The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
N. Goto - One of the best experts on this subject based on the ideXlab platform.
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Novel feed circuit for Radial-Line waveguide
1995 Ninth International Conference on Antennas and Propagation ICAP '95 (Conf. Publ. No. 407), 1995Co-Authors: H. Arai, N. GotoAbstract:Proposes a novel feed circuit for a Radial-Line waveguide. The conventional feed circuits for the Radial waveguide are a circular waveguide and a center fed probe. The former is convenient for exciting several modes simultaneously with complex feeding structure. The latter has a simple structure, however, radiation characteristics should be controlled by the arrangement of antenna elements, such as a slot, a helical antenna, and a patch antenna. The Radial-Line slot antenna for DBS reception has a center feed probe exciting an axial symmetrical outward traveling wave and a spiral slot broadside array arranged to radiate circular polarization. The spiral slot arrangement of this array reduces radiation efficiency for small-sized antennas, because it disturbs an axial symmetry of aperture distribution and increases termination losses at the end of Radial waveguide. To change this spiral arrangement to a ring array, it is necessary to excite a rotating mode by the feed circuit. Therefore, the paper proposes a new concept for the feed of a Radial-Line waveguide using a cavity resonator as the feed circuit. The authors describe four feed circuits for the Radial-Line waveguide. They compare the characteristics of these feed circuits for frequency band width and excited field distributions calculated by the mode matching method. The excitation of the rotating mode in the Radial Line waveguide is also discussed for these circuits.
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Dual circularly polarized Radial Line slot antennas
IEEE Transactions on Antennas and Propagation, 1995Co-Authors: M. Takahashi, N. Goto, M. Ando, Y. Numano, M. Suzuki, Y. Okazaki, T. YoshimotoAbstract:A Radial Line slot antenna (RLSA) is a circularly polarized high efficiency planar array. Two types of RLSAs, a single-layered and a double-layered one, have been released commercially for 12 GHz band DBS reception. The former adopts nonuniform slots excited by a Radially outward traveling wave, while the latter has uniform ones excited by an inward traveling wave. The paper merges the two into a novel, dual circularly polarized RLSA. Minimum antenna gain of 33.5 dBi in a DBS bandwidth of 500 MHz is measured for a 0.55 m diameter antenna.
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Measured performances of a wide band Radial Line slot antenna
Proceedings of IEEE Antennas and Propagation Society International Symposium and URSI National Radio Science Meeting, 1994Co-Authors: T. Yamamoto, M. Ando, M. Takahashi, N. GotoAbstract:A Radial Line slot antenna (RLSA) is a planar antenna for DBS reception. It is a kind of slotted waveguide array. The conductor losses are so small that high efficiency is expected irrespective of the aperture diameter. On the other hand, since the RLSA utilizes a travelling wave, particularly for a larger antennas, the frequency bandwith is limited by the long Line effect. Therefore, for the application of the RLSA to wideband communication, a new structure of a Radial waveguide is required. To solve this problem, the authors proposed a wideband Radial Line slot antenna (WB-RLSA). The paper presents the measured performance of a WB-RLSA.
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A rotating mode Radial Line slot antenna fed by a cavity resonator
Proceedings of IEEE Antennas and Propagation Society International Symposium and URSI National Radio Science Meeting, 1994Co-Authors: S. Hosono, M. Ando, N. Goto, J. Hirokawa, H. AraiAbstract:The Radial Line slot antenna (RLSA) is high gain and high efficiency planar antenna proposed for DBS subscribers. It is a kind of slotted waveguide array with very small conductor loss and high predicted efficiency. An efficiency of 80-87% has been realized for RLSAs with the antenna diameters of 30-60 cm at 12 GHz. A key difficulty is the aperture efficiency reduction by the rotational asymmetry due to the spiral arrangement of the slots for the RLSA. In a small sized antenna, the antenna efficiency is reduced by the propagating mode distortion due to the large slot coupling. The rotational symmetry of the field in the oversized waveguide, such as Radial Line, should be carefully maintained. We propose an RLSA with a concentric arrangement to keep the rotational symmetry. The feed circuit for this RLSA consists of a cavity resonator excited by a feeding pin which radiates a rotating mode in the Radial-Line waveguide. The basic design of a concentric array type RLSA is presented and some experimental results are included.
