Reconfigurable Receiver Front-Ends for Advanced Telecommunication Technologies

The exponential growth of converging technologies, including augmented reality, autonomous vehicles, machine-to-machine and machine-to-human interactions, biomedical and environmental sensory systems, and artificial intelligence, is driving the need for robust infrastructural systems capable of handling vast data volumes between end users and service providers. This demand has prompted a significant evolution in wireless communication, with 5G and subsequent generations requiring exponentially improved spectral and energy efficiency compared to their predecessors. Achieving this entails intricate strategies such as advanced digital modulations, broader channel bandwidths, complex spectrum sharing, and carrier aggregation scenarios. A particularly challenging aspect arises in the form of non-contiguous aggregation of up to six carrier components across the frequency range 1 (FR1). This necessitates receiver front-ends to effectively reject out-of-band (OOB) interferences while maintaining high-performance in-band (IB) operation. Reconfigurability becomes pivotal in such dynamic environments, where frequency resource allocation, signal strength, and interference levels continuously change. Software-defined radios (SDRs) and cognitive radios (CRs) emerge as solutions, with direct RF-sampling receivers offering a suitable architecture in which the frequency translation is entirely performed in digital domain to avoid analog mixing issues. Moreover, direct RF- sampling receivers facilitate spectrum observation, which is crucial to identify free zones, and detect interferences. Acoustic and distributed filters offer impressive dynamic range and sharp roll off characteristics, but their bulkiness and lack of electronic adjustment capabilities limit their practicality. Active filters, on the other hand, present opportunities for integration in advanced CMOS technology, addressing size constraints and providing versatile programmability. However, concerns about power consumption, noise generation, and linearity in active filters require careful consideration.This thesis primarily focuses on the design and implementation of a low-voltage, low-power RFFE tailored for direct sampling receivers in 5G FR1 applications. The RFFE consists of a balun low-noise amplifier (LNA), a Q-enhanced filter, and a programmable gain amplifier (PGA). The balun-LNA employs noise cancellation, current reuse, and gm boosting for wideband gain and input impedance matching. Leveraging FD-SOI technology allows for programmable gain and linearity via body biasing. The LNA's operational state ranges between high-performance and high-tolerance modes, which are apt for sensitivityand blocking tests, respectively. The Q-enhanced filter adopts noise-cancelling, current-reuse, and programmable Gm-cells to realize a fourth-order response using two resonators. The fourth-order filter response is achieved by subtracting the individual response of these resonators. Compared to cascaded and magnetically coupled fourth-order filters, this technique maintains the large dynamic range of second-order resonators. Fabricated in 22-nm FD-SOI technology, the RFFE achieves 1%-40% fractional bandwidth (FBW) adjustability from 1.7 GHz to 6.4 GHz, 4.6 dB noise figure (NF) and an OOB third-order intermodulation intercept point (IIP3) of 22 dBm. Furthermore, concerning the implementation uncertainties and potential variations of temperature and supply voltage, design margins have been considered and a hybrid calibration scheme is introduced. A combination of on-chip and off-chip calibration based on noise response is employed to effectively adjust the quality factors, Gm-cells, and resonance frequencies, ensuring desired bandpass response. To optimize and accelerate the calibration process, a reinforcement learning (RL) agent is used.Anticipating future trends, the concept of the Q-enhanced filter extends to a multiple-mode filter for 6G upper mid-band applications. Covering the frequency range from 8 to 20 GHz, this RFFE can be configured as a fourth-order dual-band filter, two bandpass filters (BPFs) with an OOB notch, or a BPF with an IB notch. In cognitive radios, the filter’s transmission zeros can be positioned with respect to the carrier frequencies of interfering signals to yield over 50 dB blocker rejection

UWB Technology

Ultra Wide Band (UWB) technology has attracted increasing interest and there is a growing demand for UWB for several applications and scenarios. The unlicensed use of the UWB spectrum has been regulated by the Federal Communications Commission (FCC) since the early 2000s. The main concern in designing UWB circuits is to consider the assigned bandwidth and the low power permitted for transmission. This makes UWB circuit design a challenging mission in today's community. Various circuit designs and system implementations are published in this book to give the reader a glimpse of the state-of-the-art examples in this field. The book starts at the circuit level design of major UWB elements such as filters, antennas, and amplifiers; and ends with the complete system implementation using such modules

