Masahiro Tanomura

TX and RX Front-Ends for 60GHz Band in 90nm Standard Bulk CMOS

This paper describes the design of a mm-wave power amplifier PA with reliability considerations for hot carrier injection (HCI) degradation. A 60GHz-band single-chip transmitter front- end with an output power of 6dBm for 2.6 Gb/s QPSK modulation and a single-chip receiver front-end are implemented in a standard IV 90 nm CMOS technology.

A High Gain 77 GHz Power Amplifier Operating at 0.7 V Based on 90 nm CMOS Technology

A 77 GHz 90 nm CMOS power amplifier (PA) demonstrates a gain of 17.4 dB and a saturated output power of 5.8 dBm at a low supply voltage of 0.7 V. To take care of hot-carrier injection degradation, the supply voltage is reduced from a standard voltage of 1.0 V. The saturated output power is increased to 9.4 dBm with a linear gain of 20.6 dB at 1.0 V operation. The amplifier consists of three-stage common-source nMOSFETs with gate widths of 40, 80, and 160 mum. To our best knowledge, the developed PA shows the highest gain ever achieved for W-band CMOS amplifier. The measured temperature characteristics suggest that a simple compensation technique is possible by gate bias control.

New concept of an electromagnetic usage for contactless communication and power transmission in the ocean

We demonstrate a new concept of an electromagnetic usage in the sea. The concept is characterized by sharing one pair of transmitting and receiving antennas for contactless communication and power transmission. The antennas are designed as electromagnetic (EM) high-Q resonators and the lowest resonant frequency is used for power transfer. The higher frequency band is used for signal communications. Using this concept, the efficiency of power transfer can be relatively high and the high transmission rate can be possible. A s a test trial for verifying the above concept, a measurement system is set up and the power transfer and signal quality are evaluated. The results show the power efficiency can be over 40%, and the transmission rate can be 20 Mbps via sea-water of the 5 cms thickness. The proposed concept can be used to realize a compact and maintenance-free wireless usage between different underwater systems, such as autonomous underwater vehicles (AUVs), remotely-operated vehicles (ROVs) and mother ships.

A 76 GHz GaN-on-silicon power amplifier for automotive radar systems

This paper describes the first demonstration of a 76 GHz gallium nitride (GaN) power amplifier (PA) on a silicon substrate. The PA microwave monolithic IC (MMIC) was fabricated by using AlGaN/GaN FET with a maximum oscillation frequency of 160GHz and a breakdown voltage of over 50 V. For reducing transmission loss, we used a CPW line on the silicon substrate with low transmission loss of 0.5 dB/mm at 76 GHz. For precise design of the PA, a large signal model of the FET was developed. The developed CPW 3-stage PA exhibited an output of over 12 dBm with over 5 dB gain at 75–81 GHz.

60-GHz-Band CMOS MMIC Technology for High-Speed Wireless Personal Area Networks

This paper presents recent progress on 60-GHz-band MMIC developments based on standard 90-nm CMOS technology. For a low-noise amplifier (LNA), a simple noise model is employed to facilitate efficient design in the millimeter- wave range. For a power amplifier (PA), a reliability issue due to degradation of hot carrier injection should be carefully considered for large-signal operation. To maximize output power while ensuring sufficient lifetime, we have established PA design process including co-simulation technique. The developed LNA achieves a noise figure of 5.7 dB with 13-dB gain at 63 GHz. On the other hand, PA exhibits a saturated output power of 8.5 dBm with 15.2-dB linear gain at 60 GHz with a supply voltage as low as 0.7 V where sufficient lifetime is expected. Finally, transmitter and receiver front-end circuits are demonstrated for 2.6-Gbps QPSK operation.

CW 20-W AlGaN/GaN FET Power Amplifier for Quasi-Millimeter Wave Applications

This paper describes an AlGaN/GaN FET power amplifier module delivering a continuous wave (CW) output power of more than 20 W at 26 GHz. To achieve high breakdown characteristics with reduced current collapse and high gain, we have developed a 0.2 µm-long recessed-gate AlGaN/GaN FET with a field-modulating plate (FP), achieving high operation voltage of 25 V even at quasi-millimeter wave frequencies. A single-ended AlGaN/GaN FP-FET amplifier module for quasi- millimeter wave frequency has been fabricated for the first time. The amplifier module developed using a 6.3-mm-wide single chip recessed-gate AlGaN/GaN FP-FET exhibited an output power of 20.7 W, a linear gain of 5.4 dB and a power-aided efficiency of 21.3% at 26 GHz. This is the highest output power in solid state power amplifiers at over 20 GHz.

