JP2005269382A - Method, system and device for calculating antenna characteristic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna characteristic calculating method for eliminating difficulty in arranging antennas for a desire wave and an interfering wave and changing positions in the case of adaptive control relative to the desired and interfering waves, raising precision in an electromagnetic wave direction, arbitrarily setting the number of the antennas to be arranged, and eliminating spatial and economic problems about a space to be required for an inspection, and to provide an antenna characteristic calculating system and its device concerning an array antenna which includes one power feeding element and a plurality of passive elements. <P>SOLUTION: Capacities of variable capacity diodes 12-1, 12-2, ... , connected to the passive elements 11-1, 11-2, ... , are adjusted concerning the array antenna 1. An RF magnetic field is measured in neighborhoods of the power feeding element 10 and the passive elements 11-1, 11-2, .... An output signal function is calculated based on an electric current value which is converted from the measured RF magnetic field and an electromagnetic function which indicates the desire and interfering waves. Moreover, a suitable condition is calculated from an index which is calculated by the use of a standard function. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an antenna characteristic calculation method for calculating characteristics of an antenna having a plurality of antenna elements, an antenna characteristic calculation system to which the antenna characteristic calculation method is applied, and an antenna characteristic calculation apparatus used in the antenna characteristic calculation system, and more particularly to an array. The present invention relates to an antenna characteristic calculation method, an antenna characteristic calculation system, and an antenna characteristic calculation apparatus that calculate an antenna directivity and realize adaptive control.

  Attention is focused on an electronically controlled waveguide array antenna device (hereinafter referred to as an array antenna) comprising a single feed element and a plurality of parasitic elements called parasite elements arranged at equal distances from the feed element. Has been. Each parasitic element included in the array antenna is connected to a variable capacitance diode (hereinafter referred to as a varactor). By controlling the voltage applied to the varactor, the capacitance of the varactor is adjusted, and thereby the directivity characteristics are adjusted. It becomes possible to control.

FIG. 6 is an explanatory diagram conceptually showing the structure of a conventional system for inspecting adaptive control of an array antenna. In FIG. 6, reference numeral 100 denotes an array antenna. A first transmission antenna 201 that transmits a desired wave and a plurality of second transmission antennas 202 and 202 that respectively transmit interference waves are arranged toward the array antenna 100. The array antenna 100 is further connected to a receiving circuit 101 for analyzing the received electromagnetic wave, and the analysis result of the receiving circuit 101 is sent to the computer 102. The computer 102 calculates the voltage value to be applied to each varactor so that the main beam of the array antenna 100 is directed in the direction of the desired wave and the direction of the disturbing wave is null based on the analysis result, and the calculated voltage value. Is sent to the voltage control circuit 103. The voltage control circuit 103 applies the voltage of the sent value to adjust the capacity of each varactor. Then, based on the state of control of the directivity of array antenna 100 by adjusting the capacity of the varactor and the reception state of the desired wave and the disturbing wave, the determination of the control method of array antenna 100 adapted to the arranged desired wave and the disturbing wave and the array antenna 100 inspections are performed. The equipment such as the array antenna 100, the first transmission antenna 201, and the second transmission antennas 202 and 202 suppresses the influence of external electromagnetic waves and the reflection of electromagnetic waves inside to avoid the influence of other electromagnetic waves. It is installed in the anechoic chamber 300, and the above-described inspection and the like are performed in the anechoic chamber 300. Such adaptive control is described in Non-Patent Document 1.
Jun CHENG and 2 others, “Adaptive Beamforming of ESPAR Antenna Based on Steepest Gradient Algorithm”, IEICE Transactions on Communications , July 2001, VOL. E84-B, NO. 7, p. 1790-1800

  However, in the conventional method, since each facility installed in the anechoic chamber becomes large, it is not possible to install an antenna for transmitting a desired wave and an interference wave toward the array antenna and to change the installed position. It is not easy, and it is difficult to arrange a transmitting antenna to increase the accuracy of the direction of electromagnetic waves transmitted to the array antenna, and there is a problem that the number of antennas to be installed is limited. Moreover, the space required for the anechoic chamber becomes large, and spatial and economical problems arise when the anechoic chamber is installed.

