JP2008241488A - Device, method and program for displaying antenna characteristics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide new technology capable of quickly and simply finding optimum control conditions of a variable directional antenna having a variable reactor mounted. <P>SOLUTION: A mathematical model of a structure with a variable reactor eliminated from an antenna having the variable reactor mounted is subjected to analysis by means of an analytical method to calculate a structural parameter independent of a reactance value of the variable reactor exhibiting antenna characteristics. While the reactance value of the variable reactor is sequentially set in a range of specified values, the calculated structural parameter and the set reactance value are substituted into a defined computing equation, thereby calculating the antenna characteristics depending on the reactance value of the variable reactor. When the antenna characteristics are thus evaluated, graphic data such as contour display having a characteristic value of the antenna characteristics as a coordinate axis indicating height are created on a coordinate plane where the reactance values of the two reactors extend and displayed on a display. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an antenna characteristic display apparatus and method for obtaining and displaying characteristics of an antenna loaded with a variable reactor, and an antenna characteristic display program used for realizing the antenna characteristic display apparatus.

  Investigation of an antenna (for example, ESPAR antenna) whose variable directivity is variable by loading a variable reactor and changing its reactance value is underway.

  When designing such an antenna, it is necessary to know what antenna characteristics will be exhibited if the reactance value of the variable reactor is changed.

  The antenna characteristics are generally simulated using an analysis method such as the moment method. When simulating antenna characteristics by the method of moments, the current flowing through each element is simulated by dividing the antenna into elements (mesh) and solving simultaneous linear equations defined in the frequency domain. The moment method is described in Non-Patent Document 1 below.

  In this way, when simulating antenna characteristics using an analysis method such as the method of moments, a mathematical model of the antenna to be simulated is constructed and the analysis method is applied to it. . At this time, when simulating the characteristics of the antenna loaded with the reactor, the simulation is performed by constructing a mathematical model with the reactor as a part of the antenna.

  From now on, when simulating the antenna characteristics of a variable directivity antenna loaded with a variable reactor, the variable reactor is calculated as part of the antenna, so the antenna characteristics when the reactance value of the variable reactor is changed If the reactance value of the variable reactor is variously changed, the mathematical model is recreated each time and the analysis method is applied.

That is, first, assuming a certain reactance value, a mathematical model of the antenna is constructed, and an analysis method is applied to it to obtain antenna characteristics such as directivity at the reactance value. By constructing a mathematical model of the antenna assuming another reactance value and applying an analysis method to it, the antenna characteristics such as directivity at the reactance value are obtained. By assuming a reactance value and constructing a mathematical model of the antenna and applying an analysis method thereto, the process of obtaining antenna characteristics such as directivity at the reactance value is repeated.
HNWang, JHRichmond and MCGilreath: "Sinusoidal reaction formulation for radiation and scattering from cond-ucting surface" IEEE TRANSACTIONS ANTENNAS PROPAGATION vol.AP-23 1975

  Thus, according to the prior art, when simulating the antenna characteristics of a variable directional antenna loaded with a variable reactor using an analysis method such as the moment method, the reactance value of the variable reactor is changed in various ways. Each time a mathematical model is re-created and the analysis method is applied, there is a problem that an enormous amount of calculation is required.

  Thus, according to the prior art, there is a problem that the antenna characteristics indicated by the variable directivity antenna loaded with the variable reactor cannot be obtained quickly.

  On the other hand, with a variable directivity antenna loaded with a variable reactor, the realizable state is unknown and the relationship with the reactance value is non-linear, so it is not easy to find the optimal control state easily. There is also a problem.

  As a method for solving the latter problem, there is a method of using the steepest gradient method. However, since the steepest gradient method has a problem that the convergence state changes depending on the initial value, there is a problem that if the steepest gradient method is used blindly, it may fall into a local optimum state.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a new technique that makes it possible to quickly and easily find the optimum control state of a variable directional antenna loaded with a variable reactor. .

