Design of broadband, highly integrated, 20-30 GHz and 35-45 GHz MMIC up-converters
The design of broadband, highly integrated up-converters is described. Two up-converters have been designed to reduce the complexity and cost of broadband millimetre wave systems by integrating a number of functions into a compact MMIC. Broadband performance was achieved for 20-30 GHz and 35-45 GHz with OIP3 exceeding 24 and 15 dBm, respectively; 2xLO leakage better than 3 dBm and excellent gain control. To our knowledge, this is the highest level of integration achieved for an up-converter at these frequencies.
Compact and broadband microstrip power amplifier MMIC with 400-mW output power using 0.15-/spl mu/m GaAs PHEMTs
The performance of a compact power amplifier MMIC for 35 to 45 GHz applications is reported. Using a standard 6-inch, 0.15-/spl mu/m GaAs power PHEMT technology on 100-/spl mu/m substrate thickness, in combination with appropriate compact circuit topologies, this microstrip power amplifier achieved a linear gain of more than 24 dB over the 36 to 45 GHz frequency range. At 5 V and 500 mA bias, an output power at 1-dB compression of 26 dBm (P/sub -1 dB/=400 mW) was measured in the 37/spl sim/40 GHz band, with a saturated output power up to 0.5 Watt (P/sub sat/=27 dBm). The total chip size is only 3.6 mm/sup 2/ (2.4 /spl times/ 1.5 mm/sup 2/); compared to conventional power amplifier MMICs operating at these frequencies, the combined output power and gain densities per chip area are a factor two higher.
Mathematical Modeling of Scour and Deposition
Electronic computers are opening up the field of sedimentation engineering by permitting the analysis of problems which heretofore have required too much time and effort. Movable stream bed profiles are being calculated in addition to water surface profiles. The initial gradation of sediment material in the stream bed may be prescribed to facilitate the calculation of an armor layer. This gradation is continually changed by the computer program in response to sediment particles being deposited on the stream bed and material on the stream bed being removed to satisfy transport capacity. Hydraulic sorting of sediment by grain size is accomodated. The stream bed does not have to be represented by a single grain size. Retardance of motion because of armor layer is calculated.