JP2005333451A - Antenna characteristic evaluation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna characteristic evaluation system capable of performing quick and highly accurate antenna characteristic evaluation while considering complicated antenna radiation characteristics and radio wave propagation characteristics including effect on human bodies. <P>SOLUTION: When an antenna directivity analysis part 11 in the antenna characteristic evaluation system 1 analyzes the directivity of an antenna by the FDTD method, the MOMENT method or the like which is an electro-magnetic field calculation method, a storage device 13 stores antenna complex directivity 12 such as amplitude and a phase obtained by the analytical results of the antenna directivity analysis part 11. A geometrical optical radio wave propagation characteristic analysis part 14 acquires the antenna complex directivity 12 stored in the storage device 13 and uses the directivity 12 as a directivity coefficient on a transmitting/receiving point. At the point, the geometrical optical radio wave propagation characteristic analysis part 14 excludes beams of directions of which directivity coefficients are small from calculation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antenna characteristic evaluation system that calculates propagation characteristics of radio waves transmitted from a radio station and evaluates antenna characteristics based on calculation result data, and in particular, searches for a plurality of light beams transmitted from a radio station. The present invention relates to an antenna characteristic evaluation system for evaluating antenna characteristics using a geometric optical analysis technique.

  Mobile phones that have been widely used in recent years can control directivity and polarization in accordance with various usage conditions and radio wave propagation environments. In order to develop an antenna for a mobile phone that can handle such control, the total solid angle complex directivity of the antenna calculated in consideration of the influence on the human body and the fine structure of the antenna and the multi-wave propagation parameter are calculated. A system (that is, means) that can integrate and evaluate effective antenna performance in an actual multiwave propagation environment is required.

Conventionally, an experimental method such as a random field method has been used as such an antenna performance evaluation system, but this method has problems such as requiring a large-scale experimental apparatus and a great deal of labor. Therefore, in order to cope with such a problem, an antenna characteristic evaluation method using a computer is widely used. Such an antenna characteristic evaluation method generally uses an electromagnetic field analysis method or a geometric optical calculation method as a means for obtaining the electric field strength distribution of an electromagnetic wave transmitted from a radio station. For example, as means for obtaining the electric field strength distribution of electromagnetic waves, an indoor propagation analysis method using the FDTD (Finite Difference Time Domain) method described in Non-Patent Document 1 below, There is a ray launching method, which is a geometric optical calculation method for searching a locus. In the ray launching method, as disclosed in Patent Document 1 below, pre-processing for calculating all rays transmitted from a transmission point, and post-processing for searching for rays reaching the reception point to obtain reception intensity There is known a method of calculating the electric field strength distribution of electromagnetic waves by performing calculation processing in two processes. Alternatively, as disclosed in Patent Document 2 below, a method of dividing a light beam transmitted from a transmission point in an arbitrary space and calculating a field intensity distribution of electromagnetic waves by a plurality of computers is known. .
JP 2001-136131 A JP 2002-232348 A IEICE TRANS COMMUN VOL.E86-B, NO.6 JUNE 2003

  However, in the radio wave propagation analysis method using the FDTD method, in general, when the frequency of radio waves is high or the analysis area of the electric field strength distribution is large, the amount of calculation increases. It becomes difficult to perform propagation analysis. In addition, in the analysis of radio wave propagation characteristics using geometric optical calculation methods, the antenna at the transmission / reception point does not consider the antenna characteristics including the effects on the human body, which is important for the development of mobile phone antennas. It is impossible to analyze radio wave propagation characteristics including effects on Furthermore, the calculation speed-up method using a plurality of computers for calculating the electric field strength distribution of the electromagnetic wave has a problem that the capital investment is very expensive.

  The present invention has been made in view of the above circumstances, and evaluates antenna characteristics at high speed and with high accuracy by integrating the antenna radiation characteristics including effects on the human body and the multi-wave propagation environment by a computer. An object of the present invention is to provide an antenna characteristic evaluation system.

  In order to solve the above problems, an antenna characteristic evaluation system of the present invention is an antenna characteristic evaluation system that calculates a propagation characteristic of a radio wave transmitted from a radio station and evaluates the antenna characteristic. By means of antenna directivity analysis means for calculating a complex directivity coefficient sequence for the discrete angle orientation of the second antenna, and by radiating a plurality of light rays from the transmission point and tracking the trajectory until the light rays reach the reception point Geometric optical wave propagation characteristic analyzing means for calculating propagation characteristics of radio waves between transmission and reception points in a predetermined radio wave propagation model, and the geometric optical wave propagation characteristic analyzing means is a complex directivity of the first antenna and the second antenna. By using the coefficient sequence as the antenna directivity coefficient at the transmission / reception point, the antenna directivity analysis means and the geometric optical wave propagation characteristic analysis means are integrated. Characterized by being configured to.

