Hiroshi Sato

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• Doctor of Engineering
• Senior Engineering Manager at Panasonic Corporation

https://search.ieice.org/bin/summary.php?id=j96-b_9_1048

https://search.ieice.org/bin/summary.php?id=j103-b_11_559

https://search.ieice.org/bin/summary.php?id=j104-b_6_543

We have decoupled the electromagnetic coupling between two closely arranged monopole antennas. This video shows the current distribution at that situation. With and without decoupling, a 1.5GHz sine wave is applied from the left port, and the opposite port is terminated with 50Ω. By decoupling, there is no current flowing into the 50Ω port, and you...

This study proposed a novel decoupling method for four planar inverted-F antennas (PIFAs) operating at 2.0 GHz (f0). The edge-to-edge and center-to-center spacings of the adjacent PIFAs are extremely small (0.05λ0 and 0.17λ0, respectively), resulting in strong mutual coupling among them. In our previous study, we proposed a structure consisting of...

In this study, we developed and investigated a small‐diameter, low‐profile, wideband orthogonal‐polarisation multiple‐input multiple‐output (MIMO) antenna. A polarisation MIMO antenna is a combination of a modified sleeve antenna for vertical polarisation and a halo antenna with four parasitic elements for horizontal polarisation. Four parasitic el...

In this paper, a simple method is proposed that allows two planar inverted-F antennas (PIFAs) maintain their bandwidth while simultaneously reducing the mutual coupling between them. By creating a slit on each PIFA patch and then connecting the two PIFAs by a bridge line (BL), the bandwidth can be maintained and the mutual coupling between them can...

We propose a method for reducing electromagnetic coupling between two monopole antennas for MIMO communications that do not use any lumped element components. In the past, the decoupling method for connecting antennas required two steps, decoupling and matching, in order, and used lumped element components for each step. The previous design method...

In this study, the characteristics of a wideband, low-profile, double-shell Halo antenna is investigated. The Halo antenna is a horizontally polarized antenna with a small diameter and a relative bandwidth of about 4%, which corresponds to a narrow bandwidth characteristic. Therefore, as a conventional broadband method, it is possible to increase t...

A reduction in mutual coupling (hereafter referred to as decoupling) is required to enhance the transmission performance of antennas in multiple-input multiple-output (MIMO) devices. In our previous study, a decoupling method was proposed that utilizes parasitic elements and a bridge line to reduce the mutual coupling between two planar inverted-F...

In this paper, we study a small-diameter, low-profile and wideband omnidirectional dual polarized antenna. We propose an antenna in which two parasitic elements with the same structure above and below the Halo antenna of the horizontally polarized element, and a dipole antenna, which is a vertically polarized element, is placed inside. The diameter...

Recently, microwave power transfer (MPT) for Internet-of-Things (IoT) devices has been actively studied. The distributed microwave power transfer (DMPT) can supply power efficiently by cooperating multiple transmit antenna arranged distributed in a relatively wide area. In this article, the advantages of DMPT are shown by using ray-trace-based Mont...

Abstract In this study, a simple technique is proposed to simultaneously achieve dual‐band characteristics and low mutual coupling between two planar inverted‐F antennas (PIFAs), which is one of the most popular antennas used in handset terminals such as mobile phones. The PIFAs initially operate only at a single band at 2.0 GHz (UTMS band). Althou...

In this study, a novel decoupling method using parasitic elements (PEs) connected by a bridge line (BL) for two planar inverted-F antennas (PIFAs) is proposed. The proposed method is developed from a well-known decoupling method that uses a BL to directly connect antenna elements. When antenna elements are connected directly by a BL, strong mutual...

In this study, we utilize an effective method called Characteristic Mode Analysis (CMA) to analyze the physical mechanisms of U-shaped Folded Dipole Antenna (UFDA), which have been proposed for WiMAX device. The proposed antenna consists of the UFDA element and small Ground Plane. As a result, it is confirmed that two types of modes in the resonanc...

MIMO technology, which uses multiple antennas, has been introduced to the mobile terminal to increase communication capacity per unit frequency. However, MIMO suffers from the problem of mutual coupling. If MIMO antennas are closely packed, as in a small wireless terminal, a strong mutual coupling occurs. The mutual coupling degrades radiation effi...

In recent years, MIMO technology is used in many mobile terminals to increase channel capacity. MIMO uses multiple antennas, however, if MIMO antennas are put closely such as a small terminal, a strong mutual coupling occurred. Then it causes decreasing radiation efficiency and channel capacity. Besides, CA technology which uses multiple frequencie...

In recent years, MIMO technology which uses multiple antennas has been introduced to the mobile terminal to increase communication capacity per unit frequency. However, if MIMO antennas are put closely, a strong mutual coupling occurred. Moreover, CA which uses multiple frequencies is also utilized to improve communication speed. Therefore, reducin...

