteristic diagram in Figure 12 is schematic and does not represent the actual frequency characteristics.

[0013] Figure 12(a) illustrates the state when the center frequency fc of the frequency characteristic representing the circulator's throughput characteristics matches the frequency f of the high-frequency power supply. Typically, when the circulator's frequency characteristic is set so that the center frequency fc matches the frequency f of the high-frequency power supply, the throughput characteristics decrease if the frequency f deviates from fc. As shown in Figure 12(b), the throughput characteristics of the high-frequency power supply with a frequency fc ± Δf deviation from the center frequency fc, compared to when the frequency f is the same as the center frequency fc, reduce the insertion loss ΔPs caused by impedance mismatch of the irreversible circuit components, thus exhibiting a narrow bandwidth characteristic. Due to the narrow bandwidth of this frequency characteristic, good throughput characteristics of the irreversible circuit components cannot be expected over a wide frequency range, making it difficult to accommodate the variable frequency range of the high-frequency power supply.

[0014] Therefore, the objective of this invention is to widen the frequency characteristics of irreversible circuit elements. Furthermore, the objective is to achieve widened frequency characteristics of irreversible circuit elements by reducing their insertion loss. [Methods used to solve problems]

[0015] The irreversible circuit element of the present invention is a circuit element having an irreversible part with the irreversible characteristic of transmitting signals only in a specific direction and not in the opposite direction. The irreversible part is composed of a ferrite, an electromagnet that applies a DC magnetic field to the ferrite, and a plurality of conductors that are short-circuited to the ferrite in an insulated state.

[0016] The irreversible circuit element of the present invention comprises a reversible circuit section connected between the other end of the conductor of the input / output port and the short-circuit terminal, with no deviation in the transmission direction, and a DC power supply control section for controlling the DC current supplied to the electromagnet.

[0017] (A) Irreversible part The conductive system connected to the input port of the irreversible part generates a high-frequency magnetic field by means of a high-frequency signal supplied from a high-frequency power supply. For ferrite, a high-frequency magnetic field generated by a conductor and a DC magnetic field generated by an electromagnet are applied.

[0018] The high-frequency magnetic field becomes a right-handed circularly polarized wave magnetic field that rotates to the right in the direction of the DC magnetic field and a left-handed circularly polarized wave magnetic field that rotates to the left.

[0019] Electromagnetic waves propagating through a ferrite magnetized by a DC magnetic field are caused by the difference in the magnitude of the permeability μ between the rotation directions of the two circularly polarized waves and the rotation direction of the spin magnetic moment of the ferrite, which are either in the same or opposite directions. This causes the propagation path of the polarization plane of the electromagnetic wave to bend, resulting in a change in the direction of propagation of the electromagnetic wave.

[0020] The composite permeability μ of ferrite differs between the permeability μ+ for a right-hand circularly polarized wave magnetic field and the permeability μ- for a left-hand circularly polarized wave magnetic field. By applying a DC magnetic field, the permeability μ+ for right-hand circularly polarized waves decreases, while the permeability μ- for left-hand circularly polarized waves increases.

[0021] (B) DC Power Supply Control Unit The DC power supply control unit of the irreversible circuit element of the present invention controls the DC current supplied to the electromagnet and makes the strength of the DC magnetic field applied to the ferrite variable. By making the strength of the DC magnetic field variable, the difference between the permeability μ+ of the right-hand circularly polarized wave and the permeability μ- of the left-hand circularly polarized wave changes, and the transmission characteristics between the terminals in the clockwise and counterclockwise directions are made variable.

[0022] The characteristics of the magnetic field strength H for permeability μ (permeability μ± of circularly polarized waves) depend on the operating frequency. Therefore, by using an electromagnet to change the magnetic field strength H of the DC magnetic field applied to the ferrite, it is possible to control the shift of the center frequency of the irreversible part's frequency characteristics to the high-frequency side or the low-frequency side. In this way, by matching the center frequency of the irreversible part with the high frequency of the high-frequency signal input to the irreversible circuit element, the throughput characteristics of the irreversible circuit element can be improved.

[0023] By controlling the DC current supplied to the electromagnet by varying the frequency of the high-frequency signal accompanying the high-frequency power supply, the strength of the DC magnetic field generated by the electromagnet is made variable. The center frequency of the irreversible part is matched with the frequency of the high-frequency signal. In this way, the frequency characteristics of the irreversible circuit element that responds to the frequency variation of the high-frequency signal from the high-frequency power supply are widened, and the fluctuation of the signal strength of the high-frequency signal output within the variable frequency range of the high-frequency power supply is suppressed.

[0024] Therefore, in addition to the aforementioned effect of widening the frequency characteristics, the irreversible circuit element of the present invention can also suppress the thermomagnetic properties caused by temperature changes.

[0025] When a permanent magnet is used to apply a DC magnetic field to ferrite, the frequency characteristics of the irreversible circuit element change due to temperature variations caused by the thermomagnetic properties of the permanent magnet. In contrast, the irreversible circuit element of the present invention controls the DC current supplied to the electromagnet by a DC power supply control unit, which allows the DC magnetic field generated by the electromagnet to be variable, thus suppressing the thermomagnetic properties caused by temperature variations.

[0026] (C) Reversible circuit section The reversible circuit section is composed of the inductive component of the irreversible conductor and a parallel resonant circuit of a capacitor connected in parallel. In addition to (a) functioning as a resonator with defined frequency characteristics, the parallel resonant circuit also functions as (b) an impedance matching device that matches the input impedance to the characteristic impedance of the input / output transmission line.