  In addition, the antenna characteristic evaluation system of the present invention further includes amplitude determination means for determining whether or not the amplitude with respect to the discrete angle azimuth exceeds a predetermined threshold in the complex directivity coefficient sequence of the antenna at the transmission point. According to the determination result of the amplitude determining means, it is configured to determine whether or not to emit a light beam from the transmission point.

  In the antenna characteristic evaluation system of the present invention, the antenna directivity analysis means is configured to use a finite difference time domain method. The antenna characteristic evaluation system according to the present invention further includes an antenna directivity measuring means for measuring a complex directivity coefficient sequence with respect to the discrete angle azimuths of the first antenna and the second antenna, and a geometric optical wave propagation characteristic analyzing means. However, the complex directivity coefficient sequence obtained by the antenna directivity measuring means is used as the antenna directivity coefficient at the transmission / reception point.

  Further, the antenna characteristic evaluation system of the present invention uses a storage means for storing a plurality of radio wave propagation models held by the geometric optical radio wave propagation characteristic analysis means, and a complex directivity coefficient sequence of the first antenna and the second antenna. The present invention is characterized by comprising an execution means for executing geometric optical wave propagation characteristic analysis on a plurality of radio wave propagation models specified in advance.

  Further, in the antenna characteristic evaluation system of the present invention, the geometric optical radio wave propagation characteristic analyzing unit executes an analysis calculation of the geometric optical radio wave propagation characteristic with respect to the radio wave propagation model stored in the storage unit in advance, and The phase composition calculation is performed using the complex directivity coefficient sequence of the antenna obtained by the characteristic analysis means or the antenna directivity measurement means.

  According to the antenna characteristic evaluation system of the present invention, highly accurate antenna characteristic evaluation in an actual multiwave propagation environment can be performed in a relatively short time by integrating the antenna directivity analysis means and the geometric optical wave propagation characteristic analysis means. Can be done. In addition, since the geometric optical wave propagation characteristic analyzing means can reduce the number of light rays transmitted from the transmission point, the calculation speed of the antenna characteristic is further improved. Furthermore, it is possible to perform antenna characteristic evaluation in consideration of antenna characteristics including effects on the human body and radio wave propagation characteristics in an actual multiwave propagation environment.

  Further, according to the antenna characteristic evaluation system of the present invention, the antenna directivity analysis means uses the finite difference time domain method, so that the antenna directivity analysis including the influence on the human body is performed with a computer with relatively high accuracy. Therefore, it is possible to perform antenna characteristic evaluation in consideration of antenna directivity analysis and geometric optical wave propagation characteristic analysis in a relatively short time. Furthermore, since the complex directivity coefficient sequence obtained by the antenna directivity measurement means can also be used as the antenna directivity coefficient at the transmission / reception point, radio wave propagation calculation using actually measured antenna characteristics can be performed. It is possible to evaluate antenna characteristics in an actual multiwave propagation environment.

  In addition, according to the antenna characteristic evaluation system of the present invention, by analyzing geometric optical wave propagation characteristics for a plurality of radio wave propagation models specified in advance and calculating antenna characteristics such as amplitude and phase difference, It is possible to evaluate antenna characteristics in all propagation models such as models and suburban models. Furthermore, according to the antenna characteristic evaluation system of the present invention, the phase synthesis calculation is performed using the complex directivity coefficient sequence of the antenna when the geometric optical radio wave propagation characteristic is analyzed, so that the operator can perform the geometric optical radio wave propagation analysis. There is no need to perform calculations again. Therefore, the antenna characteristics in the actual radio wave propagation environment can be evaluated in a relatively short time by using the propagation parameter and the complex directivity coefficient sequence obtained by the geometric optical wave propagation analysis calculation.

  The gist of the antenna characteristic evaluation system according to the present invention is that the antenna complex directivity obtained by the antenna directivity analysis unit is used as the directivity coefficient at the transmission / reception point of the geometric optical wave propagation characteristic analysis unit. Thereby, highly accurate antenna characteristic evaluation in an actual multiwave propagation environment can be performed in a relatively short time. Therefore, it can be effectively used as a highly accurate antenna characteristic evaluation system by a computer.

