Conventional optical components rely on gradual phase shifts accumulated during light propagation to shape light beams. New degrees of freedom are attained by introducing abrupt phase changes over the scale of the wavelength. A two-dimensional array of optical resonators with spatially varying phase response and subwavelength separation can imprint such phase discontinuities on propagating light as it traverses the interface between two media. Anomalous reflection and refraction phenomena are observed in this regime in optically thin arrays of metallic antennas on silicon with a linear phase variation along the interface, which are in excellent agreement with generalized laws derived from Fermat’s principle. Phase discontinuities provide great flexibility in the design of light beams, as illustrated by the generation of optical vortices through use of planar designer metallic interfaces.

http://www.zenogaburro.it/papers/LightPropagation.pdf

Light Propagation with Phase Discontinuities: Generalized Laws of Reflection and Refraction

The generation of RF/microwave power is required not only in wireless communications, but also in applications such as jamming, imaging, RF heating, and miniature dc/dc converters. Each application has its own unique requirements for frequency, bandwidth, load, power, efficiency, linearity, and cost. RF power is generated by a wide variety of techniques, implementations, and active devices. Power amplifiers are incorporated into transmitters in a similarly wide variety of architectures, including linear, Kalm, envelope tracking, outphasing, and Doherty. Linearity can be improved through techniques such as feedback, feedforward, and predistortion.

Power amplifiers and transmitters for RF and microwave

https://cup.edu.cn/peakoil/docs/20140408160524637170.pdf

Depletion of fossil fuels and anthropogenic climate change—A review

Oil is a curse, it is often said, that condemns the countries producing it to an existence defined by war, corruption and enormous inequality. Carbon Democracy tells a more complex story, arguing that no nation escapes the political consequences of our collective dependence on oil. It shapes the body politic both in regions such as the Middle East, which rely upon revenues from oil production, and in the places that have the greatest demand for energy. Timothy Mitchell begins with the history of coal power to tell a radical new story about the rise of democracy. Coal was a source of energy so open to disruption that oligarchies in the West became vulnerable for the first time to mass demands for democracy. In the mid-twentieth century, however, the development of cheap and abundant energy from oil, most notably from the Middle East, offered a means to reduce this vulnerability to democratic pressures. The abundance of oil made it possible for the first time in history to reorganize political life around the management of something now called "the economy" and the promise of its infinite growth. The politics of the West became dependent on an undemocratic Middle East.In the twenty-first century, the oil-based forms of modern democratic politics have become unsustainable. Foreign intervention and military rule are faltering in the Middle East, while governments everywhere appear incapable of addressing the crises that threaten to end the age of carbon democracy - the disappearance of cheap energy and the carbon-fuelled collapse of the ecological order. In making the production of energy the central force shaping the democratic age, Carbon Democracy rethinks the history of energy, the politics of nature, the theory of democracy, and the place of the Middle East in our common world.

Carbon Democracy: Political Power in the Age of Oil

This review presents an overview of the thermal properties of mesoscopic structures. The discussion is based on the concept of electron energy distribution, and, in particular, on controlling and probing it. The temperature of an electron gas is determined by this distribution: refrigeration is equivalent to narrowing it, and thermometry is probing its convolution with a function characterizing the measuring device. Temperature exists, strictly speaking, only in quasiequilibrium in which the distribution follows the Fermi-Dirac form. Interesting nonequilibrium deviations can occur due to slow relaxation rates of the electrons, e.g., among themselves or with lattice phonons. Observation and applications of nonequilibrium phenomena are also discussed. The focus in this paper is at low temperatures, primarily below $4\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, where physical phenomena on mesoscopic scales and hybrid combinations of various types of materials, e.g., superconductors, normal metals, insulators, and doped semiconductors, open up a rich variety of device concepts. This review starts with an introduction to theoretical concepts and experimental results on thermal properties of mesoscopic structures. Then thermometry and refrigeration are examined with an emphasis on experiments. An immediate application of solid-state refrigeration and thermometry is in ultrasensitive radiation detection, which is discussed in depth. This review concludes with a summary of pertinent fabrication methods of presented devices.

