140-220 GHz Imaging Front-end Based on 250 nm InP/InGaAs/InP DHBT Process

This paper presents a pre-amplified detector receiver based on a 250 nm InP/InGaAs/InP double heterojunction bipolar transistor (DHBT) process available from the Teledyne scientific. The front end consists of a double slot antenna followed by a five stage low noise amplifier and a detector, all integrated onto the same circuit. Results of measured responsivity and noise are presented. The receiver is characterized through measuring its response to hot (293) and cold (78) K terminations. Measurements of the voltage noise spectrum at the video output of the receiver are presented and can be used to derive the temperature resolution of the receiver for a specific video bandwidth

Sensores passivos alimentados por transmissão de energia sem fios para aplicações de Internet das coisas

Nowadays, the Wireless Sensor Networks (WSNs) depend on the battery duration of the sensors and there is a renewed interest in creating a passive sensor network scheme in the area of Internet of Things (IoT) and space oriented WSN systems. The challenges for the future of radio communications have a twofold evolution, one being the low power consumption and, another, the adaptability and intelligent use of the available resources. Specially designed radios should be used to reduce power consumption, and adapt to the environment in a smart and e cient way. This thesis will focus on the development of passive sensors based on low power communication (backscatter) with Wireless Power Transfer (WPT) capabilities used in IoT applications. In that sense, several high order modulations for the communication will be explored and proposed in order to increase the data rate. Moreover, the sensors need to be small and cost e ective in order to be embedded in other technologies or devices. Consequently, the RF front-end of the sensors will be designed and implemented in Monolithic Microwave Integrated Circuit (MMIC).Atualmente, as redes de sensores sem fios dependem da duração da bateria e,deste modo, existe um interesse renovado em criar um esquema de rede de sensores passivos na área de internet das coisas e sistemas de redes de sensores sem fios relacionados com o espaço. Os desafios do futuro das comunicações de rádio têm uma dupla evolução, sendo um o baixo consumo de energia e, outro, a adaptação e o uso inteligente dos recursos disponíveis. Rádios diferentes dos convencionais devem ser usados para reduzir o consumo de energia e devem adaptar-se ao ambiente de forma inteligente e eficiente, de modo a que este use a menor quantidade de energia possível para estabelecer a comunicação. Esta tese incide sobre o desenvolvimento de sensores passivos baseados em comunicação de baixo consumo energético (backscatter) com recurso a transmissão de energia sem fios de modo a que possam ser usados em diferentes aplicações inseridas na internet das coisas. Nesse sentido, várias modulações de alta ordem para a comunicação backscatter serão exploradas e propostas com o objectivo de aumentar a taxa de transmissão de dados. Além disso, os sensores precisam de ser reduzidos em tamanho e económicos de modo a serem incorporados em outras tecnologias ou dispositivos. Consequentemente, o front-end de rádio frequência dos sensores será projetado e implementado em circuito integrado de microondas monolítico.Programa Doutoral em Engenharia Eletrotécnic

Low-Power Integrated Circuits For Biomedical Applications

With thousands new cases of spinal cord injury reported everyday, many people suffer from paralysis and loss of sensation in both legs. Beside the healthcare costs, such a state severely deteriorates the patients' quality of life and may even lead to additional medical conditions. Therefore, there is a growing need for cyber-physical systems to restore the walking ability through bypassing the damaged spinal cord. This goal can be achieved by monitoring and processing patient's brain signals to enable brain-directed control of prosthetic legs. Among several existing methods to record brain signals, electrocorticography (ECoG) has gained popularity due to being robust to motion artifacts, having high spatial resolution and signal to noise ratio, being moderately invasive and the possibility of chronic implantation of recording grids with no or minor scar tissue formation. The latest property is of particular importance for the whole system to be a viable fully implantable solution. Furthermore, the implanted system has to operate independently with no or minimal need of external hardware (e.g. a bulky personal computer) to be individually and socially accepted. To implement a fully implantable system, low-power and miniaturized electronics are needed to reduced heat generation, increase battery life-time and be minimally intrusive. These requirements indicate that many of the system's components should be custom-designed to integrated as much functionality as possible in a given real estate. This thesis presents silicon tested prototypes of several building blocks for the envisioned system, namely, ultra low-power brain signal acquisition front-ends, a low-power and inductorless MedRadio transceiver, and a fast start-up crystal oscillator. Brain signal acquisition front-ends provide low noise amplification of weak ECoG biosignals. MedRadio transceiver enables communication between the implant and end effectors or base station (e.g. prosthetic legs or desktop computer). Crystal oscillator generates the reference signal for other system's components such as analog to digital converter. Novel techniques to improve important performance parameters (power consumption, low noise operation and interference resilience) have been introduced. Electrical, in-vitro and in-vivo experimental measurements have verified the functionality and performance of each design

High resolution, process and temperature compensated phase shifter design using a self generated look up table