[0027] The constants of the inductance component Lp of the parallel resonant circuit and the capacitance component Cp of the capacitor are expressed by the following mathematical formulas (1) to (3), and are generally determined by the irreversibility index η and the frequency ω.

[0028] Here, the composite permeability μ of the ferrite is represented by μ = μ′ - jμ″. The real part μ′ of the composite permeability μ represents the response to magnetization, and the imaginary part μ″ represents the magnetic loss. The absolute value |Δμ| of the permeability difference Δμ (= μ -′ - μ +′) between the real part μ +′ of the right-hand circularly polarized wave permeability μ + and the real part μ -′ of the left-hand circularly polarized wave permeability μ - represents the irreversibility.

[0029] (Ca: Function of the resonator) The function of the resonator is to make the resonant frequency of the parallel resonant circuit variable, and the center frequency of the reversible circuit section variable. Mathematical formulas (1) and (2) reveal that the constants of the inductor Lp and the capacitor Cp are included as parameters containing the frequency ω. This means that the resonant frequency of the parallel resonant circuit becomes variable by changing the values ​​of the constants of the inductor Lp and the capacitor Cp that constitute the inductive component of the parallel resonant circuit.

[0030] By changing the values ​​of the constant Cp of the inductor Lp and / or capacitor components, the center frequency of the reversible circuit section is matched with the frequency of the high-frequency signal from the high-frequency power supply input to the irreversible circuit element. By matching the center frequency of the reversible circuit section with the frequency of the high-frequency signal from the high-frequency power supply input to the irreversible circuit element, the throughput characteristics of the irreversible circuit element are improved.

[0031] Furthermore, the irreversible circuit element of the present invention uses the variable center frequency caused by the irreversible part as the main component, and the variable center frequency of the reversible circuit part caused by the function of the resonator as an additional component. Therefore, the variable center frequency is a control mode that controls only the magnetic field strength of the DC magnetic field of the electromagnet caused by the irreversible part, and can also be a control mode caused by the function of the resonator that performs the reversible circuit part, in addition to the control caused by the irreversible part.

[0032] (Cb: Function of impedance matching) The parallel resonant circuit of the reversible circuit section also functions as an impedance matching device to match the impedance between each conductor of the irreversible section and the input / output port side.

[0033] The inductor Lp of the parallel resonant circuit is determined by the inductance of the irreversible conductor. Therefore, by setting the constant Cp of the capacitance of the capacitor in the parallel resonant circuit according to the frequency of the high-frequency signal of the high-frequency power supply, the impedance is matched.

[0034] When matching the center frequency of the reversible circuit section with the frequency of the high-frequency signal from the high-frequency power supply, if the center frequency is changed by altering the DC magnetic field of the electromagnet in the irreversible section, impedance mismatch will occur in the transmission line system including the reversible circuit section, resulting in insertion loss. This impedance mismatch can be mitigated by using the impedance matching device provided by the reversible circuit section to achieve impedance matching and reduce the insertion loss caused by the impedance mismatch.

[0035] (Cc: Constant Change Section) The irreversible circuit element of the present invention includes a constant changing section that sets the capacitance component of the capacitor in the reversible circuit section to a variable value.

[0036] The constant-changing section modifies the capacitance of the capacitors in the reversible circuit based on the frequency of the high-frequency signal from the high-frequency power supply. By changing the capacitance, the resonant frequency of the parallel resonant circuit is altered.

[0037] The constant-changing part works by changing the frequency of the resonant frequency, thus affecting the irreversible part: (c1) A function to change the frequency characteristics by matching the center frequency with the frequency of the high-frequency signal from the high-frequency power supply; and (c2) Impedance matching function for matching the impedance of input and output ports.

[0038] The function of changing the main variable frequency characteristics caused by the irreversible part is to make the center frequency variable by controlling the DC current supplied to the electromagnet.

[0039] In contrast, the function of changing frequency characteristics (c1) serves as an additional function. When the frequency of the high-frequency power supply varies around the center frequency of the irreversible circuit element, or when the frequency of the high-frequency power supply varies within a variable frequency range, the DC power supply control unit controls the DC magnetic field generated by the electromagnet of the irreversible part, and uses the constant changing unit to set the capacitance component of the capacitor in the reversible circuit part to rationalize the frequency characteristics and widen the frequency characteristics of the irreversible circuit element.

[0040] The impedance matching function (c2) is to suppress the reduction in the transmission characteristics of high-frequency signals caused by changes in frequency characteristics.

[0041] (D) Suppression of DC current The control system for the DC current supplied to the electromagnet by the DC power supply control unit has a control mode (Da) based on the power supply quantity of the high-frequency signal input to the irreversible part, or a control mode (Db) based on the frequency of the high-frequency signal supplied to the irreversible part.

[0042] (Da: Control based on power supply) The DC power supply control unit controls the DC current value based on the power supplied from the high-frequency power supply to the irreversible part, thus allowing the strength of the DC magnetic field to be variable. This matches the center frequency of the irreversible part's frequency characteristics with the frequency of the high-frequency power supply's high-frequency signal.

[0043] A power supply detection unit is installed between the high-frequency power supply and the reversible circuit section connected to the input port to detect the power supply quantity. The power supply quantity can be any of voltage, current, power, or reflectivity. If there is a deviation between the center frequency of the frequency characteristics of the irreversible section and the frequency of the high-frequency signal of the high-frequency power supply, insertion loss will occur, resulting in a decrease in the power supply quantity such as voltage, current, power, and reflectivity.

