在矽基上高品質因素懸吊式電感之研製與其在主動帶通濾波器上的應用

Abstract

螺旋電感為實現射頻積體電路的重要元件, 它的品質因素和自振頻率關係電路的表現。但由於在現今金氧半螺旋電感,受到導電性矽基底損耗的影響,品質因素與自振頻率很低。本論文研究運用微機電技術完成懸吊式電感的製作與分析。我們得到品質因素改善至215%及自振頻率提昇至200%以上的懸吊式電感。我們運用此電感, 加上負電阻補償技術，來設計中心頻率為2.4GHz、頻寬80MHz的帶通濾波器以無線通信接收機使用。運用負電阻電路可補償電感串聯電阻損耗。兩技術的結合可使帶通濾波器有良好頻寬及假像頻率消除，可結合射頻放大器成射頻帶通放大器。此懸吊式電感還可應用在其他射頻電路上，如振盪器。

Spiral inductors are found increasing applications in RFIC’s operating at cellular, PCS, and industrial scientific and medical (ISM)-band with frequencies from 800 to 2400 MHz. Unfortunately, parasitic effects, such as coupling capacitance and substrate losses degrade their performances. This study employs the micromachining techniques to remove the substrate underneath the inductors to raise the self-resonant frequency and quality factor such that the SRF can be enhanced about 200% and the peak of Q factor can be improved about 215%. We also realize microwave active bandpass filters with good image-reject using the negative resistance configuration and high-Q suspended inductors. The simulation results show a 80MHz 3 dB-bandwidth centered on 2.44GHz, 1.1 insertion loss in the pass-band, over 35 dB of rejection on image 2.2GHz, P_1dB compression and IM3 are –18dBm and –7dBm, respectively.