Radiation and Scattering by Infinite Microstrip Patch Arrays on Anisotropic Substrates

An analysis is presented of an infinite array of printed patches on a grounded anisotropic-dielectric slab. The array is considered as both a transmitter fed by idealized probes and as a scatterer of plane waves. For the transmitter case, the input reflection coefficient versus incident angle is computed for various loads and substrates. The theory in both cases is confirmed by comparing its limit to isotropic cases with previous analyses. The inputs to the analysis are the substrate parameters, the array grid geometry, the patch dimensions including probe position, and the probe load impedance, which is assumed conjugate matched at broadside for the transmit case

Optimum Shape Synthesis of Maximum Gain Omnidirectional Antennas

Using characteristic mode shape synthesis, some antenna surfaces and their current distributions are found which produce maximum realizable gain for rotationally symmetric omnidirectional antennas. The same shape synthesis method fails to produce antennas which have maximum endfire gain

Micro-combs: a novel generation of optical sources

The quest towards the integration of ultra-fast, high-precision optical clocks is reflected in the large number of high-impact papers on the topic published in the last few years. This interest has been catalysed by the impact that high-precision optical frequency combs (OFCs) have had on metrology and spectroscopy in the last decade [1–5]. OFCs are often referred to as optical rulers: their spectra consist of a precise sequence of discrete and equally-spaced spectral lines that represent precise marks in frequency. Their importance was recognised worldwide with the 2005 Nobel Prize being awarded to T.W. Hänsch and J. Hall for their breakthrough in OFC science [5]. They demonstrated that a coherent OFC source with a large spectrum – covering at least one octave – can be stabilised with a self-referenced approach, where the frequency and the phase do not vary and are completely determined by the source physical parameters. These fully stabilised OFCs solved the challenge of directly measuring optical frequencies and are now exploited as the most accurate time references available, ready to replace the current standard for time. Very recent advancements in the fabrication technology of optical micro-cavities [6] are contributing to the development of OFC sources. These efforts may open up the way to realise ultra-fast and stable optical clocks and pulsed sources with extremely high repetition-rates, in the form of compact and integrated devices. Indeed, the fabrication of high-quality factor (high-Q) micro-resonators, capable of dramatically amplifying the optical field, can be considered a photonics breakthrough that has boosted not only the scientific investigation of OFC sources [7–13] but also of optical sensors and compact light modulators [6,14]

Microwave engineering

The 4th edition of this classic text provides a thorough coverage of RF and microwave engineering concepts, starting from fundamental principles of electrical engineering, with applications to microwave circuits and devices of practical importance.  Coverage includes microwave network analysis, impedance matching, directional couplers and hybrids, microwave filters, ferrite devices, noise, nonlinear effects, and the design of microwave oscillators, amplifiers, and mixers. Material on microwave and RF systems includes wireless communications, radar, radiometry, and radiation hazards. A larg

Microwave Engineering ed.3

xvii, 699 hlm, Ilust, 24 c

Microwave engineering / David M. Pozar.

Includes bibliographical references and index.Book fair 2012.xvii, 700 p. :Pozar emphasizes the fundamental concepts of Maxwell's equations, wave propagation, network analysis and design principles as applied to modern microwave engineering. This edition features worked examples of practical design problem

Microwave enginering

xvii, 726 p. : il.; 24 cm