Abstract    This paper presents a temperature compensation voltage controlled oscillator (VCO) based on Cross-Coupled pair and Colpitts structures which is suitable for military fields. Also, two inductors have been used for increasing the negative conductance. By using this method, start-up condition has been improved. Two varactors and a simple capacitor bank are applied for covering a wide tunning range. The VCO has been designed and simulated in TSMC 0.18 µm CMOS technology.To compensate the frequency drift over a temperature range, MOS varactors are used and biased with a complementary to absolute temperature (CTAT) voltage reference. This CTAT voltage reference has been applied to two varactors and decreased the frequncy drift over temperature range. By using this technique, the proposed VCO can achieve a very stable frequency of 11.5 PPM/°C at 24.35 GHz over a temperature range of -40~120 °C. Simulation results also show the VCO covers the frequency range of 23.75~24.8 GHz. The simulated phase noise of center frequency is -102.6 dBc/Hz at 1 MHz offset frequency. The VCO consumes 10.4 mW DC power under 1.8 V supply voltage. The figure of merit of the VCO is -179.8 after compensating.

Keywords    Colpitts; Complementary to Absolute Temperature; Cross-coupled Pair; Temperature Compensation; Voltage Controlled Oscillator

چکیده    در این مقاله یک نوسان‌ساز کنترل شونده با ولتاژ همراه با جبرانسازی حرارتی بر پایه نوسان‌سازهای کولپیتس و زوج ضربدری ارائه می‌شود. با استفاده از این ساختارها، می‌توان به نویز فاز بهتر و توان مصرفی کمتر دست پیدا کرد. این مدار در فناوری 18/0 سی‌ماس طراحی و شبیه‌سازی شده است. برای جبرانسازی حرارتی از یک جفت خازن متغیر، که به وسیله یک منبع ولتاژ CTAT تغذیه می‌شوند، استفاده شده است. این منبع به دو خازن ورکتور اعمال می‌شود و باعث پایدار شدن فرکانس در گستره دمایی بالایی می‌شود. شبیه‌سازی نشان می‌دهد که با استفاده از این روش در گستره دمایی 40- الی 120 درجه سلسيوس، ضریب تغییرات 5/11 قسمت در میلیون بر درجه سلسيوس (PPM/C) در فرکانس مرکزی 35/24 گیگاهرتز به دست می‌آید. با توجه به نتایج گستره فرکانسی پوشش داده شده توسط این نوسان‌ساز کنترل شونده با ولتاژ از 75/23 گیگاهرتز الی 8/24 گیگاهرتز می‌باشد. همچنین توان مصرفی و نویز فاز در فرکانس مرکزی و در آفست 1 مگاهرتز، 4/10 میلی‌وات و dBc/Hz 6/102- می‌باشند. مدار طراحی شده داری ضریب شایستگی dBc/Hz 8/179- می‌باشد

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