  In order to achieve this object, the antenna characteristic display device of the present invention performs processing for obtaining and displaying the characteristics of an antenna loaded with a variable reactor, and (1) mathematics of the structure of the antenna to be processed. A first calculation means for calculating a structural parameter independent of the value of the variable reactor, which is a characteristic of the antenna, by performing analysis on the dynamic model using a prescribed analysis method; and (2) the variable reactor A setting means for sequentially setting values within a range of specified values; and (3) a structural parameter calculated by the first calculating means and a variable reactor value set by the setting means as inputs, according to a specified calculation formula A second calculating means for calculating antenna characteristics depending on the value of the variable reactor; and (4) a variable reactor set by the setting means by assigning different coordinates to each of the variable reactors. Is provided with display means for generating drawing data in which the antenna characteristic value calculated by the second calculation means is a coordinate value different from those coordinates, and displaying on the display. Constitute.

  When adopting this configuration, the first calculation means has a unit current in only one port between the power supply port and the variable reactor port of the antenna to be processed, and all other ports. In some cases, an impedance indicating a voltage generated at each port and an equivalent steering vector indicating directivity are calculated as structural parameters when the is open.

  In addition, the first calculation means is for when there is a unit voltage in only one port and all other ports are short-circuited between the power supply port and the variable reactor port of the antenna to be processed. In some cases, an admittance indicating a current flowing through each port and an equivalent steering vector indicating directivity are calculated as structural parameters.

  In addition, the display unit may generate drawing data for contour display of the antenna characteristic value calculated by the second calculation unit and display the drawing data on the display.

  Each of the above processing means can also be realized by a computer program. This computer program is provided by being recorded on an appropriate computer-readable recording medium or provided via a network, and is used when implementing the present invention. The present invention is realized by being installed and operating on a control means such as a CPU.

  When obtaining the characteristics of an antenna loaded with a variable reactor, the antenna portion excluding the variable reactor does not change and can be expressed by a constant parameter (referred to as a structural parameter in the present invention).

Focusing on this point, the present inventors have the following references:
(I) For each port between the power supply port of an antenna loaded with a variable reactor and the port of the variable reactor port, each port has a unit current and all other ports are open. (Ii) One impedance between the port of the feed port and the variable reactor port of the antenna loaded with the variable reactor is calculated as a structural parameter. An invention is disclosed in which an admittance indicating the current flowing through each port and an equivalent steering vector indicating directivity are calculated as structural parameters when only the port has a unit voltage and all other ports are short-circuited. .

[References] Iigusa, Ohira, Komiyama, “Espa antenna equivalent steering vector model and structural parameter extraction method,” IEICE theory (B-II), vol.J88-B, no.1, pp.291-3 09, Jan. 2005.
If this structural parameter is used, the analysis of the antenna loaded with the variable reactor is performed according to a calculation formula (equivalent steering vector model described in the reference) that substitutes the structural parameter and the reactance value of the variable reactor without analysis each time. Characteristics can be obtained.

  From now on, in the antenna characteristic display device of the present invention, by analyzing the mathematical model of the structure excluding the variable reactor of the antenna loaded with the variable reactor using the specified analysis method, The structure parameter that does not depend on the reactance value of a certain variable reactor is calculated, and the calculated structure parameter and the set reactance value are specified while sequentially setting the reactance value of the variable reactor within the range of the specified value. By substituting into the calculation formula, the antenna characteristic depending on the reactance value of the variable reactor is calculated.

  In the antenna characteristic display device of the present invention, when the characteristic of the antenna loaded with the variable reactor is obtained by changing the reactance value of the variable reactor in this way, for example, the reactance value 1 of the variable reactor 1 and the variable reactor 1 Drawing data such as contour display using the characteristic value of the antenna characteristic as the coordinate axis representing the height is generated on the coordinate plane stretched by the reactance value 2 of 2 and processed so as to be displayed on the display.