  The present invention has been made in view of such circumstances, and electromagnetic waves are virtually input to an array antenna and the capacitance of each varactor is adjusted by an electromagnetic wave function indicating electromagnetic waves such as a desired wave and an interference wave. At the same time, by setting the array antenna to the transmission mode, a current value based on the RF magnetic field induced in the vicinity of the feeding element and the parasitic element is obtained, and an output signal function indicating the directivity characteristics of the array antenna is obtained from the obtained current value. calculate. Then, the relationship between the desired signal and the disturbing wave that are virtually input and the capacity of each varactor and the output signal of the array antenna is grasped, the determination method of the array antenna adapted to the desired wave and the disturbing wave, and the array antenna Perform the inspection. This eliminates the need for an antenna that actually transmits the desired wave and jamming wave, so there is no need to change the position and position of the antenna, and the direction and number of electromagnetic waves received by the array antenna can be arbitrarily set. In addition, it is possible to increase the measurement accuracy in the direction of receiving electromagnetic waves, and it is possible to cope with a small anechoic box without requiring a large anechoic chamber, so the antenna characteristic calculation method that is easy to install An object of the present invention is to provide an antenna characteristic calculation system to which the antenna characteristic calculation method is applied, and an antenna characteristic calculation apparatus used in the antenna characteristic calculation system.

  An antenna characteristic calculation method according to a first aspect of the present invention is an antenna characteristic calculation method for calculating characteristics of an antenna having a plurality of antenna elements. An RF magnetic field generated in the vicinity of each antenna element by supplying power to at least one antenna element. And obtaining an output signal function indicating an output signal from the fed antenna element based on the current value and an electromagnetic wave function indicating an electromagnetic wave directed to the antenna.

  According to a second aspect of the present invention, there is provided an antenna characteristic calculation method comprising: one feeding element; and a plurality of parasitic elements that are arranged at positions separated from the feeding element and to which variable capacitance devices are respectively connected. In the antenna characteristic calculation method for calculating the characteristics of an antenna whose directivity changes according to the capacity of the device, by adjusting the capacity of each variable capacitance device and supplying power to the feed element, the proximity of the feed element and the passive element A current value based on the generated RF magnetic field is acquired, and an output signal function indicating an output signal from the feed element is calculated based on the current value and an electromagnetic wave function indicating an electromagnetic wave directed to the antenna. .

  According to a third aspect of the present invention, there is provided the antenna characteristic calculation method according to the second aspect, wherein the electromagnetic wave function indicating the electromagnetic wave includes an electromagnetic wave function indicating a desired wave and an electromagnetic wave function indicating an interference wave, and an output signal function satisfying a predetermined condition is Until the calculation, the adjustment of the capacitance of each variable capacitance device, the acquisition of the current value, and the calculation of the output signal function are repeated.

  According to a fourth aspect of the present invention, there is provided an antenna characteristic calculation system including an antenna having a single feed element and a plurality of parasitic elements to which variable capacitance devices are connected, means for feeding power to the feed element of the antenna, and the antenna Means for adjusting the capacitance of the variable capacitance device connected to the parasitic element, acquisition means for acquiring a current value based on the RF magnetic field generated in the vicinity of the feeding element and the parasitic element of the antenna, and the acquired current Means for calculating an output signal function indicating an output signal from the feed element based on a value and a preset electromagnetic wave function indicating the electromagnetic wave directed to the antenna.

  An antenna characteristic calculation system according to a fifth aspect of the present invention is the antenna characteristic calculation system according to the fourth aspect of the present invention, a measuring unit that measures an RF magnetic field generated in the vicinity of a feeding element and a parasitic element that the antenna has, and a box that houses the antenna and the measuring unit The acquisition means is electrically connected to the measurement means and is obtained by converting the RF magnetic field measured by the measurement means into a current value, and the box body has an electromagnetic wave absorption means on the inner wall. It is characterized by having.

