JP2005063431A - Method and apparatus for designing high-frequency circuit and display method for designing high-frequency circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for designing a high-frequency circuit simply and accurately performing circuit design and a characteristic evaluation by eliminating the need for the preparation of the data table of an S parameter for every component item and by obtaining data for evaluation as a substitute for the S parameter by using a frequency function by an operation. <P>SOLUTION: The method and apparatus for designing the high-frequency circuit perform the replacing of respective component items constituting a basic circuit by component equivalent circuits in which corresponding component items have frequency characteristics, obtain evaluation data for the replaced component equivalent circuits, while changing a frequency, by a polynomial-frequency function expression, grasp the frequency characteristics of each component item by referring to the evaluation data, and evaluate circuit characteristics by using the frequency characteristics. When the result of evaluation indicates that the targeted circuit characteristics cannot be obtained, at least one of the component equivalent circuits in the circuit model is replaced by another component equivalent circuit corresponding to a component item having different electric characteristics. The expression is used to obtain again the evaluation data for the replaced component equivalent circuit, and the circuit characteristics are evaluated again by using the frequency characteristics based on the obtained evaluation data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a design method and design apparatus for a high-frequency circuit, and a display method for designing a high-frequency circuit.

  Recently, electronic circuit design and characteristic evaluation are generally performed by simulation using a computer, but component characteristic data generally used for high frequency circuit design, such as F parameter, Z parameter, Y parameter, h parameter, etc. When using, there arises a problem that the target circuit characteristics cannot be obtained in the designed high-frequency circuit. Therefore, recently, in order to solve the above-mentioned problems, high-frequency circuit design and characteristic evaluation have been performed using S-parameters (pointing to each element of the S matrix in the relational expression between incident wave and reflected wave) as component characteristic data. It has been broken.

  Although the S parameter is a value obtained by actually measuring the frequency characteristics of a component item using a network analyzer, there is an advantage that the characteristic evaluation can be performed with high accuracy. It is necessary to prepare a data table of S parameters for each component item provided from.

  In addition, the S parameter data table provided by the component manufacturer basically has MAG (magnitude) and ANG (angle) for each measurement frequency. Cannot be accurately characterized. Specifically, in the S parameter data table in which MAG and ANG are written only in units of 0.5 GHz such as 0.5 GHz, 1.0 GHz, 1.5 GHz, 2.0 GHz, 2.5 GHz,... Characteristic evaluation at frequencies between measurement frequencies such as 0.9 GHz, 1.2 GHz, and 2.3 GHz cannot be accurately performed.

  The present invention was created in view of the above circumstances, and the object of the present invention is to prepare an S parameter data table for each component item in advance, and to provide evaluation data in place of the S parameter. An object of the present invention is to provide a design method and design apparatus for a high-frequency circuit and a display method for designing a high-frequency circuit that can easily and accurately perform circuit design and characteristic evaluation by calculating using a frequency function.

In order to achieve the above object, an invention relating to a design method of a high-frequency circuit includes
Build a circuit model that replaces each component item that makes up the basic circuit with a component equivalent circuit that gives the component item frequency characteristics,
Xsf = Xs (n) × Freq ⁿ + Xs (n−1) × Freq ⁽ⁿ⁻¹⁾ +... Xs (0), which is a polynomial frequency function, is used for evaluation data of each component equivalent circuit constituting the circuit model. This is obtained by changing Freq according to the formula [X in the formula is a symbol representing an electric component, Xs (n) to Xs (0) are constants, Freq is a frequency, and n is an integer of 2 or more]. Understand the frequency characteristics of each component item in the basic circuit, evaluate the circuit characteristics using this frequency characteristics,
If the target circuit characteristic cannot be obtained as a result of the evaluation, at least one of the component equivalent circuits in the circuit model is replaced with another component equivalent circuit corresponding to a component item having a different electrical characteristic, Re-evaluate the data for evaluation of the component equivalent circuit after replacement using, and re-evaluate the circuit characteristics using the frequency characteristics based on this evaluation data,
It is characterized by that.

In addition, the invention relating to the design apparatus of the high frequency circuit,
Means for constructing a circuit model in which each component item constituting the basic circuit is replaced by a component equivalent circuit in which the component item has frequency characteristics;
Xsf = Xs (n) × Freq ⁿ + Xs (n−1) × Freq ⁽ⁿ⁻¹⁾ +... Xs (0), which is a polynomial frequency function, is used for evaluation data of each component equivalent circuit constituting the circuit model. This is obtained by changing Freq according to the formula [X in the formula is a symbol representing an electric component, Xs (n) to Xs (0) are constants, Freq is a frequency, and n is an integer of 2 or more]. Means to grasp the frequency characteristics of each component item in the basic circuit, and to evaluate the circuit characteristics using this frequency characteristics,
If the target circuit characteristic cannot be obtained as a result of the evaluation, at least one of the component equivalent circuits in the circuit model is replaced with another component equivalent circuit corresponding to a component item having a different electrical characteristic, Re-determining the evaluation data of the component equivalent circuit after replacement using, and re-evaluating the circuit characteristics using the frequency characteristics based on the evaluation data,
It is characterized by that.