[0044] The power supply detection unit detects the power supply and feeds back the detected power supply value to the DC power control unit. The DC power control unit compares the power supply value fed back from the power supply detection unit with a set value, and controls the DC current supplied to the electromagnet in such a way that the power supply value becomes the set value. The set value can be set as a set voltage value, a set current value, a set power value, or a set reflectivity. Each set value is set based on the values ​​when there is no insertion loss.

[0045] (Db: Control based on frequency) The DC power supply control unit controls the DC current value based on the frequency of the high-frequency signal input from the high-frequency power supply to the irreversible part, thus allowing the strength of the DC magnetic field to be variable. This matches the center frequency of the irreversible part's frequency characteristics with the frequency of the high-frequency signal from the high-frequency power supply.

[0046] The frequency characteristics of the irreversible part vary depending on the frequency of the high-frequency signal input to the high-frequency power supply. Accordingly, by controlling the DC current value according to the frequency of the high-frequency signal, the strength of the DC magnetic field can be varied, so that even when the frequency of the high-frequency signal changes, the center frequency of the frequency characteristics of the irreversible part can be matched with the frequency of the high-frequency signal from the high-frequency power supply. The control based on the frequency of the high-frequency signal of the high-frequency power supply can be set as a control mode (d1) based on the detection frequency obtained by detecting the frequency of the high-frequency signal from the high-frequency power supply input to the irreversible part, or a control mode (d2) based on the control frequency of the high-frequency power supply.

[0047] (d1) Control pattern based on detection frequency This control system detects the frequency of the high-frequency signal input from the high-frequency power supply to the irreversible section, and controls the DC current supplied to the electromagnet based on the detected frequency. This control system includes a frequency detection unit between the high-frequency power supply and the reversible circuit connected to the input port to detect the frequency of the high-frequency signal. The DC power supply control unit controls the DC current based on the frequency detected by the frequency detection unit.

[0048] (d2) Control pattern based on control frequency This control system controls the DC current supplied to the electromagnet based on the control frequency of the high-frequency power supply. This control system includes a frequency control unit that controls the frequency of the high-frequency power supply. The DC power supply control unit controls the DC current based on the control frequency of the frequency control unit.

[0049] (E) Construction of complex units The irreversible circuit element of the present invention is constructed by setting the irreversible part, the reversible circuit part and the DC power supply control part as one unit, and having a plurality of units.

[0050] Each unit's irreversible system is capable of setting the center frequency to different frequency characteristics, and outputting high-frequency signals of different frequency bands from each unit.

[0051] The center frequency of each unit's frequency characteristic is set staggered within the frequency band of the high-frequency power supply. Following the high-frequency changes of the high-frequency power supply, each unit outputs a high-frequency signal set in its respective frequency band. By sequentially staggering the frequency bands of multiple units and combining them, the frequency characteristics of irreversible circuit components can be widened.

[0052] (F: Switching the output port) The irreversible circuit element of the present invention outputs a high-frequency signal from the selected output port by switching between multiple ports.

[0053] The irreversible circuit element of the present invention can switch the output port through two states (f1) and (f2).

[0054] (f1) First pattern of output port switching During the switching of the output port in the first mode, the DC power supply control unit switches the direction of the DC current supplied to the electromagnet. By switching the direction of the supplied DC current, the direction of the DC magnetic field generated by the electromagnet is switched. By switching the direction of the DC magnetic field, the direction of the electromagnetic wave propagation of the ferrite in the irreversible part changes, thereby switching the output port for outputting high-frequency signals.

[0055] (f2) Second pattern of output port switching During the switching of the output port in the second mode, the DC power supply control unit switches the direction of the DC current and changes the current value simultaneously. This allows for simultaneous switching of the output port and modification of the frequency characteristics.

[0056] For example, the output mode of outputting a high-frequency signal with port P2 as the first output port is set as mode 1, and the output mode of outputting a high-frequency signal with port P3 as the second output port is set as mode 2. When switching the output port between the two output modes, mode 1 and mode 2, if mode 1 is switched, a high-frequency signal with frequency f1 is output from the first output port, and if mode 2 is switched, a high-frequency signal with frequency f2 is output from the second output port. In this case, the frequency of the high-frequency signal output from the output port is replaced in the opposite way. If the first mode is switched, a high-frequency signal with frequency f2 is output from the first output port. If the second mode is switched, a high-frequency signal with frequency f1 is output from the second output port. [The effects of the invention]

[0057] As explained above, according to the present invention, the frequency characteristics of irreversible circuit elements can be widened. Furthermore, the frequency characteristics of irreversible circuit elements can be widened by reducing the insertion loss of the irreversible circuit elements. Simple Explanation of the Diagram

[0058] [Figure 1] is a diagram illustrating the schematic structure of the irreversible circuit element of the present invention. [Figure 2] A diagram illustrating the frequency characteristics of the irreversible circuit element of the present invention. [Figure 3] A schematic diagram illustrating Example 1 of the construction of the irreversible circuit element of the present invention. [Figure 4] A schematic diagram illustrating Example 2 of the construction of the irreversible circuit element of the present invention. [Figure 5] A schematic diagram illustrating Example 3 of the construction of the irreversible circuit element of the present invention. [Figure 6] A schematic diagram illustrating Example 4 of the construction of the irreversible circuit element of the present invention. [Figure 7] A schematic diagram illustrating Example 5 of the construction of the irreversible circuit element of the present invention. [Figure 8] A schematic diagram illustrating Example 6 of the construction of the irreversible circuit element of the present invention. [Figure 9] A schematic diagram illustrating Example 7 of the construction of the irreversible circuit element of the present invention. [Figure 10] A schematic diagram illustrating the frequency characteristics of an example 7 of the construction of an irreversible circuit element of the present invention. [Figure 11] A structural diagram of a lumped constant type circulator with 3 ports, and a diagram showing the equivalent circuit. [Figure 12] is a diagram used to illustrate the narrow frequency band characteristics of the previously mentioned irreversible circuit element. Implementation

[0059] Hereinafter, Figures 1 and 2 will be used to illustrate the general structure of the irreversible circuit element of the present invention, and Figures 3 to 10 will be used to illustrate construction examples 1 to 7 of the irreversible circuit element of the present invention.

