Hiroshi Ogura

Packaging using microelectromechanical technologies and planar components

A novel millimeter-wave packaging structure was developed in which a micromachined low-loss planar component and flip-chip devices were integrated on a silicon substrate. A low-loss planar filter was achieved on a 7-mm-square silicon substrate employing an inverted microstrip line and a unique resonator. High attenuation in the stopband was also obtained by introducing a pole control technique. Fabrication of a compact K-band receiver front-end incorporating a built-in filter was realized using multilayered benzocyclobutene (BCB) and flip-chip bonding techniques. Furthermore, we propose an alternative BCB suspended structure and demonstrate a planar antenna for Ka-band applications. These technologies bring to reality high-performance compact packaged systems in millimeter-wave region applications.

Surface mountable liquid crystal polymer package with vertical via transition compensating wire inductance up to V-band

A high performance V-band surface mountable packaging structure has been proposed and demonstrated. We enabled the use of liquid crystal polymer (LCP) as a low-cost SMT millimeter-wave package. This package employed the wire bonding technique as the RF interconnect, and the vertical via as the vertical signal transition, despite it being meant for application up to V-band. The optimized vertical transition structure consisting of the vertical via and high-impedance transmission lines (TRLs) was designed to form a low-pass impedance matching network compensating for the parasitic inductance of the bonding wire. The overall packaging structure, including a bond wire, a vertical via and a solder joint, achieved excellent RF characteristics and a low insertion loss of less than 0.6 dB at 65 GHz. The adoption of widely used conventional technology such as a general printed circuit board (PCB) wiring process and a low-cost plastic substrate makes it possible to realize cost-effective millimeter-wave equipment.

Hole Drilling of Glass-Foam Substrates with Laser

Using 10 - 100 msec pulses and a 10.6 micrometers wavelength CO2 laser, focused to a spot size 200 micrometers , we have produced holes into glass-foam substrates. We examine the effect of pulse width on the hole structure and the pile-up around the hole in single-pulse drilling. The height of the pile-up increases 7 - 30 micrometers with increasing the pulse width. The residual melting layer is under 0.5 (mu) m in the hole walls. It seems that the glass-foam substrate is suitable for laser beam machining.

K-band receiver front-end IC integrating micromachined filter and flip-chip assembled active devices

A novel three-dimensional K-band receiver front-end IC was developed in which a micromachined low-loss filter and flip-chip devices ware integrated on a silicon substrate. An inverted microstrip line and a new resonator are newly introduced in the filter. Multilayered BCB and flip-chip bonding technologies are also adopted.

A Ka-band high-efficiency dielectric lens antenna with a silicon micromachined microstrip patch radiator

Novel antenna configurations suitable for millimeter-wave applications were proposed incorporating a dielectric lens antenna with a single microstrip patch radiator. In general high aperture efficiencies are easily obtainable with lens antennas because of flexibility in controlling the aperture-field distribution coupled with low feeder loss. The radiator was integrated with front-end circuits into a single hybrid IC using silicon micromachining and BCB (benzo-cyclobutene) multi-stacked circuit processes. The radiator was constructed on a thin suspended BCB film to suppress dielectric and conductor loss. A demonstration radiator showed good performance at 39 GHz (Ka-band). The lens was designed using geometrical optics relative to the directivity of the radiator and the aperture-field distribution. The circular polarized lens antenna assembly exhibited a gain of 15.7 dBi, 18.7 dB side-lobe level suppression and 0.17 dB axial ratio.

Millimeter-wave Transceiver MCM Usig Multi-layer BCB with Integrated Planner Antenna

A novel millimeter-wave transceiver MCM using multi-layer BCB was proposed. This MCM is based on a glass substrate laminated with three layers of BCB thin film, enabling four-layer 3-D circuitry. We report two different Ka-band MCMs of this structure; namely, a flip-chip assembled 28 GHz transceiver MCM integrating four MMICs of independent functions, and a 38 GHz receiver MCM with built-in four-element slot antenna array and flip-chip assembled MMIC.

Packaging using MEMS technologies and planar components

Three-dimensional millimeter-wave IC applying multi-layer BCB thin film and silicon micromachining technology was developed. Low loss characteristics were achieved by applying micromachining technology, despite being a quasi-planar structure, and a K-band filter was developed. Moreover, manufacture of the receiver front-end with built-in filter integrated into one package was realized by using flip-chip bonding techniques. Furthermore, we proposed an alternative BCB suspended structure and demonstrated a Ka-band antenna for the proposed package.

Simple structure holey-plate ion source

A high-efficiency, lightweight, and low-cost microwave ion source, created and sustained by evanescent waves emitted from a parallel-plate type source with a holey-plate has been studied. This source is called a holey-plate (HP) ion source. The microwaves at 2.45 GHz propagate inside the parallel-plate structure and then are converted into an evanescent mode through the use of a HP with 3-mm-diam holes. The plate dimensions are 100 mm×140 mm and are separated by 10 mm. In these experiments, the entire unit of the parallel plate is placed in a vacuum chamber. Dense plasma is produced only on the HP. A 78 mm×108 mm argon ion beam is extracted from the HP using a single grid with 3-mm-diam holes. The ion current densities are in excess of 1.2 mA/cm2 at an extraction voltage of 500 V.