  An antenna characteristic calculation apparatus according to a sixth aspect of the present invention has one feeding element and a plurality of parasitic elements that are arranged at positions separated from the feeding element and to which variable capacitance devices are respectively connected. In an antenna characteristic calculation apparatus that calculates the characteristics of an antenna whose directivity changes according to the capacity of the device, by adjusting the capacity of each variable capacitance device and supplying power to the feed element, the feed element and the parasitic element Means for receiving a current value based on an RF magnetic field generated in the vicinity; and means for calculating an output signal function indicating an output signal from the feed element based on the received current value and an electromagnetic wave function indicating an electromagnetic wave directed to the antenna; It is characterized by providing.

  In the present invention, since the desired wave and the disturbing wave are not actually transmitted, it is not necessary to install and change the position of the antenna that transmits the desired wave and the disturbing wave. Moreover, since the direction and number of electromagnetic waves received by the array antenna are virtually input as mathematical formulas, the direction and number of electromagnetic waves can be arbitrarily arranged, and the direction of receiving electromagnetic waves can be set with high accuracy. Is possible. Moreover, since it does not require the installation of an actual antenna, it is not necessary to install an anechoic chamber that requires a large space, and inspections are conducted in an anechoic box that can be easily deployed in a normal laboratory. It can be installed easily.

  In the antenna characteristic calculation method, the antenna characteristic calculation system, and the antenna characteristic calculation device according to the present invention, an antenna characteristic such as an array antenna having one feeding element and a plurality of parasitic elements is connected to the parasitic element. The capacitance of a variable capacitance device such as a variable capacitance diode is adjusted by controlling the voltage to be applied, and further, an RF magnetic field is generated in the vicinity of the feed element by feeding power to the feed element. The RF magnetic field generated by the induced current flowing in the parasitic element due to the interference with the antenna is measured by a measuring means such as a probe and converted into a current value, and the current value obtained by the conversion and the electromagnetic wave that becomes a desired wave and an interference wave are obtained. The output signal function indicating the beam pattern of the output signal of the antenna is calculated from the indicated electromagnetic wave function. Then, the output signal function is evaluated as a numerical value using the normative function, and each variable capacitor is calculated until the numerical value calculated as the evaluation result satisfies a predetermined condition such as a predetermined value or more, a predetermined value or less, a maximum value or a minimum value. The device capacity adjustment, the current value acquisition, and the output signal function calculation are repeated to calculate a set of capacity of the variable capacitance device that satisfies a predetermined condition.

  With this configuration, since it is not necessary to actually transmit the desired wave and the disturbing wave, there are excellent effects such as no need to install and change the position of the antenna that transmits the desired wave and the disturbing wave. Moreover, since the direction and number of electromagnetic waves received by the array antenna are virtually input as mathematical formulas, the direction and number of electromagnetic waves can be arbitrarily arranged, and the direction of receiving electromagnetic waves can be set with high accuracy. It has excellent effects such as being possible. Moreover, since it does not require the installation of an actual antenna, it is not necessary to install an anechoic chamber that requires a large space, and inspections are conducted in an anechoic box that can be easily deployed in a normal laboratory. Therefore, there are excellent effects such as high spatial and economical advantages and easy installation.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.

  FIG. 1 is an explanatory diagram conceptually showing the configuration of an antenna characteristic calculation system according to the present invention for inspecting adaptive control of an array antenna. In FIG. 1, reference numeral 1 denotes an electronically controlled waveguide array antenna device (hereinafter referred to as an array antenna). The array antenna 1 is a plurality of antenna elements separated from a feeding element 10 at an equal distance from the feeding element 10. Are provided with a plurality of parasitic elements 11-1, 11-2,..., 11-6 that are equally arranged at positions, and absorbing members 21, 21,. It is accommodated in a small anechoic box 2 fixed to the inner wall.

