La technologie MID (Molded Interconnect Device), fait de leur performance électrique, la flexibilitédans les circuits RF, le potentiel de réduire le nombre de composants, les étapes du processus et laminiaturisation du produit final, a conduit à de nouvelles contraintes à la RF (Radio Frequency) et ledomaine des micro-ondes. Composants moulés sont interconnectées avec des substratsthermoplastiques et les pistes conductrices sont injectés sur la surface. L'objectif de cette thèse estd'étudier la compatibilité de MID pour les applications RF. Les avantages de la technologie MID dansle domaine RF est exploitée pour les lignes de transmission, filtres passifs, coupleurs directionnels etantennes réalisation. La caractérisation RF de différents matériaux de substrat MID et l'étude de laperformance des composants RF ci-dessus sur la base de différentes technologies de fabrication MIDsont inclus dans la thèse. Enfin, le concept d'une étude d'amélioration de la permittivité de certainsthermoplastiques sont également étudiés. / MID (Molded Interconnect Devices) technology, owing to their electrical performance,flexibility in RF circuits, its potential to reduce the number of components, process steps andminiaturization of the final product, has led to some new constraints to the RF (RadioFrequency) and microwave domain. Molded components are interconnected withthermoplastic substrates and conductive traces are injected on the surface. The objective ofthis thesis is to study the compatibility of MIDs for RF applications. The advantages of MIDtechnology in the RF domain is exploited for transmission lines, passive filters, directionalcouplers and planar and 3D antennas realization. The RF characterization of various MIDsubstrate materials and the study of the performance of the above RF components based onvarious MID fabrication technologies are included in the thesis. Finally, an permittivityimprovement study of some thermoplastics are also studied.

La technologie MID (Molded Interconnect Device), fait de leur performance électrique, la flexibilitédans les circuits RF, le potentiel de réduire le nombre de composants, les étapes du processus et laminiaturisation du produit final, a conduit à de nouvelles contraintes à la RF (Radio Frequency) et ledomaine des micro-ondes. Composants moulés sont interconnectées avec des substratsthermoplastiques et les pistes conductrices sont injectés sur la surface. L'objectif de cette thèse estd'étudier la compatibilité de MID pour les applications RF. Les avantages de la technologie MID dansle domaine RF est exploitée pour les lignes de transmission, filtres passifs, coupleurs directionnels etantennes réalisation. La caractérisation RF de différents matériaux de substrat MID et l'étude de laperformance des composants RF ci-dessus sur la base de différentes technologies de fabrication MIDsont inclus dans la thèse. Enfin, le concept d'une étude d'amélioration de la permittivité de certainsthermoplastiques sont également étudiés. / MID (Molded Interconnect Devices) technology, owing to their electrical performance,flexibility in RF circuits, its potential to reduce the number of components, process steps andminiaturization of the final product, has led to some new constraints to the RF (RadioFrequency) and microwave domain. Molded components are interconnected withthermoplastic substrates and conductive traces are injected on the surface. The objective ofthis thesis is to study the compatibility of MIDs for RF applications. The advantages of MIDtechnology in the RF domain is exploited for transmission lines, passive filters, directionalcouplers and planar and 3D antennas realization. The RF characterization of various MIDsubstrate materials and the study of the performance of the above RF components based onvarious MID fabrication technologies are included in the thesis. Finally, an permittivityimprovement study of some thermoplastics are also studied.

