Tai Tanaka

Theoretical and experimental investigation of plasma antenna characteristics on the basis of gaseous collisionality and electron density

This paper reports plasma antenna characteristics investigated theoretically and experimentally, on the basis of the plasma parameters: gaseous collisionality and electron density. The antenna structure is a basic quarter-wavelength monopole antenna in the UHF band. The dependence of the antenna gain on the plasma parameters is obtained by analytical equations from plasma and antenna theory, and by numerical simulations. In the plasma antenna, the ratio of the electron elastic collision frequency to the total number of electrons at the plasma cross section determines the antenna?s internal loss and the electrical equivalent antenna length, whereas the ratio of the radio wave frequency to the total number of electrons at the plasma cross section determines the antenna?s resonant frequency. These results are confirmed by experimental results of the antenna?s impedance and radiation patterns.

A study on characteristic basis function method using combined IP-CBF

We proposed an improved technique of the analysis accuracy for the characteristic basis function method (CBFM) using the multilevel approach. In this technique, improved primary CBFs (IP-CBFs) are used for taking into account multiple scattering between each block. The radar cross section (RCS) of a perfect electric conductor cube was analyzed by using the proposed technique. It was found that analysis accuracy is improved compared by the results of the conventional method.

Verification of characteristic basis function method using fast far-field approximation

In this paper, we evaluate the fast far-field approximation (FaFFA) for the characteristic basis function method (CBFM). By adopting the FaFFA to the CBFM, impedance matrix calculation time can be accelerated. We calculate the radar cross section of the conductor plate with the use of FaFFA-CBFM, and compare the results with ordinary-CBFM. Both results are in good agreement, and FaFFA-CBFM is faster than the conventional method.

Hierarchical generation of characteristic basis functions combined with singular value decomposition

In this paper, we evaluated the hierarchical generation technique of characteristic basis function combined with singular value decomposition (SVD). This method enables us to analyze a scattering field with a high accuracy with small-scale matrix. By calculating the radar cross section (RCS) of a large conductor cylinder, we evaluated the technique. The solutions of proposed and conventional method correspond well; thus, the effectiveness was verified.

Improved Primary-Characteristic Basis Function Method for analyzing the Radar Cross Section characteristics of specific coordinate plane

In this paper, we proposed Improved Primary Characteristic Basis Function Method (IP-CBFM). This method enables us to analyze a scattering field in a specific coordinate plane with a high accuracy with small-scale matrix equations. IP-CBF is the combined CBF of Primary and Secondary CBF. By calculating the Radar Cross Section (RCS) of a perfect electric conductor plate, we evaluated the technique. The solutions of proposed and conventional method correspond well.

A study on acceleration of CBFM for analyzing the microstrip array antennas

In this paper, we verified the Poggio, Miller, Chang, Harrington, Wu and Tsai - Characteristic Basis Function Method (PMCHWT-CBFM) by applying the extended version of the CBFM for analyzing the radar cross section (RCS) of the array antenna. The method can be reduced memory usage of calculation compared with those of the direct MoM.