  Hereinafter, some embodiments of an antenna characteristic evaluation system according to the present invention will be described in detail with reference to the drawings. In the following description, components common to the drawings are given the same reference numerals, and redundant descriptions are omitted.

<Embodiment 1>
Embodiment 1 of an antenna characteristic evaluation system according to the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing integration of an antenna directivity analysis unit and a geometric optical wave propagation characteristic analysis unit in the antenna characteristic evaluation system according to Embodiment 1 of the present invention. In FIG. 1, an antenna characteristic evaluation system 1 includes an antenna directivity analysis unit (antenna directivity analysis means) 11 that analyzes an antenna complex directivity 12, and an antenna complex directivity 12 analyzed by the antenna directivity analysis unit 11. A storage device (storage means) 13 for storing, and a geometric optical radio wave propagation characteristic analysis unit (geometric optical wave propagation characteristic analysis means) that acquires the antenna complex directivity 12 stored in the storage device 13 and uses it as a directivity coefficient ) 14.

  Next, an outline of the operation of the antenna characteristic evaluation system 1 shown in FIG. 1 will be described. In the antenna characteristic evaluation system 1, when the antenna directivity analysis unit 11 analyzes the antenna directivity by the FDTD method or the MOMENT method that are electromagnetic field calculation methods, the storage device 13 analyzes the antenna directivity analysis unit 11. The antenna complex directivity 12 such as amplitude and phase obtained as a result is stored. Further, the geometric optical wave propagation characteristic analysis unit 14 acquires the antenna complex directivity 12 stored in the storage device 13 and uses it as the directivity coefficient at the transmission / reception point. At this time, the geometric optical wave propagation characteristic analysis unit 14 excludes light rays in a direction having a small directivity coefficient from the calculation. As a result, the antenna characteristics can be evaluated by a simple calculation process in a short time.

  Next, the operation of the antenna characteristic evaluation system 1 shown in FIG. 1 will be described in detail using a flowchart. FIG. 2 is a flowchart showing a pre-processing flow of radio wave propagation characteristic analysis performed by the geometric optical wave propagation characteristic analysis unit shown in FIG. FIG. 3 is a flowchart showing a post-processing flow of radio wave propagation characteristic analysis performed by the geometric optical wave propagation characteristic analysis unit shown in FIG. That is, FIG. 2 and FIG. 3 show a flowchart of the processing performed by the geometric optical wave propagation characteristic analysis unit 14 in the antenna characteristic evaluation system 1 of FIG. 1, and all the data transmitted from the transmission point as shown in FIG. The processing for calculating the light rays is defined as preprocessing, and the processing for searching the light rays reaching the reception point as shown in FIG.

  FIG. 4 is a diagram showing a data configuration stored in the storage device by the preprocessing shown in the flowchart of FIG. As shown in FIG. 4, the pre-processing of the radio wave propagation characteristic analysis causes the storage device 13 to store the total light equation 41, the total light traveling angle 42, the total light polarization equation 43, and the total light reflection surface number 44. , And the wall number 45 of all rays.

  FIG. 5 is a configuration diagram of a computer system for performing calculation of radio wave propagation characteristic analysis in the first embodiment of the present invention. That is, the hardware configuration for performing the electromagnetic field calculation of radio waves and the analysis processing of the radio wave propagation characteristics as shown in FIG. 2 and FIG. 3 is realized using, for example, a general computer system as shown in FIG. be able to.

  As shown in FIG. 5, the computer system includes a control device 51 such as a personal computer (hereinafter referred to as a personal computer) that performs calculation processing of radio wave propagation characteristics, a CRT that acquires information from the control device 51 and displays the information. Display device 52, printing device 53 such as a printer that obtains and prints information from control device 51, input device 54 such as a keyboard or mouse for inputting data, and analysis results of radio wave propagation characteristics are stored. The configuration includes a storage device 13 such as a hard disk. Note that the control device 51 determines whether or not the amplitude with respect to the discrete angle azimuth exceeds a predetermined threshold in the complex directivity coefficient sequence of the antenna at the transmission point according to claim 2. And execution means for executing geometric optical wave propagation characteristic analysis on a plurality of wave propagation models specified in advance using the complex directivity coefficient sequence of the antenna. Further, the computer system of FIG. 5 can use a storage medium 55 such as a removable CD or a floppy disk (registered trademark). Furthermore, the storage device 13 and the storage medium 55 can store programs, parameters, and the like for executing electromagnetic field calculations and radio wave propagation characteristic analysis processing shown in FIGS.