Massive multiple input multiple output - MIMO systems are a reality and modern communication systems rely upon this technology to cope with the increasing need for capacity and network usage. Antenna arrays are at the heart of the of the massive-MIMO system and are the enabling technology. The defining cost of such a system is the number of transmit receive ports TRx as they dictate the number of control points and the associated digital control computational capacity. Typically users are spread along the azimuth and there is limited angular user spread along elevation. This enables us to group the elements in elevation which of course limits the elevation scanning performance. The element grouping result in grating lobes when we do elevation scanning. In the newly introduced frequency range 3 - FR3 in the envisioned 6G communication systems that is from 6-20 GHz it will not be allowed to transmit power above the horizon and the resulting grating lobes from the standard grouping should be mitigated. This project is structured into two parts. In the first part a grating lobe mitigation technique based on irregular subarray grouping utilizing the wellknown Penrose irregular tessellation is developed. This tessellation is based into two geometrical shapes where when put together they can fully tile the space aperiodically. Introducing this apperiodicity the grating or quantization lobes of the array are mitigated. In addition, in the first part a beam forming algorithm is developed based on particle swarm optimization that is able to produce the optimal weights for the array steering as well as optimize some of the embedded patterns of the irregular grouping. The last optimization step of the irregular subarray patterns is utilized only when the grouping results in a narrow pattern in azimuth and as a result we have static single port beamforming networks. This of course is a trade off between the broadside gain and the azimuth steerability of the array. In the second part of this thesis two low loss band pass filters have been developed with a PCB integrated suspended stripline techology. The filters were optimised for the frequencies within FR3. The resulted filtering structures can further be integrated at the input port of the proposed feeding network with the same technology. The two parts of this thesis target to introduce on one hand a antenna array architecture with subarray groupings that produce no grating lobes and on the other hand the proposed filtering structures have small enough dimensions to fit within the subarray footprint. / Dagens moderna kommunikationssystem använder sig av Massive multiple input multiple output (m-MIMO) för att kunna möta det allt större kraven på kapacitet och nätverksanvändning. Gruppantenner är den mest fundamentala delen av massive-MIMO system och möjliggör dess funktion. För ett sådant system (m-MIMO-system), så kommer den största kostnaden från antalet sändare/mottagare (TRx) -portar som används. Antalet portar i ett massiveMIMO system bestämmer vilken kapacitet systemet har till hands när det gäller lobformning. Vanligtvis är användare utspridda i det horisontella planet, samtidigt som de är begränsade i sin spridning i höjdled. Detta möjliggör användandet av en gruppantenn som grupperar sina antennelement i höjdled, vilket såklart begränsar gruppantennens lobformning i höjdled. Grupperandet av antennelement skapar sidlober när gruppantennen lobformar i höjdled. I det nya frekvensbandet, 3 - FR3 i det föreställda 6G kommunikationssystemet som opererar mellan 6-20 GHz, så kommer det inte att vara tillåtet att sända ut effekt över horisonten, samtidigt som de sidlober som kommer från standardgruppering måste begränsas. Detta projekt är strukturerat i två delar. I första delen så presenteras ett sätt att lindra sidlober, som baseras på irreguljära gruppantenner via Penrose tessellation. Denna tessellation är indelad i två geometriska former sådan att när vi sätter ihop dem så kan de framgångsrikt täcka vår geometri icke-periodvist. Genom att introducera denna icke-periodicitet så kan sidloberna från gruppanetnnen lindras. Utöver detta så är också så är en lobformningsalgoritm skapad som baseras på particle swarm optimization (PSO), som kan skapa de optimala vikterna för lobformning och lobstyrning. Det sista optimiseringssteget av de irreguljära gruppantennmönstret används bara när gruppering av antennelement resulterar i ett snävt mönster i azimut-riktning. Därför använder vi ett statiskt enportsmatningsnätverk. Detta är såklart en vägning mellan bredsideförstärkning och förmågan att kunna lobforma i det horisontella planet. I den andra delen så har två låg förlust bandpassfilter utvecklats med en PCB-integrerad suspended sripline teknik. Filtrerna optimerades för frekvenser inom FR3. De resulterande filterstrukturerna kan integreras längs input-porten av det föreslagna matningsnätverket som använder sig av den samma teknik. De två delarna i denna uppsats presenterar dels en gruppantenn med irreguljär antennelementsindelning som lindrar sidlober, samt dels filterstrukturer som kan användas tillsammans med gruppantennen.

