3, a maximum output power of 33 dBm and a drain efficiency of 63% were measured at 5.5 GHz.To investigate the GaN capabilities for radar system, an UltraWide-Band (UWB) HPA to operate from 0.8 GHz to 4 GHz was designed [5]. The experimental results reported in Figure 4 have shown an output power higher than 32.5 dBm in the overall band, with associated drain efficiency higher than 45%.Finally, for communication applications, for the first time a dual band 2nd HT HPA was designed to simultaneously (i.e. concurrency) operate at 2.45 GHz and 3.3 GHz [9]. In this case a drain efficiency of 53% and 46%, with an output power of 33 dBm and 32.5 dBm at 2.45 GHz and 3.3 GHz, respectively, were measured and here reported in Figure 5. CONCLUSIONIn this contribution the features of GaN technology (provided by Selex-SI) for power applications were explored from the designer point of view. The role of the active device key parameters was highlighted underlining the potentials of GaN HEMT. As a demonstration several experimental results of different power amplifiers were reported to highlight both, the capabilities and/or drawbacks of such material. ACKNOWLEDGMENTSThe authors wish to acknowledge Dr. A. Cetronio, C. Lanzieri, and M. Peroni from Selex-SI for the technological support and Dr. A. Nanni and Dr. A. Serino for the device modeling support.

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One of the most important properties influencing the chemical behavior of an element is the electron affinity (EA). Among the remaining elements with unknown EA is astatine, where one of its isotopes, 211 At, is remarkably well suited for targeted radionuclide therapy of cancer. With the At − anion being involved in many aspects of current astatine labeling protocols, the knowledge of the electron affinity of this element is of prime importance. Here we report the measured value of the EA of astatine to be 2.41578(7) eV. This result is compared to state-of-the-art relativistic quantum mechanical calculations that incorporate both the Breit and the quantum electrodynamics (QED) corrections and the electron-electron correlation effects on the highest level that can be currently achieved for many-electron systems. The developed technique of laser-photodetachment spectroscopy of radioisotopes opens the path for future EA measurements of other radioelements such as polonium, and eventually super-heavy elements.

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This paper presents a novel approach to the design of a digital ohmmeter with a resolution of <60 μΩ based on a general-purpose microcontroller and a high-impedance instrumentation amplifier only. The design uses two digital I/O-pins to alternate the current through the sample resistor and combined with a proper firmware routine, the design is a lock-in detector that discriminates any signal that is out of phase/frequency with the reference signal. This makes it possible to selectively detect the μV drop across sample resistors down to 55.6 μΩ using only the current that can be supplied by the digital output pins of a microcontroller. This is achieved without the need for an external reference signal generator and does not rely on the computing processing power of a digital signal processor.