The growth in the number of wireless devices and applications underscores the need for characterizing and mitigating interference induced problems such as distortion and blocking. A typical interference scenario involves the detection of a small amplitude signal of interest (SOI) in the presence of a large amplitude interfering signal; it is desirable to attenuate the interfering signal while preserving the integrity of SOI and an appropriate dynamic range. If the frequency of the interfering signal varies or is unknown, an adaptive notch function must be applied in order to maintain adequate attenuation. This work explores the performance space of a phase cancellation technique used in implementing the desired notch function for communication systems in the 1-3 GHz frequency range. A system level model constructed with MATLAB and related simulation results assist in building the theoretical foundation for setting performance bounds on the implemented solution and deriving hardware specifications for the RF notch subsystem devices. Simulations and measurements are presented for a Low Noise Amplifer (LNA), voltage variable attenuators, bandpass filters and phase shifters. Ultimately, full system tests provide a measure of merit for this work as well as invaluable lessons learned. The emphasis of this project is the on-wafer LNA measurements, dependence of IC system performance on mismatches and overall system performance tests. Where possible, predictions are plotted alongside measured data. The reasonable match between the two validates system and component models and more than compensates for the painstaking modeling efforts. Most importantly, using the signal to interferer ratio (SIR) as a figure of merit, experimental results demonstrate up to 58 dB of SIR improvement. This number represents a remarkable advancement in interference rejection at RF or microwave frequencies.

Un dels problemes més importants en la Compatibilitat Electromagnètica és el control de les interferències emeses i/o rebudes per un equip electrònic a través dels seus terminals d'alimentació monofàsica. Aquestes interferències es classifiquen en mode comú i mode diferencial. La manera més usual de mitigar-les és mitjançant la utilització de filtres de xarxa. Els mètodes actuals de disseny de filtres de xarxa tracten la mitigació d'aquest tipus d'interferències per separat: no tenen en compte que ambdós tipus de senyals (mode comú i diferencial) interaccionen entre sí i es transfereixen energia en qualsevol tipus d'asimetria originada pels equips electrònics o pels mateixos filtres. Aquest fet produeix freqüentment situacions inesperades: inefectivitat dels filtres de xarxa, aparició d'interferències en mode comú o diferencial inexplicables per la topologia dels circuits, selectivitat en freqüència del filtratge de les interferències, processos de radiació, etc. Aquest tipus de situacions poden ser analitzades i corregides a partir d'un anàlisi multimodal, que tingui en compte simultàniament el mode comú i el diferencial, i la seva interacció. El treball exposat aquí pretén:- Desenvolupar sistemes de mesura multimodal per a equips electrònics i filtres de xarxa. Aquests sistemes han de tenir en compte tant el mode comú, com el diferencial, com la seva interacció, i han de millorar les prestacions dels sistemes de mesura normatius actuals.- Trobar models equivalents des d'un punt de vista multimodal (tenint en compte simultàniament el mode comú, el diferencial i la seva interacció) tant d'equips electrònics com de filtres de xarxa.- Desenvolupar una metodologia de predicció de les interferències conduïdes que l'equip electrònic subministra a la xarxa elèctrica a través del filtre de xarxa al qual es troba connectat a partir dels models multimodals equivalents proposats per a ambdós dispositius.PARAULES CLAU: Compatibilitat electromagnètica, filtre de xarxa, equip electrònic, circuit equivalent, emissió conduïda, mode comú, mode diferencial, impedància d'entrada, paràmetres S. / Uno de los problemas más importantes en Compatibilidad Electromagnética es el control de las interferencias emitidas y/o recibidas por un equipo electrónico a través de sus terminales de alimentación monofásica. Estas interferencias se clasifican en modo común y modo diferencial. La manera más usual de mitigarlas es mediante el empleo de filtros de red. Los métodos actuales de diseño de filtros de red abordan la mitigación de este tipo de interferencias por separado: no tienen en cuenta que ambos tipos de señales (modo común y diferencial) interaccionan entre sí y se transfieren energía en cualquier tipo de asimetría originada por los equipos electrónicos o por los mismos filtros. Este hecho produce frecuentemente situaciones inesperadas: inefectividad de los filtros de red, aparición de interferencias en modo común o diferencial inexplicables por la topología de los circuitos, selectividad en frecuencia del filtrado de las interferencias, procesos de radiación, etc. Este tipo de situaciones pueden ser analizadas y corregidas a partir de un análisis multimodal, que tenga en cuenta simultáneamente el modo común y el diferencial, y su interacción. El trabajo aquí expuesto pretende:- Desarrollar sistemas de medida multimodal para equipos electrónicos y filtros de red. Dichos sistemas deben tener en cuenta tanto el modo común, como el diferencial, como su interacción, y deben mejorar las prestaciones de los sistemas de medida normativos actuales.