Design of Integrated CMOS LNA using Suspended MEMS Inductor for Wireless Applications Heba El Ahmady*, Amal Zaki**, Hamed Elsimary**, and Hazem Hassan* helahmady@aaib.com *Arab Academy for Since and Technology and Maritime TransportCairo, Egypt ** Electronics Research Institute, Cairo, Egypt Abstract: - The interest in low-cost, low-power, silicon-based transceiver designs for radio frequency (RF) applications, such as cell phones and wireless sensor networking, has prompted research in wireless circuit design techniques using complementary-metal-oxide-semiconductor (CMOS) technology. A critical limitation in obtaining fully integrated CMOS wireless systems is the lack of high quality of the on-chip passive components, and in particular, on-chip inductors. In this paper design of integrated CMOS LNA using suspended MEMS Inductor for wireless applications is presented. Modeling and designing of the on-chip spiral inductor is the main objective of this work. Measurements and characterization results are presented in this work. Key-Words: - Spiral inductor, MEMS inductor, MEMS technology, High Q-factor. 1 Introduction Wireless communication triggers the research and development of RF integrated circuits (RF IC), and the rapid growing market for more portable and low cost equipments motivates the single chip with RF front-end and digital process or integrated together. This trend makes CMOS RF IC more attractive in the competition with its counterparts. CMOS low noise amplifier (LNA) is an important component in RF communication receiver. The noise performance of LNA determines the noise performance of the entire system. Therefore, to improve the sensitivity of the receiver, the noise figure of the LNA must be minimized and enough gain must be provided. Finding ways to reduce the noise figure of the CMOS LNA while using on-chip passive components becomes the greatest challenge in front of us. Its gain not only affects the linearity of the next circuit block, but also defines the overall noise performance. And its impedance matching is very important for maximum power transfer. Recently, with the rapid growth of the demands in wireless communication products such as mobile phones and wireless network, low cost and high performance on-chip radio-frequency devices are strongly needed. One important limitation in achieving higher levels of integration and further reduction of fabrication costs in the front-end of microwave transceivers is set by the difficulty of achieving high-Q on-chip inductors. The approach used in this paper is the use of silicon micromachining techniques to remove the substrate underneath the planar inductors such that to increase both the inductor self-resonant frequency f srf and quality factor Q. LNA design used in this research from a paper “MOS COMMON-SOURCE LNA Design Tutorial” by J P Silver where the LNA circuits were simulated using ideal inductor with no losses and the output was compared to the circuit simulation using the designed MEMS inductors. 2 Inductors Design and Model Three rectangular spiral inductors have been designed using and simulated using ADS. The spiral inductors have a 1 μm aluminum line thickness Table 1 lists the number of turns, line spacing, and line width for these di spirals. Table 1 Spirals different geometries. Device Number N number of turns S line spacing (μm ) W line width (μm) Di Inner Diameter (μm) 1 1.5 5 10 100 2 2.5 5 20 175 3 3.5 5 20 165 The S-parameters which are calculated using ADS then transformed into the Y-parameters from which the Proceedings of the International Conference on Circuits, Systems, Signals 374