  According to this configuration, according to the antenna characteristic display device of the present invention, the designer of the variable directivity antenna can quickly and easily find the optimum control state of the variable directivity antenna.

  In the present invention, the characteristics of the antenna portion excluding the variable reactor are independently analyzed as structural parameters, and the characteristics of the variable directional antenna loaded with the variable reactor are calculated based on the structural parameters and the reactance values of the variable reactor. As a result, the characteristics of the variable directional antenna can be calculated quickly, and the antenna characteristics can be presented in a form that is easy to understand by graphically displaying the antenna characteristics. Thus, the designer of the variable directional antenna can quickly and easily find the optimal control state of the variable directional antenna.

  Hereinafter, the present invention will be described in detail according to embodiments.

  FIG. 1 illustrates an embodiment of an antenna characteristic display device 1 having the present invention.

  The antenna characteristic display device 1 of the present invention performs a process of obtaining the characteristic of an antenna loaded with a variable reactor and displaying the characteristic on the display 2. In order to perform this process, a simulator 10 and a reactance value setting unit 11 are provided. A reactance value-dependent antenna characteristic calculation unit 12, a reactance value-dependent antenna characteristic storage unit 13, and an antenna characteristic drawing data generation unit 14.

  The simulator 10 stores antenna structure information storage unit 100 that stores the structural information of the antenna loaded with the variable reactor to be simulated, and stores a mathematical model of the structure excluding the variable reactor of the antenna, and antenna structure information. An antenna structure information reading unit 101 that reads a mathematical model of an antenna to be simulated from the storage unit 100, and a moment method, a finite element method, an FDTD method (Finite method) for the mathematical model read by the antenna structure information reading unit 101 An antenna characteristic calculation unit 102 that calculates a structural parameter that does not depend on the reactance value of the variable reactor that is the characteristic of the antenna to be simulated by performing simulation using an analysis method such as Difference Time Domain Method) .

  At this time, the antenna characteristic calculation unit 102 calculates the impedance (or admittance) and the equivalent steering vector described in the above-mentioned reference as structural parameters.

  That is, the antenna characteristic calculation unit 102 (i) between the power supply port and the variable reactor port of the antenna loaded with the variable reactor, there is a unit current in only one port, and all the other ports are open. When calculating the structure parameters, the impedance indicating the voltage generated at each port and the equivalent steering vector indicating directivity are used as structural parameters, or (ii) between the feed port and variable reactor port of the antenna loaded with the variable reactor. Between ports, when only one port has a unit voltage and all other ports are short-circuited, admittance indicating the current flowing through each port and equivalent steering vector indicating directivity are calculated as structural parameters. To do.

  The reactance value setting unit 11 sets the reactance value of the variable reactor of the antenna to be simulated within a range of values that the reactance value can take in response to a setting request from the reactance value dependent antenna characteristic calculation unit 12. , The reactance value-dependent antenna characteristic calculation unit 12 is passed. Here, the range of values that the reactance value can take is set according to an instruction from the designer of the variable directivity antenna.

  The reactance value dependent antenna characteristic calculation unit 12 receives the structural parameter calculated by the simulator 10 and the reactance value of the variable reactor set by the reactance value setting unit 11 as input, according to the equivalent steering vector model described in the above-mentioned reference document. The antenna characteristic depending on the reactance value of the antenna to be processed (the antenna loaded with the variable reactor) is calculated.

  The antenna characteristics calculated at this time include, in addition to the antenna characteristics directly calculated from the equivalent steering vector model, the antenna characteristics derived from the directly calculated antenna characteristics (for example, the antenna characteristics depending on the angle) In this case, there is an antenna characteristic such as what the maximum value is), and from this, the reactance value dependent antenna characteristic calculation unit 12 calculates the antenna characteristic calculated directly from the equivalent steering vector model A primary antenna characteristic calculation unit 120, and a secondary antenna characteristic calculation unit 121 that calculates an antenna characteristic derived from the antenna characteristic calculated by the primary antenna characteristic calculation unit 120.

