金氧半射頻壓控震盪器設計與分析

Abstract

本論文研製一個2GHz的金氧半壓控震盪器，其架構為雙交叉耦合對 (cross-coupled pair)，採用內在共振調諧電路，具有nMOS 和pMOS 以提高負電導，輸出為差動信號。閘極電阻的效應及可變電容的特性均詳加討論。應用於放大器和混波器的驗證，有考量閘極電阻之下，增益會降低，動態範圍會變大，實驗與模擬結果非常吻合。再將此結果應用於震盪器的設計上以確保達到起振臨界條件。模擬結果如下：震盪頻率為2.078GHz~2.152GHz，單端電壓輸出為10mW，在600kHz相位雜訊為–102dBc/Hz和3V的電源供應。此壓控震盪器將可廣泛應用於無線通信系統中。

The fabrication of the VCO via 0.5um CMOS technology is designed for 2GHz wireless application. The architecture is the complementary nMOS and pMOS cross-coupled pair to enhance the negative conductance with internal resonator. The output signals are differential. The gate resistance is especially emphasized to assure the stationary of oscillation. The varactor from nMOS is also discussed. In the application of LNA and Mixer, with gate effect the dynamic range is increased due to conversion gain be reduced. The measurement and simulation have good match. The result is applied to VCO design in order to achieve the stationary of oscillation. The simulated results with output frequency 2.078~2.152GHz, single output power 10mW, and phase noise –102dBc at 600kHz offset are obtained. The power supply is 3V. It can be used as a local oscillator in a wide variety of wireless system.