The Archimedean spiral antenna is well-known for its broadband characteristics with circular polarization and has been investigated for several decades. Since their development in the late 1950's, establishing an analytical expression for the characteristics of spiral antenna has remained somewhat elusive. This has been studied qualitatively and evaluated using numerical and experimental techniques with some success, but many of these methods are not convenient in the design process since they do not impart any physical insight into the effect each design parameter has on the overall operation of the spiral antenna. This work examines the operation of spiral antennas and obtains a closed-form analytical solution by conformal mapping and transmission line model with high precision in a wide frequency band. Based on the analysis of spiral antenna, we propose two novel design processes for the stripline-fed Archimedean spiral antenna. This includes a stripline feed network integrated into one of the spiral arms and a broadband tapered impedance transformer that is conformal to the spiral topology for impedance matching the nominally-high input impedance of the spiral. A Dyson-style balun located at the center facilitates the transition between guided stripline and radiating spiral modes. Measured and simulated results for a probe-fed design operating from 2 GHz to over 20 GHz are in excellent agreements to illustrate the synthesis and performance of a demonstration antenna. The research in this work also provides the possibility to achieve conformal integration and planar structural multi-functionality for an Unmanned Air Vehicle (UAV) with band coverage across HF, UHF, and VHF. The proposed conformal mapping analysis can also be applied on periodic coplanar waveguides for integrated circuit applications.

The thesis is focused on the design of a measuring antenna for 1 – 6 GHz band. It deals with the types of log periodic antennas with the the detailed elaboration of log periodic dipole antennas (LPDA). One can find the description of their functions, maximum features and the possibilities to use the asymmetrical feeder. Also there is the procedure of LPDA design and the realization of the design itself including simulation in 4NEC2 programme. In the next part there is a planar LPDA realization with the microstrip-to-balanced stripline balun symmetrization. This design was simulated and tested within the frames of Zeland IE3D programme. The last part contains the measuring results of S parametres as well as beam characteristics of the planar version of LPDA.

This thesis investigates into possibilities of a design of a workplace for device endurance experiments against strong high-frequency electromagnetic field. It deals with testing methods, describes advantages and disadvantages of such methods. It investigates possibiities of testing devices, possible magnitudes of fieldstrenght. One can find in the thesis a review of a way of testing using a high-intensity electromagnetic field. A concept of a construction of a stripline including a practical example is a part of the thesis.

Ces travaux de thèse concernent le développement de combineur de puissance faibles pertes et compact selon une architecture planaire pour des applications amplificateur de forte puissance à état solide en bande X. La conception du combineur de puissance s’appuie sur l’étude de structures multicouches faibles pertes et compactes en triplaque à air suspendu. Une étude électromagnétique et thermique est proposée pour déterminer les performances de ces structures de transmission dans la bande X. Un système de refroidissement est également mis en place pour permettre aux structures de transmission de tenir des puissances moyenne de l’ordre de 50 W. La réalisation et la caractérisation de ces structures triplaques à air ont permis de démontrer les caractéristiques de faibles pertes et de compacité de ces circuits imprimés. Cette technologie triplaque à air suspendue est alors compatible pour des applications de forte puissance comme les émetteurs à état solide. / This PhD thesis deals with planar architecture design development of low loss and compact power combiner for solid-state high power amplification in X-band. The design is based on the study of innovative multilayer air dielectric stripline transmission structures. A reliable printed circuit process allows to obtain low loss, compact and replicable stripline structures. Electromagnetic FEM and thermal studies are proposed to evaluate transmission structures performances in X-band. Two compact and scalable structures were developed and may be integrated into complex multilayer systems. Finally a cooling system with periodic ceramic contacts is developed to improve the power handling capability of these stripline structures up to 50 W. The study, development and benchmark of these stripline structures demonstrated their compactness and low loss behaviour. Ultimately, these attributes make them excellent candidates for high power solid-state emitters.

This diploma thesis deal with the design of log-periodic antenna. The log-periodic antenna is self-complementary and broadband antenna. Antenna self-complementary structures are described only by angles. Input impedance of log-periodic antenna is equal to theoretical impedance ohms. The input impedance and radiation patterns of broadband antenna structures are independent of frequency over theoretically unlimited bandwidths. The log-periodic antennas provide linearly polarized radiation pattern. In this thesis is designed antenna for bandwidths 1 to 5GHz. In this diploma thesis is introduced design balanced unit, this is compound broadband balun and broadband impedance transformer. The broadband balun is based on conversion of microstrip line to balanced stripline. The Klopfenstein impedance taper is used for design. For simulation was used software from firma Zeland software IE3D.