  The reactance value-dependent antenna characteristic storage unit 13 stores the antenna characteristic depending on the reactance value calculated by the reactance value-dependent antenna characteristic calculation unit 12 in correspondence with the reactance value.

  The antenna characteristic drawing data generation unit 14 generates drawing data (for example, drawing data for displaying the antenna characteristic in a contour line) schematically showing the antenna characteristic stored in the reactance value dependent antenna characteristic storage unit 13 and displays it on the display 2. .

  FIG. 2 shows an example of a flowchart executed by the simulator 10, FIGS. 3 and 4 show an example of a flowchart executed by the reactance value-dependent antenna characteristic calculation unit 12, and FIG. 5 shows generation of antenna characteristic drawing data. An example of the flowchart which the part 14 performs is illustrated.

  Next, processing executed by the antenna characteristic display device 1 of the present invention configured as shown in FIG. 1 will be described according to these flowcharts.

  In the antenna characteristic display device 1 of the present invention, the simulator 10 is activated when processing for obtaining the characteristic of the antenna loaded with the variable reactor and displaying it on the display 2 is performed.

  When the simulator 10 is activated, as shown in the flowchart of FIG. 2, first, in step S100, a mathematical model of a structure excluding the variable reactor is obtained for the antenna loaded with the variable reactor to be simulated. create.

  Subsequently, in step S101, the created mathematical model is simulated using an analysis method such as the moment method, the finite element method, or the FDTD method, so that the antenna characteristic does not depend on the reactance value of the variable reactor. Calculate structural parameters. That is, the aforementioned impedance or admittance and equivalent steering vector are calculated.

  Subsequently, in step S102, the calculated structural parameter is designated, the reactance value-dependent antenna characteristic calculation unit 12 is called, and the process is terminated.

  Next, processing executed by the reactance value dependent antenna characteristic calculation unit 12 will be described.

  When called in this way, the reactance value dependent antenna characteristic calculation unit 12 first selects one variable reactor possessed by the antenna to be simulated in step S200, as shown in the flowchart of FIG. .

  Subsequently, in step S201, a reactance value setting request is issued to the reactance value setting unit 11 to set the reactance value of the selected variable reactor. At this time, the initial value of the reactance value is set.

  Subsequently, in step S202, a reactance value setting request is issued to the reactance value setting unit 11, thereby setting the reactance values of the remaining variable reactors of the antenna to be simulated.

  Subsequently, in step S203, based on the set reactance value of the variable reactor, the structural parameter designated by the simulator 10, and the equivalent steering vector model (the calculation formula for calculating the reactance-dependent antenna characteristic), The antenna characteristic depending on the reactance value is calculated, and if there is an antenna characteristic derived therefrom, the antenna characteristic is calculated and stored in the reactance value dependent antenna characteristic storage unit 13.

  Subsequently, in step S204, it is determined whether or not all reactance values have been set in step S202, and when it is determined that all reactance values have not been set, the process returns to step S202.

  On the other hand, when it is determined in step S202 that the setting of all reactance values has been completed according to the determination process in step S204, the process proceeds to step S205, and it is determined whether or not setting of all reactance values has been completed in step S201. When it is determined that the setting of all reactance values has not been completed, the process returns to step S201.

  On the other hand, when it is determined in step S201 that the setting of all reactance values has been completed according to the determination process in step S205, the process proceeds to step S206, and it is determined in step S200 whether selection of all variable reactors has been completed.

  According to the determination process of step S206, when it is determined in step S200 that selection of all variable reactors has not been completed, the process returns to step S200, and when it is determined that selection of all variable reactors has been completed, step S207 is performed. Then, the antenna characteristic drawing data generation unit 14 is called to finish the process.

  Here, in the flowchart of FIG. 3, the reactance value-dependent antenna characteristic calculation unit 12 sets the combination of all reactance values (reactance values within a range of possible values) for all variable reactors to set the antenna characteristics. Although the configuration of calculating was adopted, two variable reactors were selected, a combination of all reactance values (reactance values within a range of possible values) for the two selected variable reactors was set, and the remaining The reactance value of the variable reactor may be set to a fixed value and the antenna characteristics may be calculated.

