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Active damping method and load current feedforward control method has been studied for control dc bus voltage in DC microgrid. Since load current feedforward control method requires information through communication, performance of controller is affected by communication time delay. This paper analyzes time delay performance of DC bus voltage variation with four control strategies based on the two control methods. DC bus voltage variation with four control strategies are simulated and analyzed considering three time delay cases.

Three compact microwave radiometers are developed for a lightweight solar-powered HALE UAV (High-Altitude, Long Endurance; Unmanned Aerial Vehicle) or pseudo-satellite. The platform aims to operate at UTLS, i.e. altitude of 16~20 km, where air becomes thin enough to prevent operation of a conventional fossil fuel engines. Despite atmospheric science community has long been attracted in its potential scientific and operational value as an observation platform, only limited opportunities were available. The payload aims to obtain vertical temperature profiles and column-averaged water vapour for entire troposphere where most weather system takes place. Given total weight (< 3 kg) and maximum power (< 50 W) constraints are not the only challenges for design of the CHAISR. It requires nominal operation in thermal range between −75 and +43 °C and from 1013 to 50 hPa. Along with optical cameras and in situ sensors in the CHASIR, three microwave radiometers with 16 channels from 18 to 60 GHz are to fit in 130 mm diameter and 290 mm length with total weight less than 1.5 kg for cross-track scan unit. Maximum power consumption of less than 15 W does not allow conventional internal blackbody calibration facility onboard, and alternative methods has been developed. This study represents calibration of miniature microwave radiometer followed by preliminary results of a series of test flights conducted in 2017. While CHAISR has reached 2/3 of its target altitude, data from test flight showed effective performance of tipping curve calibration with altitude as expected. On the contrary, pre-flight calibration with liquid nitrogen indicates there are rooms to improve method of lab-based characterisation of the CHAISR. The result suggests feasibility of in situ cold reference for microwave radiometer and better than 1°K of total RMSE can be achievable once accuracy of warm reference is available from noise diode or ambient temperature readings. Continuous improvement of quality of instrument is currently explored at the same time, researching way of improving current specification of microwave radiometer in CHAISR.

In this work we present a miniaturized electronic nose (E-Nose) sensor platform made by integrating film bulk acoustic resonators (FBARs) with arrays of CMOS oscillators. Each of the FBARs in the array is chemically activated to differing vapors (odors) after depositing a variety of polymers on the active areas of the resonators. To simulate the detection of primary indoor pollutants, we present the experimental results of polymer-gas interaction between 6 different coating polymers and various solvents. Chemical selectivity of the sensor arrays proved by highly distinctive real-time sensor graphs as well as apparent clusters in PCA graph confirms that this integrated FBAR-CMOS sensor arrays can be an essential platform for the miniaturized indoor air-quality monitoring device.

Boron-doped nanodiamond (NCD) films were synthesized on silicon substrates by microwave plasma chemical vapor deposition (MPCVD) technique. The effect of vacuum annealing on the field emission characteristics of NCD films has been investigated. The surface morphology and quality of films was characterized by scanning electron microscope (SEM) and Raman spectroscopy. The SEM images clearly reveal formation of nanocrystalline diamond (NCD) on the entire substrate surface. The Raman spectra of the as-synthesized films and films annealed at different temperatures in vacuum showed the characteristics peaks at ~1140, 1350 and 1480 cm-1 confirming the nanocrystalline nature of the diamond crystallites. The field emission properties of NCD films were enhanced by the rapid annealing process. The threshold fields of thermal treated boron doped NCD film are observed to be low as compared to as grown. The enhanced field emission properties may be attributed to the atomic defects created due to annealing, which play active role in the emission mechanism.

A low-cost, high-performance clock recovery (CR) module using a phase-locked loop (PLL) for 40 Gb/s optical receivers have been successfully designed and implemented. The recovered 40 GHz clock is synchronized with a stable 10 GHz VC-DRO. The timing jitter of the implemented PLL clock recovery module is significantly reduced as compared with the conventional open-loop type clock recovery module with a DR filter. The measured RMS jitter with the phase-locked CR module is about 250 fs. In addition, the CR module has been operated error-free during a 30-minute BER test with 40 Gb/s optical transceivers.

High performance, compact, and low-cost up/down-converter modules utilizing self-heterodyne detection scheme for 60 GHz WPAN applications have been designed and implemented using CPW-connected unit circuit blocks. The implemented up-converter module provides the gain of 13 dB and the output P/sub 1dB/ of +8 dBm with an IF frequency of 140 MHz and an LO frequency of 58 GHz. The down-converter module provides the gain of 40 dB with an RF input power of -42 dBm. These converter modules have been used for the demonstration of bidirectional real-time data transmission of 25 Mb/s.

A new analog phase shifter at 40 GHz using phase-locked loops have been successfully designed and implemented. With this phase shifter, a 40 GHz input signal is synchronized with a stable 10 GHz oscillator, phase-shifted with a reflection-type phase shifter at 10 GHz, and then quadrupled by a multiplier. The implemented phase shifter achieves continuous phase shift from 0/spl deg/ to 640/spl deg/ at 40 GHz.