  Hereinafter, the calculation procedure of the radio wave propagation characteristic analysis in the first embodiment of the present invention will be described using the flowcharts of FIGS. 2 and 3. The flowchart will be described with reference to FIGS. 1 to 5 as necessary.

  First, the flow of preprocessing for radio wave propagation characteristic analysis shown in FIG. 2 will be described. First, in the parameter input procedure, the operator inputs various parameters such as the maximum number of reflections Rmax of light rays, a threshold value, a frequency, a wall surface material, the number of radiation rays, and a transmission position from the input device 54 (step ST1). In the procedure for deriving the wall surface equation, the control device 51 derives the wall surface equation based on the shape of the wall surface corresponding to the input parameter, and stores this wall surface equation in the storage device 13 (step ST2). Further, the control device 51 determines the amplitude of the radio wave for each angle of the antenna complex directivity 12 obtained from the number of radiated rays N of the parameter input in step ST1 in the procedure for deriving the amplitude in each direction of the complex directivity. Is obtained (step ST3).

  Next, the control device 51 determines whether or not the amplitude of the radio wave is greater than or equal to a predetermined threshold (step ST4). Here, if the amplitude of the radio wave is equal to or greater than a predetermined threshold value (in the case of YES in step ST4), the control device 51 derives a radiation ray equation (step ST5). On the other hand, if the amplitude of the radio wave is less than the predetermined threshold value (in the case of NO in step ST4), one ray number n of the number of radiated rays N is added to be n + 1 (step ST6), and the process returns to step ST3 and the antenna complex pointing Continue to derive the amplitude in each orientation of gender 12. In this way, the calculation time of the radio wave propagation characteristic analysis can be shortened by reducing the rays emitted using the antenna complex directivity 12 of each azimuth input.

  In the radiation beam equation derivation process in step ST5, an equation of light rays radiated in all directions is obtained for each predetermined discrete angle obtained from the number N of radiation rays at the parameter input in step ST1 with the transmission point as the center. If the ray number n is smaller than the ray number N, the ray number n is incremented by 1 as in the procedure of step ST7 (that is, the ray number is set to n + 1), and the procedure returns to the amplitude derivation procedure of step ST3. Each step is repeated to derive the radiation ray equation.

  Next, the radiation ray equation obtained in the step of deriving the radiation ray equation in step ST5 is multiplied by the antenna complex directivity 12 such as amplitude and phase (step ST8). Then, in the procedure for deriving the reflected ray equation, a reflection wall surface of a specific ray is determined, and a desired reflected ray equation is derived from the reflection wall surface (step ST9). Each time such a reflected ray equation derivation process is performed, the number of reflections R is incremented by 1 (that is, each time the reflected ray equation is derived, the number of reflections is R + 1), and the maximum number of reflections Rmax is obtained. The process of deriving the reflected ray equation is repeated until step ST10. Alternatively, the ray number n is incremented by 1 until the reflected ray equation for the total emitted ray Nα is obtained (that is, the ray number is set to n + 1 every time the reflected ray equation is derived), and the maximum number of emitted rays Nmax The derivation process is repeated until it becomes (step ST11).

  By the pre-processing of the radio wave propagation characteristic analysis as shown in FIG. 2, the data input in the parameter input procedure of step ST1 and the total ray equation 41 as shown in FIG. The traveling angle 42, the polarization equation 43 of all rays, the reflection surface number 44 of all rays, and the wall number 45 of all rays are stored. Note that the total number of emitted rays Nα is obtained by subtracting the number of rays excluded when the amplitude is larger than the threshold value in step ST4 from the number N of emitted rays input as parameters at the transmission point in step ST1.

Next, the post-processing flow of radio wave propagation characteristic analysis shown in FIG. 3 will be described. First, in the parameter input procedure, the operator inputs the antenna complex directivity 12 obtained by the antenna analysis in the preprocessing shown in FIG. 2, the reception position, and the frequency of the radio wave from the input device 54 as parameters (step ST21). Then, the control device 51 derives the distance d to the reception point of the ray number a read from the storage device 13 in the procedure for deriving the reception sphere, and when the transmission angle interval is φ, the radius r of the reception sphere in post-processing. Is obtained by the following equation (1) (step ST22).
r = 2 ^1/2 d · sin (φ / 2) (1)

  Next, the control device 51 searches for the reaching ray by obtaining the intersection of the reflected ray equation and a sphere having a radius r centered on the receiving point, and determines whether or not the ray has reached the receiving point ( Step ST23). Here, when the light beam reaches the reception point (YES in step ST23), the light beam reaching the reception point is multiplied by the antenna complex directivity 12 corresponding to the light beam arrival angle (step ST24). On the other hand, when the ray with the ray number a has not reached the reception point (in the case of NO at step ST23), 1 is added to the ray number a to become a + 1 (step ST25), and the received sphere is derived at step ST22. Returning to the step, the process proceeds to the reception sphere derivation process for the next ray number (a + 1).

