首先，本論文探討一新型CMOS雙頻壓控振盪器，此振盪器由一雙頻共振腔與兩組nMOSFET電容性交叉耦合對組合而成，此次提出之電路採用台積電0.18微米製程來實現，面積為0.9×0.97 mm^2，電路在VDD=1.1V時，可以產生2.4GHz、6.9GHz之輸出，其功率消耗分別為高頻3.19 mW與低頻1.25mW，而此電路在某些偏壓條件下，能產生多共振之現象。
其次，我們探討一個 六階共振腔之三頻帶壓控振盪器，其共振腔由左手共振腔與右手共振腔並聯而成，使用兩組變容器來切換頻帶，此電路採用台積電0.18微米矽鍺製程，面積為1.045 × 1.064 mm^2，此電路在提供電壓VDD=0.8V時，消耗功率為高頻3.824mW、中頻3.192mW、低頻3.488mW，而其輸出可調頻率範圍則分別為8.25-8.64GHz、6.87-6.90GHz、4.63-4.80GHz與4.24-4.50GHz，可觀察到遲滯現象對可調頻率範圍所造成之影響。
最後，我們探討的電路是一個切換式雙頻壓控振盪器，該電路由兩組子振盪器、切換模態電感以及變容器所組成，藉由變容器容值的改變，可將電路切換到另一模態，產生兩組不同的輸出頻帶，此電路採用台積電0.18微米製程，面積為0.976×1.092mm^2，在供應電壓為VDD=0.76V之下，其功率消耗分別為高頻3.557mW與低頻5.206mW，輸出頻率則為高頻5.24GHz，低頻3.27GHz，此電路能觀察到可調頻率範圍之遲滯迴路，且在某些偏壓狀況下能產生多共振之現象。

First, we study a new dual-band CMOS class-C voltage-controlled oscillator (VCO). The oscillator consists of a dual-resonance LC resonator in shunt with two pairs of capacitive cross-coupled nMOSFETs. The proposed oscillator has been implemented with the TSMC 0.18μm CMOS technology. The oscillator can generate differential signals at 2.4GHz and 6.9GHz and it also can generate concurrent frequency oscillation. With the supply voltage of VDD = 1.1 V, the VCO-core current and power consumption of the low/high-band oscillator are 2.90/1.14 mA and 3.19/1.25 mW, respectively. The die area of the concurrent oscillator is 0.9×0.97 mm^2.
Secondly, we will briefly present a triple-band (TB) oscillator using two 4th order LC resonator to form a 6th order resonator. The TB oscillator uses a pair of cross-coupled nMOSFETs to emulate a negative differential resistance and two pairs of back-to-back varactors for band switching. The proposed oscillator has been implemented with CMOS devices in the TSMC 0.18μm SiGe 3P6M BiCMOS technology and the core oscillator current and power consumption at the high (middle, low)-band are 4.78(3.99, 4.36) mA and 3.824(3.192, 3.488) mW, respectively at the dc drain-source bias of 0.8V. The oscillator can generate differential signals in the frequency range of 8.25-8.64GHz, 6.87-6.90GHz, 4.63-4.80GHz and 4.24-4.50GHz, and the tuning range of oscillator shows the hysteresis effect. The die area of the triple-band oscillator is 1.045 × 1.064 mm^2.
Finally, a mode-switched CMOS voltage-controlled oscillator (VCO) with two sub-frequency bands will be studied. The VCO consists of two cross-coupled VCOs coupled by a pair of mode-switched inductors. With the varactors as the mode switches, the VCO operates at the two different frequency bands. The proposed oscillator has been implemented with the TSMC 0.18μm CMOS technology. The oscillator can generate differential signals at 5.24GHz and 3.27GHz, and the core oscillator power consumption at the high/low-band is 4.68/6.85 mA and 3.557/5.206 mW, respectively at the dc drain-source bias of 0.76V, the hysteresis effect and concurrent oscillation are found. The die area of the dual-band VCO is 0.976×1.092mm^2.

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