  FIG. 4 illustrates an example of a flowchart executed by the reactance value-dependent antenna characteristic calculation unit 12 when calculating the antenna characteristic in such a form.

  When executing the flowchart of FIG. 4, the reactance value-dependent antenna characteristic calculation unit 12 first, in step S300, in accordance with an instruction from the designer of the variable directivity antenna, Variable reactors Xa and Xb are selected.

  Subsequently, in step S301, in accordance with an instruction from the designer of the variable directivity antenna, a range of reactance values that can be taken by the selected two variable reactors Xa and Xb is set.

  Subsequently, in step S302, in accordance with an instruction from the designer of the variable directivity antenna, the reactance value of the variable reactor not selected is set.

  Subsequently, in step S303, by issuing a reactance value setting request to the reactance value setting unit 11, the reactance value of the selected one of the variable reactors Xa is set within the range of the reactance values that can be set. . At this time, the initial value of the reactance value is set.

  Subsequently, in step S304, by issuing a reactance value setting request to the reactance value setting unit 11, the reactance value of the other selected variable reactor Xb is set within a set range of reactance values. .

  Subsequently, in step S305, based on the set reactance value of the variable reactor, the structural parameter designated by the simulator 10, and the equivalent steering vector model (the calculation formula for calculating the reactance-dependent antenna characteristic), The antenna characteristic depending on the reactance value is calculated, and if there is an antenna characteristic derived therefrom, the antenna characteristic is calculated and stored in the reactance value dependent antenna characteristic storage unit 13.

  Subsequently, in step S306, it is determined whether or not all reactance values have been set for the variable reactor Xb in step S304, and when it is determined that all reactance values have not been set, the processing in step S304 is performed. Return to.

  On the other hand, when it is determined in step S304 that the setting of all reactance values for the variable reactor Xb has been completed according to the determination process in step S306, the process proceeds to step S307, and the setting of all reactance values for the variable reactor Xa is completed in step S303. If it is determined whether or not the setting of all reactance values has not been completed, the process returns to step S303.

  On the other hand, when it is determined in step S303 that the setting of all reactance values for the variable reactor Xa has been completed according to the determination process in step S307, the process proceeds to step S308 to call the antenna characteristic drawing data generation unit 14 and terminate the process. To do.

  In this way, when the reactance value-dependent antenna characteristic calculation unit 12 follows the flowchart of FIG. 4, the reactance value-dependent antenna characteristic calculation unit 12 selects two variable reactors, and all the reactance values (values of possible values) for the two selected variable reactors. The combination of the reactance values within the range is set, and the reactance values of the remaining variable reactors are set to fixed values, and the antenna characteristics are calculated.

  Next, processing executed by the antenna characteristic drawing data generation unit 14 will be described.

  When called up in this way, the antenna characteristic drawing data generation unit 14 first sets the coordinates for each variable reactor of the antenna to be simulated in step S400, as shown in the flowchart of FIG. assign.

  For example, if the antenna to be simulated has two variable reactors, for example, the X axis is assigned to one of them and the Y axis is assigned to the other. When the reactance value dependent antenna characteristic calculation unit 12 executes the flowchart of FIG. 4, for example, the X axis is assigned to the variable reactor Xa and the Y axis is assigned to the variable reactor Xb.

  Subsequently, in step S401, unassigned coordinates are assigned to the antenna characteristics to be displayed. For example, the Z axis, which is an unassigned coordinate, is assigned to the antenna characteristic to be displayed.

  Subsequently, in step S402, the reactance value-dependent antenna characteristic storage unit 13 that stores the antenna characteristic value while corresponding to the reactance value is read out, and the reactance value-dependent antenna characteristic is read and the coordinates assigned in steps S400 and 401 are used. Then, drawing data having the reactance value of the variable reactor and the antenna specific value as the coordinate values is generated.