  Further, in step ST24, when the light beam that has reached the reception point is multiplied by the antenna complex directivity 12 corresponding to the light beam arrival angle, the path that reaches the reception point differs for each light beam. And amplitude difference occurs. Therefore, the phase synthesis is performed by adding the amplitudes of the light beams having different paths in consideration of the phase difference (step ST26). Then, the process from step ST22 to step ST26 is repeated by following the feedback loop from step ST26 to step ST25 until the phase synthesis is performed for the rays of all the arrival angles.

  Next, the electric field strength of the light beam subjected to phase synthesis in the procedure for deriving the electric field strength is obtained, and this electric field strength is stored in the storage device 13 (step ST27). In this way, when the electric field strength of the phase-combined light beam at a certain reception point is obtained, the reception point m is tracked (that is, the reception point is set to m + 1), and the P reception points set by the operator are moved. (Step S28), the process returns to the reception sphere derivation process of Step ST22, and the process is repeated in the same steps as described above. In the result output procedure, the received electric field intensity at each reception point is stored in the storage device 13 as a result output (step ST29).

  As described above, according to the antenna characteristic evaluation system of Embodiment 1 of the present invention, the antenna complex directivity 12 obtained by the antenna directivity analysis unit 11 is used as the directivity coefficient at the transmission point and the reception point. By using a method that does not radiate light beams with a small amplitude at the transmission point, it is possible to analyze radio wave propagation characteristics with high accuracy in the real field of antennas that have complex characteristics including effects on the human body. . Furthermore, according to the antenna characteristic evaluation system of Embodiment 1 of the present invention, the number of radiation rays can be reduced by the antenna complex directivity 12 used at the transmission point. For example, by using unidirectional antenna characteristics such as Yagi Antenna (registered trademark), the number of rays emitted can be reduced to about 40%.

  In this way, the antenna directivity analysis unit 11 for obtaining the antenna complex directivity uses the FDTD method, which is an electromagnetic field calculation method, so that the antenna complex directivity 12 having complicated characteristics including the influence on the human body and the like can be obtained. It can be calculated more accurately. The antenna characteristic evaluation system 1 according to the present invention is configured to include the antenna directivity analysis unit 11 such as the FDTD method and the MOMENT method and the geometric optical wave propagation characteristic analysis unit 14 in the same personal computer system. Is not limited to such a system. For example, the antenna directivity analysis unit 11 and the geometric optical wave propagation characteristic analysis unit 14 are provided in different personal computer systems, and the antenna complex directivity 12 is transferred via the storage device 13 or the removable storage medium 55 as a medium. However, the antenna characteristic evaluation system of the present invention can be realized.

<Embodiment 2>
Next, the antenna characteristic evaluation system according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 6 is a configuration diagram of a computer system for performing a radio wave propagation characteristic analysis calculation in the second embodiment of the present invention. That is, this figure shows the configuration of the antenna characteristic analysis apparatus and the computer according to Embodiment 2 of the present invention. The configuration of the computer system in the antenna characteristic evaluation system of the second embodiment shown in FIG. 6 is different from that of the first embodiment shown in FIG. 5 in the antenna characteristic measuring device 61 such as a network analyzer, the antenna to be measured 62 and the reception. An antenna (or transmission antenna) 63 is added, and can be configured by a general personal computer system. The control device 51, the display device 52, the printing device 53, the input device 54, the storage device 13, and the storage medium 55, which are constituent elements other than those described above, are the same as those in the first embodiment shown in FIG. . The storage device 13 and the storage medium 55 can store programs, parameters, and the like for executing electromagnetic field calculation and radio wave propagation analysis processing, and antennas such as amplitude and phase obtained by the antenna characteristic measurement device 61. The complex directivity 12 can be stored.

  FIG. 7 is a block diagram functionally showing the radio wave propagation characteristic analysis process performed by the storage device of FIG. That is, this figure is a functional block diagram showing a state in which information such as phase and amplitude from the antenna characteristic analysis apparatus is delivered for radio wave propagation characteristic analysis processing in Embodiment 2 of the present invention. The functional block of the radio wave propagation characteristic analysis processing shown in FIG. 7 includes a storage device 13 that stores the antenna complex directivity 12 and a plurality of radio wave propagation models 71, a measured antenna 62, and a reception antenna (or transmission antenna) 63. The antenna characteristic measuring device (antenna directivity measuring means) 61 and a geometric optical wave propagation characteristic analyzing unit 14 that executes pre-processing 30 and post-processing 31 of radio wave propagation characteristic analysis are provided.