Switchable Broadband-to-Tunable Narrowband Magnetic Probe for Near-Field Measurements

This paper presents a printed magnetic probe that can switch from broadband to tunable narrowband for near-field measurement. In the early design stage, we created a printed loop gap resonator as a magnetic reference sensor for the pre-compliance test in a band up to 6 GHz. Consequently, the results showed a good response in terms of the S11 and S21 parameters of the proposed probe compared with the commercial magnetic sensor XF-R 3-1. The source noise might spread among different frequency bands, making the broadband magnetic probe the closest choice for estimating the magnetic field in the near-field region. Unfortunately, broadband magnetic probes have lower sensitivity than narrowband ones. One of the solutions to get high sensitivity is to connect the LNA to the output of the passive magnetic sensor. This work proposes a novel method to solve this issue using a PIN diode to change the broadband status into a high sensitivity narrowband status and then tune this narrowband across the most critical applications such as 3.5 GHz, 3.75 GHz, 4.8 GHz, and 5.2 GHz with the help of a varactor diode. Compared to the broadband status, an improvement of more than 10 dB has been obtained across all these wireless bands. Furthermore, the proposed structure’s isolation between the electrical and magnetic fields is about 13 dB

Switchable wideband receiver frontend for 5G and satellite applications

Modern day communication architectures provides the requirement for interconnected devices offering very high data rate (more than 10 Gbps), low latency, and support for multiple service integration across existing communication generations with wideband spectrum coverage. An integrated satellite and 5G architecture switchable receiver frontend is presented in this thesis, consisting of a single pole double throw (SPDT) switch and two low noise amplifiers (LNAs) spanning X-band and K/Ka-band frequencies. The independent X-band LNA (8-12 GHz) has a gain of 38 dB at a centre design frequency of 9.8 GHz, while the K/Ka-band (23-28 GHz) has a gain of 29 GHz at a centre design frequency of 25.4 GHz. Both LNAs are a three-stage cascaded design with separated gate and drain lines for each transistor stage. The broadband high isolation single pole double throw (SPDT) switch based on a 0.15 μm gate length Indium Gallium Arsenide (InGaAs) pseudomorphic high electron transistor (pHEMT) is designed to operate at the frequency range of DC-50 GHz with less than 3 dB insertion loss and more than 40 dB isolation. The switch is designed to improve the overall stability of the system and the gain. A gain of about 25 dB is achieved at 9.8 GHz when the X-band arm is turned on and the K/Ka-band is turned off. A gain of about 23 dB is achieved at 25.4 GHz when the K/Ka-band arm is turned on and the X-band arm is off. This presented switchable receiver frontend is suitable for radar applications, 5G mobile applications, and future broadband receivers in the millimetre wave frequency range

Advances in Integrated Circuit Design and Implementation for New Generation of Wireless Transceivers

User’s everyday outgrowing demand for high-data and high performance mobile devices pushes industry and researchers into more sophisticated systems to fulfill those expectations. Besides new modulation techniques and new system designs, significant improvement is required in the transceiver building blocks to handle higher data rates with reasonable power efficiency. In this research the challenges and solution to improve the performance of wireless communication transceivers is addressed. The building block that determines the efficiency and battery life of the entire mobile handset is the power amplifier. Modulations with large peak to average power ratio severely degrade efficiency in the conventional fixed-biased power amplifiers (PAs). To address this challenge, a novel PA is proposed with an adaptive load for the PA to improve efficiency. A nonlinearity cancellation technique is also proposed to improve linearity of the PA to satisfy the EVM and ACLR specifications. Ultra wide-band (UWB) systems are attractive due to their ability for high data rate, and low power consumption. In spite of the limitation assigned by the FCC, the coexistence of UWB and NB systems are still an unsolved challenge. One of the systems that is majorly affected by the UWB signal, is the 802.11a system (5 GHz Wi-Fi). A new analog solution is proposed to minimize the interference level caused by the impulse Radio UWB transmitter to nearby narrowband receivers. An efficient 400 Mpulse/s IR-UWB transmitter is implemented that generates an analog UWB pulse with in-band notch that covers the majority of the UWB spectrum. The challenge in receiver (RX) design is the over increasing out of blockers in applications such as cognitive and software defined radios, which are required to tolerate stronger out-of-band (OB) blockers. A novel RX is proposed with a shunt N-path high-Q filter at the LNA input to attenuate OB-blockers. To further improve the linearity, a novel baseband blocker filtering techniques is proposed. A new TIA has been designed to maintain the good linearity performance for blockers at large frequency offsets. As a result, a +22 dBm IIP3 with 3.5 dB NF is achieved. Another challenge in the RX design is the tough NF and linearity requirements for high performance systems such as carrier aggregation. To improve the NF, an extra gain stage is added after the LNA. An N-path high-Q band-pass filter is employed at the LNA output together with baseband blocker filtering technique to attenuate out-of-band blockers and improve the linearity. A noise-cancellation technique based on the frequency translation has been employed to improve the NF. As a result, a 1.8dB NF with +5 dBm IIP3 is achieved. In addition, a new approach has been proposed to reject out of band blockers in carrier aggregation scenarios. The proposed solution also provides carrier to carrier isolation compared to typical solution for carrier aggregation

