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This paper describes the application of a SMA stub contact panel as an insulated monopole sensor for determination of moisture content in hevea rubber latex. Comparison results between measured and calculated reflection coefficient using King’s model are presented. Calibration equations relating moisture content to phase shift have been established in the frequency range from 100 MHz to 5 GHz. The accuracy of the technique was 1.3% when compared to actual moisture content obtained using the gravimetric method.

The article discusses the simulation and analysis of silicon schottky (Si) diode and silicon carbide schottky (SiC) diodes. It states that Si diode can produce higher reverse recovery electricity current and dissipate higher power losses by 91.12 percent compared to SiC diodes. It also mentions that Sic diode has become the favorite device for high frequency and power applications due to its covalent carbide substance bonding.

A comprehensive review of resonant gate drive (RGD) circuits operating in very high frequency (VHF) switching is discussed. The specific RGD circuits are normally applied only for certain applications due to their design limitations and drawbacks. The isolation techniques must be considered to avoid mismatch and interruption of signals as well as the dead time delay, size of components and choice of optimized parameter values. Low conduction losses and higher switching speed are important in achieving high efficiency of the driver. A new RGD circuit is proposed using power MOSFET device to show its robustness in achieving low conduction loss and high switching speed. In the near future, high power GaN HEMT can be used as a substitute for power MOSFET switch in VHF switching operation. Even though this device is not yet commercially available, the simulation study on RGD circuits can be realized through modeling. Studies have shown that some RGD circuit designs using power MOSFET can be modified and replaced with this device. However, the investigation on circuit performance and reliability on signal integrity have to be further investigated due to their differences in semiconductor properties and electrical characteristics. [ABSTRACT FROM AUTHOR]

A high output power density VHF converter has become important in recent years. This output power density of the converter is experiencing an adverse effect resulted from the applied switching frequency. In addition, the frequency which is higher than 20 MHz will no longer be applicable on the discreet SMT technology hence lowers the output power density. Thus, further improvement on circuit analysis and PCB layout design could help in the improvement of higher operating frequency. Even though it is suggested that power density and efficiency do not necessarily require a high switching frequency to achieve, the resonant network topology still has to be considered. In spite of issues resulted from the VHF converter design, power device selection and PCB layout circuit design are among the critical factors to consider, to maximize the capability of frequency-output power product in the VHF converter applications. [ABSTRACT FROM AUTHOR]