Yasuhiro Nishioka

Miniaturized broadband circularly polarized antenna allocated in a rotational symmetry

This paper proposes a broadband circularly polarized antenna that is composed of inverted F and L antennas on the ground plane, and is allocated in a rotational symmetry. The height and diameter of our proposed antenna is respectively 0.10λ<inf>0</inf> and 0.33λ<inf>0</inf>. The relative bandwidth satisfied with VSWR<3 in each band is 10.7% and 6.9%.

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.

Design and evaluation of HF/UHF dual-band RFID tag utilizing HF-coil as UHF antenna conductor

The demand for RFID tags that can be read by both HF and UHF RFID systems has been rapidly increasing. In this paper, we propose a novel HF/UHF dual-band tag antenna configuration that utilizes an HF coil conductor positively as a UHF antenna conductor. In order to control UHF current flowing on the coil and to achieve high radiation efficiency, the coil windings are coupled capacitively. The inductively coupled feed technique is adopted to obtain wider impedance bandwidth. It is shown by numerical electro-magnetic simulation that the fractional bandwidth of the actual gain of more than 1 dBi and 0 dBi are approximately 11% and 16%, respectively. The readable ranges of the prototype tag are 8-m and more than 10-cm in the UHF and HF, respectively.

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.