Reduction of Thermal Resistance of High-Power Amplifiers by Carbon Fiber-Reinforced Carbon Composite-Based Package

This paper deals with the thermal design of an electronics package and a demonstration of reduced thermal resistance for high-power amplifiers (HPAs). The focus is package internal thermal management. A carbon fiber-reinforced carbon composite- (C/C composite) based heat sink is proposed as a means of enhancement over the more conventional CuMo material. The C/C composite has anisotropic thermal properties. Thermal performance of the material with anisotropic thermal properties depends strongly on taking advantage of superior properties in the desired directions. Finite-element analysis is performed to determine the correct orientation of the C/C composite material with anisotropic thermal conductivities to minimize thermal resistance. A 32% reduction in thermal resistance of the HPA has been predicted in the initial simulation. A package incorporating the C/C composite material is built with the optimal orientation of thermal anisotropy obtained by numerical simulations. A 20% reduction in thermal resistance has been successfully obtained by surface temperature measurements for the HPA with the C/C composite material. The difference between numerical (32%) and experimental results (20%) is well explained by the difference in boundary conditions at the package base. Also, nonlinearity in thermal resistance is explained by taking account of temperature dependence of semiconductor materials, such as SiC and GaN.

Long distance high efficient underwater wireless charging system using dielectric-assist antenna

We demonstrated a long-distance high-efficient underwater wireless charging system, which composed of a wireless power transfer antenna and a charging unit. To suppress the seawater conductor loss, which has a high conductivity of ~4 S/m, we analyzed underwater near field EM characteristics and designed dielectric-assist radiative antenna in a magnetic type. It is found that the propagation is dominantly guided by eddy current and low-frequency-operation is suitable from this analysis. The designed antenna size is 24 cm × 24 cm × 1.5 cm. Using this antenna in the sea, high efficiency of 60% through over 10 cm of sea water was achieved. The charging unit composed of a matching circuit, a rectifier, a DC-DC converter and a battery charging circuit. The wireless charging system achieved transmission distance of 5 cm and system efficiency of approximately 50%.

Analogue Dynamic Supply Voltage L-band GaN High Power Amplifier with Improvement of Efficiency and Linearity

This paper describes an analogue dynamic gate supply voltage L-band 10W GaN power amplifier which can provide improved efficiency and linearity for two tone and WCDMA signals. The developed analogue dynamic supply voltage method employs an envelope detector and a high speed low power dissipation CMOS level shift converter. The dynamic gate supply voltage is adjusted with the instantaneous input power. This simple method achieved a 6dB reduction in IM3 at 30dBm and 10% improvement of drain efficiency at IM3 of -20dBc.

Analysis of mineral composition by infrared spectral imaging using quantum dot focal plane array sensor

In this report, mineral composition of rock samples including conglomerate, sandstone, and dolomite was analyzed by IR spectral imaging using QDIP focal plane arrays (FPAs) with a peak-responsivity wavelength of 6.5 μm (FPA 1) and 5.5 μm (FPA 2). The qualitative and quantitative analyses are presented, and the key factor that determines the quantitative precision is discussed. In the qualitative analysis, the luminance of the different components in the rock samples was compared in the image. In the FPA 1 images, the shell fossil in the conglomerate sample and the limestone in the sandstone sample were darker than the other parts of the rocks due to their low emittance at 6.5 μm. In contrast, the difference in the luminance is hardly observed in the FPA 2 images under the same conditions. In the quantitative analysis, the emittance of dolomite was measured. Ten points in the IR image were randomly selected and the average emittance was calculated. The obtained emittances were 0.544±0.012 (FPA 1) and 0.941±0.019 (FPA 2), which means the coefficient of variation of the emittance measurement is ±2.1%~2.2%. By calculating the propagation of error, the precision of thermocouples for monitoring the temperature of the rocks in the calibration contributes most significantly (73%) to the total error.