| Summary: | 博士 === 國立中興大學 === 電機工程學系所 === 97 === Clearly, the CMOS technology dominates the huge amount of communication markets. The reasons that CMOS is considerably popular include high integration ability, low cost, and low power. To provide more divers mediate information in the data-communication and telecom systems, it exploits the advance modulation skills to transmit data in the limited channel capacity. However, the congestion of spectrum has been getting worse even though it uses these modulation techniques. Therefore, operating toward high carrier frequency or using MIMO (Multi Input Multi Output) techniques will be promising in the future. On the other hand, the characterizations of devices and the excellent circuit designs in the high frequency are essential to implement the whole communication system successfully.
The dissertation is composed of circuit and device parts. On the circuit side, it demonstrates three techniques to improve the performances of RF sub-circuits such as noise figure of low noise amplifier (LNA), isolation of Mixer and phase noise of voltage control oscillator (VCO). The first circuit, LNA, with inductive feedback network is demonstrated to reduce the noise figure and extend the bandwidth. Moreover, the wide-band LNA just only uses an inductor to save the chip area. Next, the even harmonic mixer is designed to increase the LO-RF isolation with half local oscillator frequency. It can ease the design requirement of millimeter-wave oscillator. Lastly, a novel DT-MOS transistor whose DC and RF performances are more excellent than the standard MOSFET is proposed. Using the proposed DT-MOS replaces the cross-couple pairs of VCO not to reduce the phase noise but also keep the same power consumption and chip area.
On the device side, the RF characteristics of MOSFETs, the cut-off frequency (ft), maximum oscillation frequency (fmax), stability factor frequency (fk), minimum noise figure (NFmin), noise matching and flicker noise, affected by the secondary effects are investigated with the identical total transistor size. Based on these results, it is also helpful to give some guidelines for RF circuit designers. Moreover, a new noise matching method different from traditional one is also proposed. In addition to the active device, the floating shield CPW transmission line is proposed. The CPW line achieves low loss than traditional one in the millimeter-wave. Finally, these works and extensions of the dissertation will be summarized.
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