Takayuki Yoshida

A novel millimeter-wave IC on Si substrate using flip-chip bonding technology

A new MM-wave IC, constructed by flip-chip bonded heterojunction transistors and microstrip lines formed on Si substrate, has been proposed and demonstrated. Good agreements between calculated and measured characteristics of this new IC (named MFIC: millimeter-wave flip-chip IC) have been obtained up to 60 GHz band by using micro bump bonding technology. Several MFICs such as HFET/HBT amplifiers have been fabricated to confirm their designed performance.<<ETX>>

Improvement of Coupling Efficiency for Passive Alignment of Stacked Multifiber Tapes to a Vertical-Cavity Surface-Emitting Laser Array

High-efficiency coupling of stacked multifiber tapes to a vertical-cavity surface-emitting laser (VCSEL) array is demonstrated. Three fiber tapes, each of which includes four multimode fibers, are coupled to a 4 x 3 VCSEL array simply by inserting fibers into guiding holes fabricated on the back side of the substrate. Mirrorlike smooth floors of the holes are formed by electron cyclotron resonance reactive ion beam etching, which results in great improvement of coupling efficiency. The average measured coupling efficiency is 81.3%.

An advanced millimeter-wave flip-chip IC integrating different kinds of active devices

On the basis of our proposed Millimeter-wave Flip-chip IC (MFIC) concept, K-band receiver front-end circuits integrated with both HFETs and HBTs using flip-chip bonding on the same Si substrate are newly developed. Two key technologies are newly introduced for the advanced MFIC structure. (1) BCB (Benzocyclobutene) is adopted to the dielectric material to produce low-loss lines. (2) Thin-film technology is introduced for the integration of a bias network. The newly developed advanced MFIC shows good performance, such as 1 dB of conversion loss and 6 dB of noise figure. The advanced MFIC is also expected as a low-cost millimeter(mm)-wave device for use in V-band as well as K-band.

A highly miniaturized receiver front-end hybrid IC using on-chip high-dielectric constant capacitors for mobile communication equipment

A highly miniaturized and low power consumption receiver front-end hybrid IC(HIC) including input matching circuits for 880 MHz bands using on-chip high-dielectric constant (/spl epsi//sub r/) capacitors has been newly developed. The HIC is composed of a GaAs IC chip and a ceramic substrate with spiral inductors on its surface. The HIC showed conversion gain of 20.2 dB and noise figure of 4.2 dB at supply voltage of 2.7 V and dissipation current of 3.7 mA. The HIC measures only 5.0 mm/spl times/5.0 mm/spl times/1.0 mm.<<ETX>>

A highly miniaturized front-end HIC for 1.9 GHz bands

A miniaturized receiver front-end hybrid IC (HIC) using MBB (microbump bonding) technology has been demonstrated. A GaAs IC die was dip-chip bonded on a ceramic substrate with matching circuits on its surface. New technologies such as 0.5 /spl mu/m gate buried p-layer MESFETs, on-chip high-dielectric constant capacitors, and intermediate tuned circuits have enabled miniaturization and low power-consumption at the same time. The fabricated HIC measured only 3.5/spl times/4.0/spl times/1.0 mm which corresponded to a 64% reduction from the conventional one. Conversion gain of 16.0 dB, IP3 out of 0 dBm, noise figure of 5.1 dB, and image rejection ratio over 20 dBc were obtained for the new HIC at 1.9 GHz, 3.0 V, and 4.5 mA of power supply.