Research Journal of Applied Sciences, Engineering and Technology 5(6): 2196-2202, 2013 ISSN: 2040-7459; e-ISSN: 2040-7467 © Maxwell Scientific Organization, 2013 Submitted: August 07, 2012 Accepted: September 03, 2012 Published: February 21, 2013 Corresponding Author: Syedul Amin, Department of Electrical, Electronic and Systems Engineering, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia 2196 Design of an Inductor-Less LNA Using Resistive Feedback Topology for UWB Applications Rozi Rifin, Mamun, Syedul Amin and Hafizah Husain Department of Electrical, Electronic and Systems Engineering, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia Abstract: Low Noise Amplifier (LNA) is one of the essential components in Ultra Wideband (UWB) devices. Conventional LNA suffers from large chip area, high power consumption and inadequate Noise Figure (NF). A compact UWB LNA in the bandwidth of 3.1 to 10.6 GHz is proposed. The design is based on inductor-less configuration using the resistive shunt feedback topology and noise canceling techniques for wideband and high gain characteristics. Designed in 0.18-µm CMOS technology without applying any inductors and capacitors in the core circuit, the chip area is only 0.001 mm 2 and consumes 16.11 mW of power at 1.5-V supply. The maximum gain is 18.01 dB and the minimum NF noise is 1.324 dB. Keywords: CMOS, inductor, LNA, noise-canceling, resistive feedback, UWB INTRODUCTION UWB system is a wireless technology which is capable of data transmission over a wide spectrum of frequency bands from 3.1-10.6 GHz with very low power and high data rates (Akter et al., 2008a, b; Reaz et al., 2007a, b; Marufuzzaman et al., 2010; Reaz et al., 2003; Reaz et al., 2005; Chang et al., 2008; Chang and Hsu, 2010; Chen and Liu, 2012). LNA is one of the essential components in developing UWB devices (Reaz et al., 2006; Reaz and Wei, 2004; Mohd-Yasin et al., 2004; Mogaki et al., 2007; Lu et al., 2006; Moezzi and Bakthiar, 2012; Belmas et al., 2012). Due to Federal Communication Committee’s (FCC) limitation on bandwidth (not lesser than 500 MHz) and low power emission (EIRP lower than 41.3 dBM/MHz) for an UWB applications, several stringent requirement in designing an UWB LNA needs to be fulfilled. The UWB LNA needs to provide a good input matching over the bandwidth of 500 MHz and sufficient gain to amplify the weak signal at the receiver as well as to overcome the noise effects from subsequent stages. On top of that, the NF of the UWB LNA must be minimized as low as possible since it plays a main role in defining the receiver’s sensitivity. Moreover, the size of LNA needs to be physically small in order to provide power efficient and reduce the fabrication cost respectively. Significant research and various approaches have been proposed to design UWB LNA. There are several techniques that commonly used to achieve wideband input matching for UWB LNA such as the inductive peaking, the Distributed Amplifier (DA), the filter type amplifiers, the common gate amplifier and the resistive shunt feedback amplifier (Chen et al., 2011). However, these techniques may suffer from several disadvantages which include large chip area, high power consumption and inadequate NF (Nilsaz et al., 2010; Hsu et al., 2010). This study presents the design of an UWB LNA that aims to achieve low power, small size and medium gain (Power gain >10 dB). The gain enhanced resistive shunt feedback based on noise canceling techniques is used in designing inductor less UWB LNA as it is able to accomplish wideband input matching, relative low NF, sufficient voltage gain and high linearity. Furthermore, this technique is widely used to release the tradeoff in the UWB LNA. CONVENTIONAL ARCHITECTURE Resistive feedback topology: Basically, feedback is a common technique that is applied in the design of wideband amplifiers to obtain the input matching. In the resistive feedback, LNA can achieve very wideband (from 0-22 GHz) and also it has low power consumption and high gain. This technique takes into the consideration since negative feedback had a tendency to minimize the input impedance of amplifier as well as extend its bandwidth with reduction of trade- off gain. As compared to the other techniques, a smaller chip area can be achieved by resistive feedback LNAs configuration since there are no or less inductors being introduced and utilized. To enhance the performance of