Web Page sponsor Oxley Developments
26 Jul 05. Plextek has designed a compact, low loss, high power microwave switch that offers substantially improved performance compared to current commercially available microwave switch ICs. The design was funded by an MOD Defence Technology Centre (DTC) and demonstrates the success of this initiative in fostering UK research and development. The switch could offer a number of benefits, such as reduced cost, weight and power dissipation, for a wide range of defence applications including the gain/phase control modules used in active phased array radars. The research study was commissioned to investigate the realisation of compact, low loss, high power, multi-way microwave switches with an aim to develop a MMIC-based microwave switch topology that simultaneously offers low insertion loss and a high power handling capability. The study was funded through the Electro Magnetic Remote Sensing (EMRS) DTC. The DTCs are a collaborative research initiative where industry and the scientific community work in partnership with the MOD to develop innovative defence technology. The switch topology designed by Plextek covers an operating bandwidth of 7 to 11 GHz with a mid-band insertion loss of 0.7 dB and a predicted power handling capability of 6.3 W. The mid-band loss is significantly lower than current commercially available X-band switch MMICs while the estimated power handling capability comfortably exceeds the initial target of 2 W. The design makes use of the PHEMT MMIC process of Filtronic Plc and would therefore be available from a UK source.
27 Jul 05. SONEX RESEARCH, INC. has received a $300,000 follow-on task from DARPA to continue development of a multi-cylinder, four-stroke, high power output, “heavy fuel” engine (HFE) combustion process for potential Department of Defense (DoD) applications such as UAVs. Sonex, a small business, has performed a best efforts technology development and demonstration of the patented Sonex Combustion System (SCS) to enable the use of JP-5/8 military kerosene-based “heavy fuel” in lightweight, four-stroke piston engines. This project is sponsored by DARPA as a technology feasibility demonstration of a means for lightweight piston engines to comply with a DoD policy directive that mandates heavy fuel for all engines. Gasoline engines are typically 25% to 30% lighter than diesel engines. The SCS improves the combustion of fuels in four-stroke, direct injected (DI) engines through design modification of the pistons to achieve chemical/turbulent enhancement of combustion. One form of the SCS, called Sonex Controlled Auto Ignition (SCAI), allows ignition and combustion of low cetane fuels, such as JP-5/8, by controlled auto-ignition at moderate compression ratios, and operates at controlled peak cylinder pressures, which should allow the design of lighter weight HFEs rather than the heavy weight required by normal diesel engines. Sonex has already adapted an engine to the SCAI combustion process to run on JP5 heavy fuel. In addition, Sonex adapted its 3-cylinder turbocharged diesel laboratory engine to compare a diesel-like combustion chamber to the gasoline-like combustion chamber of the first engine. With its SCAI process using heavy fuel, Sonex achieved the following laboratory results: Complete control of ignition by means of SCAI chemical ignition using fuel injection timing; control of peak cylinder pressures consistent with lightweight aluminum engine design; demonstration of the advantages of the diesel-like combustion chamber and turbocharging for high power output and low smoke at a fuel consumption rate of 0.35 lbs. of fuel per horsepower hour. This is in the range of modern diesel engines.
05 July 05. New EU legislation on vibration levels impacts on military and commercial vehicles. QinetiQ has been advising the Ministry of Defence (MOD) on new EU legislation that becomes law in the UK on 6 July.