UWB FastlyTunable 0.550 GHz RF Transmitter based on Integrated Photonics

Currently, due to the 6G revolution, applications ranging from communication to sensing are experiencing an increasing and urgent need of software-defined ultra-wideband (UWB) and tunable radio frequency (RF) apparatuses with low size, weight, and power consumption (SWaP). Unfortunately, the coexistence of ultra-wideband and software-defined operation, tunability and low SWaP represents a big issue in the current RF technologies. Recently, photonic techniques have been demonstrated to support achieving the desired features when applied in RF UWB transmitters, introducing extremely wide operation and instantaneous bandwidth, tunable filtering, tunable photonics-based microwave mixing with very high port-to-port isolation, and intrinsic immunity to electromagnetic interferences. Moreover, the recent advances in photonics integration also allow to obtain very compact devices. In this article, to the best of our knowledge, the first example of a complete tunable software-defined RF transmitter with low footprint (i.e. on photonic chip) is presented exceeding the state-of-the-art for the extremely large tunability range of 0.5-50 GHz without any parallelization of narrower-band components and with fast tuning (< 200 s). This first implementation represents a breakthrough in microwave photonics

Energy-efficient, short-range ultra-wideband radio transceivers

Short-range wireless communications continually attract interest from both industry and academia, and it is changing our life in every aspect in the last decade. The design of wireless transceivers is the bottleneck for variety applications, due to RF modeling inaccuracy, stringent FCC regulations over the transmitted power spectrum, interference, multi-path reflections, modulation scheme, receiver sensitivity, and synchronization. In addition, energy efficiency is always one of the most important design goals. Ultra-Wideband(UWB) is found to be very energy-efficient due to its low duty cycle and potentially high data rate due to its wide bandwidth. However, there still remain unsolved issues with UWB transceivers, such as pulse shaping, multi-path reflections, and receiver clock synchronization. To address these, novel techniques such as wireless multi-path equalization, pulse injection-locking for receiver clock synchronization, reconfigurable pulse shaping, low power wireless clock distribution, and an ultra-low-power super-regenerative receiver are implemented and verified on silicon. Three chips are designed and verified: a 3-5GHz Impulse-Radio(IR) UWB transceiver, a 3-60GHz all digital reconfigurable transmitter, and a 402-405MHz MICS/UWB(Sub-GHz) super-regenerative receiver incorporating wireless clock synchronization. A detailed design methodology, measurement results, and discussions are presented

Design and Implementation of a Low‐Power Wireless Respiration Monitoring Sensor

Wireless devices for monitoring of respiration activities can play a major role in advancing modern home-based health care applications. Existing methods for respiration monitoring require special algorithms and high precision filters to eliminate noise and other motion artifacts. These necessitate additional power consuming circuitry for further signal conditioning. This dissertation is particularly focused on a novel approach of respiration monitoring based on a PVDF-based pyroelectric transducer. Low-power, low-noise, and fully integrated charge amplifiers are designed to serve as the front-end amplifier of the sensor to efficiently convert the charge generated by the transducer into a proportional voltage signal. To transmit the respiration data wirelessly, a lowpower transmitter design is crucial. This energy constraint motivates the exploration of the design of a duty-cycled transmitter, where the radio is designed to be turned off most of the time and turned on only for a short duration of time. Due to its inherent duty-cycled nature, impulse radio ultra-wideband (IR-UWB) transmitter is an ideal candidate for the implementation of a duty-cycled radio. To achieve better energy efficiency and longer battery lifetime a low-power low-complexity OOK (on-off keying) based impulse radio ultra-wideband (IR-UWB) transmitter is designed and implemented using standard CMOS process. Initial simulation and test results exhibit a promising advancement towards the development of an energy-efficient wireless sensor for monitoring of respiration activities

Timed array antenna system : application to wideband and ultra-wideband beamforming receivers