  Subsequently, in step S403, the generated drawing data is displayed on the display 2, and the process is terminated.

  As described above, the antenna characteristic display device 1 of the present invention uses an analysis method such as the moment method, the finite element method, or the FDTD method for the mathematical model of the structure excluding the variable reactor of the antenna loaded with the variable reactor. By using the simulation to calculate a structural parameter that does not depend on the reactance value of the variable reactor that is the characteristic of the antenna, while setting the reactance value of the variable reactor within the range of the specified value sequentially, Based on the calculated structural parameter, the set reactance value, and the equivalent steering vector model, the antenna characteristic depending on the reactance value of the variable reactor is calculated, and the calculated antenna characteristic is graphically displayed. To do.

  Next, a process performed by the antenna characteristic display device 1 of the present invention will be described with a specific example of a process for a planar variable directional antenna in which two slots loaded with variable reactors are arranged on both sides of the power supply slot. Will be described in detail.

  FIG. 6 shows the basic structure of the slot array antenna used in this specific processing.

  In this slot array antenna, the slot is processed by a printing technique or the like. In order to suppress the radiation to the rear, a ground plane conductor is provided on the back surface, and in order to prevent radiation from a gap between two parallel flat plates, a cavity structure is formed by surrounding with a conductor wall. The antenna element spacing is 1/4 wavelength, the slot length is 0.45 wavelength, and the feed point and variable reactor loading point are at the center of each slot. Other parameters are shown in the figure. A varactor diode is used as the variable reactor, and the electric capacity is controlled by a DC voltage. Since both sides of the slot have the same DC voltage, a DC voltage cannot be applied even if a varactor diode is connected. Therefore, varactor diodes are connected in anti-series pairs.

  Although the antenna characteristics can be analyzed using the method of moments, calculating the antenna characteristics of all combinations of reactance values using the method of moments is very inefficient and inefficient.

  Therefore, in the antenna characteristic display device 1 of the present invention, the reactance value dependency of the antenna characteristic is obtained using an equivalent steering vector model.

That is, the inter-port impedance Z _nm and the equivalent steering vector u ^(v) _m (θ, φ), which are structural parameters, are obtained using the moment method, and the electric field E (θ, φ) and the operating gain G _w (θ , Φ) and voltage standing wave ratio vswr are calculated according to the following equation (equivalent steering vector model) based on their structural parameters. In the equation, θ represents an angle from the Z axis, φ represents an angle from the X axis, and diag represents a diagonal matrix.

Here, X _1, X ₂ reactance values of the two variable reactors, v _s is powered open circuit voltage when considered in transmission, Z _s is the characteristic impedance (real) feed line, v _m is the m-th port voltage (m = 0 represents a feeding port), M is the number of variable reactors, gamma is the reflection coefficient, G _a represents an absolute gain.

  The relationship between the reactance value and the antenna characteristic is non-linear as shown in Equation (2). Furthermore, since the antenna characteristics that can be realized are limited to a state that can be controlled by the reactance value, and the antenna control state that can be realized is unknown, the optimum control state cannot be obtained by a normal method. As described above, the steepest gradient method is used as one method, but it may converge to a local optimum state and a global optimum value may not be found.

Therefore, in the antenna characteristic display device 1 of the present invention, the antenna designer displays the entire characteristic on the coordinate system of the reactance values X _{1 and} X ₂ with contour lines, so that the antenna designer can see the entire control state. Use techniques that allow you to find them.

7 shows the maximum value G _wmax of the operating gain in the beam scanning plane (plane including the normal direction of the conductor plate and the slot arrangement direction, E plane) of the antenna shown in FIG. 6, that is, the reactance value of the operating gain of the main beam. FIG. 8 shows the dependence of the main beam direction θ _{max on} the reactance value, and FIG. 9 shows the dependence of the voltage standing wave ratio vswr on the reactance value.