[0060] Examples 1 to 4 are examples of controlling the frequency characteristics of the irreversible part. The construction example 1 shown in Figure 3 is an example of controlling the DC current based on the power supplied from the high-frequency power source to the irreversible part. The construction examples 2 and 3 shown in Figures 4 and 5 are examples of controlling the DC current based on the frequency of the high-frequency signal supplied from the high-frequency power source to the irreversible part. The construction example 4 shown in Figure 6 is an example of changing the constant of the reversible circuit section based on the frequency of the high-frequency signal supplied from the high-frequency power source to the irreversible part.

[0061] Examples of construction 5 to 7 are examples of the usage of the irreversible circuit element of the present invention. The structure example 5 shown in Figure 7 is an example of switching the output port by switching the direction of the DC current supplied to the electromagnet. The structure example 6 shown in Figure 8 is an example of switching the output port and simultaneously switching the frequency of the high-frequency signal output. The structure examples 7 shown in Figures 9 and 10 are examples of having multiple units with different frequency characteristics.

[0062] [Simplified Structure of the Invention] Based on Figures 1 and 2, the general structure of the irreversible circuit element of the present invention is described. Figure 1 illustrates an example of a lumped constant type 3-port circulator, which outputs a high-frequency signal from a high-frequency power supply 8 to port P1 to port P2 or port P3, as an irreversible circuit element 1. In Figure 1, the irreversible circuit element 1 has an irreversible part 6 that has the characteristic of transmitting signals only in a specific direction and not in the opposite direction.

[0063] The irreversible part 6 includes a ferrite 2, an electromagnet 4 that applies a DC magnetic field to the ferrite 2, and a complex conductor 3. In the lumped constant type 3-port circulator, the conductor 3 consists of three conductors 3a, 3b, and 3c, which are arranged in a cross configuration with respect to the ferrite 2 in an insulated state. One end of each conductor is connected to the input / output port side, and the other end is grounded.

[0064] Ferrite 2a and ferrite 2b are disposed on both sides of the conductor 3. Ferrite 2 is not limited to being disposed on both sides of the conductor 3, but can also be disposed on one side of the conductor 3.

[0065] Electromagnet 4 generates a DC magnetic field by means of a DC current supplied from DC power supply 7, which is applied to ferrite 2. A DC power supply control unit 9 is provided between DC power supply 7 and electromagnet 4. The DC power supply control unit 9 controls the DC current Idc supplied from DC power supply 7 to electromagnet 4, thereby controlling the strength of the DC magnetic field generated in electromagnet 4.

[0066] The terminals on the opposite side of the short-circuit terminals of each conductor 3 (3a, 3b, 3c) of the irreversible section 6 are connected to ports P1 to P3 through reversible circuit sections 5a, 5b, 5c. A high-frequency power supply 8 is connected to port P1, and the high-frequency signal of the high-frequency power supply 8 is supplied to conductor 3a through the reversible circuit section 5a to generate a high-frequency magnetic field.

[0067] For ferrites 2 (2a, 2b), a high-frequency magnetic field generated by conductor 3a and a DC magnetic field generated by electromagnet 4 are applied. The high-frequency magnetic field becomes a right-handed circularly polarized wave magnetic field that rotates to the right in the direction of the DC magnetic field and a left-handed circularly polarized wave magnetic field that rotates to the left. By controlling the strength of the DC magnetic field and the permeability of the right-handed circularly polarized wave magnetic field, the direction of electromagnetic wave propagation can be set to a predetermined angle. The permeability μ of the ferrite varies with the frequency f of the high-frequency signal and the magnetic field strength Hdc of the DC magnetic field, and the frequency characteristics of the irreversible part 6 follow the magnetic field strength Hdc of the DC magnetic field.

[0068] Figure 2(a) shows the frequency characteristics schematically illustrating the transmission characteristics of a high-frequency signal passing through the reversible circuit section 5 and the irreversible section 6. In Figure 2(a), the center frequency fc of the frequency characteristics indicates the condition where the magnetic field strength Hdc of the DC magnetic field is a fixed value. At this time, the frequency f1 of the high-frequency signal is consistent with the center frequency fc, and the transmission characteristics are in a good state. If the frequency f of the high-frequency signal deviates from the center frequency fc by Δf from f1 to f2 (=fc+Δf) from this state, impedance mismatch will occur in the reversible circuit section 5 and the irreversible section 6. Due to this impedance mismatch, an insertion loss ΔP occurs, and the strength of the high-frequency signal output from the irreversible section 6 will decrease. Figure 2(b) shows the frequency characteristics schematically illustrating the transmission characteristics when the frequency f of the high-frequency signal deviates from the center frequency fc.