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Characteristics of dual circularly polarized Radial Line slot antennas
Proceedings of IEEE Antennas and Propagation Society International Symposium and URSI National Radio Science Meeting, 1994Co-Authors: M. Takahashi, N. Goto, M. Ando, M. Suzuki, T. Yoshimoto, Y. Ukazaki, Y. Yoshida, Y. NumanoAbstract:The possible design of a dual circularly polarized Radial Line slot antenna is proposed. The slot design comprising the single- and double-layered RLSA is presented which are simultaneously fed by a double coaxial adapter. Theoretical efficiency is no less than 70%. Experiments confirm these results. The peak efficiency of about 600% is observed in dual polarization for a 0.55m/spl phi/ model prototype antenna. The cross polarization level is about 20dB and DBS band is covered by more than 33.5dBi.
M. Takahashi - One of the best experts on this subject based on the ideXlab platform.
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Dual circularly polarized Radial Line slot antennas
IEEE Transactions on Antennas and Propagation, 1995Co-Authors: M. Takahashi, N. Goto, M. Ando, Y. Numano, M. Suzuki, Y. Okazaki, T. YoshimotoAbstract:A Radial Line slot antenna (RLSA) is a circularly polarized high efficiency planar array. Two types of RLSAs, a single-layered and a double-layered one, have been released commercially for 12 GHz band DBS reception. The former adopts nonuniform slots excited by a Radially outward traveling wave, while the latter has uniform ones excited by an inward traveling wave. The paper merges the two into a novel, dual circularly polarized RLSA. Minimum antenna gain of 33.5 dBi in a DBS bandwidth of 500 MHz is measured for a 0.55 m diameter antenna.
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Measured performances of a wide band Radial Line slot antenna
Proceedings of IEEE Antennas and Propagation Society International Symposium and URSI National Radio Science Meeting, 1994Co-Authors: T. Yamamoto, M. Ando, M. Takahashi, N. GotoAbstract:A Radial Line slot antenna (RLSA) is a planar antenna for DBS reception. It is a kind of slotted waveguide array. The conductor losses are so small that high efficiency is expected irrespective of the aperture diameter. On the other hand, since the RLSA utilizes a travelling wave, particularly for a larger antennas, the frequency bandwith is limited by the long Line effect. Therefore, for the application of the RLSA to wideband communication, a new structure of a Radial waveguide is required. To solve this problem, the authors proposed a wideband Radial Line slot antenna (WB-RLSA). The paper presents the measured performance of a WB-RLSA.
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Characteristics of dual circularly polarized Radial Line slot antennas
Proceedings of IEEE Antennas and Propagation Society International Symposium and URSI National Radio Science Meeting, 1994Co-Authors: M. Takahashi, N. Goto, M. Ando, M. Suzuki, T. Yoshimoto, Y. Ukazaki, Y. Yoshida, Y. NumanoAbstract:The possible design of a dual circularly polarized Radial Line slot antenna is proposed. The slot design comprising the single- and double-layered RLSA is presented which are simultaneously fed by a double coaxial adapter. Theoretical efficiency is no less than 70%. Experiments confirm these results. The peak efficiency of about 600% is observed in dual polarization for a 0.55m/spl phi/ model prototype antenna. The cross polarization level is about 20dB and DBS band is covered by more than 33.5dBi.
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Dual circular polarized Radial Line slot antennas
Proceedings of IEEE Antennas and Propagation Society International Symposium, 1993Co-Authors: M. Takahashi, N. Goto, K. Yamamoto, M. Ando, Y. Numano, M. Suzuki, Y. Okazaki, T. YoshimotoAbstract:A possible design of a dual circular polarized Radial Line slot antenna is proposed, and its basic characteristics are shown. An efficiency of about 50% is observed for a 0.5m/spl phi/ model prototype antenna.