/pdf/opportunities-for-mesoscopics-in-thermometry-and-10z63yzsh2.pdf

Opportunities for mesoscopics in thermometry and refrigeration: Physics and applications

In this paper, we compare the performance of the newly introduced distributed active transformer (DAT) structure to that of conventional on-chip impedance-transformations methods. Their fundamental power-efficiency limitations in the design of high-power fully integrated amplifiers in standard silicon process technologies are analyzed. The DAT is demonstrated to be an efficient impedance-transformation and power-combining method, which combines several low-voltage push-pull amplifiers in series by magnetic coupling. To demonstrate the validity of the new concept, a 2.4-GHz 1.9-W 2-V fully integrated power-amplifier achieving a power-added efficiency of 41% with 50-/spl Omega/ input and output matching has been fabricated using 0.35-/spl mu/m CMOS transistors.

/pdf/distributed-active-transformer-a-new-power-combining-and-1ibh5e8zwi.pdf

Distributed active transformer-a new power-combining and impedance-transformation technique

Integrated-circuit antennas.

A novel on-chip impedance matching and power-combining method, the distributed active transformer is presented. It combines several low-voltage push-pull amplifiers efficiently with their outputs in series to produce a larger output power while maintaining a 50-/spl Omega/ match. It also uses virtual ac grounds and magnetic couplings extensively to eliminate the need for any off-chip component, such as tuned bonding wires or external inductors. Furthermore, it desensitizes the operation of the amplifier to the inductance of bonding wires making the design more reproducible. To demonstrate the feasibility of this concept, a 2.4-GHz 2-W 2-V truly fully integrated power amplifier with 50-/spl Omega/ input and output matching has been fabricated using 0.35-/spl mu/m CMOS transistors. It achieves a power added efficiency (PAE) of 41 % at this power level. It can also produce 450 mW using a 1-V supply. Harmonic suppression is 64 dBc or better. This new topology makes possible a truly fully integrated watt-level gigahertz range low-voltage CMOS power amplifier for the first time.

/pdf/fully-integrated-cmos-power-amplifier-design-using-the-1dbx97ym4d.pdf

Fully integrated CMOS power amplifier design using the distributed active-transformer architecture

A new family of switching amplifiers, each member having some of the features of both class E and inverse F, is introduced. These class-E/F amplifiers have class-E features such as incorporation of the transistor parasitic capacitance into the circuit, exact truly switching time-domain solutions, and allowance for zero-voltage-switching operation. Additionally, some number of harmonics may be tuned in the fashion of inverse class F in order to achieve more desirable voltage and current waveforms for improved performance. Operational waveforms for several implementations are presented, and efficiency estimates are compared to class-E.

/pdf/the-class-e-f-family-of-zvs-switching-amplifiers-uawalmoybg.pdf

The class-E/F family of ZVS switching amplifiers

Many millimeter and far-infrared imaging systems are limited in sensitivity and speed because they depend on a single scanned element. Because of recent advances in planar detectors such as Schottky diodes, superconducting tunnel junctions, and micro-boiometers, an attractive approach to this problem is a planar antenna array with integrated detectors. A planar line antenna array and optical system for imaging has been developed by the authors. The significant advances are a "reverse-microscope" optical configuration and a modified bow-tie antenna design. In the "reverse-microscope" configuration, a lens is attached to the bottom of the substrate containing the antennas. Imaging is done through the substrate. This configuration eliminates the troublesome effects of substrate surface waves. The substrate lens has only a single refracting surface, making possible a virtually aplanatic system, with little spherical aberration or coma. The array is characterized by an optical transfer function that is easily measured. An array with 19 dB crosstalk levels between adjacent antennas has been tested and it was found that the array captured 50 percent of the available power. This imaging system was diffraction limited.

David B. Rutledge

Papers

Distributed active transformer-a new power-combining and impedance-transformation technique

Integrated-circuit antennas.

Fully integrated CMOS power amplifier design using the distributed active-transformer architecture

The class-E/F family of ZVS switching amplifiers

Imaging antenna arrays