  In the vicinity of the feeding element 10 and the plurality of parasitic elements 11-1, 11-2,..., 11-6, measuring means 22-0, 22-such as a low disturbance magnetic field probe for measuring an RF magnetic field (evanescent magnetic field). , 22-6 are arranged, and the RF magnetic field measured by the measuring means 22-0, 22-1, 22-2,..., 22-6 is acquired outside the anechoic box 2. It is converted into a current value by means 23 and sent to the antenna characteristic calculation device 3 using a computer such as a general-purpose computer that detects the characteristics of the array antenna 1.

  The antenna characteristic calculation device 3 includes variable capacitance devices (hereinafter referred to as varactors) 12-1, 12- connected to the parasitic elements 11-1, 11-2,..., 11-6, respectively. In order to adjust the capacity of 2,..., 12-6, voltage control means 4 for controlling the voltage applied to the varactors 12-1, 12-2,.

FIG. 2 is a perspective view conceptually showing the array antenna 1 used in the antenna characteristic calculation system of the present invention. The rod-shaped power feeding element 10 is disposed perpendicularly to the base 13 at the center of the disk-shaped base 13, and the circumference of a circle centering on the power feeding element 10 in the base 13 is equally distributed. A plurality of parasitic elements 11-1, 11-2,..., 11-6 having a rod shape are arranged perpendicular to the base 13 at the positions. 2 shows an example in which six parasitic elements 11-1, 11-2,..., 11-6 are arranged at a distance d from the feeding element 10, respectively. The number of is not limited to six. If the wavelength of the desired wave to be received by the array antenna 1 is λ, the distance d = λ / 4. In the following description, a spherical coordinate system having a phase center at a position A ₀ where the feeding element 10 is arranged on the base 13 is assumed, and the angle in the circumferential direction of the base 13 is set to the parasitic element 11 in FIG. The azimuth angle φ with respect to the direction of −1 is used as the reference, and the elevation angle is indicated using the elevation angle θ.

  Varactors 12-1, 12-2,..., 12-6 are connected to one end side of each parasitic element 11-1, 11-2,..., 11-6, and in the example shown in FIG. The capacity of each varactor 12-1, 12-2,..., 12-6 is adjusted by the voltage applied by the voltage control means 4. Further, one end side of the power feeding element 10 is connected with a power feeding means 14 for feeding a high frequency signal. Then, by feeding a high frequency signal from the power feeding means 14 to the power feeding element 10, the power feeding element 10 is excited, and the array antenna 1 is in the transmission mode. When the array antenna 1 enters the transmission mode, an RF magnetic field is generated in the vicinity of the feed element 10, and the generated RF magnetic field is electromagnetically coupled to the parasitic elements 11-1, 11-2, ..., 11-6. The parasitic elements 11-1, 11-2,..., 11-6 induce a current. Then, an RF magnetic field is generated in the vicinity of the parasitic elements 11-1, 11-2,. The directivity characteristic of the array antenna, that is, the beam pattern is determined by the induced RF magnetic field.

  FIG. 3 is a block diagram showing the configuration of the antenna characteristic calculation apparatus 3 used in the antenna characteristic calculation system of the present invention. The antenna characteristic calculation device 3 is a CD-ROM for reading various information from a control unit 31 such as a CPU for controlling the entire device, a computer program 5 of the present invention and a recording medium such as a CD-ROM recording various information such as data. An auxiliary storage unit 32 such as a drive, a recording unit 33 such as a hard disk for recording various information read by the auxiliary storage unit 32, and a storage unit 34 such as a RAM for storing temporarily generated information are provided.

  Then, the computer program 5 of the present invention recorded in the recording means 33 is stored in the storage means 34 and executed by the control means 31, whereby the general-purpose computer operates as the antenna characteristic calculation device 3 of the present invention.

  Furthermore, the antenna characteristic calculation device 3 includes a first connection unit 35 that receives the current value acquired by the acquisition unit 23 from the RF magnetic field, a second connection unit 36 that transmits a command for controlling the voltage control unit 4, a keyboard, and the like. Input means 37 and display means 38 such as a liquid crystal display.

