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.
A new FET frequency multiplier
A new FET frequency multiplier is presented. The FET multiplier works in a similar way as a resistive mixer. The FET can be operated either as a series or a parallel switch. The multiplier has essentially no DC power dissipation and its stability properties are good, since the drain-to-source bias-voltage is zero. The multiplier is insensitive to device parameter variations. Different configurations are analysed. The preliminary measurements show a conversion loss of 4.5 dB. The authors believe that the conversion efficiency can be further improved.
HYPERGOLIC REACTION MECHANISMS OF CATALYTICALLY PROMOTED FUELS WITH ROCKET GRADE HYDROGEN PEROXIDE
Abstract The coupling of the physical and chemical processes controlling the ignition delays (τ ign ) of hypergolic propellants complicates the direct analysis of the transient ignition processes. The transport properties of both the propellants and the ambient gas, and the heat of vaporization and reaction affect τ ign and must be considered experimentally. Furthermore, since hypergolic ignition occurs, by definition, on contact, the mechanics of initial contact and subsequent mixing can affect τ ign and must also be considered. Experimental results from a study of the hypergolic ignition of a catalytically promoted fuel with rocket grade hydrogen peroxide (RGHP) are presented. Statistical analysis of the experimental data was conducted to evaluate the relative effects of RGHP concentration, initial ambient pressure, and the ambient gas on τ ign . At RGHP concentrations of less than 92% in water, stable ignition was difficult to achieve. At sufficiently high Lewis number, an oscillatory ignition process is observed. A phenomenological model comprising mixing, RGHP decomposition, fuel heating and vaporization, and auto-ignition is presented and compared to the experimental results.