Current reuse topology in UWB CMOS LNA

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A Multiband Low Noise Amplifier for Software Defined Radio Using Switchable Active Shunt Feedback Input Matching

Radio frequency (RF) receivers are the key front-end blocks in wireless devices such as smartphones, pagers, PDAs etc. An important block of the RF receiver is the Low-noise amplifier. It’s function is to amplify with little noise addition, the RF signal received at the atenna. Modern wireless devices for example the smartphone, incorporates multiple functionalities supported by various RF standards- GPS, Bluetooth, Wifi, GSM etc. Thus, the current trend in the wireless technology is to integrate radio receivers for each RF standard into a single system-on-chip (SoC) in order to reduce cost and area of the devices. In view of this, multiband RF receivers have been developed which feature multiband LNAs. This thesis presents the design and implementation of a multiband LNA for Software Defined Radio Applications. In this thesis, basic radio-frequency concepts are discussed which is followed by a discussion of pros and cons of various multistandard low-noise amplifier topologies. This is then followed by the design of the proposed reconfigurable LNA. The LNA is designed and fabricated in IBM 0.18um CMOS technology. It is made up of dual LC resonant tanks, one to switch between 5.2GHz and 3.5GHz frequency bands and the other, to switch between 2.4GHz and 1.8GHz bands. The input matching of the LNA is achieved using a switchable shunt active feedback network. The LNA achieves S21 of between 10.1dB and 13.43dB. It achieves an input matching (S11) between -13.44 dB and -11.97 dB. The noise figure measured ranges from 2.8 dB to 4.3 dB. The LNA also achieves an IIP3 from -7.12 dBm to -3.45 dBm at 50 MHz offset. The power consumption ranges from 7 mW to 7.2 mW

Design and Applications of Minimally Invasive All-Pole Analog Filters

A new design technique for minimally invasive all-pole analog lowpass filters is introduced and the concept of minimally invasive filtering has been generalized for higher orders both in voltage-mode and current-mode operations. The proposed fully differential solution has minimal impact on the in-band signal in terms of added noise and nonlinearity, whereas it has comparable performance for out-of-band signals using smaller number of active devices. Extending the concept of current-mode minimally invasive filters, a novel baseband circuit with third order filtering has been designed, which has comparable linearity and noise with approximately half the power consumption when compared to the conventional solution. The proposed baseband circuit has a bandwidth of 10MHz, achieves 44dB rejection at 50MHz (40dB in post-layout simulations), low broad-band input impedance of 10.16ohm with a comparable noise and linearity at a lower power consumption when compared to a third order conventional circuit. The circuit has been designed in TSMC 130nm technology and is integrated with a broad-band receiver front-end including an LNA and a mixer

Characterization and modelling of software defined radio front-ends

Doutoramento em Engenharia ElectrotécnicaO presente trabalho tem por objectivo estudar a caracterização e modelação de arquitecturas de rádio frequência para aplicações em rádios definidos por software e rádios cognitivos. O constante aparecimento no mercado de novos padrões e tecnologias para comunicações sem fios têm levantado algumas limitações à implementação de transceptores rádio de banda larga. Para além disso, o uso de sistemas reconfiguráveis e adaptáveis baseados no conceito de rádio definido por software e rádio cognitivo assegurará a evolução para a próxima geração de comunicações sem fios. A ideia base desta tese passa por resolver alguns problemas em aberto e propor avanços relevantes, tirando para isso partido das capacidades providenciadas pelos processadores digitais de sinal de forma a melhorar o desempenho global dos sistemas propostos. Inicialmente, serão abordadas várias estratégias para a implementação e projecto de transceptores rádio, concentrando-se sempre na aplicabilidade específica a sistemas de rádio definido por software e rádio cognitivo. Serão também discutidas soluções actuais de instrumentação capaz de caracterizar um dispositivo que opere simultaneamente nos domínios analógico e digital, bem como, os próximos passos nesta área de caracterização e modelação. Além disso, iremos apresentar novos formatos de modelos comportamentais construídos especificamente para a descrição e caracterização não-linear de receptores de amostragem passa-banda, bem como, para sistemas nãolineares que utilizem sinais multi-portadora. Será apresentada uma nova arquitectura suportada na avaliação estatística dos sinais rádio que permite aumentar a gama dinâmica do receptor em situações de multi-portadora. Da mesma forma, será apresentada uma técnica de maximização da largura de banda de recepção baseada na utilização do receptor de amostragem passa-banda no formato complexo. Finalmente, importa referir que todas as arquitecturas propostas serão acompanhadas por uma introdução teórica e simulações, sempre que possível, sendo após isto validadas experimentalmente por protótipos laboratoriais.This work investigates the characterization and modeling of radio frequency front-ends for software defined radio and cognitive radio applications. The emergence of new standards and technologies in the wireless communications market are raising several issues to the implementation of wideband transceiver systems. Also, reconfigurable and adaptable systems based on software defined and cognitive radio models are paving the way for the next generation of wireless systems. In this doctoral thesis the fundamental idea is to address the particular open issues and propose appropriate advancements by exploring and taking profit from new capabilities of digital signal processors in a way to improve the overall performance of the novel schemes. Receiver and transmitter strategies for radio communications are summarized by concentrating on the usability for software defined radio and cognitive radio systems. Available instrumentation and next steps for analog and digital radio frequency hardware characterization is also discussed. Wideband behavioral model formats are proposed for nonlinear description and characterization of bandpass sampling receivers, as well as, for multi-carrier nonlinear systems operation. The proposed models share a great flexibility and have the freedom to be simply expanded to other fields. A new design for receiver dynamic range improvement in multi-carrier scenarios is proposed, which is supported on the useful wireless signals statistical evaluation. Additionally, receiver-side bandwidth maximization based on higher-order bandpass sampling approaches is evaluated. All the proposed designs and modeling strategies are accompanied by theoretical backgrounds and simulations whenever possible, being then experimentally validated by laboratory prototypes

