Excitation energies for 2lϪ3lЈ hole-particle states of Ne-like ions are determined to second order in relativistic many-body perturbation theory ͑MBPT͒. Reduced matrix elements, line strengths, and transition rates are calculated for electric-dipole (E1), magnetic-quadrupole (E2), magnetic-dipole (M 1), and magneticquadrupole (M 2) transitions in Ne-like ions with nuclear charges ranging from Zϭ11 to 100. The calculations start from a 1s 2 2s 2 2p 6 closed-shell Dirac-Fock potential and include second-order Coulomb and BreitCoulomb interactions. First-order many-body perturbation theory ͑MBPT͒ is used to obtain intermediatecoupling coefficients, and second-order MBPT is used to determine the matrix elements. Contributions from negative-energy states are included in the second-order E1, M 1, E2, and M 2 matrix elements. The resulting transition energies are compared with experimental values and with results from other recent calculations. Trends of E1, E2, M 1, and M 2 transition rates as functions of nuclear charge Z are shown graphically for all transitions to the ground state.
Energies of 3l3lЈ3lЉ states of aluminumlike ions with Zϭ14-100 are evaluated to second order in relativistic many-body perturbation theory starting from a 1s 2 2s 2 2p 6 Dirac-Fock potential. Intrinsic three-particle contributions to the energy are included in the present calculation and found to contribute about 10-20 % of the total second-order energy. Corrections for the frequency-dependent Breit interaction and the Lamb shift are included in lowest order. A detailed discussion of contributions to the energy levels is given for aluminumlike germanium (Zϭ32). Comparisons are made with available experimental data. We obtain excellent agreement for term splitting, even for low-Z ions. These calculations are presented as a theoretical benchmark for comparison with experiment and theory.
A Q-band 40-GHz GaN monolithic microwave integrated circuit voltage controlled oscillator (VCO) based on AlGaN/GaN high electron mobility transistor technology has been demonstrated. The GaN VCO delivered an output power of +25 dBm with phase noise of 92 dBc/Hz at 100-KHz offset, and 120 dBc/Hz at 1-MHz offset. To the best of our knowledge, this represents the state-of-the-art for GaN VCOs in terms of frequency, output power, and phase noise performance. This work demonstrates the potential for the use of GaN technology for high frequency, high power, and low phase noise frequency sources for military and commercial applications. Index Terms-Gallium nitride, monolithic microwave integrated circuit (MMIC) oscillator, phase noise.
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