Research of Quadrature Voltage-Controlled Oscillator and Injection Locked Frequency Dividers Using Special Inductors

• Main Authors: Hsiu-An Yeh, 葉修安
• Other Authors: Sheng-Lyang Jang
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/61714219567241259505

碩士 === 國立臺灣科技大學 === 電子工程系 === 98 === In wireless communication system, frequency synthesizers are used to implement the frequency up/down converting of signal. In a frequency synthesizer, voltage-controlled oscillator (VCO) and divider are the key blocks. For VCOs, low phase-noise output is required to avoid corrupting the mixer-converted signal by close interfering tones. The frequency of output signal of VCO is divided down to the level of reference signal, and is compared with reference signal by a phase frequency detector (PFD) to adjust the output of VCO. Therefore the dividers must have the ability of high frequency operation. Because of wireless application, both of them should operate at low power consumption. This thesis proposes one VCO and two frequency dividers. The VCO provides quadrature outputs by diode-coupling technique. One divider is an injection locked frequency divider (ILFD) using active-inductor. The above circuits are fabricated in the TSMC 0.18 μm CMOS process. Another one is a dual-resonance ILFD using 3-dimensinal (3-D) transformer implemented in the UMC 90 nm process. Firstly, a diode-ring coupling technique has been used to design a quadrature voltage-controlled oscillator (QVCO), which consists of two n-core VCOs. The oscillating low-band frequency of the QVCO can be tuned from 4.50 GHz to 4.72 GHz, and the oscillating high-band frequency of the QVCO can be tuned from 11.61 GHz to 11.84 GHz while the tuning voltage varies from 0 V to 1.2 V. The phase noise of the high band oscillation frequency 4.5 GHz is -115.54 dBc/Hz at 1 MHz frequency offset. Secondly, we present a low power wide-locking range ILFD with tunable active inductor (TAI) which is based on two pairs of cross-coupled transistors stacked in series. The divide-by-2 function is performed by injecting a signal to the gate of direct injection MOSFETs across the active LC resonator. At the supply voltage of 1.6 V, the free-running divider is tunable from 1.3 to 0.8 GHz. At the incident power of -3 dBm the operation range in the divide-by-2 mode is from the incident frequency 1.5 to 3.8 GHz. Finally, a dual-band CMOS LC-tank ILFD is proposed. It is realized with a cross-coupled nMOS oscillator with a dual-resonance LC-tank. A 3-D transformer is used in the implemented ILFD. At the dc drain-source voltage of 0.7 V, the free-running ILFD can have two frequency bands without tuning, and the high-band oscillation frequency is 24.4 GHz. The low-band oscillation frequency is 5.5 GHz. The low-frequency band is an excited band. The measured locking range is from 46.5 (10.4) GHz to 51.4 (11.9) GHz for the high- (low-) frequency band.