Hiroiku Tayama

A roof automobile module for LTE-MIMO antennas

A roof automobile antenna module for Long Term Evolution (LTE) application is proposed. The module consists of two LTE antennas for the multiple-input multiple-output (MIMO) method which requests low mutual coupling between the antennas for larger capacity. On the other hand, the installation location for a roof-top module is limited from safety or appearance viewpoint and this makes the multiple LTE antennas located there cannot be separated with enough space. In order to retain high isolation between the two antennas in such compact space, the two antennas are designed to have different shapes, different heights and different polarizations, and their ground planes are placed separately. In the proposed module, one antenna is a monopole type and has its element printed on a shark-fin-shaped substrate which is perpendicular to the car-roof. Another one is a planar inverted-F antenna (PIFA) and has its element on a lower plane parallel to the roof. In this manner, the two antennas cover the LTE-bands with omni-directional radiation in the horizontal directions and high radiation gain. The two antennas have reasonably good isolation between them even the module is compact with a dimension of 62×65×73 mm3.

A see-through wire-grid film antenna for WLAN applications

A see-through film antenna is proposed for 2.4 GHz WLAN applications. The antenna is made by a high-quality wire-grid film where very thin copper wires are used so that the antenna is almost transparent. Several kinds of wire-grids are applied and the performance is investigated experimentally and theoretically. It is found that the deterioration on radiation efficiency is limited and the transparency remains for practical applications, if the wire-grid is chosen appropriately.

A flat roof automobile antenna module for LTE, GPS and SDARS applications

A flat car-roof antenna module for LTE, GPS and SDARS applications is proposed. The module consists of a planar inverted-F antenna (PIFA), a square loop one and a circular loop one, for the LTE, GPS and SDARS operations, respectively. The three antennas are located in a same plane parallel to car roof and put close to each other so that the dimension of the module is only 70 × 70 mm2 in plane. Gap between the antenna plane and the car roof is only 20 mm. This low profile makes the module almost invisible when it is installed on a car roof.

An invisible vehicle roof antenna

An invisible vehicle roof antenna for the long term evolution (LTE) application is proposed. The antenna is a bended ultra-wideband monopole with a low profile of 30 mm and covers the LTE operation bands. The antenna is embedded into a hole with a depth of 30 mm which is opened on the roof and is surrounded by metal. The antenna becomes completely invisible when the hole is covered by a dielectric lid. A slit is made on the horizontal part of the antenna to suppress a zenith-directional radiation so that the antenna has enough gain in horizontal directions, even the antenna is surrounded by the metal wall of the hole. The antenna has a dimension of 85×85×30 mm3 and is embedded into a hole of 200×200×30 mm3.

A flat car-roof antenna module for phone and GPS applications

A flat car-roof antenna module for phone and GPS applications is proposed. The module consists of a planar inverted-F antenna (PIFA) for the phone operation and a planar loop antenna for the GPS one. The two antennas are located in a same plane parallel to car roof and put close to each other so that the dimension of the module is only 50 × 80 mm2 in plane. Gap between the antenna plane and the car roof is only 19 mm. This low profile makes the module almost invisible when it is installed on a car roof. Even with this narrow gap, the two antennas keep high performance in their operation frequencies.

A film antenna for digital terrestrial television reception

Recently, many countries are switching their terrestrial television broadcasting from analog to digital [1] and the demand of TV reception increases for mobile terminals, such as mobile phones and notebook PCs. Accordingly, the antennas used in these terminals are required to be compact, operate at multibands and have sufficient gain. Some antennas have been developed for the purpose but they are large in size or have only narrow bandwidth [2]–[4].

A wire-grid type transparent film UWB antenna

In this paper we have introduced transparent wire-grid type conductive film antenna, made of Ag-paste. The wire-grid has wire-width of only a few microns and makes the conductive film almost invisible. The antenna is designed to cover an ultra-wide band (UWB) from 2 to 6 GHz and the radiating part is made with different mesh sizes of the conductive film and ground has been taken with continuous sheet. Performance of these mesh antennas is compared with a full Cu-sheet antenna. Input characteristics and radiation patterns are approximately the same as that of the Cu-antenna. Even the wire-grid is so sparse, the radiation efficiency is higher than 50% at most frequencies. In the later part of this paper, vertical slit and horizontal slit antennas made of Cu-sheet are investigated. The horizontal slit antenna shows deviation in the results, whereas the vertical slit and full Cu antenna are matching the results to each other for the UWB of 2–6 GHz. Vertical and horizontal slit antennas confirm the appropriate polarization.

A folded film antenna for digital terrestrial television reception

Recently, many countries are switching their terrestrial television broadcasting from analog to digital and the demand of television reception increases for mobile devices. The antenna for this purpose is required to be compact, light-weight, and operate at the broadband covering the broadcasting frequencies. In this paper, we propose a compact antenna for digital terrestrial television reception. The antenna is made of film with a dimension of 78×56 mm2 and operates at the broadcasting frequencies in planar form. The antenna is further optimized to maintain the performance when it is compactly folded to a dimension of 78 × 20 × 4 mm3. A fabricated prototype antenna demonstrates that the folded antenna operates in a frequency range from 470 to 890 MHz, which covers the frequency range of most digital terrestrial television systems in the world, such as the Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) (470–770 MHz), the Advanced Television Systems Committee (ATSC) (470–860 MHz), the Digital Terrestrial Multimedia Broadcast (DTMB) (470–860 MHz) and the Digital Video Broadcasting-Terrestrial (DVB-T) (470–890 MHz).

A UWB band-rejected antenna with embedded nonuniform microstrip line

An ultra-wide band (UWB) antenna with band rejection on the range of the wireless local area network (WLAN) is proposed. The antenna consists of a radiation element with broadband radiation and a nonuniform microstrip line for necessary band rejection. The nonuniform microstrip line is designed by the inverse scattering technique. A fabricated antenna is well designed and radiates properly in the UWB range except the WLAN range.