  By looking at the antenna characteristics of these contour lines, the antenna designer can acquire the following information.

That is, the reactance value dependency of the maximum operating gain _Gwmax and the voltage standing wave ratio vswr is very similar, and therefore, it is considered that the matching of the maximum value of the operating gain is determined dominantly. Further, since the main beam direction θ _max changes depending on the reactance value, it can be seen that the beam can be controlled by the reactance value. Further, since the region where the main beam direction θ _max continuously changes depending on the reactance value is widened, it can be seen that if the region is used, the beam can be scanned by the continuous control of the reactance value.

On the other hand, it can be seen from the boundary shown in FIG. 8 that there is a boundary where the main beam direction θ _max changes discontinuously with respect to the reactance value. Since the maximum operating gain G _wmax continuously changes with respect to the reactance value across the boundary line, the direction in which the beam is formed changes discontinuously because the magnitude relationship between the two beams is switched. it is conceivable that. In the steepest gradient method, since a change in gain with respect to a difference in reactance value is calculated, it is considered that inconvenience occurs on such a boundary.

By looking over the contours of the operating gain of the main beam and the reactance values X _{1 and} X ₂ in that direction, the following becomes possible.

  That is, (1) Find the global maximum value and direction of the operational gain, that is, the operational gain and direction of the main beam, and the reactance value that realizes it. (2) If the reactance value range is determined, the beam scannable angle range and the operating gain change are foreseen. (3) A necessary reactance variable range is obtained from an angle range for scanning a desired beam. (4) The possible beam scanning angle and the necessary reactance variable width are obtained from the necessary operating gain.

Further, by drawing the reactance values X ₁ and X ₂ for realizing a certain beam scanning as a locus on the X ₁ X ₂ coordinates, the connection of control can be visualized, so that it is easy to consider. It can be seen that the trajectory representing the beam scanning has a degree of freedom of selection. To obtain the maximum operating gain in each desired direction, draw a line along the contour line that gives the beam direction on the contour map of the main beam operating gain G _wmax , and then select the reactance value that maximizes G _wmax By doing so, the trajectory can be determined. Further, when priority is given to the angular width at which beam scanning can be performed over operating gain, different trajectories are optimal.

Furthermore, control with one of X _{1 and} X ₂ fixed is also possible. In this case, two types as shown by trajectories β and γ in FIG. 8 can be considered. In the control of the locus β, the point A (around 43 degrees) where G _wmax is maximum can be realized, but the operation gain in the 0 degree direction is reduced. On the other hand, the control of the trajectory γ is characterized in that the minimum value of the main beam is suppressed to about 0 dBi, and the operation gain can be made almost constant regardless of the scanning angle. In any case, in the case of control in which one of X _{1 and} X ₂ is fixed, it is only necessary to fix one reactance value and control only the other reactance value, so that control is possible with one DC voltage. is there.

In this way, in the antenna characteristic display device 1 of the present invention, the antenna designer displays the antenna characteristics on the coordinate system of the reactance values X _{1 and} X ₂ with contour lines, etc. It becomes possible to find the correct control state.

  The present invention can be applied to the case where the characteristics of an antenna loaded with a variable reactor are obtained. According to the present invention, the designer of the variable directional antenna can quickly and easily determine the optimum control state of the variable directional antenna. To be able to find.

It is an example of one Embodiment of the antenna characteristic display apparatus of this invention. It is an example of the flowchart which a simulator performs. It is an example of the flowchart which a reactance value dependence antenna characteristic calculation part performs. It is another example of the flowchart which a reactance value dependence antenna characteristic calculation part performs. It is an example of the flowchart which an antenna characteristic drawing data generation part performs. It is a block diagram of a slot array antenna. It is a figure which shows the operation gain _Gwmax of the main beam which the antenna characteristic display apparatus of this invention displays. It is a figure which shows direction (theta) _max of the main beam which the antenna characteristic display apparatus of this invention displays. It is a figure which shows the voltage standing wave ratio vswr which the antenna characteristic display apparatus of this invention displays.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna characteristic display apparatus 2 Display 10 Simulator 11 Reactance value setting part 12 Reactance value dependence antenna characteristic calculation part 13 Reactance value dependence antenna characteristic memory | storage part 14 Antenna characteristic drawing data generation part 100 Antenna structure information storage part 101 Antenna structure information reading part 102 Antenna characteristic calculation unit 120 Primary antenna characteristic calculation unit 121 Secondary antenna characteristic calculation unit

