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We developed an improved particle measurement spectroscopic technique, real-time laser transmission spectroscopy (RTLTS), to detect the number-weighted distribution of particles in real time. The measurement system used a deuterium-tungsten lamp for the light source and a spectrometer as the detector. The operating wavelength range was 300-810 nm. To obtain a physically reasonable number concentration from the experimental results, a sequential regularization method was used during the calculations. To verify the feasibility and reliability of RTLTS, the number-weighted distribution of polystyrene particle suspensions was determined over diameters ranging from 0.005 to 2.000 μm in 0.005-μm increments. The measured concentration error was 0.67-32.67%. A mean diameter of the smallest particle we had detected was 0.09 μm, with a 16% oversizing. The measurable concentration range was ∼10 8 #/cc to ∼10 11 #/cc for 0.895-μm-diameter particles. The measurable concentration range could be adjusted simply by changing the system configuration. This technique is available for both waterborne and airborne particles.

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In this study, we propose a 5‐GHz differential RF CMOS low noise amplifier (LNA) with electrostatic discharge (ESD) protection method in the RF input and output using spiral transformers. Spiral transformers are used as the ESD protection elements as well as the components of the input and output matching networks. During an ESD event, the transformers become the path through which the ESD current shunts because the frequency of the ESD is much lower than the operating frequency of the general RF circuit. The designed LNA is implemented using a 0.18‐µm RF CMOS process. The measured ESD survival level is higher than 1.4 kV. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:684–689, 2014