A novel low-cost beam-steering technique based on the extended-resonance power-dividing method
A novel phased array based on the extended-resonance power-dividing method has been presented. This method eliminates the need for separate power splitter and phase shifters in a conventional phased-array system, resulting in a substantial reduction in circuit complexity and cost. As a proof of principle, a 2-GHz extended-resonance-based phased array using varactor diodes and microstrip patch antennas has been designed, fabricated, and tested. The measured scan range is 20/spl deg/ and the measured efficiency of the extended-resonance phased-array feed is typically 80%, which corresponds to 1 dB of insertion loss.
A new lumped-elements power-combining amplifier based on an extended resonance technique
A technique for combining power FETs in the output stage of a power amplifier is presented. The active devices are combined with simple inductor/capacitor networks and can be laid out across a single die while still allowing each device to be independently accessed for biasing. The inductors can range from fully integrated spirals to simple wire bonds, making this technique applicable over a broad range of frequencies. For linear RF power applications this is an effective technique for spreading more heat, while at high frequencies the junction parasitics are easily absorbed into this type of design. DC losses are minimized since each device can be biased individually, furthermore, it is possible to adjust the bias separately for each device to account for device nonuniformity across the die.
Can Centauros or Chirons BE the First Observations of Evaporating Mini Black Holes
We argue that the signals expected from the evaporation of mini black holes — predicted in TeV-gravity models with large extra dimensions, and possibly produced in ultrahigh energy collisions in the atmosphere — are quite similar to the characteristics of the Centauro events, an old mystery of cosmic-ray physics.