Ryouhei Hosono

A ultra low-loss silica-based transformer between microstrip line and post-wall waveguide for millimeter-wave antenna-in-package applications

We fabricated a post-wall waveguide (PWW) into silica substrate having thickness of 520 μm and integrated a transformer between microstrip transmission line (MSL) and the PWW. The estimated loss of the transformer associated with the mode conversion and the measured loss of the PWW is 0.06 dB and 0.017 dB/mm at 60 GHz, respectively. This work would be a first attempt to apply silica substrate for microwave waveguide, to our knowledge.

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 millimeter-wave transformer between microstrip line and flexible post-wall waveguide on liquid crystal polymer substrates

We propose a simple transformer between microstrip line and flexible post-wall waveguide fabricated on liquid-crystal polymer substrates. Matching to 50 Ω impedance is accomplished by a combination of blind-via and microstrip-elements. The estimated loss of the transformer associated with the mode conversion and the measured loss of the PWW is 0.6 dB and 0.9 dB/mm at 60 GHz, respectively. We also found out that the transmission property of the PWW for bending remains unchanged.

Compact and low-loss bandpass filter realized in silica-based post-wall waveguide for 60-GHz applications

This paper presents compact and low-loss bandpass filters (BPFs) with ground-signal-ground interfaces that can easily be integrated with RFICs. The filters are realized by post-wall waveguide fabricated into a silica-substrate for the first time. A 59.11-GHz five-pole BPF with a 3.10% fractional bandwidth and a 2.62-dB insertion loss including input- and output- transitions is presented. Its intrinsic area is 8.4 mm by 2.0 mm. The proposed technology can offer practical integrated passive solutions for millimeter-wave applications.

A simple millimeter-wave transformer between microstrip line and post-wall waveguide

We propose a new transformer between microstrip line and post-wall waveguide fabricated on liquid-crystal polymer substrates. Matching to 50 Ω impedance is accomplished by a combination of a through-hole with an anti-pad and open-ended stubs. The bandwidth of the transformer for a reflection smaller than -15 dB is 8 GHz. The estimated loss of the transformer associated with the mode conversion and the measured loss of the PWW is 0.45 dB and 0.1 dB/mm at 60 GHz, respectively.

UWB antenna with multiple controlled rejection-bands

In this paper, an ultra-wide band (UWB) antenna with multiple band rejections is proposed. The antenna consists of a radiation element that supports radiation in a range from 3.1 to 15 GHz and a ground plane. The antenna is fed by a microstrip line embedded on the back of the ground plane. The microstrip line is designed to have nonuniform width along longitudinal direction by using the inverse scattering theory so as it has band rejections at 5 to 6 GHz and 10.6 to 13 GHz. A fabricated antenna shows that the measurement agrees with the theory very well. The antenna radiates properly in the UWB range except the WLAN range from 5 to 6 GHz and the radiation outside the UWB range is successfully suppressed.

A 60-GHz six-pole quasi-elliptic bandpass filter with novel feeding mechanisms based on silica-based post-wall waveguide

This paper presents a 60-GHz six-pole quasi-elliptic bandpass filter (BPF) realized in silica-based post-wall waveguide (PWW). We also propose a novel feeding mechanism that can control external quality factor. The mechanism has several parameters for the control. The BPF with a 8.1% fractional bandwidth and a 1.1-dB insertion loss at 60 GHz is presented. The dimension of the BPF is 3.6mm by 5.4mm.

Characterization of 60-GHz silica-based post-wall waveguide and low-loss substrate dielectric

This paper presents the measured propagation constant of a low-loss fused-silica-glass-based post-wall waveguide (PWW) designed for the 60-GHz band and proposes a simple estimation method of relative dielectric constant and loss tangent of the substrate dielectric from the propagation constant. The attenuation constant α of the PWW at 60 GHz is as low as 0.013 dB/mm. The relative dielectric constant and loss tangent are estimated by performing eigen-mode analysis using a commercial 3D electromagnetic software. The estimates are consistent with those from a conventional cavity resonator-based method. Unlike resonator-based methods, no additional samples are needed to provide estimates of dielectric properties at multiple frequencies.

DGA-designed bended film antenna for dual-band WLAN operation

In this paper, we apply a distributed genetic-algorithm (DGA) to the design of bended film antenna operating at the 2.4/5 GHz wireless local area network. The DGA is performed by selection, crossover, mutation and migration of individuals in sub-populations (islands) grouped by bending angles. Multi-objective optimization for antenna characteristics is solved. Several methods are proposed for the migration and the effect is demonstrated by comparing their simulated results.

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).