[0069] Here, when ΔPre represents the insertion loss caused by impedance mismatch of reversible circuit section 5 and ΔPire represents the insertion loss caused by impedance mismatch of irreversible section 6, the total insertion loss ΔP of reversible circuit section 5 and irreversible section 6 is expressed as ΔP = ΔPre + ΔPire, which is the sum of the insertion loss ΔPre of reversible circuit section 5 and the ΔPire of irreversible section 6.

[0070] In Figure 2(b), the solid line represents the frequency characteristics of the high-frequency signal before the frequency f deviates, and the broken line represents the frequency characteristics of the high-frequency signal after the frequency f deviates. Here, the center frequency fc represents the center frequency of the frequency characteristics of the high-frequency signal after the frequency f deviates. In the frequency characteristics of the high-frequency signal after the frequency f deviates, due to the impedance mismatch caused by the frequency f deviation, an insertion loss ΔP occurs at the center frequency fc, resulting in a decrease in the output of the high-frequency signal. The insertion loss ΔP is the sum of the insertion loss ΔPre of the reversible circuit section 5 and the insertion loss ΔPire of the irreversible section 6. Furthermore, the internal loss of the irreversible circuit element 1 does not exist here.

[0071] The insertion loss ΔPire of the irreversible section 6 can be compensated by aligning the center frequency fc of the frequency characteristic of the irreversible section 6 with the frequency f2 of the high-frequency signal and by matching the impedance. Furthermore, the insertion loss ΔPre of the reversible circuit section 5 can be compensated by changing the constant of the capacitance component of the reversible circuit section 5 and by matching the impedance.

[0072] The frequency response shown in Figure 2(c) illustrates the state in which the insertion loss ΔP caused by impedance mismatch is suppressed by adjusting the frequency response of the irreversible section 6 and the capacitance component of the reversible circuit section 5. The suppression of insertion loss ΔP is achieved by aligning the center frequency fc of the irreversible section 6 with the frequency f2 of the high-frequency signal during frequency response transitions, thus performing impedance matching of the irreversible section 6, and by changing the constant of the capacitance component of the reversible circuit section 5 to perform impedance matching of the reversible circuit section 5.

[0073] The DC power supply control unit 9 controls the frequency characteristics of the irreversible part 6 by controlling the DC current supplied to the electromagnet 4 and setting the magnetic field strength Hdc of the DC magnetic field applied to the ferrite 2 to be variable.

[0074] When the frequency of the high-frequency signal of the high-frequency power supply 8 can be varied within the variable frequency range, the frequency characteristics of the irreversible part 6 are suppressed by controlling the magnetic field strength Hdc of the DC magnetic field, which can make the intensity of the high-frequency signal output from the irreversible circuit element 1 uniform.

[0075] When the frequency of the high-frequency power supply 8 varies around a predetermined frequency, the frequency characteristics of the irreversible part 6 can be suppressed by controlling the magnetic field strength Hdc of the DC magnetic field, thereby suppressing the intensity variation of the high-frequency signal output from the irreversible circuit element 1.

[0076] Hereinafter, construction examples 1 to 7 of the present invention will be described. In construction examples 1 to 7, the internal loss of the irreversible circuit element 1 is not present.

[0077] [Construction Example 1] Based on Figure 3, an example 1 of the construction of the irreversible circuit element of the present invention will be described. Example 1 is an example of controlling the DC current caused by the DC power supply control unit 9 based on the power supplied from the high-frequency power supply 8 to the irreversible section 6. In the schematic structure shown in FIG. 1, Example 1 includes a power supply detection unit 10 between the high-frequency power supply 8 and the reversible circuit section 5a. The power supply detection unit 10 detects the power supplied from the high-frequency power supply 8 to the irreversible section 6.

[0078] Due to the insertion loss caused by the impedance mismatch between the reversible circuit section 5 and the irreversible section 6, the voltage, current, and power decrease, while the reflectivity increases. The power supply detection section 10 detects the changes in voltage, current, power, or reflectivity caused by the insertion loss due to the impedance mismatch between the reversible circuit section 5 and the irreversible section 6, based on the power supply quantity, and feeds this information back to the DC power supply control section 9. In Example 1, the changes caused by reverse loss and forward loss are detected by detecting the power supply quantity, and these changes are fed back to the DC power supply control section 9.

[0079] The DC power supply control unit 9 controls the DC current supplied from the DC power supply 7 to the electromagnet 4 based on the feedback power supply, controls the DC magnetic field generated by the electromagnet 4, and controls the frequency characteristics of the irreversible part 6. The DC power supply control unit 9 controls the power supply by comparing the detected power supply with a reference value and minimizing the difference obtained in the comparison. The reference value can be, for example, the power supply when the reverse loss or forward loss is a preset value.

[0080] In Example 1, the frequency fRF of the high-frequency signal output by the high-frequency power supply 8 can also be configured to be variable via the frequency control unit 11. The frequency control unit 11 controls the frequency fRF of the high-frequency signal output by the high-frequency power supply 8 within a variable frequency range.

[0081] [Construction Example 2] Based on Figure 4, an example 2 of the construction of the irreversible circuit element of the present invention will be described. Example 2 is an example of controlling the DC current caused by the DC power supply control unit 9 based on the frequency fRF of the high-frequency signal input from the high-frequency power supply 8 to the irreversible part 6.

