頻率合成器在RF射頻收發機中扮演著重要的角色，其需要產生一個穩定、乾淨的振盪訊號源傳送至混波器進行升頻、降頻，而為了追求低功率、低相位雜訊與較寬鎖定範圍的除頻、倍頻器，這其中又以VCO和注入鎖定除頻器(ILFD)、倍頻器(ILFM)最為重要，所以本篇論文分別呈現了三篇VCOs以及一篇ILFM的設計，所有的晶片都是使用tsmc 0.18-μm CMOS mixed-signal and RF 1P6M technology工藝製造。
第一部分呈現一個節省面積的環形行波壓控振盪器(RTWO)將主動元件電晶體與可變二極體設計於電感內部，晶片面積為1.18×1.18 mm2。VCO的諧振頻率是可調的，調頻範圍從3.16 GHz至4.04 GHz (24.44%)。當供應電源為1.2 V時，功耗為12.36 mW。當振盪頻率為3.16 GHz時，量測到的相位雜訊在1 MHz的頻率偏移下為 -124.37 dBc/Hz。當供應電壓為1.2 V時，FOM值為 -183.44 dBc/Hz。此VCO架構使用雙絞電感傳輸線以抑制磁場的干擾。
第二部分提出一個使用LC諧振的注入鎖頻倍二倍頻器 (×2 ILFD)。此架構由pMOS注入鎖定振盪器產生一倍諧振，再經由堆疊其上方的雙推式架構產生二倍頻率訊號，並將此二倍頻訊號單端輸出。此注入鎖定振盪器使用兩顆八字電感當作共振腔。當供應電源為1.2 V時，功耗為9.832 mW、二倍振盪頻率為4.175 GHz。當注入訊號功率為 0 dBm 時，輸入端注入鎖定的頻率範圍為1.6 GHz至3.2 GHz，並在輸出端產生頻率範圍從3.2 GHz至6.4 GHz (66.66%) 的訊號。晶片總面積為0.7 × 0.8 mm2。
第三部分使用設計了一個新穎的高品質因素八字型同相位變壓器以降低電磁輻射的干擾。此變壓器分別由兩組兩路徑並聯的主要電感及次要電感相互耦合而成，並將兩組一匝線圈做串聯。當供應電源為0.7 V時，功耗為19.5 mW。當頻率為4.56 GHz時，VCO的相位雜訊在1 MHz的頻率偏移下為 -124.07 dBc/Hz、FOM值為 -185.89 dBc/Hz。晶片面積為0.549 × 0.938 mm2。
最後部分是使用兩個三圈的八字電感設計環型壓控振盪器。架構上使用兩組差動疊接nMOS放大器做迴授。頻率調頻從2.34 GHz至3.05 GHz，中心頻率為2.695 GHz，有26.34% 的調頻範圍。當供應電源為1.3 V時，功耗為21.58 mW。當頻率為2.34 GHz時，VCO的相位雜訊在1MHz的頻率偏移下為 -125.03 dBc/Hz，FOM為 -179.07 dBc/Hz，FOMT為 -187.48 dBc/Hz，晶片總面積為1.12 × 0.96 mm2。

The frequency synthesizer plays an important role in the RF transceiver, and it needs to provide a stable and pure oscillating signal source for the mixer to up-convert and down-convert signals. So as to pursue low power supply, low phase noise, and a wider locking range of divider and multiplier, the VCO and Injection-locked Frequency Divider (ILFD) or Multiplier (ILFM) are especially crucial. Therefore, this thesis presents three designs of VCO and one design of ILFM. All of the chips designed in this thesis are fabricated in tsmc 0.18-μm CMOS mixed-signal and RF 1P6M technology.
The first part presents an area-saving rotary traveling-wave oscillator (RTWO) with active FETs and varactors inside on-chip inductors and the die area is 1.18×1.18 mm2. The free-running oscillation frequency of the VCO is tuneable. The tuning range is from 3.16 to 4.04 GHz (24.44%). The total power consumption shows 12.36 mW at the supply voltage of 1.2 V. The measured phase noise at 1MHz frequency offset is -124.37 dBc/Hz at the oscillation frequency of 3.16 GHz. At the supply voltage of 1.2 V, the figure of merit (FOM) of the proposed VCO is -183.44 dBc/Hz. The VCO uses the concept of the twisted-inductor transmission line to suppress magnetic field interference.
The second part proposes an LC-tank injection-locked frequency doubler (×2 ILFD). The ×2 ILFD circuit is composed of a pMOS first-harmonic injection-locked oscillator (ILO) stacked below a push-push frequency doubler, which provides the single-phase output signal. The ILO uses two 8-shaped inductors as the resonator. The total power consumption shows 9.84 mW at the supply voltage of 1.2 V, and the free-running oscillation frequency of the ×2 ILFD is 4.175 GHz. At the incident power of 0 dBm, the input locking range is from the incident frequency 1.6 to 3.2 GHz to provide a signal source from the frequency 3.2 GHz to 6.4 GHz (66.66%). The die area is 0.7 ×0.8 mm2.
The third part presents a novel high Q-factor 8-shaped concentric transformer which aims at low radiation interference. The transformer is coupled by two 2-path parallel primary and secondary inductors. They use two 1-turn coils twisted in series. The total power consumption shows 19.5 mW at the supply voltage of 0.7 V. At 4.56 GHz, the phase noise of VCO is -124.07 dBc/Hz at 1 MHz frequency offset, and the FOM is −185.89 dBc/Hz. The die area is 0.549 ×0.938 mm2.
The last part designs a ring-type VCO using two 3-turn 8-shaped inductors. The VCO consists of two differential cascode nMOS amplifiers for feedback connection. The frequency tuning is from 2.34 GHz to 3.05 GHz with a center frequency of 2.695 GHz and presents a 26.34% tuning range. At the supply voltage of 1.3 V, the total power consumption is 21.58 mW. At 1 MHz offset frequency the measured phase noise of the VCO at 2.34 GHz is −125.03 dBc/Hz and the FOM is -179.07 dBc/Hz and the FOMT is -187.48 dBc/Hz. The die area is 1.12 × 0.96 mm2.

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