設計5GHz低相位雜訊之共模回授壓控震盪器及適用於WLAN應用之微型曲折天線

Abstract

本論包含兩部分，其中所提出電路之晶片製作皆由TSMC 0.18μm mixed-signal/RF CMOS 1P6M製程來實現。 第一部分為一個採用共模回授之壓控震盪器，此方法為在尾電流源作改變，用switch bias的方法切換尾電流源進而降低flicker noise的memory effect，此外還採用去耦合電容來阻礙flicker noise的差模電流路徑，以達到好的phase noise。根據量測結果顯示:本VCO震盪頻率範圍為4.96~6.12 GHz，在供應電壓為1.8 V之條件下，功率損耗約為2.34 mW，相位雜訊為 -120.4 dBc/Hz @ 1 MHz，而figure-of-merit (FOM)則為-190.8 dBc/Hz。 第二部分為微小化WLAN天線，此設計採用meandering結構來達到微小化的目的，除此之外還結合了strip-line和slot-line的組合來來涵蓋2.4,5~6GHz之頻段，最後還應用ground boost方法(把能量耦合到ground 上，激發ground的輻射模態) 來達到在小的面積 (20 mm*15 mm)下有好的輻射效率。

This thesis consists of two parts. All the proposed circuits were implemented in TSMC 0.18μm mixed-signal/RF CMOS 1P6M technology. Part1 presents a VCO designed with common mode feedback technique which switch bias current source to suppress FET memory effect of flicker noise. In addition, we also use decoupling capacitor to block flicker noise path of current source. Because of those technique, we have good performance in measured results ( phase noise -120.4 dBc/Hz @ 1 MHz, tuning range 4.96~6.12 GHz, power consumption 2.34 mW and figure-of-merit (FOM) is-190.8 dBc/Hz). Part II presents the design of a planar antenna which uses meandering structure to achieve miniaturizing effect. In addition, this design also combine strip-line and slot-line combination to cover 2.4 and 5~6 GHz WLAN frequency bands . Finally this design also uses ground boost technique to improve radiating efficiency in small size (20 mm*15 mm) .