[0082] Example 2 includes a frequency detection unit 12 that detects the frequency of a high-frequency signal. The frequency detection unit 12 transmits the frequency fRF of the detected high-frequency signal to the DC power supply control unit 9. The DC power supply control unit 9 controls the DC current supplied from the DC power supply 7 to the electromagnet 4 based on the frequency fRF of the transmitted high-frequency signal, thereby controlling the DC magnetic field generated by the electromagnet 4.

[0083] The DC power supply control unit 9 predetermines the relationship between the center frequency fc and the DC current Idc within the variable frequency range. The DC power supply control unit 9 sets the frequency fRF of the detected high-frequency signal as the center frequency fc of the frequency characteristic of the irreversible part 6. Based on the predetermined relationship between the center frequency fc and the DC current Idc, the DC current Idc is calculated from the center frequency fc corresponding to the frequency fRF of the detected high-frequency signal. The calculated DC current Idc is supplied to the electromagnet 4 to control the DC magnetic field and control the frequency characteristic of the irreversible part 6.

[0084] In Construction Example 2, similar to Construction Example 1, the frequency fRF of the high-frequency signal output by the high-frequency power supply 8 can also be configured to be variable via the frequency control unit 11. The frequency control unit 11 controls the frequency fRF of the high-frequency signal output by the high-frequency power supply 8 within a variable frequency range.

[0085] [Example 3] Based on Figure 5, an example 3 of the construction of the irreversible circuit element of the present invention will be described. Construction Example 3 is the same as Construction Example 2, and is an example of controlling the DC current caused by the DC power supply control unit 9 based on the frequency fRF of the high-frequency signal input from the high-frequency power supply 8 to the irreversible part 6. Construction Example 2 is a construction in which the frequency fRF of the high-frequency signal is obtained from the detection signal detected by the frequency detection unit 12. In contrast, Construction Example 3 is a construction in which the frequency fRF of the high-frequency signal is obtained from the frequency control unit 11 that controls the frequency fRF of the high-frequency signal output from the high-frequency power supply 8.

[0086] Example 3 includes a frequency control unit 11, which controls the frequency fRF of the high-frequency signal output by the high-frequency power supply 8. The frequency control unit 11 transmits the frequency fRF of the high-frequency signal to the DC power supply control unit 9. The DC power supply control unit 9 controls the DC current supplied from the DC power supply 7 to the electromagnet 4 based on the transmitted high-frequency signal fRF, and controls the DC magnetic field generated by the electromagnet 4, thereby controlling the frequency characteristics of the irreversible part 6.

[0087] The DC power supply control unit 9 is the same as in Example 2, and the relationship between the center frequency fc and the DC current Idc is predetermined within the variable frequency range. The DC power supply control unit 9 sets the frequency fRF of the detected high-frequency signal as the center frequency fc of the frequency characteristic of the irreversible part 6. Based on the predetermined relationship between the center frequency fc and the DC current Idc, the DC current Idc is calculated from the center frequency fc corresponding to the frequency fRF of the detected high-frequency signal, and the calculated DC current Idc is supplied to the electromagnet 4 to generate a DC magnetic field.

[0088] [Example 4] Based on Figure 6, an example 4 of the construction of the irreversible circuit element of the present invention will be described. Construction Example 4 is the same as Construction Example 1, and has a control system that feeds back the power supply detected by the power supply detection unit 10 to the DC power supply control unit 9 to control the 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 irreversible part 6.

[0089] In addition to the control system that controls the frequency characteristics of the irreversible part 6 by controlling the DC current caused by the DC power supply control unit 9, the system also has a control system that controls the frequency characteristics of the irreversible part 6 by changing the constant of the capacitance component of the capacitor in the reversible circuit unit 5a.

[0090] Example 4 includes a constant changing unit 13, which changes the constant Cp of the capacitance component of the capacitor in the reversible circuit unit 5a. The constant changing unit 13 obtains the frequency fRF of the high-frequency signal from the frequency control unit 11, calculates the constant Cp of the capacitance component according to the relationship of mathematical formula (2), and changes the constant of the capacitance component of the reversible circuit unit 5a according to the calculated constant Cp. In this way, the reversible circuit unit 5a can match the center frequency fc of the frequency characteristic of the irreversible part 6 with the frequency fRF of the high-frequency signal of the high-frequency power supply 8.

[0091] [Example 5] Based on Figure 7, Example 5 of the construction of the irreversible circuit element of the present invention will be described. Example 5 is an example of switching the output port of the irreversible part 6. The switching of the output port can be performed in any of Examples 1 to 4. Example 1 will be used as an example for explanation below.

[0092] The switching of the output port of the irreversible part 6 is performed by reversing the direction of the DC magnetic field generated by switching the direction of the DC current Idc supplied to the electromagnet 4. The switching of the current direction of the DC current Idc is performed by controlling the DC power supply control unit 9 through the control unit 14. Figure 7(a) shows the state when port P2 is switched to the output port, and Figure 7(b) shows the state when port P3 is switched to the output port.

[0093] [Example 6] Referring to Figure 8, Example 6 of the construction of the irreversible circuit element of the present invention will be described. Construction Example 6 is the same as Construction Example 5, which is a construction example of switching the output port of the irreversible part 6, and a construction example of switching the frequency of the high-frequency signal output from the output port at the same time.

[0094] The switching of the output port and frequency of the irreversible part 6 is achieved by switching the direction of the DC current Idc supplied to the electromagnet 4 and simultaneously switching the frequency of the high-frequency output of the high-frequency power supply 8.

[0095] Example 6 has a control unit 14, which performs current method control to switch the current direction of DC current Idc and frequency control to switch the frequency of the high-frequency signal output by the high-frequency power supply 8.