Next, processing of various devices used in the antenna characteristic calculation system of the present invention will be described. First, the outline of the process will be described. In the antenna characteristic calculation system of the present invention, the directivity characteristics of the antenna beam of the array antenna 1 are detected in a transmission mode in which a high-frequency signal is fed from the feeding unit 14 to the feeding element 10 to excite the feeding element 10. The directivity of the antenna beam controls the voltage applied to each varactor 12-1, 12-2,..., 12-6, and adjusts the capacity of each varactor 12-1, 12-2,. Is done. In order to express by the generalized expression here, the reactance vector x when the number of varactors 12-1, 12-2,... Of the array antenna 1 is M is represented as varactors 12-1, 12-2,. Each capacity of −M is defined by the following equation 1 using x ₁ , x ₂ ,..., X _M.

The directivity characteristics of the array antenna 1 are detected by measuring the RF magnetic field induced in the vicinity of the feeding element 10 and the parasitic elements 11-1, 11-2,. , 22-2,..., 22-6, and converted into a current value by the acquisition means 23. Here, the current vector i when the number of parasitic elements of the array antenna 1 is M in order to express it by a generalized expression is represented by measuring means 22-0, 22-1, 22-2,..., 22-6. The high frequency current values i ₀ , i ₁ , i ₂ ,..., I _M converted from the RF magnetic field in the vicinity of the feed element 10 and the parasitic elements 11-1, 11-2,. It is defined by the following formula 2. At this time, the directivity characteristic of the antenna beam can be expressed by Equation 3 shown below.

As shown in Equation 3, each current i ₀ , i ₁ , i ₂ ,..., I _M is equivalent to a weight vector in the array antenna. Therefore, the output signal function y (t) indicating the output signal from the power feeding element 10 can be expressed by the following Expression 4.

In addition, the array manifold A (θ, φ) in Expression 4 means the steering vectors a (θ ₁ , φ ₁ ), a (θ ₂ , φ) of the parasitic elements 11-1, 11-2,. ₂ ),..., A vector sequence defined by Equation 5 below using a (θ _M , φ _M ).

  In Equation 4, s (t) is an electromagnetic wave function that virtually indicates a desired wave that should be received and an interference wave that should not be received toward the array antenna 1, and k electromagnetic waves are directed to the array antenna 1. Is defined by a vector of Equation 6 shown below having those k signal waveforms as components.

  In the antenna characteristic calculation system of the present invention, voltages to be applied to the varactors 12-1, 12-2,..., 12-M are set, and the feeding element 10 and the parasitic elements 11-1, 11-2,. The RF magnetic field in the vicinity of −M is measured by the measuring means 22-0, 22-1, 22-2,..., 22-M, and the acquisition magnetic means 23 converts the RF magnetic field into a current value. The varactors 12-1, 12-2,..., 12 are obtained by performing such processing of detecting the directivity characteristics of the array antenna 1 based on the acquired current value and the electromagnetic wave function indicating the desired wave and the interference wave. Repeat each time the voltage is changed to adjust the capacity of −M, and calculate a set of applied voltages suitable for the electromagnetic wave indicated by the electromagnetic wave function. The directivity detection is calculated from the acquired current value by using the output signal function shown in Expression 3, and the evaluation is performed using the index function calculated by using the norm function that calculates the index serving as a reference for control. Do by value.

  As the reference function, for example, an MCCC (Maximum Cross Correlation Coefficient) function shown in the following Expression 7 is used. In the conventional adaptive antenna inspection of the array antenna, a reference signal is included in the header of the transmission packet in order to determine the reception status of the desired wave and the disturbing wave, and the desired wave and the reference signal received by the array antenna The reception situation was determined based on the cross-correlation. However, the present invention is characterized in that the desired wave and the disturbing wave are set as virtual electromagnetic wave functions. Therefore, the reference signal is also set virtually.