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Efficiency enhancement of Radial Line slot antennas by reducing termination loss
IEEE Antennas and Propagation Society International Symposium 1992 Digest, 1992Co-Authors: M. Takahashi, M. Ando, J. Takada, N. GotoAbstract:The efficiency of single-layered Radial Line slot antennas has been enhanced by adopting nonuniform aperture illumination, which reduces the termination loss. An efficiency enhancement of 5-10% is observed. A measured gain of 36.7 dBi (87%) and 32.9 dBi (81%) and an axial ratio around 1 dB for 0.6-m phi and 0.4-m phi antennas, respectively, verify this technique.
M. Ando - One of the best experts on this subject based on the ideXlab platform.
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Analysis of a slot pair coupling on a Radial Line filled with double-layer dielectric
2005 IEEE Antennas and Propagation Society International Symposium, 2005Co-Authors: K. Sudo, J. Hirokawa, M. AndoAbstract:A Radial Line slot antenna (RLSA) is a high-gain, high-efficiency and low-cost planar antenna. This paper proposes an analysis method of slot coupling on a Radial Line filled with a double-layer dielectric by using method of moments (MoM) with eigenmode expansions and discusses the design of the RLSA.
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High gain Radial Line slot antennas for millimetre wave applications
IEE Proceedings - Microwaves Antennas and Propagation, 2000Co-Authors: A. Akiyama, M. Ando, T. Yamamoto, J. Hirokawa, E. Takeda, Y. AraiAbstract:Radial Line slot antennas (RLSAs) are designed for high gain millimetre wave systems. Two types of RLSA are tested in the 60 GHz band: one is the conventional structure consisting of three separate parts, two conducting disks and a foaming dielectric material, while the other is a PTFE substrate which seems to be more suitable for mass production. The antenna characteristics are measured in the 60 GHz band and an excellent efficiency of 50% at 33 dBi is obtained.
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Conical beam Radial Line slot antennas for 60 GHz band wireless LAN
IEEE Antennas and Propagation Society International Symposium. 1998 Digest. Antennas: Gateways to the Global Network. Held in conjunction with: USNC U, 1998Co-Authors: A. Akiyama, M. Ando, T. Yamamoto, E. TakedaAbstract:In this paper, we fabricate a conical beam small aperture Radial Line slot antenna (RLSA) for a 60-GHz band wireless LAN. Measured results are also shown for demonstrating the feasibility.
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Dual circularly polarized Radial Line slot antennas
IEEE Transactions on Antennas and Propagation, 1995Co-Authors: M. Takahashi, N. Goto, M. Ando, Y. Numano, M. Suzuki, Y. Okazaki, T. YoshimotoAbstract:A Radial Line slot antenna (RLSA) is a circularly polarized high efficiency planar array. Two types of RLSAs, a single-layered and a double-layered one, have been released commercially for 12 GHz band DBS reception. The former adopts nonuniform slots excited by a Radially outward traveling wave, while the latter has uniform ones excited by an inward traveling wave. The paper merges the two into a novel, dual circularly polarized RLSA. Minimum antenna gain of 33.5 dBi in a DBS bandwidth of 500 MHz is measured for a 0.55 m diameter antenna.
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Measured performances of a wide band Radial Line slot antenna
Proceedings of IEEE Antennas and Propagation Society International Symposium and URSI National Radio Science Meeting, 1994Co-Authors: T. Yamamoto, M. Ando, M. Takahashi, N. GotoAbstract:A Radial Line slot antenna (RLSA) is a planar antenna for DBS reception. It is a kind of slotted waveguide array. The conductor losses are so small that high efficiency is expected irrespective of the aperture diameter. On the other hand, since the RLSA utilizes a travelling wave, particularly for a larger antennas, the frequency bandwith is limited by the long Line effect. Therefore, for the application of the RLSA to wideband communication, a new structure of a Radial waveguide is required. To solve this problem, the authors proposed a wideband Radial Line slot antenna (WB-RLSA). The paper presents the measured performance of a WB-RLSA.