Furthermore, the invention related to the display method related to the design of the high-frequency circuit,
Display a circuit model in which each component item that constitutes the basic circuit is replaced with a component equivalent circuit in which the component item has frequency characteristics.
Xsf = Xs (n) × Freq ⁿ + Xs (n−1) × Freq ⁽ⁿ⁻¹⁾ +... Xs (0), which is a polynomial frequency function, is used for evaluation data of each component equivalent circuit constituting the circuit model. This is obtained by changing Freq according to the formula [X in the formula is a symbol representing an electric component, Xs (n) to Xs (0) are constants, Freq is a frequency, and n is an integer of 2 or more]. Understand the frequency characteristics of each component item in the basic circuit, display the evaluation of circuit characteristics using this frequency characteristic,
If the target circuit characteristic cannot be obtained as a result of the evaluation, at least one of the component equivalent circuits in the circuit model is replaced with another component equivalent circuit corresponding to a component item having a different electrical characteristic, The evaluation data of the component equivalent circuit after replacement is obtained again by using the frequency characteristics based on the evaluation data, and the evaluation of the circuit characteristics is displayed again.
It is characterized by that.

  According to the present invention, it is not necessary to prepare an S parameter data table for each component item in advance, and circuit design and characteristic evaluation can be performed by obtaining evaluation data in place of the S parameter by calculation using a frequency function. Can be performed easily and accurately.

  The above object and other objects, structural features, and operational effects of the present invention will become apparent from the following description and the accompanying drawings.

  FIG. 1 shows a basic configuration of a design apparatus. Reference numeral 1 in the figure denotes a computer configuration control unit, 2 an input unit including a keyboard, a mouse, etc. 3 a display unit composed of an LCD, a CRT, etc. 4 a first storage unit composed of a hard disk, a semiconductor memory, etc. Reference numeral 5 denotes a second storage unit composed of a hard disk, a semiconductor memory, or the like.

  The first storage unit 4 is a circuit database in which an F special component equivalent circuit (an equivalent circuit in which a component item has frequency characteristics) and a frequency function corresponding to each of the F special component equivalent circuits are stored for each component item. Is remembered. The second storage unit 5 is a component database, in which constants and the like included in each frequency function of the F special component equivalent circuit stored in the first storage unit 4 are stored for each component item. Incidentally, a program for performing circuit design to be described later is stored in the memory of the control unit 1, the first storage unit 4, or the second storage unit 5.

  FIG. 2 shows the basic flow of the design method. Hereinafter, a design flow of a high-frequency circuit realized by the design apparatus shown in FIG. 1 will be specifically described by taking a high-pass filter having a predetermined cutoff frequency as an example.

  When designing a high-pass filter with a predetermined cut-off frequency, first, a circuit that provides the desired circuit characteristics by combining the necessary component items as appropriate based on the designer's own technical knowledge and empirical rules. 3 is a basic circuit shown in FIG. 3 constituted by connecting two low-capacitance capacitors C having a predetermined capacitance in series, and connecting one high-frequency inductor L having a predetermined inductance in parallel. Contemplate (see step S1 in FIG. 2).

  Next, by operating the input unit 2, the F special component equivalent circuit corresponding to the capacitor C and the inductor L of the basic circuit shown in FIG. 3 is read from the first storage unit 4, and the capacitor C and the inductor L of the basic circuit are read. The circuit model shown in FIG. 4 is constructed in place of the F special component equivalent circuit (see step S2 in FIG. 2). The circuit model after replacement is displayed on the display unit 3.

  Ce1 in the circuit model shown in FIG. 4 is an F special component equivalent circuit corresponding to the capacitor C. Here, considering the phenomenon that the value of the resistance component Rs decreases with frequency and increases after the resonance point, only the resistance component Rs is taken into account. Is given frequency characteristics, and the capacitance component Cs and the inductance component Ls are not given frequency characteristics. Further, Le1 is an F special component equivalent circuit corresponding to the inductor L. Here, the resistance component Rs and the inductance component are considered in consideration of the phenomenon that the resistance component Rs increases with frequency and the inductance component Ls decreases with frequency. Only Ls has a frequency characteristic, and the other resistance component Rs and capacitance component Cs do not have a frequency characteristic.

