毫米波可重置CMOS-MEMS前端電路之設計

Design of Millimeter-wave Reconfigurable CMOS-MEMS Front-end Circuit

張家維(Chia-Wei Chang)

指導教授 ： 張嘉展

國立中正大學/工學院/電機工程學系/碩士(2014年)

摘要

本論文利用TSMC 0.18-μm以及UMC 0.18-μm CMOS微機電製程實現四顆電路，分別是兩顆DC-70 GHz具低驅動電壓之單刀單擲CMOS微機電開關、CMOS-MEMS 致動器與可變電容測試鍵以及利用CMOS微機電技術設計之
V-Band壓控振盪器。
第一個電路是DC-70 GHz具低驅動電壓之單刀單擲CMOS微機電開關。此機械結構是由一根單端固定之主懸臂(main arm)，與多跟附加懸臂由中柱(post)貫穿成魚骨狀(fishbone)組成。這樣的架構可以有效降低驅動電壓，改善傳統MEMS機械結構需要大電壓驅動之缺點。此外，傳統單T頭會有因懸臂傾斜而無法同時接觸之缺點，為了改善此一問題，本論文採用工字頭之設計，當懸臂動作後可讓兩個地同時接觸主懸臂，進而使RF訊號短路。第二顆電路乃利用UMC 0.18-μm CMOS微機電製程設計一CMOS-MEMS 致動器與可變電容測試鍵，由於UMC CMOS-MEMS為一新製程，我們將透過此次下線經驗了解其模擬的致動器驅動電壓和實際量測的誤差。並且萃取出指叉電容之電容值，將此電路設計在V-band，得知其電容特性更有助於未來本團隊整合其他微波電路之設計。
第三個電路為利用CMOS 0.18-μm製程實現V-Band壓控振盪器，以一靜電式驅動魚骨致動器設計出一切換式微機電電容作整合，利用微機電切換式可變電容高Q值與高線性度的優勢來改善傳統固態可變電容之振盪器操作於高頻時之輸出頻率調控範圍小與相位雜訊表現較差之缺點。模擬之頻率調控範圍為54.19-55.28 GHz，輸出功率大於-8.4 dBm，相位雜訊為-98 dBc/Hz於1 MHz offset。量測結果顯示開關電路及震盪器電路，致動器無法如預期正常動作, 確實問題仍有待進一步驗證探討。

關鍵字

微機電

並列摘要

In this thesis, four CMOS-MEMS circuits, including two low pull-in voltage, DC-70 GHz CMOS-MEMS switches, an actuators-driven tunable capacitors, and a V-Band voltage controlled oscillator, are designed and implemented using TSMC 0.18-μm CMOS process and UMC 0.18-μm CMOS process.With parallel fishbone-like cantilever beams, the driving voltage can be effectively reduced. In switch design,the traditional T-shape contact tip can’t simultaneously contact RF ground due to the cantilever tilt. To overcome this issue, an I-shape contact tip was proposed in this work so that it can well contact the ground, thereby shortening the RF signals.
To investigate the newly-released UMC 0.18-μm CMOS-MEMS process, a tunable interdigital capacitor based on the fishbone actuator has been fabricated and tested. By extracting the capacitance value, the capacitor’s characteristics as well as the process parameters can be further learned, which will be essentially useful in future design.
The third circuit is V-Band voltage controlled oscillator in TSMC CMOS 0.18-μm process. The actuator-driven varactor has been employed in LC tank so that the frequency range can be further improved. The simulation result shows that the frequency can be tuned from 54.19 GHz to 55.28 GHz. Output power is better than -8.4 dBm, and phase noise is -98 dBc/Hz on 1 MHz offset.
Unfortunately, the measurement results show that the actuators fabricated using TSMC process did work as expected, and this issue still needs further investigation before being resolved.

並列關鍵字

CMOS-MEMS

參考文獻

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