Wideband and multiband CMOS LNAs: State-of-the-art and future prospects S. Arshad, F. Zafar n , R. Ramzan, Q. Wahab NED University of Engineering & Technology, Electronic Engineering, University Road, Karachi, Sindh 75270, Pakistan article info Article history: Received 2 May 2012 Received in revised form 22 April 2013 Accepted 25 April 2013 Keywords: CMOS distributed LNA Dual-band LNA Inductorless LNA Multiband LNA Tunable LNA Wideband LNA abstract The realization of Software Defined Radio (SDR) requires flexible RF front-end to accommodate multiple standards in different frequency bands. In this review paper, we survey the literature over the period 1995–2011 and discuss the state-of-the-art multiband and wideband LNAs in context of different receiver architectures suitable for SDR. Wideband and multiband LNA designs reported in open literature are categorized on the basis of their circuit architecture. Measured results of the sample LNA designs from each category are tabulated and discussed with emphasis on power consumption, NF, gain, linearity, and impedance matching tradeoffs. We have also discussed our own three wideband inductorless LNA design prototypes which are manufactured in 0.13 mm and 90 nm CMOS. This review infers that future LNAs suitable for SDR must be highly linear and scalable with future technology nodes. & 2013 Elsevier Ltd. All rights reserved. 1. Introduction HE demand of wireless transceiver RFICs is exp expanding rapidly because of its huge market ranging from pagers, cordless phones, cell phones, WLAN terminals, nodes for sensor networks and GPS to recently introduced DAB/DVB enabled PDAs [1]. These diverse range of mobile terminals have their own standard and require separate RF front-end and digital resources for baseband processing. As, Today, mobile terminals are no more a standalone product rather they are a small part of consumer electronics e.g. WLAN and Bluetooth in Laptops and GSM, 3G, GPS and Bluetooth terminals in PDAs etc. This demands the mobile terminals to be flexible in nature with low power and low cost. Therefore, the designer is urged to integrate all radio blocks on a single chip along with hardware reuse/sharing which not only results in cost reduction due to reduced silicon area but allows exclusion of separate RF packaged chips at the same time. On-chip integration and placing a lower limit on the power consumption of performance centric analog circuits helps to reduce the power consumption [2]. In case of single chip radio receiver, only the LNA input interface needs to be matched to 50 Ω antenna. Since all other RF blocks are on the same chip with interconnect length much smaller as compared to wavelength of interest, no reflection occurs. Therefore, power matching is not required and signal is transferred using voltage divider rule (low output impedance connected with high input impedance) as in low frequency circuit. This results in much smaller power dissipation. A modern wireless terminal should support multiple standards (mobile: GSM, UMTS, WiMAX, LTE etc.; LAN: IEEE 802.11a/b/g etc.; PAN: ZigBee, Bluetooth etc.) receive multiple frequency bands (0.4–6 GHz), and allow any modulation scheme [3]. This mobile terminal is termed as commercial Soft- ware Defined Radio (SDR), as proposed by Mitiola [4]. SDR is still not a reality because of design challenges in domains of antenna, RF Front-end, A/D & D/A conversion and baseband processing. A paradigm shift in radio design strategy and some technological breakthroughs are mandatory to overcome these challenges. Recently, the integration of MEMS in RF circuits has increased the possibility of developing wideband smart antennas and on-chip high Q filter design [5]. Metamaterials have brought a new possibility for multiband high efficiency smart antennas [6,7]. Similarly, the Rapid Single Flux Quantum (RSFQ) technology opens gateway to high performance ADCs/DACs [5]. Larson predicted in 1998 [1] that CMOS has the potential to meet the future demands in comparison with SiGe based HBTs, GaAs based HEMTs and BJTs. With its ability of highest level of integration, low cost for bulk fabrication and low power consump- tion, CMOS has become the technology of choice for RFICs in consumer electronic products [8]. Moreover, due to CMOS scaling the unity gain frequencies are in hundreds of GHz (e.g. for 65 nm f T ¼ 200 GHz [9]) allowing the design of RF circuits operating at frequencies near and above 60 GHz [10]. Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/mejo Microelectronics Journal 0026-2692/$ - see front matter & 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.mejo.2013.04.011 n Corresponding author. Tel.: +92 2199261203. E-mail address: faizazafar@neduet.edu.pk (F. Zafar). Please cite this article as: S. Arshad, et al., Wideband and multiband CMOS LNAs: State-of-the-art and future prospects, Microelectron. J (2013), http://dx.doi.org/10.1016/j.mejo.2013.04.011i Microelectronics Journal ∎ (∎∎∎∎) ∎∎∎–∎∎∎