A Framework to Analyze Energy Efficiency of Multi-Band Spectrum Sensing Algorithms

Cognitive radio (CR) is a device which can detect wireless communication channels that are not in use and adapt its parameters intelligently. Networks with CRs use the available frequency bands much more efficiently and hence have higher data rates compare to traditional radios. Spectrum sensing is the class of techniques used by CRs to understand its wireless environment. Recent research on evaluating multi-band spectrum sensing algorithms is limited to only algorithm complexity and optimization; therefore, the primary goal of the study is to devise a novel framework that analyzes a multi-band spectrum sensing algorithm in terms of energy consumption and algorithm efficiency. The proposed structure leads to a comparison and evaluation of a large class of multi-band spectrum sensing algorithms. Multi-band spectrum sensing search methods such as linear, random and binary are evaluated for energy loss and detection performance using the proposed framework

Energy efficiency analysis in wireless communication systems with reconfigurable RF

Orientador: Prof. Dr. André Augusto MarianoCoorientador: Prof. Dr. Glauber Gomes de Oliveira BranteTese (doutorado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia Elétrica. Defesa : Curitiba, 28/05/2021Inclui referências: p. 74-84Área de concentração: Sistemas EletrônicosResumo: Alta eficiˆencia energ'etica (EE) 'e crucial para aplicac¸ ˜oes da Internet das Coisas que operam remotamente, uma vez que os n'os sem fio s˜ao tipicamente alimentados por bateria. Diferentes t'ecnicas de diversidade espacial tais com o uso de m'ultiplas antenas (MIMO) nos n'os do transmissor e receptor, bem como o uso de comunicac¸ ˜ao cooperativa podem ser exploradas para melhorar a EE. Al'em disso, o uso de transceptores de r'adio frequˆencia (RF) reconfigur'aveis s˜ao considerados uma soluc¸ ˜ao interessante para sistemas com restric¸ ˜ao de energia, pois permitem alterar o seu ponto de funcionamento, bem como o seu consumo de potˆencia, adaptando-se aos diferentes requisitos de comunicac¸ ˜ao. Nessa tese, uma nova abordagem para economizar energia inclui no modelo do sistema de comunicac¸ ˜ao o uso de transceptores de RF reconfigur'aveis. Mais especificamente, os componentes envolvidos em nossa estrutura de otimizac¸ ˜ao de consumo de potˆencia s˜ao o amplificador de potˆencia (PA) no transmissor e o amplificador de baixo ru'?do (LNA) no receptor. Nosso objetivo 'e mostrar que os circuitos de RF baseados em operac¸ ˜oes mult'?modo podem melhorar significativamente a EE. Assim, realizamos uma selec¸ ˜ao conjunta dos melhores modos de operac¸ ˜ao para os circuitos do PA e do LNA para diferentes esquemas de transmiss˜ao em dois cen'arios de rede: i) comunicac¸ ˜ao n˜ao-cooperativa em que os n'os s˜ao equipados com m'ultiplas antenas, para a qual consideramos a selec¸ ˜ao de antenas (AS) e a decomposic¸ ˜ao por valores singulares (SVD); e ii) comunicac¸ ˜ao cooperativa em que os n'os s˜ao equipados com uma 'unica antena, para a qual consideramos decodificac¸ ˜ao incremental e encaminha (IDF) por rel'e. Em nosso primeiro cen'ario proposto, comparamos os circuitos reconfigur 'aveis do PA e do LNA com amplificadores de RF n˜ao-reconfigur'aveis do estado-da-arte dispon'?veis na literatura. Nesta comparac¸ ˜ao, ao explorar as caracter'?sticas dos amplificadores reconfigur'aveis de RF, mostramos uma melhora de EE de mais de 40% em distˆancias curtas para as comunicac¸ ˜oes MIMO. Ao comparar os esquemas MIMO, a t'ecnica AS apresenta melhor desempenho para distˆancias mais curtas, enquanto que o SVD permite transmiss˜oes mais longas, pois explora todas as antenas dispon'?veis. Al'em disso, a otimizac¸ ˜ao da eficiˆencia espectral contribui para aumentar ainda mais a EE. Por fim, investigamos o efeito do n'umero de antenas, em que a EE do AS sempre aumenta com o n'umero de antenas, enquanto que o SVD apresenta um n'umero 'otimo de antenas. Para o segundo cen'ario, propomos uma an'alise de EE para