  Next, by operating the input unit 2, constants and the like corresponding to the F special component equivalent circuits Ce1 and Le1 of the circuit model shown in FIG. 4 are read from the second storage unit 5, and the F special component equivalent circuit is constructed when the circuit model is constructed. In addition, evaluation data for each of the F special component equivalent circuits Ce1 and Le1 is obtained using the frequency function read out earlier, and the frequency characteristics of each component item of the basic circuit shown in FIG. Then, the circuit characteristics are evaluated using the frequency characteristics (see step S3 in FIG. 2). The evaluation data and the evaluation result are displayed on the display unit 3.

Specifically, the F-special component equivalent circuit Ce1 corresponding to the capacitor shown in FIG. 4 has frequency characteristics only in the resistance component Rs, and therefore, the read constants Rs (n) to Rs (0) are used. Rsf = Rs (n) × Freq ⁿ + Rs (n−1) × Freq ⁽ⁿ⁻¹⁾ +... Rs (0) where R is a symbol representing a resistance component, Rs (N) to Rs (0) are constants, Freq is a frequency, and n is an integer of 2 or more].

Further, since the F-specific component equivalent circuit Le1 corresponding to the inductor shown in FIG. 4 has frequency characteristics for the resistance component Rs and the inductance component Ls, the evaluation data Rsf is obtained and read in the same manner as described above. Using the constants Ls (n) to Ls (0), the evaluation data Lsf is expressed as Lsf = Ls (n) × Freq ⁿ + Ls (n−1) × Freq ⁽ⁿ⁻¹⁾ +... Ls (0) It is obtained by changing Freq (frequency) according to an equation [L in the equation is a symbol representing an inductance component, Ls (n) to Ls (0) are constants, Freq is a frequency, and n is an integer of 2 or more].

  Then, the frequency characteristics of the capacitor C and the inductor L selected first are grasped from the evaluation data Csf and Lsf, and the circuit characteristics are evaluated using the frequency characteristics.

  Since each expression is a polynomial function with frequency as a variable, the evaluation data can be easily calculated by determining the frequency and the value of n. Further, since it is possible to obtain evaluation data that is continuous in an arbitrary frequency unit and frequency range as substantially the same value as actual measurement, the frequency characteristics of the capacitor C and the inductor L can be accurately determined based on the obtained evaluation data. It is possible to grasp.

  If the target circuit characteristics cannot be obtained as a result of the evaluation, at least one of the F special component equivalent circuit Ce1 corresponding to the capacitor and the F special component equivalent circuit Le1 corresponding to the inductor in the circuit model has different electrical characteristics. Replace with another F special component equivalent circuit CeN, LeN corresponding to the item (corresponding to the act of replacing the capacitor C and inductor L selected at first with capacitors and inductors having different specifications), and using the above formula, The evaluation data Csf and Lsf of the F special component equivalent circuits CeN and LeN are obtained again, and the circuit characteristics are evaluated again using the frequency characteristics based on the evaluation data Csf and Lsf (see steps S4 and S5 in FIG. 2). ). The evaluation data and the evaluation result are displayed on the display unit 3.

  When the target circuit characteristics are obtained in steps S3 to S5, the design is completed (see step S6 in FIG. 2). Of course, if the target circuit characteristics are obtained in step 3, the design is completed without proceeding to steps 4 and 5.

  In this way, each of the component items constituting the basic circuit shown in FIG. 3 is replaced with a component equivalent circuit in which the component item has frequency characteristics, and the evaluation data for each of the replaced component equivalent circuits is a polynomial frequency function. Since the frequency characteristics of each component item can be obtained from the evaluation data by changing the frequency according to the formula consisting of the above, a conventional S parameter data table for each component item is prepared in advance. There is no need.

  In addition, since each expression is a polynomial function with a frequency as a variable, the evaluation data can be easily calculated by determining the frequency and the value of n, and the evaluation data can be continuously evaluated in an arbitrary frequency unit and frequency range. Since the data can be obtained as substantially the same value as the actual measurement, the frequency characteristics of each component item (capacitor C and inductor L) can be accurately grasped based on the obtained evaluation data. The circuit characteristics can be accurately evaluated using

  That is, there is no need to prepare an S parameter data table for each component item in advance for high frequency circuit design as in the prior art, and evaluation data in place of the S parameter is obtained by calculation using a frequency function. Thus, circuit design and characteristic evaluation can be performed easily and accurately.

4 shows the F special component equivalent circuit Ce1 corresponding to the low-capacitance capacitor C. However, when a large-capacity capacitor C is used, the F special component equivalent circuit Ce2 (N In this case, considering the phenomenon that the resistance component Rs decreases with frequency and increases after the resonance point, and the capacitance component Cs decreases with frequency, only the resistance component Rs and the capacitance component Cs have frequency characteristics. The inductance component Ls does not have frequency characteristics. Incidentally, the formula for obtaining the evaluation data Csf in this case is Csf = Cs (n) × Freq ⁿ + Cs (n−1) × Freq ⁽ⁿ⁻¹⁾ +... Cs (0) [C in the formula Is a symbol representing a capacitance component, Cs (n) to Cs (0) are constants, Freq is a frequency, and n is an integer of 2 or more. The formula for obtaining the evaluation data Rsf is the same as described above.