Antenna array systems have a broad range of applications in radio frequency (RF) and ultra-wideband (UWB) communications to receive/transmit electromagnetic waves from/to the sky. They can enhance the amplitude of the input signals, steer beams electronically, and reject interferences thanks to beamforming technique. In an antenna array beamforming system, delay cells with the tunable capability of delay amount compensate the relative delay of signals received by antennas. In fact, each antenna almost acts individually depending upon time delaying effects on the input signals. As a result, the delay cells are the basic elements of the beamforming systems. For this purpose, novel active true time delay (TTD) cells suitable for RF antenna arrays have been presented in this thesis. These active delay cells are based on 1st- and 2nd-order all-pass filters (APFs) and achieve quite a flat gain and delay within up to 10-GHz frequency range. Various techniques such as phase linearity and delay tunability have been accomplished to improve the design and performance. The 1st-order APF has been designed for a frequency range of 5 GHz, showing desirable frequency responses and linearity which is comparable with the state-of-the-art. This 1st-order APF is able to convert into a 2nd-order APF via adding a grounded capacitor. A compact 2nd-order APF using an active inductor has been also designed and simulated for frequencies up to 10 GHz. The active inductor has been utilized to tune the amount of delay and to reduce the on-chip size of the filter. In order to validate the performance of the delay cells, two UWB four-channel timed array beamforming receivers realized by the active TTD cells have been proposed. Each antenna channel exploits digitally controllable gain and delay on the input signal and demonstrates desirable gain and delay resolutions. The beamforming receivers have been designed for different UWB applications depending on their operating frequency ranges (that is, 3-5 and 3.1-10.6 GHz), and thus they have different system requirements and specifications. All the circuits and topologies presented in this dissertation have been designed in standard 180-nm CMOS technologies, featuring a unity gain frequency ( ft) up to 60 GHz.Els sistemes matricials d’antenes tenen una àmplia gamma d’aplicacions en radiofreqüència (RF) i comunicacions de banda ultraampla (UWB) per rebre i transmetre ones electromagnètics. Poden millorar l’amplitud dels senyals d’entrada rebuts, dirigir els feixos electrònicament i rebutjar les interferències gràcies a la tècnica de formació de feixos (beamforming). En un sistema beamforming de matriu d’antenes, les cèl·lules de retard amb capacitat ajustable del retard, compensen aquest retard relatiu dels senyals rebuts per les diferents antenes. De fet, cada antena gairebé actua individualment depenent dels efectes de retard de temps sobre el senyals d’entrada. Com a resultat, les cel·les de retard són els elements bàsics en el disseny dels actuals sistemes beamforming. Amb aquest propòsit, en aquesta tesi es presenten noves cèl·lules actives de retard en temps real (TTD, true time delay) adequades per a matrius d’antenes de RF. Aquestes cèl·lules de retard actives es basen en cèl·lules de primer i segon ordre passa-tot (APF), i aconsegueixen un guany i un retard força plans, en el rang de freqüència de fins a 10 GHz. Diverses tècniques com ara la linealitat de fase i la sintonització del retard s’han aconseguit per millorar el disseny i el rendiment. La cèl·lula APF de primer ordre s’ha dissenyat per a un rang de freqüències de fins a 5 GHz, mostrant unes respostes freqüencials i linealitat que són comparables amb l’estat de l’art actual. Aquestes cèl·lules APF de primer ordre es poden convertir en un APF de segon ordre afegint un condensador més connectat a massa. També s’ha dissenyat un APF compacte de segon ordre que utilitza una emulació d’inductor actiu per a freqüències de treball de fins a 10 GHz. S’ha utilitzat l'inductor actiu per ajustar la quantitat de retard introduït i reduir les dimensions del filtre al xip. Per validar les prestacions de les cel·les de retard propostes, s’han proposat dos receptors beamforming basats en matrius d’antenes de 4 canals, realitzats por cèl·lules TTD actives. Cada canal d’antena aprofita el guany i el retard controlables digitalment aplicats al senyal d’entrada, i demostra resolucions de guany i retard desitjables. Els receptors beamforming s’han dissenyat per a diferents aplicacions UWB segons els seus rangs de freqüències de funcionament (en aquest cas, 3-5 i 3,1-10,6 GHz) i, per tant, tenen diferents requisits i especificacions de disseny del sistema. Tots els circuits i topologies presentats en aquesta tesi s’han dissenyat en tecnologies CMOS estàndards de 180 nm, amb una freqüència de guany unitari (ft) de fins a 60 GHz.Postprint (published version

Ultra-Low-Power Uwb Impulse Radio Design: Architecture, Circuits, And Applications

Recent advances in home healthcare, environmental sensing, and low power computing have created a need for wireless communication at very low power for low data rate applications. Due to higher energy/bit requirements at lower data -rate, achieving power levels low enough to enable long battery lifetime (~10 years) or power-harvesting supplies have not been possible with traditional approaches. Dutycycled radios have often been proposed in literature as a solution for such applications due to their ability to shut off the static power consumption at low data rates. While earlier radio nodes for such systems have been proposed based on a type of sleepwake scheduling, such implementations are still power hungry due to large synchronization uncertainty (~1[MICRO SIGN]s). In this dissertation, we utilize impulsive signaling and a pulse-coupled oscillator (PCO) based synchronization scheme to facilitate a globally synchronized wireless network. We have modeled this network over a widely varying parameter space and found that it is capable of reducing system cost as well as providing scalability in wireless sensor networks. Based on this scheme, we implemented an FCC compliant, 3-5GHz, timemultiplexed, dual-band UWB impulse radio transceiver, measured to consume only 20[MICRO SIGN]W when the nodes are synchronized for peer-peer communication. At the system level the design was measured to consume 86[MICRO SIGN]W of power, while facilitating multi- hop communication. Simple pulse-shaping circuitry ensures spectral efficiency, FCC compliance and ~30dB band-isolation. Similarly, the band-switchable, ~2ns turn-on receiver implements a non-coherent pulse detection scheme that facilitates low power consumption with -87dBm sensitivity at 100Kbps. Once synchronized the nodes exchange information while duty-cycling, and can use any type of high level network protocols utilized in packet based communication. For robust network performance, a localized synchronization detection scheme based on relative timing and statistics of the PCO firing and the timing pulses ("sync") is reported. No active hand-shaking is required for nodes to detect synchronization. A self-reinforcement scheme also helps maintain synchronization even in the presence of miss-detections. Finally we discuss unique ways to exploit properties of pulse coupled oscillator networks to realize novel low power event communication, prioritization, localization and immediate neighborhood validation for low power wireless sensor applications