Phase resolution is one of the most important parameters in phased array RADAR determining the precision of antenna beam direction and side-lobe level. Especially, in tracking applications the antenna directivity should be high and side-lobe levels must be low in order to abstain from the signals of Jammers. Phase shifters (PS) set phase resolution and directivity; therefore, they are the key components for phased arrays. Among the PS topologies, vector sum type comes forward due to its significant advantage over the other design techniques, in terms of insertion loss, phase error, area and operation bandwidth. However, in design of vector sum type PS, phase and amplitude errors in vectors, and phase insertion of variable gain amplifiers degrades the phase resolution performance of the PS. In order to overcome these issues and improve bit resolution (reduced phase step size and lower phase error while covering 360° phase range), and improve the tolerance on process - temperature variations, the proposed solution in this thesis is the design of a calibration circuit consisting of Power detector (PD), Analog to Digital Converter (ADC) and a Digital Processing Unit (DPU). The main objective of the calibration loop is the generation of a Look up Table (LUT) for target frequency band and at operating temperature. With this technique, the first 7-bit Phase shifter is designed in SiGe- BiCMOS technology, which also has highest fractional bandwidth in literature

MILLIMETER-WAVE QUADRATURE RECEIVERS FOR ATMOSPHERIC SENSING AND RADIOMETRY

The objective of this research is to investigate the design challenges of millimeter wave (mm-wave) quadrature receivers for emerging applications and develop new ideas to ad- dress these challenges. Next-generation wireless networks, satellite communications, atmospheric sensing instruments, autonomous vehicle radars, and body scanners are targeting to operate at mm-wave frequencies, and high-performance electronics are needed to enable these technologies. In this research, we investigate novel circuit topologies to improve the performance of existing mm-wave quadrature receivers, particularly for radiometry and remote sensing applications. A transformer-based front-end switch is co- designed with an LNA where the transformer acts as the input matching network of the LNA, reducing the front-end loss and system noise figure. Broadband and low-loss quadrature signal generation networks are proposed to provide highly balanced quadrature signals to reject the image frequency content. In addition, a high-efficiency frequency multiplier topology is demonstrated, achieving superior performance compared to the state-of-the-art designs. Lastly, the reliability and noise performance of on-chip noise source devices (PN junctions) in a SiGe BiCMOS platform was characterized and compared. To confirm the advantages of our ideas, the measurement and simulation results of all fabricated circuits are presented and discussed.Ph.D

W/D-Bands single-chip systems in a 0.13μm SiGe BiCMOS technology-dicke radiometer, and frequency extension module for VNAs

Recent advances in silicon-based process technologies have enabled to build low-cost and fully-integrated single-chip millimeter-wave systems with a competitive, sometimes even better, performance with respect to III-V counterparts. As a result of these developments and the increasing demand for the applications in the millimeter-wave frequency range, there is a growing research interest in the field of the design and implementation of the millimeter-wave systems in the recent years. In this thesis, we present two single-chip D-band front-end receivers for passive imaging systems and a single-chip W-band frequency extension module for VNAs, which are implemented in IHP’s 0.13μm SiGe BiCMOS technology, SG13G2, featuring HBTs with ft/fmax of 300GHz/500GHz. First, the designs, implementations, and measurement results of the sub-blocks of the radiometers, which are SPDT switch, low-noise amplifier (LNA), and power detector, are presented. Then, the implementation and experimental test results of the total power and Dicke radiometers are demonstrated. The total power radiometer has a noise equivalent temperature difference (NETD) of 0.11K, assuming an external calibration technique. In addition, the dependence of the NETD of the total power radiometer upon the gain-fluctuation is demonstrated. The NETD of the total power radiometer is 1.3K assuming a gain-fluctuation of %0.1. The front-end receiver of the total power radiometer occupies an area of 1.3 mm2. The Dicke radiometer achieves an NETD of 0.13K, for a Dicke switching of 10 kHz, and its total chip area is about 1.7 mm2. The quiescent power consumptions of the total power and Dicke radiometers are 28.5 mW and 33.8 mW, respectively. The implemented radiometers show the lowest NETD in the literature and the Dicke switching concept is employed for the first time beyond 100 GHz. Second, we present the design methodologies, implementation methods, and results of the sub-blocks of the frequency extension module, such as down-conversion mixer, frequency quadrupler, buffer amplifier, Wilkinson power divider, and dual-directional coupler. Later, the implementation, characterization and experimental test results of the single-chip frequency extension module are demonstrated. The frequency extension module has a dynamic range of about 110 dB, for an IF resolution bandwidth of 10 Hz, with an output power which varies between -4.25 dBm and -0.3 dBm over the W-band. It has an input referred 1-dB compression point of about 1.9 dBm. The directivity of the frequency extension module is better than 10 dB along the entire W-band, and its maximum value is approximately 23 dB at around 75.5 GHz. Finally, the measured s-parameters of a W-band horn-antenna, which are performed by either the designed frequency extension module and a commercial one, are compared. This study is the first demonstration of a single-chip frequency extension module in a silicon-based semiconductor technology