[0096] Control unit 14 controls DC power supply control unit 9 to switch the direction of DC current Idc, thereby reversing the direction of the DC magnetic field generated therefrom. Furthermore, control unit 14 controls high-frequency power supply 8 to switch the frequency of high-frequency signals.

[0097] Figure 8(a) shows the situation where port P2 is switched to an output port, and a high-frequency signal with frequency f1 is output from port P2. Figure 8(b) shows the situation where port P3 is switched to an output port, and a high-frequency signal with frequency f2 is output from port P3. Furthermore, the frequencies f1 and f2 of the high-frequency signals output from ports P2 and P3 can be arbitrarily set within the variable frequency range of the high-frequency power supply.

[0098] [Construction Example 7] Based on Figures 9 and 10, an example 7 of the construction of the irreversible circuit element of the present invention will be described. Example 7 is constructed with complex units having different frequency characteristics, and outputs high-frequency signals from irreversible circuit elements of units having frequency characteristics suitable for high-frequency signals input from high-frequency power supplies.

[0099] The variable frequency range of the variable frequency characteristics caused by changing the DC magnetic field has its limitations. When the variable frequency range of a high-frequency power supply is wide, it is difficult to cover all regions of the variable frequency range with a single irreversible circuit element. Example 7 uses multiple units with frequency characteristics that are separated into different frequency ranges. By separating high-frequency signals of different frequency ranges by each unit, the entire region of the variable frequency range of the high-frequency power supply can be separated.

[0100] Each unit 20 has an irreversible part 6, a reversible circuit part 5, and a DC power supply control part 9. Structural Example 7 discloses a structure in which the complex unit 20 has three units 20A, 20B, and 20C.

[0101] The reversible circuit section 5 of each unit 20A, 20B, and 20C is set with constants corresponding to each frequency range. The irreversible section 6 of each unit 20A, 20B, and 20C expands the frequency range in which the frequency characteristics of the reversible circuit section 5 are transferred and separated by controlling the DC magnetic field of the electromagnet 4.

[0102] By staggering the frequency ranges of each unit 20A, 20B, and 20C, the frequency ranges of all irreversible circuit elements can be combined into the frequency ranges of each unit, thus creating a wideband frequency range.

[0103] Figure 10 schematically illustrates the frequency characteristics of the irreversible circuit element constructed using a complex number of units in Example 7. Figure 10 shows an example of constructing the entire frequency bandwidth BW of the irreversible circuit element by combining three bandwidths: BW1, BW2, and BW3. In this example, the frequency characteristics of units 20A, 20B, and 20C are set as center frequencies fc1, fc2, and fc3, respectively, and bandwidths BW1, BW2, and BW3 are set.

[0104] Figure 10(a) shows the bandwidth BW1 obtained by making the DC magnetic field of the electromagnet variable and transferring the frequency response with frequency fc1 as the center frequency in unit 20A. The bandwidth BW1 is set by transferring the frequency response.

[0105] Figure 10(b) shows the bandwidth BW2 of the frequency characteristics in unit 20B with frequency fc2 as the center frequency, and Figure 10(c) shows the bandwidth BW3 of the frequency characteristics in unit 20C with frequency fc3 as the center frequency.

[0106] Furthermore, the bandwidth of the transfer frequency characteristic is determined based on the relationship between the change amplitude of the DC magnetic field of the electromagnet and the change amplitude of the frequency characteristic, and is set according to the change amplitude of the frequency characteristic that can be changed by the change of the DC magnetic field of the electromagnet.

[0107] Figure 10(d) shows the state in which the entire frequency bandwidth BW of the irreversible circuit element is constructed by combining the bandwidths BW1, BW2, and BW3 of the combination units 20A, 20B, and 20C.

[0108] According to construction example 7, even in situations where the frequency bandwidth that can be adjusted by each unit is narrow, the entire frequency bandwidth BW of the irreversible circuit element can be expanded by combining multiple units with frequency characteristics having different center frequencies, thereby achieving broadband.

[0109] In each construction example, the power loss caused by reflection and return generated in the output target of the circulator, i.e., the reverse loss (isolation), can be detected by adding power supply detection units at ports P2 and P3, in addition to the power supply detection unit set at port P1.

[0110] Through the circulator, high-frequency current is transmitted from port P1 to the load at port P2, from the load at port P2 to the load at port P3, and from the load at port P3 to port P1. The power supply detection unit at port P2 detects the electrical charge reflected from the load connected to the output of the circulator, and the power supply detection unit at port P3 detects the electrical charge reflected from the load and input to the circulator.

[0111] Reverse loss is calculated by adding the electrical quantity detected by the power supply detection unit. By feeding back the detected electrical quantity to the DC power supply control unit, control measures to reduce reverse loss can be implemented.

[0112] Furthermore, the foregoing description of embodiments and variations is one example of the irreversible circuit element of the present invention. The present invention is not limited to each embodiment. Various modifications can be made according to the intent of the present invention, and these modifications are not intended to exclude the present invention from its scope. [Potential for industrial application]

[0113] The irreversible circuit element of the present invention is applicable, for example, to high-frequency power supplies (RF generators) used in semiconductor manufacturing apparatus and liquid crystal panel manufacturing apparatus.