  The MCCC function shown in Equation 7 is an algorithm that maximizes the cross-correlation coefficient between the desired wave and the reference signal. On the other hand, while the index ρ is obtained, it is evaluated that the set of applied voltages at which the index ρ is the maximum or a predetermined value or more is a set suitable for the electromagnetic wave set as the electromagnetic wave function.

  Next, the processing procedure of the antenna characteristic calculation system of the present invention will be described. 4 and 5 are flowcharts showing the processing of the antenna characteristic calculation apparatus 3 of the present invention. In the following description, the electromagnetic wave function s (t) indicating the desired wave and the disturbing wave is set in advance using, for example, the input means 37. In the processing shown in FIGS. 4 and 5, the main beam of the array antenna 1 is set. Are applied to the varactors 12-1, 12-2,... So that the direction of the desired wave is directed and the direction of the disturbing wave is null. In the antenna characteristic calculation device 3, the computer program 5 is stored in the storage unit 34, and the stored computer program 5 is executed under the control of the control unit 31 to perform the following processing. First, the antenna calculation device 3 sets an initial value 1 for the number of repetitions n, and performs an initialization process for setting a preset initial value V (1) as a voltage to be applied to the feed element 10 (step S1). An initial value 0 is set to a variable m associated with the parasitic elements 11-1, 11-2,... (Step S2). The measuring means 22-0, 22-1, 22-2,... Measure the RF magnetic field induced in the vicinity of the feeding element 10 and the parasitic elements 11-1, 11-2,. The high-frequency current value converted from the RF magnetic field is sent from the acquisition means 23 to the antenna characteristic calculation device 3.

In the antenna characteristic calculation device 3, the current measurement value i (0) -i (m) of the high-frequency current is received from the acquisition unit 23 (step S3), the received current value i (0) -i (m), and preset. The output signal function y (n) indicating the output signal from the feed element 10 is calculated from the electromagnetic wave function s (t) indicating the desired wave and the disturbing wave by the above-described equation 4 (step S4). The index ρ _n is calculated from the output signal function y (n) by the normative function shown by the above-described equation 6, and the calculated index ρ _n is set as ρ _n ⁽⁰⁾ as a reference value (step S5). The current value i (0) -i (m) means the current value i (0) converted from the RF magnetic field in the vicinity of the feeding element 10 and the RF in the vicinity of the parasitic elements 11-1, 11-2,. Current values i (1) to i (m) converted from a magnetic field are shown. Here, the variable m is a variable associated with the parasitic elements 11-1, 11-2,..., And the M parasitic elements are replaced with the first parasitic element 11-1 and the second parasitic element, respectively. Elements 11-2,... Are shown as Mth parasitic elements 11-M. Therefore, the current value i (1) is a current value obtained by converting the RF magnetic field in the vicinity of the first parasitic element 11-1, and the current value i (m) is the mth parasitic element 11-m. , I (m) corresponds to i ₀ , i ₁ ,..., I _M in the above-described equation 2. The current values i (0), i (1),. To do.

In the antenna characteristic calculation device 3, 1 is added to the variable m (step S6), and the perturbation value ΔV _m is added to the voltage V _m set as the voltage value to be applied to the varactor 12-m. A voltage V _m to be applied to _m is newly set (step S7). As described above, the variable m is a variable associated with the parasitic elements 11-1, 11-2,..., 11-M, and the M parasitic elements are designated as the first parasitic elements 11-1. , Second parasitic element 11-2,..., Mth parasitic element 11-M. Therefore, the voltage V _m indicates a voltage value applied to the m-th varactor 12-m connected to the m-th parasitic element 11-m. The voltage value set in step S6 is sent to the voltage control means 4, and the voltage control means 4 applies the set voltage value to the m-th varactor 12-m, whereby the m-th varactor 12-m. Adjust the volume of m. And the measurement means 22 measures the RF magnetic field induced in the vicinity of the feeding element 10 and the parasitic elements 11-1, 11-2, ..., 11-M, and the high-frequency current value converted from the measured RF magnetic field is , Is sent from the acquisition means 23 to the antenna characteristic calculation device 3.

