There are two words that describe the direction of today's electronic technology, smaller and faster. With the ever decreeing size scientists and engineers must have a way to characterize materials in the nm range. In this thesis characterization of nano-materials is discussed based on scanning probe microscopy and an in-depth look at RF/microwave frequencies by scanning microwave microscopy. Recently, low-temperature spin-sprayed ferrite films (Fe3O4) with a high self-biased magnetic anisotropy field have been reported, showing FMR frequency>5 GHz. Such films hold great potential for RF/microwave devices and find immediate applications. In this study, we performed in situ scanning microwave microscopy (SMM) characterization at frequencies between 2.0 GHz and 8.0 GHz. The grain boundary appeared to be more conductive, which might be caused by charge accumulation in the grain boundary space-charge region.

This book targets new trends in microwave engineering by downscaling components and devices for industrial purposes such as miniaturization and function densification, in association with the new approach of activation by a confined optical remote control. It covers the fundamental groundwork of the structure, property, characterization methods and applications of 1D and 2D nanostructures, along with providing the necessary knowledge on atomic structure, how it relates to the material band-structure and how this in turn leads to the amazing properties of these structures. It thus provides new graduates, PhD students and post-doctorates with a resource equipping them with the knowledge to undertake their research.

The development of high speed, high frequency circuits and systems requires an understanding of the properties of materials functioning at the microwave level. This comprehensive reference sets out to address this requirement by providing guidance on the development of suitable measurement methodologies tailored for a variety of materials and application systems. Bringing together coverage of a broad range of techniques in one publication for the first time, this book: Provides a comprehensive introduction to microwave theory and microwave measurement techniques. Examines every aspect of microwave material properties, circuit design and applications. Presents materials property characterisation methods along with a discussion of the underlying theory. Outlines the importance of microwave absorbers in the reduction in noise levels in microwave circuits and their importance within defence industry applications. Relates each measurement technique to its application across the fields of microwave engineering, high-speed electronics, remote sensing and the physical sciences. This book will appeal to practising engineers and technicians working in the areas of RF, microwaves, communications, solid-state devices and radar. Senior students, researchers in microwave engineering and microelectronics and material scientists will also find this book a very useful reference.

This book is a practical engineering guide to microwave material measurements for both laboratory and manufacturing/field environments, including nondestructive inspection (NDI) and nondestructive evaluation (NDE). The book covers proven methods for characterizing materials at microwave frequencies, including both resonant and wide-bandwidth techniques, and gives you the necessary theory and equations for implementing these methods. You’ll understand how to invert dielectric and/or magnetic material properties from free space transmission and reflection, and how to measure traveling wave attenuation. You’ll also know how to measure dielectric and/or magnetic material properties from transmission line fixtures, and learn how to use computational electromagnetic modeling with a measurement fixture. The book shows you how to build and use microwave NDE equipment for radomes and/or structural dielectric materials. This is an excellent resource for Engineers/scientists conducting or analyzing RF/Microwave/MMW material measurements for applications in electromagnetic materials, as well as those who are developing or applying microwave non-destructive evaluation (NDE) methods to their manufacturing problems.

The microwaves electromagnetic properties, i.e. the complex permittivity, of single cells determine how this radiation is transmitted, reflected or absorbed by biological tissues. This information is important for the development microwave medical applications in diagnostics and therapy. Moreover, it is also crucial to assess the potential dangerous effects of the exposure to microwave radiations. Dielectric spectroscopy performed allowed to quantify the complex permittivity of tissues and whole single cells. However, there is a lack of information at the sub-cellular and intracellular level, due to the inherent limitations of the techniques, to resolve the dielectric response at the nanoscale. In recent years, Near-Field Scanning Microwave Microscopy (NF-S03) has appeared as promising alternative to obtain images related to the dielectric response of samples, with high spatial resolution. In S03, the local reflection of microwaves from the sample is measured by means of a sharp probe scanned in close proximity to the sample, i.e. within the near-field region. The reflection can be related to the electrical impedance of the samples, and from this, the local complex permittivity can be retrieved. The near-field region ensures the good lateral resolution of the technique, far below the wavelength of the radiation used. S03 has been only scarcely applied to biological samples, and the few studies are limited to qualitative findings. This is due, among other reasons, to the complexity of the interpretation of the data, especially in case of tall irregular samples like cells, where the topography crosstalk effect dominates the signal acquired, thus masking the dielectric response. The objective of my Thesis was precisely to use this technique to quantify the local nanoscale dielectric response of a single cell at microwave frequency. My research focused primarily in the elaboration and implementation of the analysis methodologies suitable to obtain quantitative information from S03 measurements. I elaborated a methodology to disentangle and remove the topography crosstalk effect in the capacitance images acquired by S03, which allows to extract new capacitance images only related to the intrinsic dielectric response of the sample, and therefore suitable for the quantification. I extracted the permittivity of the sample from the intrinsic capacitance images, by means of data analysis procedures which I adapted from the one available for low frequency measurements within the research group. Among these, the procedures to determine tip and sample geometries and to obtain the permittivity. The procedures were validated on reference samples. I first analysed heterogeneous inorganic thin film, exhibiting large height variations comparable to the ones of bacterial cells. I obtained intrinsic capacitance images at around 19 GHz in contact mode and show these can be directly related to the permittivity of the samples, without the need of theoretical models or the knowledge of the system geometry, and therefore represent maps of the microwave permittivity. I also show that in case of images acquired in intermittent contact mode the interpretation of the capacitance images in terms of the electric permittivity is much more complex. Finally, I obtained intrinsic images, at ̃19 GHz, of a single E.coli bacterium, in dry and humid conditions, and, with the help of theoretical models, I extracted the local permittivity. These findings represent the first quantification of the of a single cell ever done at microwaves at the nanoscale, and thus show that S03 is sensitive to the cell constituent and the environment humidity. The results obtained prove that, despite the complexity of the data analysis, the microwave permittivity of biological samples can be quantified with nanoscale resolution, from S03 capacitance images.

Microwave Materials Characterization is an edited book discussing recent researches on basic and innovative measurement techniques for the characterization of materials at microwave frequencies, in terms of quantitative determination of their electromagnetic parameters, namely the complex permittivity and permeability. It is divided into two parts: Part 1, including original contributions on advanced techniques for the characterization of dielectric materials, and Part 2, devoted to the microwave characterization of biological tissues.

Nano-scale materials have unique electronic, optical, and chemical properties that make them attractive for a new generation of devices. In the second edition of Modeling, Characterization, and Production of Nanomaterials: Electronics, Photonics, and Energy Applications, leading experts review the latest advances in research in the understanding, prediction, and methods of production of current and emerging nanomaterials for key applications. The chapters in the first half of the book cover applications of different modeling techniques, such as Green’s function-based multiscale modeling and density functional theory, to simulate nanomaterials and their structures, properties, and devices. The chapters in the second half describe the characterization of nanomaterials using advanced material characterization techniques, such as high-resolution electron microscopy, near-field scanning microwave microscopy, confocal micro-Raman spectroscopy, thermal analysis of nanoparticles, and applications of nanomaterials in areas such as electronics, solar energy, catalysis, and sensing. The second edition includes emerging relevant nanomaterials, applications, and updated modeling and characterization techniques and new understanding of nanomaterials. Covers the close connection between modeling and experimental methods for studying a wide range of nanomaterials and nanostructures Focuses on practical applications and industry needs through a solid outlining of the theoretical background Includes emerging nanomaterials and their applications in spintronics and sensing