Radiofrequency architectures and technologies for software defined radio

Six-port network is an interesting radiofrequency architecture with multiple possibilities. Since it was firstly introduced in the seventies as an alternative network analyzer, the six-port network has been used for many applications, such as homodyne receivers, radar systems, direction of arrival estimation, UWB (Ultra-Wide-Band), or MIMO (Multiple Input Multiple Output) systems. Currently, it is considered as a one of the best candidates to implement a Software Defined Radio (SDR). This thesis comprises an exhaustive study of this promising architecture, where its fundamentals and the state-of-the-art are also included. In addition, the design and development of a SDR 0.3-6 GHz six-port receiver prototype is presented in this thesis, which is implemented in conventional technology. The system is experimentally characterized and validated for RF signal demodulation with good performance. The analysis of the six-port architecture is complemented by a theoretical and experimental comparison with other radiofrequency architectures suitable for SDR. Some novel contributions are introduced in the present thesis. Such novelties are in the direction of the highly topical issues on six-port technique: development and optimization of real-time I-Q regeneration techniques for multiport networks; and search of new techniques and technologies to contribute to the miniaturization of the six-port architecture. In particular, the novel contributions of this thesis can be summarized as: - Introduction of a new real-time auto-calibration method for multiport receivers, particularly suitable for broadband designs and high data rate applications. - Introduction of a new direct baseband I-Q regeneration technique for five-port receivers. - Contribution to the miniaturization of six-port receivers by the use of the multilayer LTCC (Low Temperature Cofired Ceramic) technology. Implementation of a compact (30x30x1.25 mm) broadband (0.3-6 GHz) six-port receiver in LTTC technology. The results and conclusions derived from this thesis have been satisfactory, and quite fruitful in terms of publications. A total of fourteen works have been published, considering international journals and conferences, and national conferences. Aditionally, a paper has been submitted to an internationally recognized journal, which is currently under review

Design of frequency synthesizers for short range wireless transceivers

The rapid growth of the market for short-range wireless devices, with standards such as Bluetooth and Wireless LAN (IEEE 802.11) being the most important, has created a need for highly integrated transceivers that target drastic power and area reduction while providing a high level of integration. The radio section of the devices designed to establish communications using these standards is the limiting factor for the power reduction efforts. A key building block in a transceiver is the frequency synthesizer, since it operates at the highest frequency of the system and consumes a very large portion of the total power in the radio. This dissertation presents the basic theory and a design methodology of frequency synthesizers targeted for short-range wireless applications. Three different examples of synthesizers are presented. First a frequency synthesizer integrated in a Bluetooth receiver fabricated in 0.35μm CMOS technology. The receiver uses a low-IF architecture to downconvert the incoming Bluetooth signal to 2MHz. The second synthesizer is integrated within a dual-mode receiver capable of processing signals of the Bluetooth and Wireless LAN (IEEE 802.11b) standards. It is implemented in BiCMOS technology and operates the voltage controlled oscillator at twice the required frequency to generate quadrature signals through a divide-by-two circuit. A phase switching prescaler is featured in the synthesizer. A large capacitance is integrated on-chip using a capacitance multiplier circuit that provides a drastic area reduction while adding a negligible phase noise contribution. The third synthesizer is an extension of the second example. The operation range of the VCO is extended to cover a frequency band from 4.8GHz to 5.85GHz. By doing this, the synthesizer is capable of generating LO signals for Bluetooth and IEEE 802.11a, b and g standards. The quadrature output of the 5 - 6 GHz signal is generated through a first order RC - CR network with an automatic calibration loop. The loop uses a high frequency phase detector to measure the deviation from the 90° separation between the I and Q branches and implements an algorithm to minimize the phase errors between the I and Q branches and their differential counterparts

Design and Applications of Minimally Invasive All-Pole Analog Filters

A new design technique for minimally invasive all-pole analog lowpass filters is introduced and the concept of minimally invasive filtering has been generalized for higher orders both in voltage-mode and current-mode operations. The proposed fully differential solution has minimal impact on the in-band signal in terms of added noise and nonlinearity, whereas it has comparable performance for out-of-band signals using smaller number of active devices. Extending the concept of current-mode minimally invasive filters, a novel baseband circuit with third order filtering has been designed, which has comparable linearity and noise with approximately half the power consumption when compared to the conventional solution. The proposed baseband circuit has a bandwidth of 10MHz, achieves 44dB rejection at 50MHz (40dB in post-layout simulations), low broad-band input impedance of 10.16ohm with a comparable noise and linearity at a lower power consumption when compared to a third order conventional circuit. The circuit has been designed in TSMC 130nm technology and is integrated with a broad-band receiver front-end including an LNA and a mixer

State of the art baseband DSP platforms for Software Defined Radio: A survey

Software Defined Radio (SDR) is an innovative approach which is becoming a more and more promising technology for future mobile handsets. Several proposals in the field of embedded systems have been introduced by different universities and industries to support SDR applications. This article presents an overview of current platforms and analyzes the related architectural choices, the current issues in SDR, as well as potential future trends.Peer reviewe