The antenna characteristic calculation device 3 receives the high-frequency current value i (0) -i (m) from the acquisition unit 23 (step S8). From the received current value i (0) -i (m) and the electromagnetic wave function s (t), the output signal function y (n) indicating the output signal from the power feeding element 10 is calculated by the above-described equation 4 (step) S9). The index ρ _n is calculated from the calculated output signal function y (n) by the norm function expressed by the above-described equation 6 (step S10), and the difference between the calculated ρ _n and ρ _n ⁽⁰⁾ is expressed as δρ _n. / ΔV _m is recorded in the recording means 33 or the storage means 34 (step S11). That is, δρ _n / δV _m indicates the fluctuation of the index ρ.

In the antenna characteristic calculation unit 3, by subtracting the perturbation values [Delta] V _m from the voltage V _m which is set as a voltage value to be applied to the varactor 12-m of the m, a voltage is applied to the varactor 12-m of the m V _m is newly set (step S12). The result is that returned based on the settings of the voltage V _m to be applied to the varactor 12-m of the m set in step S7.

  In the antenna characteristic calculation device 3, the variable m is compared with the number M of parasitic elements 11-1, 11-2,..., 11-M (step S13), and when m is smaller than M (step S13: YES). ), The process proceeds to step S6, and the subsequent processing is repeated. That is, in steps S7 to S13, a process of changing the voltage value and recording the fluctuation of the index ρ is performed for each of the varactors 12-1, 12-2, ..., 12-M.

  In step S13, when m is M or more (step S13: NO), the index ρ is calculated by changing the voltage values of all the varactors 12-1, 12-2,. The antenna characteristic calculation device 3 determines that the process has been completed, and changes the reactance vector setting using the following equation 8 (step S14).

  Then, the antenna characteristic calculation device 3 adds 1 to the number of repetitions n (step S15), and compares the number of repetitions n after the addition with a preset upper limit value N of the number of repetitions (step S16). When it is N or less (step S16: YES), the process returns to step S2 and the subsequent processing is repeated.

In step S16, when n is larger than N (step S16: NO), the antenna characteristic calculation device 3 compares δρ _n / δV _m recorded based on the index ρ and takes each varactor 12-1 when taking the maximum value. , 12-2,..., 12-M are calculated as a set suitable for the electromagnetic wave indicated by the electromagnetic wave function s (t) (step S17). When the above process is repeated a predetermined number of times (M times N times), δρ _n / δV _m is not compared, but δρ _n / δV _m takes a value equal to or greater than a predetermined value. The applied voltage in that case may be calculated as a set suitable for the electromagnetic wave indicated by the electromagnetic wave function s (t), and the processing may be terminated.

  In the above-described embodiment, a mode in which M = 6, that is, a mode in which there are six parasitic elements is shown, but the present invention is not limited to this, and M = 3, M = 8, etc. can be appropriately set. It is.

In the above embodiment, the MCCC function is used as the reference function for calculating the index. However, the present invention is not limited to this, and another reference function such as an MMMC function may be used as the reference function. . A set of applied voltages in which δρ _n / δV _m takes a minimum value or a value equal to or less than a predetermined value may be calculated according to the nature of the normative function used.

  Furthermore, in the above-described embodiment, the form using the steepest gradient method has been shown. However, the present invention is not limited to this, and a numerical solution method that is performed by repeating a random method, a random method, a high-dimensional bisection method, or the like is used. May be.

It is explanatory drawing which shows notionally the structure of the antenna characteristic calculation system of this invention which test | inspects the adaptive control of an array antenna. It is a perspective view which shows notionally the array antenna used with the antenna characteristic calculation system of this invention. It is a block diagram which shows the structure of the antenna characteristic calculation apparatus used with the antenna characteristic calculation system of this invention. It is a flowchart which shows the process of the antenna characteristic calculation apparatus of this invention. It is a flowchart which shows the process of the antenna characteristic calculation apparatus of this invention. It is explanatory drawing which shows notionally the structure of the system which test | inspects the adaptive control of the conventional array antenna.

