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The polarization-corrected temperature (PCT) method is used to quantitatively estimate rainfall associated with typhoons over Taiwan. The satellite rainfall retrieval algorithms for TRMM/TMI (Tropical Rainfall Measuring Mission/TRMM Microwave Imager) have been developed according to rain types to improve the accuracy of the rainfall estimation. Measurements from precipitation radar (PR) are used to classify the rain types into three kinds including convective rain, stratiform rain with bright band and stratiform rain without bright band. Finally, rainfall retrievals are verified using PR near-surface rain rate (PR_RR), which is regarded as the "correct value." Data from typhoons during 2001 to 2006 are used to set up the rain rate retrieval equations. First, cloud-free areas are identified using infrared satellite images as cases of no-scattering condition and the PCT equations are set up for Taiwan. Second, from the statistical analyses of the PCT values with no-rain status, the rainfall threshold of 270 K is derived. Finally, the rain rate retrieval algorithms are set up using coincident PCT values and PR_RR for different rain types. Data from typhoons occurring from 2007 to 2008 are used for verification. The results show that the estimated values for convective and stratiform rain with bright band rain areas have better accuracy when the PCT method was used. For the stratiform rain without bright band, we find that the PCT method is not suitable. Applying this approach to estimate the rain rates associated with Typhoon Haitang (2005), the PCT method shows to have more reasonable rain rate estimation than the SIL (scattering index on land) method, with or without rain type classification. In addition, using 85 GHz data only, the PCT method shows higher rain rate retrieval resolution than the SIL method. Overall, we recommend that the PCT method can be used for quantitative precipitation estimation. [ABSTRACT FROM AUTHOR]

The design and performance of two new miniature 360° continuous-phase-control monolithic microwave integrated circuits (MMICs) using the vector sum method are presented. Both are implemented using commercial 0.18-μm CMOS process. The first phase shifter demonstrates all continuous phase and an insertion loss of 8 dB with a 37-dB dynamic range from 15 to 20 GHz. The chip size is 0.95 mm × 0.76 mm. The second phase shifter can achieve all continuous phase and an insertion loss of 16.2 dB with a 38.8-dB dynamic range at the same frequency range. The chip size is 0.71 mm × 0.82 mm. To the best of the authors' knowledge, these circuits are the first demonstration of microwave CMOS phase shifters using the vector sum method with the smallest chip size for all MMIC phase shifters with 360° phase-control range above 5 GHz reported to date. [ABSTRACT FROM AUTHOR]

A downconversion double-balanced oscillator mixer using 0.18-μm CMOS technology is proposed in this paper. This oscillator mixer consists of an individual mixer stacked on a voltage-controlled oscillator (VCO). The stacked structure allows entire mixer current to be reused by the VCO cross-coupled pair to reduce the total current consumption of the individual VCO and mixer. Using individual supply voltages and eliminating the tail current source, the stacked topology requires 1.0-V low supply voltage. The oscillator mixer achieves a voltage conversion gain of 10.9 dB at 4.2-GHz RF frequency. The oscillator mixer exhibits a tuning range of 11.5% and a single-sideband noise figure of 14.5 dB. The dc power consumption is 0.2 mW for the mixer and 2.94 mW for the VCO. This oscillator mixer requires a lower supply voltage and achieves a higher operating frequency among recently reported Si-based self-oscillating mixers and mixer oscillators. The mixer in this oscillator mixer also achieves a low power consumption compared with recently reported low-power mixers. [ABSTRACT FROM AUTHOR]

This article summarizes the development of mature and highly integrated SiGe BiCMOS ICs for gigabit-per-second communications according to the requirements of the IEEE 802.15.3c and 802.11.ad-draft standards. A single-element transceiver chipset for point-to-point communications is described with emphasis on a featurerich yet compact 60-GHz receiver. Next, a 16-element phased-array transceiver chipset for non-line-of-sight communications is described, with emphasis on a new power-efficient phasedarray transmitter. Examples of gigabit-per-second line-of-sight and non-line-of-sight link experiments are provided, and system-level implementation trade-offs are discussed. [ABSTRACT FROM PUBLISHER]