Tsugumichi Shibata

Characterization of MIS structure coplanar transmission lines for investigation of signal propagation in integrated circuits

A full-wave analysis of metal-insulator-semiconductor (MIS) structure micron coplanar transmission lines on doped semiconductor substrates is carried out using a finite-difference time-domain approach. Metal conductor loss is taken into account in the analysis. Line parameters and electromagnetic field distributions are calculated over a wide frequency range involving slow-wave and dielectric quasi-transverse-electromagnetic mode limits. Measurements of these line parameters, varying substrate resistivity from 1 to 1000 Omega -cm, in the frequency range up to 40 GHz are also presented, and these agree with the analysis quite well. On the basis of these results, an equivalent circuit line model is induced and some considerations on the relationship between line structure and properties made. >

Generalized-scattering-matrix modeling of waveguide circuits using FDTD field simulations

This paper presents a hybrid-analysis method for metal waveguide structures. The method is based on the generalized-scattering-matrix approach. The whole structure is divided into several components, each of which is characterized independently. Some components are analyzed using the finite-difference time-domain (FDTD) method, while the others are characterized analytically. For the FDTD simulations, we introduce a new technique for efficient and rigorous calculation of the scattering parameters. This hybrid method inherits the universality of the FDTD method and enables us to analyze larger and more complex structures using limited computer resources compared to the single FDTD analysis of a whole structure. A few results are given as examples to illustrate the validity of the method.

High-directivity photonic emitter using photodiode module integrated with HEMT amplifier for 10-Gbit/s wireless link

We present a high-directivity photonic emitter with a high-gain antenna and waveguide-output photodiode module (WG-PM) for extending the transmission distance of a wireless link that uses a 120-GHz millimeter wave. The module employs a uni-traveling-carrier photodiode, broad-band high electron-mobility transistor (HEMT) amplifier, and planar-circuit-to-waveguide transition substrate. The maximum output power of the WG-PM is 8 dBm at a frequency of 120 GHz, and it has a 3-dB bandwidth of over 16 GHz. The wireless link with the high-directivity photonic emitter achieved 10-Gbit/s wireless data transmission, and using a high-gain Gaussian optic lens antenna and an HEMT amplifier reduced the input optical power necessary for error-free transmission. The transmission characteristics of the link showed that its transmission distance can be extended to over 100 m.

Passband-width broadening design for WDM filter with lattice-form interleave filter and arrayed-waveguide gratings

We successfully fabricated a high channel count and flat-top wavelength-division-multiplexing filter by integrating a waveguide-type interleave filter and two arrayed-waveguide grating on one chip. Optimizing the loss ripple of the interleave filter, we realized a 50-GHz spacing, 102-channel ports, a 1-dB passband of 30 GHz, and an insertion loss of 4 dB.

A 120-GHz millimeter-wave MMIC chipset for future broadband wireless access applications

A flexible CPW-MMIC (coplaner-waveguide monolithic microwave integrated circuit) chipset has been fabricated for 120 GHz future broadband wireless systems. The power amplifier has small signal gain of 8.5 dB from 115 to 135 GHz. The 1 dB compression point is 3 dBm at 120 GHz. We employed a traveling wave switch configuration for the ASK modulator. The insertion loss of the switch is less than 1.5 dB and the on-off ratio is more than 13.5 dB at 120 GHz. For the ASK modulator-demodulator chipset, the measured BER is 1e/sup -10/ for 10 Gbit/s PRBS 2/sup 11/-1 data at -13 dBm input power and 120 GHz RF frequency. The frequency doubler has an output power of -11 dBm at 120 GHz with fundamental and harmonics rejection better than 30 dBc.

A design technique for a 60 GHz-bandwidth distributed baseband amplifier IC module

A DC-60 GHz, 9 dB distributed amplifier IC module is fabricated with 0.15 /spl mu/m InAlAs-InGaAs low-noise HEMTs with 155 GHz f/sub T/ and 234 GHz f/sub max/. The device is mounted in a metal package with 1.8 mm coaxial cable signal interfaces. The package is specially designed using three-dimensional electromagnetic field analyses, resulting in very flat frequency characteristics of the module within 1.5 dB gain ripples over the entire bandwidth. A multichip module loaded with two amplifier ICs in cascade is also fabricated, and operates at a 17.5 dB gain from 60 kHz to 48 GHz. The 1 dB gain compression output power is about 5 dBm for both modules. The noise figure of the single-chip module is approximately 4 dB over a 10-40 GHz frequency range. >

Low loss fully reconfigurable wavelength-selective optical 1/spl times/N switch based on transversal filter configuration using silica-based planar lightwave circuit

A low loss wavelength-selective switch is proposed and demonstrated. The switch has a 1/spl times/4 transversal filter configuration that includes arrayed waveguide gratings and thermooptic phase shifters, and can route arbitrary wavelength input light to arbitrary outputs with no loss variation. We confirmed its operating principle and obtained an average loss of 2.7 dB and a worst extinction ratio of more than 20 dB.

A 24-Gsps 3-bit Nyquist ADC using InP HBTs for electronic dispersion compensation

A 3-bit flash analog-to-digital converter (ADC) for electronic dispersion compensation (EDC) was developed using InP HBTs. Nyquist operation was developed using InP HBT. Nyquist operation was confirmed up to 24 Gsps, which enables oversampling acquisition for 10 Gbits/s nonreturn-to-zero (NRZ) signals. The ADC can also be operated at up to 37 Gsps for low input frequencies. To reduce aperture jitter and achieve a wideband of over 7 GHz, an analog input signal for all latched comparators are provided as travelling waves through coplanar transmission lines.

Millimeter-wave photonic integrated circuit technologies for high-speed wireless communications applications

This paper describes an IC technology for high-speed wireless-link systems, using photonic techniques, which provides 10 Gb/s at 120 GHz. Optical signals are converted to electrical signals and radiated into freespace using Si-based circuitry. Both the preamp and PA utilize 0.1 /spl mu/m gate InAlAs/InGaAs HEMTs with gains of 6-10 dB and 8.5 dB, respectively.

A 43-Gb/s clock and data recovery OEIC integrating an InP-InGaAs HPT oscillator with an HBT decision circuit

This paper presents a 43-Gb/s clock and data recovery (CDR) optoelectronic integrated circuit (OEIC) that consists of a 43-GHz heterojunction phototransistor (HPT) oscillator as an optoelectronic clock recovery circuit and a 40-Gb/s-class heterojunction bipolar transistor (HBT) decision circuit. The layer and fabrication process of the HPT and HBT are fully compatible, and the HPT has a photocoupling window in the emitter electrode for optical access from the top. When the HPT is directly illuminated, the HPT oscillator successfully extracts a 43-GHz electrical clock signal from a 43-Gb/s optical data stream by itself. The OEIC regenerates the data signal input into the HBT decision circuit by using the electrical clock signal optoelectronically extracted by the HPT oscillator. The CDR OEIC achieves error-free operation for a 2/sup 31/-1 PRBS data signal. The power dissipation of the OEIC is only 0.79 W, which is less than half that of a fully electrical 40-Gb/s-class CDR IC. This is the first successful demonstration of HPT-based OEICs integrated with HBT digital circuits operating at such a high bit rate.