[0114] 1: Irreversible circuit elements 2: Ferrite 2a: Ferrite 2b: Ferrite 3: Conductor 3a: Conductor 3b: Conductor 3c: Conductor 4: Electromagnet 5: Reversible circuit section 5a: Reversible circuit section 5b: Reversible circuit section 5c: Reversible circuit section 6: Irreversible part 7: DC power supply 8: High-frequency power supply 9: DC Power Supply Control Section 10: Power Supply Testing Department 11: Frequency Control Department 12: Frequency Detection Unit 13: Constant Change Section 14: Control Department Unit 20 20A: Unit 20B: Unit 20C: Unit 100: Ideal Circulator 101: Lumped constant type circulator 102: Ferrite 103: Conductor 103a: Conductor 103b: Conductor 103c: Conductor 104: Permanent magnet 104a: Permanent magnet 104b: Permanent magnet 105: Capacitor 105a: Capacitor 105b: Capacitor 105c: Capacitor 106: Parallel Resonant Circuit 106a: Parallel Resonant Circuit 106b: Parallel Resonant Circuit 106c: Parallel Resonant Circuit BW: Frequency bandwidth BW1: Bandwidth BW2: Bandwidth BW3: Bandwidth Cp: ​​capacitance constant Hdc: Magnetic field strength of DC magnetic field Idc: DC current Lp: Inductor P1: Port P2: Port P3: Port ΔP: Insertion loss ΔPre: Insertion loss ΔPire: Insertion loss ΔPs: Insertion loss fc: Center frequency fc1: Center frequency fc2: Center frequency fc3: Center frequency η: Irreversibility index

Claims

1. An irreversible circuit element, characterized by comprising: an irreversible portion having a ferrite, an electromagnet applying a DC magnetic field to the ferrite, and a plurality of conductors having multiple terminals short-circuited in an insulated state respectively; a reversible circuit portion connected between the other end of each of the conductors and an input / output port, wherein the resonant frequency of a parallel resonant circuit formed by the inductive component of the conductors of the irreversible portion and the capacitor of the reversible circuit portion is set to be variable; and a DC power supply control portion controlling the DC current supplied to the electromagnet based on a high-frequency signal input from a high-frequency power supply to the irreversible portion; wherein the DC power supply control portion controls the frequency characteristics of the irreversible portion by setting the strength of the DC magnetic field applied to the ferrite to be variable by controlling the DC current supplied to the electromagnet.

2. The irreversible circuit element as described in claim 1, wherein, The aforementioned DC power supply control unit controls the current value of the aforementioned DC current based on the power supplied from the high-frequency signal input from the high-frequency power supply to the aforementioned irreversible part, thereby making the strength of the DC magnetic field variable and matching the center frequency of the frequency characteristics of the aforementioned irreversible part with the frequency of the high-frequency signal from the high-frequency power supply.

3. The irreversible circuit element as described in claim 2, wherein, Between the aforementioned high-frequency power supply and the reversible circuit section connected to the input port, there is a power supply detection section for detecting the aforementioned power supply quantity; the aforementioned power supply quantity is any one of voltage, current, power, or reflectivity.

4. The irreversible circuit element as described in claim 1, wherein, The aforementioned DC power supply control unit controls the aforementioned DC current based on the frequency of the high-frequency signal input from the high-frequency power supply to the aforementioned irreversible part, thereby making the strength of the DC magnetic field variable and matching the center frequency of the frequency characteristics of the aforementioned irreversible part with the high-frequency signal of the high-frequency power supply.

5. The irreversible circuit element as described in claim 4, wherein, Between the aforementioned high-frequency power supply and the reversible circuit section connected to the input port, there is a frequency detection section that detects the frequency of the aforementioned high-frequency signal; the aforementioned DC power supply control section controls the aforementioned DC current based on the frequency detected by the aforementioned frequency detection section.

6. The irreversible circuit element as described in claim 4, wherein, It includes: a frequency control unit that controls the frequency of the aforementioned high-frequency power supply; and a DC power supply control unit that controls the aforementioned DC current based on the control frequency of the aforementioned frequency control unit.

7. The irreversible circuit element as described in claim 1, wherein, The aforementioned reversible circuit section includes a capacitor that, together with the inductive component of the aforementioned conductor, forms a parallel resonant circuit.

8. The irreversible circuit element as described in claim 7, wherein, It includes: a constant changing section that makes the capacitance component of the capacitor in the aforementioned reversible circuit section variable; the aforementioned constant changing section that changes the capacitance component of the capacitor in the aforementioned reversible circuit section according to the frequency of the high-frequency signal of the high-frequency power supply; by changing the capacitance component, changing the frequency of the resonant frequency of the aforementioned parallel resonant circuit; by changing the frequency of the resonant frequency, performing the following on the aforementioned irreversible section: (a) changing the frequency characteristics to match the center frequency with the frequency of the high-frequency signal of the high-frequency power supply; and (b) impedance matching to match the impedance of the input and output ports.

9. The irreversible circuit element described in any of claims 1 to 8, wherein, It includes: multiple units, each having the aforementioned irreversible part, the aforementioned reversible circuit part, and the aforementioned DC power supply control part; the irreversible part of each of the aforementioned units is equipped with a center frequency set to different frequency characteristics, and outputs high-frequency signals of different frequency bands from each unit.

10. The irreversible circuit element described in any of claims 1 to 8, wherein, The aforementioned DC power supply control unit switches the output port of the aforementioned irreversible part that outputs high-frequency signals by switching the direction of the DC current supplied to the electromagnet.

11. The irreversible circuit element as described in claim 10, wherein, The aforementioned DC power supply control unit changes the current value along with the switching of the DC current direction, thereby switching the output port and changing the frequency characteristics.

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