Explanation of symbols

1 Electronically controlled waveguide array antenna device (array antenna)
DESCRIPTION OF SYMBOLS 10 Feeding element 11 Parasitic element 12 Variable capacity device (variable capacity diode: Varactor)
DESCRIPTION OF SYMBOLS 13 Base 14 Feeding means 2 Anechoic box 21 Absorbing member 22-0, 22-1, 22-2, ..., 22-6 Measuring means 23 Acquisition means 3 Antenna characteristic calculation device 31 Control means 32 Auxiliary storage means 33 Recording means 34 Storage Means 35 First connection means 36 Second connection means 37 Input means 38 Display means 4 Voltage control means 5 Computer program

Claims (6)

In the antenna characteristic calculation method for calculating the characteristic of an antenna having a plurality of antenna elements,
Obtaining a current value based on an RF magnetic field generated in the vicinity of each antenna element by feeding at least one antenna element;
An antenna characteristic calculation method comprising: calculating an output signal function indicating an output signal from a fed antenna element based on the current value and an electromagnetic wave function indicating an electromagnetic wave directed toward the antenna. One feed element and a plurality of parasitic elements arranged at positions separated from the feed element and connected to variable capacitance devices, respectively, and directivity changes according to the capacitance of each variable capacitance device In the antenna characteristic calculation method for calculating the antenna characteristic,
Adjust the capacity of each variable capacity device,
By supplying power to the feed element, a current value based on the RF magnetic field generated in the vicinity of the feed element and the parasitic element is obtained,
An antenna characteristic calculation method, comprising: calculating an output signal function indicating an output signal from a feed element based on the current value and an electromagnetic wave function indicating an electromagnetic wave directed toward the antenna. The electromagnetic wave function indicating the electromagnetic wave includes an electromagnetic wave function indicating a desired wave and an electromagnetic wave function indicating an interference wave,
The antenna characteristic calculation according to claim 2, wherein the adjustment of the capacity of each variable capacitance device, the acquisition of the current value, and the calculation of the output signal function are repeated until an output signal function that meets a predetermined condition is calculated. Method. An antenna having a plurality of parasitic elements each having one feeding element and a variable capacitance device connected thereto;
Means for feeding power to the feeding element of the antenna;
Means for adjusting the capacitance of a variable capacitance device connected to a parasitic element of the antenna;
Obtaining means for obtaining a current value based on an RF magnetic field generated in the vicinity of a feeding element and a parasitic element of the antenna;
Means for calculating an output signal function indicating an output signal from the feed element based on the acquired current value and a preset electromagnetic wave function indicating the electromagnetic wave directed to the antenna; and an antenna characteristic calculation system comprising: . Measuring means for measuring an RF magnetic field generated in the vicinity of a feeding element and a parasitic element of the antenna;
A box that houses the antenna and the measuring means,
The acquisition means is electrically connected to the measurement means, and is obtained by converting the RF magnetic field measured by the measurement means into a current value,
The antenna characteristic calculation system according to claim 4, wherein the box has an electromagnetic wave absorbing means on an inner wall. One feeding element and a plurality of parasitic elements that are arranged at positions separated from the feeding element and to which variable capacitance devices are respectively connected, and the directivity changes according to the capacitance of each variable amount device. In the antenna characteristic calculation device for calculating the antenna characteristic,
Means for adjusting the capacity of each variable capacity device;
Means for receiving a current value based on an RF magnetic field generated in the vicinity of the feeding element and the parasitic element by feeding power to the feeding element;
An antenna characteristic calculation apparatus comprising: means for calculating an output signal function indicating an output signal from a power feeding element based on an accepted current value and an electromagnetic wave function indicating an electromagnetic wave directed to the antenna.

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