o esquema IDF, auxiliada por um canal de retorno para realizar a selec¸ ˜ao de rel'es. Al'em disso, comparamos o desempenho do IDF com os esquemas MIMO n˜ao-cooperativos. Os resultados mostram que uma melhor EE 'e obtida por meio de t'ecnicas de selec¸ ˜ao de antenas, principalmente quando aplicadas tanto no transmissor quanto no receptor. Tamb'em analisamos o impacto do rel'e na cooperac¸ ˜ao, uma vez que o n'o do rel'e opera apenas se necess'ario, a maior parte da carga de reconfigurabilidade 'e do rel'e, enquanto os modos de operac¸ ˜ao do PA e do LNA tendem a ser razoavelmente fixados nos n'os de origem e destino. Por fim, os resultados mostram que o n'umero de rel'es contribui para alcanc¸ar transmiss˜oes de longa distˆancia. Palavras-chave: Eficiˆencia Energ'etica, Transceptores de RF Reconfigur'aveis, Diversidade Espacial, M'ultiplas Antenas, Comunicac¸ ˜oes Cooperativas.Abstract: High energy efficiency (EE) is crucial for Internet of Things applications that operate remotely, since wireless nodes are typically battery-powered. Different spatial diversity techniques such as the use of multiple antennas (MIMO) at the transmitter and receiver nodes, as well as the use of cooperative communication can be exploited to improve the EE. In addition, the use of radio frequency (RF) transceivers are considered an interesting solution for powerrestricted systems, as they allow changing their operating point, as well as their power consumption, adapting to different communication requirements. In this thesis, a novel energy-saving approach includes in the communication system model the use of reconfigurable RF transceivers. More specifically, the components involved in our power consumption optimization framework are the power amplifier (PA) at the transmitter and the low noise amplifier (LNA) at the receiver. Our goal is to show that RF circuits based on multimode operation can significantly improve the EE. Thus, we perform a joint selection of the best operating modes for the PA and LNA circuits for different transmission schemes in two network scenarios: i) non-cooperative communication where the nodes are equipped with multiple antennas, for which we consider antenna selection (AS) and singular value decomposition (SVD) beamforming; and ii) cooperative communication where the nodes are equipped with single antenna, for which we consider incremental decode and forward (IDF) relaying. In our first proposed scenario, we compare the reconfigurable PA and LNA circuits with state-of-the-art non-reconfigurable RF amplifiers available in the literature. In this comparison, by exploiting the characteristics of reconfigurable RF amplifiers, we show an EE improvement of more than 40% at short distances for MIMO communications. When comparing MIMO schemes, the AS technique performs better for shorter distances, while the SVD allows for longer transmissions, as it exploits all available antennas. In addition, the optimization of the spectral efficiency contributes to further increase the EE. Finally, we investigate the effect of the number of antennas, in which the EE of AS always increases with the number of antennas, while SVD presents an optimal number of antennas. For the second scenario, we propose an EE analysis for the IDF scheme, aided by a feedback channel to perform relay selection. In addition, we compare the performance of the IDF with non-cooperative MIMO schemes. The results show that a better EE is obtained through antenna selection techniques, especially when applied at both transmitter and receiver. We also analyze the impact of the relay on cooperation, as the relay node operates only if necessary, most of the reconfigurability charge ends up at the relay, whereas the PA and LNA operating modes tend to be reasonably fixed at the source and destination nodes. Finally, results show that the number of relays contributes to achieving long distance transmissions. Keywords: Energy Efficiency, Reconfigurable RF Transceivers, Spatial Diversity, Multiple Antennas, Cooperative Communications