  Next, the operation of the antenna characteristic evaluation system according to Embodiment 2 will be described with reference to FIGS. First, the control device 51 measures the antenna complex directivity 12 such as the amplitude and phase of radio waves using an antenna characteristic measuring device 61 such as a network analyzer, and stores the measurement information (that is, the antenna complex directivity 12) as a storage device. 13 is stored. The storage device 13 stores in advance a program for performing pre-processing 30 and post-processing 31 of the geometric optical analysis method defined in Embodiment 1, and a plurality of radio wave propagation models 71. Then, the storage device 13 passes the antenna complex directivity 12 acquired from the antenna characteristic measurement device 61 and stored therein as an input parameter to the preprocessing 30 and the postprocessing 31 of the geometric optical wave propagation characteristic analysis unit 14. That is, the storage device 13 serves as a medium, and the antenna complex directivity 12 measured by the antenna characteristic measuring device 61 is passed to the preprocessing 30 and the postprocessing 31 for performing the radio wave propagation characteristic analysis. Thereafter, the operator selects one desired radio wave propagation model 71 from a plurality of radio wave propagation models 71 stored in advance, such as an urban area model and a suburban model.

  According to the antenna characteristic evaluation system of the second embodiment of the present invention, the antenna complex directivity 12 such as the amplitude and phase obtained from the antenna characteristic measuring device 61 such as a network analyzer is stored in the storage device 13 (for example, It is used as a transmission / reception point for the pre-processing 30 and post-processing 31 of the geometric optical radio wave propagation characteristic analyzing unit 14 using a computer or the like as a medium. Thus, when the operator selects the radio wave propagation model 71, the antenna characteristics in the actual multiwave environment can be calculated in a relatively short time without inputting detailed parameters of the radio wave propagation model 71 each time. .

  In the pre-processing 30, the antenna complex directivity 12 at the transmission point is limited to a predetermined value, and the pre-processing 30 and the post-processing 31 are executed in advance, and then the reception obtained using the antenna characteristic measuring device 61 is performed. If the antenna complex directivity 12 at the point is multiplied by the arrival light and phase-combined, the antenna characteristics in the actual multiwave environment can be calculated in a shorter time.

  Next, the operation of the antenna characteristic evaluation system according to Embodiment 2 of the present invention will be described using a flowchart. FIG. 8 is a flowchart showing a flow of post-processing A of radio wave propagation characteristic analysis according to Embodiment 2 of the present invention. FIG. 9 is a diagram showing a data configuration stored in the storage device by post-processing A of the radio wave propagation characteristic analysis shown in FIG. As shown in FIG. 9, the storage device 13 stores, as data 80, a reaching light equation 81, a reaching light traveling angle 82, a reaching light polarization equation 83, and a reaching light propagation distance 84. Furthermore, FIG. 10 is a flowchart showing a flow of post-processing B of radio wave propagation characteristic analysis in Embodiment 2 of the present invention. Therefore, the flow of post-processing of radio wave propagation characteristic analysis in the second embodiment will be described with reference to FIG. 8, FIG. 9, and FIG.

  First, post-processing A of radio wave propagation characteristic analysis in FIG. 8 will be described. First, in the parameter input procedure, the operator inputs the reception position and radio wave frequency as parameters from the input device 54 (step ST31). Then, the control device 51 derives the distance d to the reception point of the ray number a read from the storage device 13 in the procedure for deriving the reception sphere, and when the transmission angle interval is φ, the radius of the reception sphere in the post-processing A r is obtained by the above-described equation (1) (step ST32).

  Next, the control device 51 searches for a reaching ray by obtaining an intersection of the reflected ray equation and a sphere having a radius r centered on the receiving point, and determines whether or not the radio wave has reached the receiving point ( Step ST33). Here, when the radio wave arrives at the reception point (YES in step ST33), the procedure proceeds to the procedure for outputting the reaching ray data (step ST34). On the other hand, when the ray with the ray number a has not reached the reception point (NO in step ST33), 1 is added to the ray number a to become a + 1 (step ST35), and the reception sphere derivation in step ST32 is performed. Returning to the step, the process proceeds to the reception sphere derivation process for the next ray number (a + 1).