Claims (6)

An antenna characteristic display device for obtaining and displaying characteristics of an antenna loaded with a variable reactor,
A first calculation for calculating a structural parameter that does not depend on the value of the variable reactor, which is the characteristic of the antenna, by analyzing the mathematical model of the structure of the antenna to be processed using a specified analysis method. Means,
Setting means for sequentially setting the value of the variable reactor within the range of the specified value;
Second calculation means for calculating the antenna characteristic depending on the value of the variable reactor according to a prescribed calculation formula using the structural parameter calculated by the first calculation means and the variable reactor value set by the setting means as inputs. When,
Different coordinates are assigned to each of the variable reactors, the variable reactor values set by the setting means are used as the values of those coordinates, and the antenna characteristic values calculated by the second calculation means are different from those coordinates. Generating drawing data as coordinate values and displaying on a display;
A characteristic antenna characteristic display device. The antenna characteristic display device according to claim 1,
The first calculation means has a unit current between only one port and a port between the power supply port and the variable reactor port of the antenna to be processed when all other ports are open. Calculating an impedance indicating a voltage generated at each port and an equivalent steering vector indicating directivity as a structural parameter;
A characteristic antenna characteristic display device. The antenna characteristic display device according to claim 1,
The first calculation means has a unit voltage for only one port and a short circuit for all other ports between the power supply port and the variable reactor port of the antenna to be processed. Calculating the admittance indicating the current flowing through each port and the equivalent steering vector indicating directivity as structural parameters,
A characteristic antenna characteristic display device. The antenna characteristic display device according to any one of claims 1 to 3,
The display means generates drawing data for contour display of the antenna characteristic value calculated by the second calculation means, and displays it on the display.
A characteristic antenna characteristic display device. An antenna characteristic display method executed by an antenna characteristic display device that obtains and displays the characteristics of an antenna loaded with a variable reactor,
A process for calculating a structural parameter that does not depend on the value of the variable reactor that is the characteristic of the antenna by performing analysis using a specified analysis method on the mathematical model of the structure of the antenna to be processed,
The process of sequentially setting the value of the variable reactor within the range of the specified value,
Based on the calculated structural parameter and the set variable reactor value, a process of calculating an antenna characteristic depending on the value of the variable reactor according to a prescribed calculation formula;
Assign different coordinates to each of the variable reactors, generate the drawing data with the set variable reactor values as the values of those coordinates, and the calculated antenna characteristic values as the values of coordinates different from those coordinates And providing a process for displaying on the display,
A characteristic antenna characteristic display method. An antenna characteristic display program used for realizing an antenna characteristic display device that obtains and displays characteristics of an antenna loaded with a variable reactor,
Computer
A first calculation for calculating a structural parameter that does not depend on the value of the variable reactor, which is the characteristic of the antenna, by analyzing the mathematical model of the structure of the antenna to be processed using a specified analysis method. Means,
Setting means for sequentially setting the value of the variable reactor within the range of the specified value;
Second calculation means for calculating the antenna characteristic depending on the value of the variable reactor according to a prescribed calculation formula using the structural parameter calculated by the first calculation means and the variable reactor value set by the setting means as inputs. When,
Different coordinates are assigned to each of the variable reactors, the variable reactor values set by the setting means are used as the values of those coordinates, and the antenna characteristic values calculated by the second calculation means are different from those coordinates. An antenna characteristic display program for generating drawing data as coordinate values and causing them to function as display means for displaying on a display.

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