A Stochastic Approach to Design MIMO Antenna with Parasitic Elements Based on Propagation Characteristics

Mitsuteru YOSHIDA†a) , Kei SAKAGUCHI †b) , Members, and Kiyomichi ARAKI †c) , Fellow SUMMARYIn recent years, wireless communication technology has been studied intensively. In particular, MIMO which employs several transmit and receive antennas is a key technology for enhancing spectral efficiency. However, conventional MIMO architectures require some transceiver circuits for the sake of transmitting and receiving separate signals, which incurs the cost of one RF front-end per antenna. In addition to that, MIMO systems are assumed to be used in low spatial correlation environment between antennas. Since a short distance between each antenna causes high spatial correlation and coupling effect, it is difficult to miniaturize wireless terminals for mobile use. This paper shows a novel architecture which enables mobile terminals to be miniaturized and to work with a single RF front-end by means of adaptive analog beam-forming with parasitic antenna elements and antenna switching for spatial multiplexing. Furthermore, statistical analysis of the proposed architecture is also discussed in this paper. key words: single front-end architecture, parasitic antenna elements, MIMO, equal gain combining IntroductionConventional MIMO architectures need a transceiver circuit for each antenna, which means that multiple antenna systems increase power consumption and size of RF frontend circuit. Hence, a single RF front-end architecture is an ideal one to overcome this problem. Some techniques realizing MIMO with a single RF front-end circuit have been proposed. One such technique is to use parasitic antenna elements. The elements are not supplied with power and only reflect incident radio waves [1]. The single RF frontend MIMO can be realized when the value of variable reactances connecting to parasitic antenna elements are controlled properly so as to generate orthogonal directivity patterns, because each orthogonal directivity pattern is spatially independent and can receive spatial distinct signals [2]. Another technique for realizing MIMO with a single RF frontend is antenna switching method based on sampling theorem for band-limited signal [3]. In [4], spatial multiplexing with phase state preserved can be realized using antenna switching. If the phase of signals is obtained in addition to its' amplitude, a diversity combining technique of multiple antenna systems can be operated effectively in digital signal processing (DSP) stages. However, both techniques decrease the SNR because these processes cause aliasing and interference effect from other channels against desired signals. In order to avoid undesired effects, the rotation speed of antenna directivity or the antenna switching rate must be higher than signal bandwidth. Furthermore, channel selection filters are needed in front of these processes [5]. The problem common to both methods is deterioration in quality of the SNR. Beam-forming techniques in digital or analog dimension are well known as the method to improve the SNR by steering a directivity to desired signals...

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“…Then, a scattering matrix of free space including parasitic antenna elements,S, is expressed by Eq. (9) [8].…”

Section: Statistical Analysis Of Parasitic Antenna Element Systemmentioning

confidence: 99%

“…Then, a scattering matrix of free space including parasitic antenna elements,S, is expressed by Eq. (9) [8].Therefore, the spectral efficiency in this model is formulated by Eq. (10) where γ is average branch SNR, provided |Γ P | ≤ 1 holds: the PAE are passive.…”

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confidence: 99%

Single Front-End MIMO Architecture with Parasitic Antenna Elements

Yoshida

Sakaguchi

Araki

2012

IEICE Trans. Commun.

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“…To increase communication efficiency, adaptive beamforming becomes an important issue in 5G technologies. The beamforming techniques have been developed toward compact and simple architectures such as conventional analog/hybrid/digital beamformings [2], retrodirective arrays [3], smart antennas [4,5], reconfigurable patterns [6], and Electrically Steerable Parasitic Array Radiator (ESPAR) antennas [7][8][9][10][11]. The ESPAR antenna has switchable beams with orthogonal four directions.…”

Section: Introductionmentioning

confidence: 99%

Planar Beam Steerable Parasitic Array Antenna System Design Based on the Yagi-Uda Design Method

Lee

Yoon

Han

2019

International Journal of Antennas and Propagation

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A planar beam steerable array antenna system is proposed with dual-control circuits for feeding and reactive loadings. Two orthogonally arranged planar dipoles are excited by SPDT switching circuits, while the forward and backward beam directions are controlled by the adjusted effective electric lengths of the parasitic dipole elements. The adjusted parasitic dipoles are designed to play the alternative roles of directors and reflectors based on the Yagi-Uda antenna theory. The proposed antenna system with four-way switchable beams has been implemented on a planar substrate and evaluated for orthogonal four-way beam steering performance with good agreement.

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“…Among the system schemes, space diversity using switching beam control is one of the most promising candidates to efficiently increase channel capacity. However, it has the limitations of high antenna complexity and a large form factor of the beam-switchable antennas at mobile terminals [1][2][3][4]. An Electrically Steerable Parasitic Array Radiator (ESPAR) antenna has been developed for a compact and simple beam controllable antenna design, and one active element and parasitic elements are used to adjust the beam direction.…”

Section: Introductionmentioning

confidence: 99%

“…The ESPAR antenna is a type of reactively steerable array antenna and a single-port array antenna with only one central active element surrounded by several reactively controlled parasitic radiating elements. The ESPAR antenna pattern is controlled by adjusting the reactance load values, including capacitance and inductance [1][2][3][4][5][6]. The ESPAR antenna has been developed using various parasitic structures, such as monopoles [5], dipoles [6], and patch antennas [7].…”

Section: Introductionmentioning

confidence: 99%

Planar Directional Beam Antenna Design for Beam Switching System Applications

Lee¹,

Yoon²,

Han³

2017

Journal of electromagnetic engineering and science

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In this paper, a planar directional beam-switchable antenna with four orthogonal beam directions is proposed. The proposed antenna is designed with two crossed active elements and two parasitic elements for each direction. The design methodology is described on the basis of the Yagi-Uda method for the active and parasitic elements, respectively. By adjusting the effective electric lengths of the parasitic elements, the roles of a director and a reflector are exchanged with each other. The planar four-way beam-switchable Yagi-Uda antenna is implemented. From the experimental results. The proposed design method is verified for orthogonal radiation beam switching. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ⓒ

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A Stochastic Approach to Design MIMO Antenna with Parasitic Elements Based on Propagation Characteristics

Cited by 10 publications

References 22 publications

Single Front-End MIMO Architecture with Parasitic Antenna Elements

Single Front-End MIMO Architecture with Parasitic Antenna Elements

Planar Beam Steerable Parasitic Array Antenna System Design Based on the Yagi-Uda Design Method

Planar Directional Beam Antenna Design for Beam Switching System Applications

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