A Millimeter-Wave Coexistent RFIC Receiver Architecture in 0.18-µm SiGe BiCMOS for Radar and Communication Systems

Innovative circuit architectures and techniques to enhance the performance of several key BiCMOS RFIC building blocks applied in radar and wireless communication systems operating at the millimeter-wave frequencies are addressed in this dissertation. The former encapsulates the development of an advanced, low-cost and miniature millimeter-wave coexistent current mode direct conversion receiver for short-range, high-resolution radar and high data rate communication systems. A new class of broadband low power consumption active balun-LNA consisting of two common emitters amplifiers mutually coupled thru an AC stacked transformer for power saving and gain boosting. The active balun-LNA exhibits new high linearity technique using a constant gm cell transconductance independent of input-outputs variations based on equal emitters’ area ratios. A novel multi-stages active balun-LNA with innovative technique to mitigate amplitude and phase imbalances is proposed. The new multi-stages balun-LNA technique consists of distributed feed-forward averaging recycles correction for amplitude and phase errors and is insensitive to unequal paths parasitic from input to outputs. The distributed averaging recycles correction technique resolves the amplitude and phase errors residuals in a multi-iterative process. The new multi-stages balun-LNA averaging correction technique is frequency independent and can perform amplitude and phase calibrations without relying on passive lumped elements for compensation. The multi-stage balun-LNA exhibits excellent performance from 10 to 50 GHz with amplitude and phase mismatches less than 0.7 dB and 2.86º, respectively. Furthermore, the new multi-stages balun-LNA operates in current mode and shows high linearity with low power consumption. The unique balun-LNA design can operates well into mm-wave regions and is an integral block of the mm-wave radar and communication systems. The integration of several RFIC blocks constitutes the broadband millimeter-wave coexistent current mode direct conversion receiver architecture operating from 22- 44 GHz. The system and architectural level analysis provide a unique understanding into the receiver characteristics and design trade-offs. The RF front-end is based on the broadband multi-stages active balun-LNA coupled into a fully balanced passive mixer with an all-pass in-phase/quadrature phase generator. The trans-impedance amplifier converts the input signal current into a voltage gain at the outputs. Simultaneously, the high power input signal current is channelized into an anti-aliasing filter with 20 dB rejection for out of band interferers. In addition, the dissertation demonstrates a wide dynamic range system with small die area, cost effective and very low power consumption

A Concurrent Dual-Band Inverter-Based Low Noise Amplifier (LNA) for WLAN Applications

low noise amplifier (LNA); concurrent; dual-band; inverter-basedIn this paper, a two-stage concurrent dual-band low noise amplifier (DB-LNA) operating at 2.4/5.2-GHz is presented for Wireless Local Area Network (WLAN) applications. The current-reused structure using resistive shunt-shunt feedback is employed to reduce power dissipation and achieve a wide frequency band from DC to-5.5-GHz in the inverter-based LNA. The second inverter-based stage is employed to increase the gain and obtain a flat gain over the frequency band. An LC network is also inserted at the proposed circuit output to shape the dual-band frequency response. The proposed concurrent DB-LNA is designed by RF-TSMC 0.18-µm CMOS technology, which consumes 10.8 mW from a power supply of 1.5 V. The simulation results show that the proposed DB-LNA achieves a direct power gain (S 21 ) of 13.7/14.1 dB, a noise figure (NF) of 4.2/4.6 dB, and an input return loss (S 11 ) of −12.9/−14.6 dBm at the 2.4/5.2-GHz bands