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152 results on '"Ohira, Masataka"'

27. Miniature dual‐band bandpass filter using modified quarter‐wavelength SIRs with controllable passbands

Author

Haiwen Liu, Pin Wen, Xuehui Guan, Baoping Ren, Zhewang Ma, Ohira Masataka, and Xiaolong Wang

Subjects
Coupling, Physics, business.industry, 020208 electrical & electronic engineering, 02 engineering and technology, Dual band bandpass filter, Transmission zeros, Wavelength, Resonator, Optics, Band-pass filter, Filter (video), 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, business, Individual Adjustment
Abstract

A modified quarter-wavelength ( λ /4) stepped-impedance resonator (SIR) is proposed to design a miniature dual-band bandpass filter (BPF). The proposed λ /4 SIR has two individually controllable resonances for constructing dual passbands. Moreover, two independent geometrical parameters are adopted to realise individual adjustment of the coupling strengths between two adjacent λ /4 SIRs at the dual passbands. As a result, both the centre frequencies and bandwidths of the two passbands of the filter can be individually designed. Furthermore, multiple transmission zeros are created by the introduced source-load coupling, which improves highly the selectivity of both passbands. The dual-band BPF is designed at 2.35 and 5.8 GHz, and its simulated and measured responses are presented and show good agreement.

Published
2019

28. Novel waveguide filters with multiple attenuation poles using dual-behavior resonance of frequency-selective surfaces

Author

Ohira, Masataka, Deguchi, Hiroyuki, Tsuji, Mikio, and Shigesawa, Hiroshi

Subjects
Algorithms -- Research, Algorithms -- Technology application, Waveguides -- Research, Electric filters -- Research, Algorithm, Technology application, Business, Computers, Electronics, Electronics and electrical industries
Abstract

This paper develops novel waveguide filters consisting of frequency-selective surfaces (FSSs) in order to realize both the drastic size reduction and multiple attenuation poles in stopbands at both sides of passband. The FSS provides not only a passband but also attenuation-pole frequencies in stopbands since the FSS has both the aperture-element and the patch-element behaviors. In the present design method, the shape of each FSS is designed by a genetic algorithm so that the resonant curve of FSS can be fitted to that obtained from an equivalent-circuit approach. By using such FSSs and quarter-wavelength waveguides, a bandpass filter with six attenuation poles like an elliptic-function filter has been constructed. Furthermore, a technique of the size reduction by controlling adequately the resonant response of each FSS is presented. In this filter, the FSSs are closely located at the interval of the length much shorter than a quarter wavelength. It is shown from the design example that the half longitudinal length of the former example can be obtained, keeping both the passband response and attenuation poles in stopbands. The effectiveness of the waveguide filters with FSSs is validated by good agreement between the calculated and the measured results. Index Terms--Frequency-selective surfaces (FSSs), genetic algorithms (GAs), resonance, waveguide filters.

Published
2005

29. Multiband single-layer frequency selective surface designed by combination of genetic algorithm and geometry-refinement technique

Author

Ohira, Masataka, Deguchi, Hiroyuki, Tsuji, Mikio, and Shigesawa, Hiroshi

Subjects
Genetic research, Business, Computers, Electronics, Electronics and electrical industries
Abstract

This paper proposes an optimization-design method for the frequency selective surface (FSS) based on the genetic algorithm (GA) incorporated with a geometry-refinement technique. The present method takes the connectivity condition of the elements into consideration, thereby resulting in an easy fabrication. As an example, we design the multiband single-layer FSS for transmitting L band (1.5 GHz band) and S band (2.5 GHz band) and also reflecting Ka band (20/30 GHz band). The designed FSS has bandwidths broader than previous FSSs. Finally, the validity of the present method is proved by the agreement between the calculated and the measured transmission responses for the designed FSS. Index Terms--Broadband, frequency selective surface (FSS), genetic algorithm (GA), geometry-refinement technique, multiband.

Published
2004

40. Authors’ Reply

Author

Wang, Xiaolong, primary, Xie, Taiyang, additional, Lu, Geyu, additional, Ma, Zhewang, additional, and Ohira, Masataka, additional

Published
2018
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