- Hallar modelos equivalentes desde un punto de vista multimodal (teniendo en cuenta simultáneamente el modo común, el diferencial y su interacción) tanto de equipos electrónicos como de filtros de red.- Desarrollar una metodología de predicción de las interferencias conducidas que el equipo electrónico suministra a la red eléctrica a través del filtro de red al cual está conectado a partir de los modelos multimodales equivalentes propuestos para ambos dispositivos.PALABRAS CLAVE: Compatibilidad electromagnética, filtro de red, equipo electrónico, circuito equivalente, emisión conducida, modo común, modo diferencial, impedancia de entrada, parámetros S. / One of the most important problems in EMC is the control of the common and differential mode interferences emitted or received by an electronic device through its single phase power-line cable. These interferences are mitigated using power-line filters. The present power-line filter methodologies treat separately the mitigation of this kind of interferences: they do not take into account that both modes interact and exchange energy at any kind of asymmetry originated by the devices connected to the power-line, or by the power-line filters themselves. This fact leads to unexpected situations: power-line filter infectivity, appearance of common and differential mode interferences not accountable by the circuit topology, frequency selectivity of the interferences, radiation processes, etc. This kind of situations can be analyzed and corrected using multimodal analysis, which takes into account at the same time the common mode, the differential mode and their interaction. This project aims to:- Develop accurate multimodal measurement systems for both electronic devices and power-line network filters. They have to consider the common and differential modes, and their interaction, and have to improve the features of present normative measurement systems. - Derive equivalent models from a multimodal point of view (taking into account simultaneously the common mode, the differential mode and their interaction) for both electronic devices and power-line filters.- Develop a methodology for predicting the level of conducted emissions that an electronic device supplies to the power-line network through the power-line filter to which it is connected, using the equivalent multimodal models proposed for both devices.KEYWORDS: Electromagnetic compatibility, power-line filter, electronic device, equivalent circuit, conducted emissions, common mode, differential mode, input impedance, S parameters.

Medical devices have made a big step forward in the past decades. One of the most noticeable medical events of the twenties century was the development of long-lasting, wireless electronic implants such as identification tags, pacemakers and neuronal stimulators. These devices were only made possible after the development of small scale radio frequency electronics. Small radio electronic circuits provided a way to operate in both transmission and reception mode allowing an implant to communicate with an external world from inside a living organism. Bidirectional communication is a vital feature that has been increasingly implemented in similar systems to continuously record biological parameters, to remotely configure the implant, or to wirelessly stimulate internal organs. Further miniaturisation of implantable devices to make the operation of the device more comfortable for the patient requires rethinking of the whole radio system concept making it both power efficient and of high performance. Nowadays, high data throughput, large bandwidth, and long term operation requires new radio systems to operate at UHF (ultra-high frequency) bands as this is the most suitable for implantable applications. For instance, the MICS (Medical Implant Communication System) band was introduced for the communication with implantable devices. However, this band could only enable communication at low data rates. This was acceptable for the transmission of telemetry data such as heart beat rate, respiratory and temperature with sub Mbps rates. Novel developments such as neuronal and prosthetic implants require significantly higher data rates more than 10 Mbps that can be achieved with large bandwidth communicating systems operating at higher frequencies in a GHz range. Higher operating frequency would also resolve a strong issue of MICS devices, namely the scale of implants defined by dimensions of antennas used at this band. Operation at 2.4 GHz ISM band was recognized to be the most adequate as it has a moderate absorption in the human body providing a compromise between an antenna/implant scale and a total power efficiency of the communicating system. This thesis addresses a key challenge of implantable radio communicating systems namely an efficient and small scale antenna design which allows a high yield fabrication in a microelectronic fashion. It was demonstrated that a helical antenna design allows the designer to precisely tune the operating frequency, input impedance, and bandwidth by changing the geometry of a self-assembled 3D structure defined by an initial 2D planar layout. Novel stimuli responsive materials were synthesized, and the rolled-up technology was explored for fabrication of 5.5-mm-long helical antenna arrays operating in ISM bands at 5.8 and 2.4 GHz. Characterization and various applications of the fabricated antennas are successfully demonstrated in the thesis.

