Special Section on Recent Progress in Antennas and Propagation in Conjunction with Main Topics of ISAP2020
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Hiroyoshi YAMADA
2022 Volume E105.B Issue 6 Pages
684
Published: June 01, 2022
Released on J-STAGE: June 01, 2022
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Bo Kum JUNG, Thomas KÜRNER
Article type: INVITED PAPER
2022 Volume E105.B Issue 6 Pages
685-693
Published: June 01, 2022
Released on J-STAGE: June 01, 2022
Advance online publication: December 03, 2021
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With the increasing densification of 5G and future 6G networks high-capacity backhaul links to connect the numerous base stations become an issue. Since not all base stations can be connected via fibre links for either technical or economic reasons wireless connections at 300GHz, which may provide data rates comparable to fibre links, are an alternative. This paper deals with the planning of 300GHz backhaul links and describes two novel automatic planning approaches for backhaul links arranged in ring and star topology. The two planning approaches are applied to various scenarios and the corresponding planning results are evaluated by comparing signal to interference plus noise ratio under various simulation conditions including weather impacts showing the feasibility of wireless backhaul links.
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Jerdvisanop CHAKAROTHAI, Katsumi FUJII, Yukihisa SUZUKI, Jun SHIBAYAMA ...
Article type: INVITED PAPER
2022 Volume E105.B Issue 6 Pages
694-706
Published: June 01, 2022
Released on J-STAGE: June 01, 2022
Advance online publication: December 29, 2021
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In this study, we develop a numerical method for determining transient energy deposition in biological bodies exposed to electromagnetic (EM) pulses. We use a newly developed frequency-dependent finite-difference time-domain (FD2TD) method, which is combined with the fast inverse Laplace transform (FILT) and Prony method. The FILT and Prony method are utilized to transform the Cole-Cole model of biological media into a sum of multiple Debye relaxation terms. Parameters of Debye terms are then extracted by comparison with the time-domain impulse responses. The extracted parameters are used in an FDTD formulation, which is derived using the auxiliary differential equation method, and transient energy deposition into a biological medium is calculated by the equivalent circuit method. The validity of our proposed method is demonstrated by comparing numerical results and those derived from an analytical method. Finally, transient energy deposition into human heads of TARO and HANAKO models is then calculated using the proposed method and, physical insights into pulse exposures of the human heads are provided.
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Rong LU, Chao YU, Wei HONG
Article type: INVITED PAPER
2022 Volume E105.B Issue 6 Pages
707-714
Published: June 01, 2022
Released on J-STAGE: June 01, 2022
Advance online publication: December 03, 2021
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In this paper, millimeter wave (mmWave) filtenna arrays for 5G applications are proposed. Two kinds of 2-element subarrays are designed for horizontal and vertical polarizations. Each subarray consists of three substrate integrated waveguide (SIW) cavities and two sets of stacked patches. Fully-shielded combined eighth-mode SIW (FSD-CEMSIW) cavities are used in the filtenna design. This cavity not only works as the first-stage resonator but also as the power divider for the subarray. As a result, a four-order bandpass filtering response is achieved. Filtenna arrays were fabricated and measured for demonstration. The impedance bandwidths of these subarrays cover 24-30GHz, including the 5G mmWave bands (n257, n258, and n261) with measured average gains of 8.2dBi and more than 22dB out-of-band suppression. The proposed antennas can be good candidates for 5G mmWave communication to reduce the system complexity and potential cost of the mmWave front-ends.
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Yuki KIMURA, Sakuyoshi SAITO, Yuichi KIMURA, Masahiro TATEMATSU
Article type: PAPER
Subject area: Antennas
2022 Volume E105.B Issue 6 Pages
715-721
Published: June 01, 2022
Released on J-STAGE: June 01, 2022
Advance online publication: December 17, 2021
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This paper presents improvement of port-to-port isolation characteristics of a linearly dual-polarized dual-band and wideband multi-ring microstrip antenna (MR-MSA) fed by two L-probes. The linearly dual-polarized dual-band and wideband MR-MSA consists of two circular ring patches and two L-probes arranged in a multi-layered dielectric substrate. By using a thick substrate for the L-probe and arranging two ring patches as radiation elements, the proposed antenna operates wideband and dual-band characteristics. Furthermore, by arranging two L-probes at the orthogonal positions, the proposed antenna can radiate dual linear polarizations. In this paper, for improving port-to-port isolation characteristics of the linearly dual-polarized dual-band and wideband MR-MSA fed by two L-probes, a via connected to the ground plane at the center of the radiation elements is arranged. The fractional bandwidths below -10dB reflection obtained by the simulation of the MR-MSA with the via were 17.0% and 14.4%. Furthermore, the simulated isolation characteristics were more than 21.0dB and 17.0dB in the two bands. Improvement of the isolation characteristics between two ports as well as the dual-band and wideband performance of the proposed MR-MSA with the via were confirmed by the simulation and the measurement.
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Takumi NISHIME, Hiroshi HASHIGUCHI, Naobumi MICHISHITA, Hisashi MORISH ...
Article type: PAPER
Subject area: Antennas
2022 Volume E105.B Issue 6 Pages
722-728
Published: June 01, 2022
Released on J-STAGE: June 01, 2022
Advance online publication: December 14, 2021
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Platform-mounted small antennas increase dielectric loss and conductive loss and decrease the radiation efficiency. This paper proposes a novel antenna design method to improve radiation efficiency for platform-mounted small antennas by characteristic mode analysis. The proposed method uses mapping of modal weighting coefficient (MWC) and infinitesimal dipole and evaluate the metal casing with 100mm × 55mm × 23mm as a platform excited by an inverted-F antenna. The simulation and measurement results show that the radiation efficiency of 5% is improved with the whole system from 2.5% of the single antenna.
