Ryohei Hosono

A Bandwidth-enhanced millimeter-wave microstrip comb-line array antenna with parasitic elements on liquid crystal polymer substrate

In this paper, a microstrip comb-line array antenna with parasitic elements for bandwidth enhancement at 60 GHz band is proposed. The antenna is fabricated on liquid crystal polymer (LCP) substrate due to its low dielectric loss. The antenna consists of a waveguide-to-microstrip mode transition, 16 radiation elements which construct an one-dimensional array and a terminated element. Two side-coupled parasitic elements are set symmetrically on both sides of each radiation element and an end-coupled parasitic element is set at the edge of the element for the sake of bandwidth enhancement. The antenna can be made consistently for the emerging market in the near future. Good agreement between simulated and measured results is obtained. Around 5% impedance bandwidth for |S11| less than -10 dB and 10% gain bandwidth for maximum gain over 10 dBi are finally obtained.

A broadband microstrip array antenna with rectangular waveguide mode transition at millimeter-wave band

In this paper, a broadband microstrip array antenna with rectangular waveguide mode transition operating at lower E-band is proposed. The microstrip array antenna is corporate-feed structure configured by microstrip line with a mode transition from rectangular waveguide. Broadband operation can be achieved by using a slit in the transition and employing a set of feed point in the center of microstrip-line feeder which also results in fixed-beam radiation. Validity is confirmed by the evaluation of a fabricated antenna. This antenna is suitable for E-band applications such as mobile back-haul.

Development of millimeter-wave devices based on liquid crystal polymer (LCP) substrate

Millimeter-wave (mm-Wave) technology is a promising solution to meet ever-increasing demand in wireless data transmission capacity thanks to the availability of large bandwidths at mm-Wave frequencies, where the choice of dielectric materials is one of important issues because the high water absorption at mm-Wave frequencies restricts remarkably the choice. Liquid crystal polymer (LCP) is one of materials available for mm-Wave applications and is able to provide cost-effective solution. In this paper, features of LCP will be introduced for applications at V-band (60GHz) and E-band (70GHz, 80GHz) in terms of dielectric constant, feasible structure, process and reliability. Some LCP-based devices such as transmission line, mode transition between different transmission-lines, antenna and filter will be reviewed. It is demonstrated that LCP-based devices actually have shown good performance and LCP is especially suitable for consumer applications that require high reliability and cost-effectiveness.

70-GHz band corporate-feed array antenna with multi-layered glass substrate

In this paper, a corporate-feed array antenna with multi-layered glass substrate operating at 70-GHz band is proposed. The array antenna has slot and microstrip radiation elements with post-wall waveguide corporate-feeding circuit. The feeding circuit and radiation elements are fabricated on separated glass substrates which are connected by diffusion bonding for Cu. Reasonable agreement in both reflection and radiation characteristics between simulated and measured results is obtained. Frequency independent beam direction is also observed so that the proposed antenna is suitable for 70-GHz band applications.

A broadband waveguide to microstrip-line transition on multi-layered LCP substrate

In this paper, a broadband waveguide WR-15 to microstrip-line (MSL) transition is proposed. The transition is structured on a multi-layered liquid crystal polymer (LCP) substrate. The substrate has two LCP layers and a metal back-short block is mounted on the substrate and is connected to ground plane. The WR-15 waveguide is directly connected to the substrate and is coupled with the MSL via rectangular apertures formed in the substrate. Small patches are put inside the apertures for enhancing the suppression of reflection. As a result, better mode transition is obtained if compared with one without the patches. A bandwidth of 16% (55-65 GHz) in which |S11|<; -10 dB is obtained in measurement.

Millimeter-wave broadband mode-transition between grounded coplanar waveguide and postwall waveguide

In this paper, a broadband mode-transition between grounded coplanar waveguide (GCPW) and post-wall waveguide (PWW) is proposed. The transition is composed of GCPW, microstrip line (MSL) and PWW. The transition is fabricated on liquid crystal polymer (LCP) substrate due to its low dielectricity and availability of roll-to-roll process for fabrication of devices with cost reduction. The GCPW GSG pad has two through-holes at longitudinal direction and a rectangular slot are added in each pattern of ground pads. Broadband impedance matching is obtained by these structures thanks to an addition of lumped inductance and capacitance to the mode-transition. In the mode-transition between MSL to PWW, a shape of microstirp line is tapered and dimension is optimized for broadband operation. A 24% impedance bandwidth for |S 11 | less than −15 dB is achieved in measurement of fabricated mode-transition. Loss of GCPW GSG pad and MSL-PWW transition with 0.120 dB and 0.276 dB at 60 GHz are evaluated from measured results. This mode-transition is one of candidate for usage of low loss antenna-in-package with substrate at higher frequency band.