  Further, when the procedure proceeds to the procedure of the reaching ray data output in step ST34, as shown in FIG. 9, the reaching ray equation 81, the reaching ray traveling angle 82, the reaching ray polarization equation 83, and the propagation of the reaching ray. Data 80 consisting of the distance 84 is stored in the storage device 13 (step ST34). Then, it is determined whether or not the number of emitted light rays Nα is smaller than the light ray number a (that is, whether or not Nα <a) (step ST36). If Nα <a (NO in step ST36), the light ray 1 is added to the number a to make it a + 1 (step ST35), the process returns to the reception sphere derivation procedure of step ST32 described above, and the processing from step ST32 to step ST36 is repeated until Nα <a.

  On the other hand, if the number of radiated rays Nα is smaller than the ray number a, that is, if Nα <a (in the case of YES in step ST36), P preset reception points are moved and the same as the above-described steps. It is determined whether or not the number P of reception points to be moved from now on is less than the reception point m (that is, whether P <m) (step ST37). If P <m is not satisfied (step ST37). In the case of NO), while tracking the reception point m (that is, the reception point is set to m + 1), the P reception points set by the operator are moved (step ST38), and the reception sphere derivation process in step ST32 is performed. Return and repeat the process in the same steps as described above. In this way, when the number P of reception points to be moved from now on falls below the reception point m, that is, when P <m (in the case of YES in step ST37), the processing is terminated.

  Next, post-processing B of radio wave propagation characteristic analysis in FIG. 10 will be described. First, the operator inputs the antenna complex directivity 12 obtained by the antenna characteristic measuring device 61 from the input device 54 (step ST41). Then, the control device 51 stores the data 80 (that is, the reaching ray equation 81, the reaching ray traveling angle 82, the reaching ray polarization equation 83, and the reaching ray) stored in the storage device 13 in the post-processing A of FIG. Is read (step ST42). Further, the control device 51 multiplies these data 80 by the antenna complex directivity 12 having an angle corresponding to the incoming light beam (step ST43).

  In this way, it is determined whether or not the number of incoming rays Q from which data 80 is to be read has fallen below a predetermined incoming ray number q (that is, whether Q <q) (step ST44). (In the case of NO in step ST44), 1 is added to the incoming ray number q to obtain q + 1 (step ST45), and the process returns to step ST42 and repeats the processing from step ST42 to step ST44 until Q <q.

  In this way, the above-described processing is repeated Q times, and if the number of incoming rays Q from which data 80 is to be read falls below a predetermined incoming ray number q, that is, if Q <q (in the case of YES in step ST44), the phase The Q incoming rays are phase-combined in the combining procedure (step ST46), and the electric field strength at the receiving point is calculated in the electric field strength derivation procedure (step ST47).

  Next, it is determined whether or not the number of reception points P at the reception point is lower than the reception point m (that is, whether P <m) (step ST48). If P <m is not satisfied (NO in step ST48). Then, while tracking the reception point m (that is, the reception point is set to m + 1), the P reception points set by the operator are moved (step ST49), and the process returns to the incoming ray data reading process of step ST42. The process is repeated in the same steps. If the number P of reception points to be moved from now on is less than the reception point m by the above procedure, that is, if P <m (YES in step ST48), the process is terminated. In other words, the same processing is performed by moving P reception points set in advance.

  As described above, by calculating only the post-processing B shown in FIG. 10, it is possible to obtain the antenna characteristics in a predetermined actual multiwave environment in a relatively short time, and it is easy to compare and examine the antenna characteristics. Can be done. Further, since the data 80 necessary for the post-processing B is only the light beam reaching the reception point, the amount of data stored in the storage device 13 of the computer system when evaluating the antenna characteristics is about several tens of megabytes. For this reason, since the amount of calculation of antenna characteristics is also reduced, it is possible to calculate antenna characteristics even in a computer system with relatively low calculation performance such as a notebook personal computer. In the above description, the antenna complex directivity measured by the network analyzer is used as the antenna characteristic measuring device 61. However, the present invention is not limited to this, and the antenna complex directivity obtained by the electromagnetic field calculation may be used. Good.

  The antenna characteristic evaluation system according to the present invention uses an antenna complex directivity obtained by an antenna directivity analysis unit as a directivity coefficient at a transmission / reception point of a geometric optical radio wave propagation characteristic analysis unit, thereby realizing an actual multiwave propagation environment. The antenna characteristics can be evaluated with high accuracy. Therefore, it can be effectively used as a highly accurate antenna characteristic evaluation system by a computer.