Within the military there is great need for reliable communication between vehicles. During the planning and construction of a military RIB, Rigid-hulled Inflatable Boat, it is important to design an efficient antenna system that does not deteriorate out of disorder. It must also be ensured that the antennas transmitted power does not stay in the RIB boat. We have been given assignment to model and simulate a proposed antenna system and assess which tool is best suitable for the task. To analyze the antenna system we will look at the radiated electrical field together with the reflectionand EMC properties. The tool that we choose to use is a software called EMPro produced by Keysight Technologies. In this program we will create 3Dstructures for each individual object, the boat, the three antennas and the seawater. It’s also important to include each objects properties concerning material, so that they correctly reflect the reality. We are covering a broad spectrum with our antennas reaching from 1.6-30MHz, 30-88MHz and 100512MHz. The resulting simulation verifies that electromagnetic field would be powerful enough and that the antennas would not affect each other with the proposed placement. We could also confirm that our antennas reflected an inordinate amount of power but with cause that our models were not an exact replica of the antenna. The software EMPro is a suitable tool for this kind of projects concerning modeling and simulating antenna systems.Within the military there is great need for reliable communication between vehicles. During the planning and construction of a military RIB, Rigid-hulled Inflatable Boat, it is important to design an efficient antenna system that does not deteriorate out of disorder. It must also be ensured that the antennas transmitted power does not stay in the RIB boat. We have been given assignment to model and simulate a proposed antenna system and assess which tool is best suitable for the task. To analyze the antenna system we will look at the radiated electrical field together with the reflectionand EMC properties. The tool that we choose to use is a software called EMPro produced by Keysight Technologies. In this program we will create 3Dstructures for each individual object, the boat, the three antennas and the seawater. It’s also important to include each objects properties concerning material, so that they correctly reflect the reality. We are covering a broad spectrum with our antennas reaching from 1.6-30MHz, 30-88MHz and 100512MHz. The resulting simulation verifies that electromagnetic field would be powerful enough and that the antennas would not affect each other with the proposed placement. We could also confirm that our antennas reflected an inordinate amount of power but with cause that our models were not an exact replica of the antenna. The software EMPro is a suitable tool for this kind of projects concerning modeling and simulating antenna systems. / Inom militären finns stort behov av pålitlig kommunikation mellan fordon. Vid konstruktion av ett småfartyg i militärtoch bevakningssyfte är det viktigt att designa ett välfungerande antennsystem som inte försämras utav störningar, det ska även ses till att antennernas utsända effekt inte fastnar i småfartyget. Vi har fått en ritning av hur antennplaceringen är planerad, denna rapport går ut på att verifiera dess funktionalitet samt hitta en mjukvara som kan användas för att verifiera olika antennsystem. För att bedöma antennsystemet kommer denna rapport att undersöka att dess elektriska fält samt reflektionsoch EMC egenskaper, en uppgift som kan lösas med programvaran EMPro (Keysight). I programvaran skapas en 3Dstruktur som innehåller småfartyget, dess 3 stycken antenner samt omfattande havsvatten. Här tas hänsyn till objektens materialegenskaper, antennernas jordning samt de frekvenser antennerna arbetar på, 1.6-30MHz, 30-88MHz samt 100-512MHz. Simulering av systemet gav positiva resultat kring antennsystemets elektromagnetiskafält, antennerna kommer inte heller att störa varandra. Antennerna som vi har modellerat reflekterar orimligt mycket effekt, detta bortser vi från då vi inte haft tillgång till exakt avbildning av antennerna. EMPro är ett verktyg som är lämpligt att använda i detta samt liknande projekt. Dock krävs det att en kraftig dator finns tillgänglig då simuleringar av stora antennsystem baseras på stora uträkningar, som generellt tar lång tid.