  In the above description, an expression using a multinomial frequency function is shown as an expression for obtaining evaluation data. However, a variable and a coefficient such as temperature and time other than frequency and a coefficient term are added to the frequency function as an addition / subtraction term. A thing may be used as an expression for obtaining evaluation data.

It is a figure which shows the basic composition of a design apparatus. It is a figure which shows the basic flow of a design method. It is a figure which shows a basic circuit. It is a figure which shows the circuit model constructed | assembled by replacing each component item of the basic circuit shown in FIG. 3 with F special component equivalent circuit. It is a figure which shows F special component equivalent circuit of a high capacity | capacitance capacitor | condenser.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Control part, 2 ... Input part, 3 ... Display part, 4 ... 1st memory | storage part, 5 ... 2nd memory | storage part, C ... Capacitor, L ... Inductor, Ce1, CeN, Ce2 (N) ... F corresponding to a capacitor Special component equivalent circuit, Le1, LeN, F special component equivalent circuit for inductor, Rs, resistance component, Cs, capacitance component, Ls, inductance component.

Claims (3)

Build a circuit model that replaces each component item that makes up the basic circuit with a component equivalent circuit that gives the component item frequency characteristics,
Xsf = Xs (n) × Freq ⁿ + Xs (n−1) × Freq ⁽ⁿ⁻¹⁾ +... Xs (0), which is a polynomial frequency function, is used for evaluation data of each component equivalent circuit constituting the circuit model. This is obtained by changing Freq according to the formula [X in the formula is a symbol representing an electric component, Xs (n) to Xs (0) are constants, Freq is a frequency, and n is an integer of 2 or more]. Understand the frequency characteristics of each component item in the basic circuit, evaluate the circuit characteristics using this frequency characteristics,
If the target circuit characteristic cannot be obtained as a result of the evaluation, at least one of the component equivalent circuits in the circuit model is replaced with another component equivalent circuit corresponding to a component item having a different electrical characteristic, Re-evaluate the data for evaluation of the component equivalent circuit after replacement using, and re-evaluate the circuit characteristics using the frequency characteristics based on this evaluation data,
A method for designing a high-frequency circuit. Means for constructing a circuit model in which each component item constituting the basic circuit is replaced by a component equivalent circuit in which the component item has frequency characteristics;
Xsf = Xs (n) × Freq ⁿ + Xs (n−1) × Freq ⁽ⁿ⁻¹⁾ +... Xs (0), which is a polynomial frequency function, is used for evaluation data of each component equivalent circuit constituting the circuit model. This is obtained by changing Freq according to the formula [X in the formula is a symbol representing an electric component, Xs (n) to Xs (0) are constants, Freq is a frequency, and n is an integer of 2 or more]. Means to grasp the frequency characteristics of each component item in the basic circuit, and to evaluate the circuit characteristics using this frequency characteristics,
If the target circuit characteristic cannot be obtained as a result of the evaluation, at least one of the component equivalent circuits in the circuit model is replaced with another component equivalent circuit corresponding to a component item having a different electrical characteristic, Re-determining the evaluation data of the component equivalent circuit after replacement using, and re-evaluating the circuit characteristics using the frequency characteristics based on the evaluation data,
A design apparatus for a high-frequency circuit. Display a circuit model in which each component item that constitutes the basic circuit is replaced with a component equivalent circuit in which the component item has frequency characteristics.
Xsf = Xs (n) × Freq ⁿ + Xs (n−1) × Freq ⁽ⁿ⁻¹⁾ +... Xs (0), which is a polynomial frequency function, is used for evaluation data of each component equivalent circuit constituting the circuit model. This is obtained by changing Freq according to the formula [X in the formula is a symbol representing an electric component, Xs (n) to Xs (0) are constants, Freq is a frequency, and n is an integer of 2 or more]. Understand the frequency characteristics of each component item in the basic circuit, display the evaluation of circuit characteristics using this frequency characteristic,
If the target circuit characteristic cannot be obtained as a result of the evaluation, at least one of the component equivalent circuits in the circuit model is replaced with another component equivalent circuit corresponding to a component item having a different electrical characteristic, The evaluation data of the component equivalent circuit after replacement is obtained again by using the frequency characteristics based on the evaluation data, and the evaluation of the circuit characteristics is displayed again.
A display method according to the design of a high-frequency circuit.

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