Takashi Katagi - One of the best experts on this subject based on the ideXlab platform.
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Radial Line planar monopulse antenna
IEEE Transactions on Antennas and Propagation, 1996Co-Authors: H Miyashita, Takashi KatagiAbstract:In recent years, mobile satellite communications have been growing rapidly. Monopulse tracking operations for beam pointing to the satellite are often employed for those systems which, in general, require rather severe EIRP and G/T specifications. Thus, the development of a monopulse antenna with a good antenna efficiency is of great interest. A Radial Line planar monopulse antenna is proposed. An analysis of the probes in a Radial Line has been carried out which gives an understanding of why the monopulse patterns can be synthesized, and a simple and effective theory is presented about a realization of uniform-aperture field distribution. The antenna has been fabricated and the radiation characteristics have been measured which supports the theory as well as verifies the capability of the antenna for the monopulse tracking operation.
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Four-point fed Radial Line planar antenna array for monopulse tracking operation
Proceedings of IEEE Antennas and Propagation Society International Symposium, 1993Co-Authors: H Miyashita, Takashi KatagiAbstract:A four-point fed Radial Line planar antenna (RLPA) array which has the capability of monopulse tracking operation is proposed. A simple analytical model which describes the performance of the array is presented. A four-point fed Radial Line power divider which has 90 output port probes was fabricated. Sum and difference patterns evaluated from the measured transmission amplitude and phase data are shown verifying the capability of the four-point fed RLPA for monopulse tracking operation.
H Miyashita - One of the best experts on this subject based on the ideXlab platform.
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Wave analysis of aperture field distribution for probe-fed Radial Line planar antennas
2005 IEEE Antennas and Propagation Society International Symposium, 2005Co-Authors: N. Takemura, H Miyashita, S. MakinoAbstract:Probe-fed Radial Line planar antennas (RLPAs) have high efficiency, because the excitation probes of the radiating elements can be fed by a standing wave in the Radial Line with a short-circuited termination of its end. We propose a method for the wave analysis of a probe-fed RLPA. Good correspondence has been confirmed between measured and calculated values on the aperture field distribution. By observing the parameter dependence of the feeding network, a method is proposed to achieve a uniform aperture field distribution. The method is efficient for general geometries of probe-fed RLPAs.
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Radial Line planar monopulse antenna
IEEE Transactions on Antennas and Propagation, 1996Co-Authors: H Miyashita, Takashi KatagiAbstract:In recent years, mobile satellite communications have been growing rapidly. Monopulse tracking operations for beam pointing to the satellite are often employed for those systems which, in general, require rather severe EIRP and G/T specifications. Thus, the development of a monopulse antenna with a good antenna efficiency is of great interest. A Radial Line planar monopulse antenna is proposed. An analysis of the probes in a Radial Line has been carried out which gives an understanding of why the monopulse patterns can be synthesized, and a simple and effective theory is presented about a realization of uniform-aperture field distribution. The antenna has been fabricated and the radiation characteristics have been measured which supports the theory as well as verifies the capability of the antenna for the monopulse tracking operation.
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Four-point fed Radial Line planar antenna array for monopulse tracking operation
Proceedings of IEEE Antennas and Propagation Society International Symposium, 1993Co-Authors: H Miyashita, Takashi KatagiAbstract:A four-point fed Radial Line planar antenna (RLPA) array which has the capability of monopulse tracking operation is proposed. A simple analytical model which describes the performance of the array is presented. A four-point fed Radial Line power divider which has 90 output port probes was fabricated. Sum and difference patterns evaluated from the measured transmission amplitude and phase data are shown verifying the capability of the four-point fed RLPA for monopulse tracking operation.