The block diagram which shows integration of the antenna directivity analysis part and geometric optical wave propagation characteristic analysis part in the antenna characteristic evaluation system of Embodiment 1 of this invention The flowchart which shows the flow of the pre-processing of the radio wave propagation characteristic analysis which the geometric optical wave propagation characteristic analysis part shown in FIG. 1 performs The flowchart which shows the flow of the post-process of the radio wave propagation characteristic analysis which the geometric optical wave propagation characteristic analysis part shown in FIG. 1 performs The figure which shows the data structure memorize | stored in a memory | storage device by the pre-process shown by the flowchart of FIG. Configuration diagram of a computer system for performing calculation of radio wave propagation characteristic analysis in Embodiment 1 of the present invention Configuration diagram of a computer system for performing calculation of radio wave propagation characteristic analysis in Embodiment 2 of the present invention Block diagram functionally showing the radio wave propagation characteristic analysis processing performed by the storage device of FIG. The flowchart which shows the flow of the post-process A of the electromagnetic wave propagation characteristic analysis in Embodiment 2 of this invention The figure which shows the data structure memorize | stored in a memory | storage device by the post-process A of the radio wave propagation characteristic analysis shown in FIG. The flowchart which shows the flow of the post-process B of the radio wave propagation characteristic analysis in Embodiment 2 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna characteristic evaluation system 11 Antenna directivity analysis part 12 Antenna complex directivity 13 Storage device 14 Geometric optical wave propagation characteristic analysis part 30 Preprocessing 31 Postprocessing 41 Equation of all rays 42 Progression angle of all rays 43 Deviation of all rays Wave equation 44 Reflecting surface number of all rays 45 Wall number of all rays 51 Control device 52 Display device 53 Printing device 54 Input device 55 Storage medium 61 Antenna characteristic measuring device 62 Antenna to be measured 63 Receiving antenna (or transmitting antenna)
71 Radio propagation model 80 Data 81 Reaching ray equation 82 Traveling angle of reaching ray 83 Polarization equation of reaching ray 84 Propagating distance of reaching ray

Claims (6)

An antenna characteristic evaluation system that evaluates antenna characteristics by calculating the propagation characteristics of radio waves transmitted from a radio station,
Antenna directivity analysis means for calculating a complex directivity coefficient sequence for discrete angular orientations of the first antenna and the second antenna;
Geometric optical wave propagation characteristics analysis that calculates the propagation characteristics of radio waves between transmission and reception points in a given radio wave propagation model by radiating multiple rays from the transmission point and tracing the trajectory until the rays reach the reception point Means and
The geometric optical radio wave propagation characteristic analyzing means uses the complex directivity coefficient sequence of the first antenna and the second antenna as a directivity coefficient of the antenna at the transmission / reception point, so that the antenna directivity analysis means and the antenna directivity analysis means An antenna characteristic evaluation system that integrates geometric optical wave propagation characteristic analysis means. Furthermore, an amplitude determination means for determining whether or not an amplitude with respect to a discrete angle azimuth exceeds a predetermined threshold in the complex directivity coefficient sequence of the antenna at the transmission point,
2. The antenna characteristic evaluation system according to claim 1, wherein whether or not to radiate a light beam from the transmission point is determined according to a determination result of the amplitude determination unit.   The antenna characteristic evaluation system according to claim 1 or 2, wherein the antenna directivity analysis means uses a finite difference time domain method. And antenna directivity measurement means for measuring the complex directivity coefficient sequence with respect to discrete angular orientations of the first antenna and the second antenna,
3. The geometric optical wave propagation characteristic analyzing means uses the complex directivity coefficient sequence obtained by the antenna directivity measuring means as an antenna directivity coefficient at a transmission / reception point. Antenna characteristic evaluation system described in 1. Storage means for storing a plurality of radio wave propagation models possessed by the geometric optical radio wave propagation characteristic analysis means;
Executing means for performing geometric optical wave propagation characteristic analysis on the plurality of wave propagation models specified in advance using the complex directivity coefficient sequences of the first antenna and the second antenna;
The antenna characteristic evaluation system according to any one of claims 1 to 4, further comprising: The geometric optical radio wave propagation characteristic analyzing means includes:
Execute geometric optical wave propagation characteristic analysis calculation for the radio wave propagation model stored in advance in the storage means,
6. The antenna characteristic evaluation system according to claim 5, wherein a phase synthesis calculation is performed using the complex directivity coefficient sequence of the antenna obtained by the antenna directivity analysis means or the antenna directivity measurement means.

Images