In recent years, MIMO technology which uses multiple antennas has been introduced in mobile terminal to increase communication capacity. However, if MIMO antennas are put closely, a strong mutual coupling occurred. Then it causes decreasing radiation efficiency and channel capacity. Therefore, reducing the mutual coupling is required. In previous s...

https://search.ieice.org/bin/summary.php?id=j101-b_11_968&category=-&lang=J&year=2018

Technology of MIMO using multiple antennas and Carrier Aggregation operating multiple frequency bands are introduced in a mobile terminal to improve communication capacity. However, if plural MIMO antennas are installed closely, mutual coupling between the antennas must be reduced to suppress deterioration of radiation efficiency and increase of co...

Recently, the technology of MIMO (Multiple-Input Multiple-Output) using multiple antennas and CA (Carrier Aggregation) using multiple frequency bands are introduced in a mobile terminal. If plural MIMO antennas are installed closely, mutual coupling between the antennas must be reduced to suppress deterioration of radiation efficiency and increase...

In this paper, a method of calculating the mean channel capacity based on S-parameter of MIMO (Multiple-Input Multiple-Output) antenna is proposed. This method exploits the correlation matrix calculated from the antenna S-parameter matrix, and offers highly accurate estimates of the mean channel capacity without dependence on SNR (Signal-to-Noise R...

MIMO technology has been widely used for several years for the purpose of improving communication speed and communication capacity. However, if MIMO antenna is mounted closely, radiation efficiency and throughput of MIMO are decreased due to strong mutual coupling. In this paper, a decoupling method using meander branch antenna is proposed. It is c...

This paper presents a three-axis decoupling stubloaded parallel dipole array antenna with tri-orthogonal polarization directivity. The decoupling characteristics are realized using the phase shifter composed of a quarter-wavelength stub placed at two sides of three parallel dipole array antenna for creating the opposite phase of the current distrib...

This paper presents the detailed investigations on a simple multi-band method that allows inverted-F antennas (IFAs) to achieve good impedance matching in many different frequency bands. The impressive simplicity of the method arises from its sharing of a shorting strip among multiple branch elements to simultaneously generate independent resonant...

This paper presents a bilateral fading emulator for MIMO-OTA testing with a function of controlling the correlation of base station. On the basis of the Jakes theory, a methodology for achieving the spatial correlation of a base station antenna by setting the initial phases of scatterers in the two-dimensional channel model is introduced. The exper...

This paper presents a disk-loaded monopole stacked with patch antenna (DLMP) with a low-profile structure. The DLMP has three driven ports, each of which can create independent radiation patterns with orthogonally polarized characteristics. A design example is presented to achieve an overall height of 10 mm at 2 GHz. The calculated results show tha...

This study presents a concept of requisite design antenna volume to evaluate the space-saving effectiveness in the design of a wire inverted-F antennas (IFA) inside a smartphone terminal. By adjusting properly the loading position, the IFAs shape, and the deployment of other device components around the IFAs, we propose an antenna model that can bo...

Since the evaluation of multiple-input multiple-output (MIMO) antennas requires full information of its complex radiation patterns as well as propagation channels, its design procedures and analyses are cumbersome and complicated in general. In this letter, the accuracy of a closed-form capacity formula for mean MIMO channel capacity is investigate...

MIMO techniques using multiple antennas for improving communication capacity per unit frequency have been introduced. However, when multiple antennas are arranged in close proximity, the throughput is reduced because of the strong coupling between antennas, which causes low antenna efficiency. In this paper, to solve this problem, we propose a new...

This study presents a proposal for space-saving design of built-in antennas for handset terminals based on the concept of requisite design antenna volume. By investigating the relation between antenna input characteristic and electric near-field around the antenna element and surrounding components inside the terminal, and then evaluating the requi...

In this paper, we present a very simple multi-band technique for a wire inverted-F antenna designed for cellular application inside handset terminals, using multiple branch elements, single feeding port and only one shorting strip to simultaneously obtain good impedance matching at many different frequencies. The results in our investigation show t...

This paper presents a simple multi-band improvement technique for a linear inverted-F antenna designed for mobile devices using only one shorting strip to obtain good impedance matching at many different frequencies. Our results show that the proposed technique is very straightforward, and can be simply applied to multi-band design of inverted-F an...

This paper presents a method of dual-frequency antenna decoupling between closely spaced 2-element monopole. The method utilizes a newly developed decoupling circuit between two elements, realizing a reduction of mutual coupling in the two frequency bands simultaneously. It is confirmed that MIMO antennas using the proposed decoupling technique pro...

Recently, MIMO technologies for mobile phones have been investigated to achieve high-speed data communication. It is preferable to have a smaller and more efficient antenna system for the MIMO terminal. Although built-in antennas are more convenient, coupling between antennas and the human body is larger than with extended antennas. So far, for the...

In the communication systems expected to be used indoors, such as PHS, wireless LAN and MMAC, degradation of the communication quality by transmitting waves from the exterior to the room and the information leaks by the electromagnetic waves from the room to the exterior are of concern. Absorption and shielding of the electromagnetic waves with str...

https://search.ieice.org/bin/summary.php?id=j85-b_4_568&category=B&lang=J&year=2002

With an advance of office automation and intelligent offices, use of various electrical and electronic devices has proliferated. Accordingly, the interference of electromagnetic waves generated by these devices with other equipment, causing malfunction and wave leakage through walls, is of concern. Especially for wireless LANs, the degradation of c...