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Chi-Min LI, Dong-Lin LU, Pao-Jen WANG
Article type: PAPER
Subject area: Propagation
2022 Volume E105.B Issue 6 Pages
729-736
Published: June 01, 2022
Released on J-STAGE: June 01, 2022
Advance online publication: December 03, 2021
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Currently, as the widespread usage of the smart devices in our daily life, the demands of high data rate and low latency services become important issues to facilitate various applications. However, high data rate service usually implies large bandwidth requirement. To solve the problem of bandwidth shortage below 6GHz (sub-6G), future wireless communications can be up-converted to the millimeter-wave (mm-wave) bands. Nevertheless, mm-wave frequency bands suffer from high channel attenuation and serious penetration loss compared with sub-6G frequency bands, and the signal transmission in the indoor environment will furthermore be affected by various partition materials, such as concrete, wood, glass, etc. Therefore, the fifth-generation (5G) mobile communication system may use multiple small cells (SC) to overcome the signal attenuation caused by using mm-wave bands. This paper will analyze the attenuation characteristics of some common partition materials in indoor environments. Besides, the performances, such as the received signal power, signal to interference plus noise ratio (SINR) and system capacity for different SC deployments are simulated and analyzed to provide the suitable guideline for each SC deployments.
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Hiroaki NAKABAYASHI, Kiyoaki ITOI
Article type: PAPER
Subject area: Propagation
2022 Volume E105.B Issue 6 Pages
737-747
Published: June 01, 2022
Released on J-STAGE: June 01, 2022
Advance online publication: December 14, 2021
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Basic characteristics for relating design and base station layout design in land mobile communications are provided through a propagation model for path loss prediction. Owing to the rapid annual increase in traffic data, the number of base stations has increased accordingly. Therefore, propagation models for various scenarios and frequency bands are necessitated. To solve problems optimization and creation methods using the propagation model, a path loss prediction method that merges multiple models in machine learning is proposed herein. The method is discussed based on measurement values from Kitakyushu-shi. In machine learning, the selection of input parameters and suppression of overlearning are important for achieving highly accurate predictions. Therefore, the acquisition of conventional models based on the propagation environment and the use of input parameters of high importance are proposed. The prediction accuracy for Kitakyushu-shi using the proposed method indicates a root mean square error (RMSE) of 3.68dB. In addition, predictions are performed in Narashino-shi to confirm the effectiveness of the method in other urban scenarios. Results confirm the effectiveness of the proposed method for the urban scenario in Narashino-shi, and an RMSE of 4.39dB is obtained for the accuracy.
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Hirokazu YAMAKURA, Gilbert SIY CHING, Yukiko KISHIKI, Noboru SEKINO, I ...
Article type: PAPER
Subject area: Propagation
2022 Volume E105.B Issue 6 Pages
748-756
Published: June 01, 2022
Released on J-STAGE: June 01, 2022
Advance online publication: December 03, 2021
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In this study, we investigate outdoor propagation measurements performed in an industrial park environment at 28.3GHz band. The propagation characteristics were evaluated with the measurement result regarding the path loss characteristics. Ray tracing simulation was also studied and compared with the measurement data to evaluate the quantitative accuracy of ray tracing in millimeter-wave band wireless propagations. Ray tracing, whose accuracy was evaluated based on a comparison with the measurement results, can aid in the theoretical design of the coverage area and deterministic channel modeling.
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Yasuyuki MAEKAWA, Yoshiaki SHIBAGAKI
Article type: PAPER
Subject area: Propagation
2022 Volume E105.B Issue 6 Pages
757-765
Published: June 01, 2022
Released on J-STAGE: June 01, 2022
Advance online publication: December 03, 2021
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Rain attenuation characteristics due to typhoon passage are discussed using the Ku-band BS satellite signal observations conducted by Osaka Electro-Communication University in Neayagawa from 1988 to 2019. The degree of hourly rain attenuation due to rainfall rate is largely enhanced as typhoon passes the east side of the station, while it becomes smaller in the case of west side passage. Compared to hourly ground wind velocities of nearby AMeDAS, the equivalent path lengths of rain attenuation become larger as the wind directions approach the same angle to the satellite, while they become smaller as the wind directions approach the opposite angle to the satellite. The increase and decrease of the equivalent path lengths are confirmed in other Ku-band and Ka-band satellite paths with different azimuth angles, such as CS, SKP, and SBC. Modified equivalent path lengths calculated by a simple propagation path model including horizontal wind speeds along the same direction to the satellite agree well with the equivalent path lengths observed by each satellite. The equivalent path lengths are, for the first time, proved to be largely affected by the direction of typhoon passage and the horizontal wind velocities.
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Shohei HAMADA, Koichi ICHIGE, Katsuhisa KASHIWAGI, Nobuya ARAKAWA, Ryo ...
Article type: PAPER
Subject area: DOA Estimation
2022 Volume E105.B Issue 6 Pages
766-774
Published: June 01, 2022
Released on J-STAGE: June 01, 2022
Advance online publication: December 03, 2021
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This paper proposes two accurate source-number estimation methods for array antennas and multi-input multi-output radar. Direction of arrival (DOA) estimation is important in high-speed wireless communication and radar imaging. Most representative DOA estimation methods require the source-number information in advance and often fail to estimate DOAs in severe environments such as those having low signal-to-noise ratio or large transmission-power difference. Received signals are often bandlimited or narrowband signals, so the proposed methods first involves denoising preprocessing by removing undesired components then comparing the original and denoised signal information. The performances of the proposed methods were evaluated through computer simulations.
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