Showing papers by "Daniel J. Hoppe published in 2009"

Advanced Component Development to Enable Low-Mass, Low-Power High-Frequency Microwave Radiometers for Coastal Wet-Tropospheric Correction on SWOT

Abstract: Current satellite ocean altimeters include a nadir-viewing, co-located 18-37 GHz multi-channel microwave radiometer to measure wet-tropospheric path delay. Due to the large diameters of the surface instantaneous fields of view (IFOV) at these frequencies, the accuracy of wet path retrievals begins to degrade at approximately 50 km from the coasts. Conventional microwave radiometers do not provide wet path delay over land. In order to meet the needs of the recommended SWOT mission, higher-frequency microwave channels need to be added to the JASON-class radiometers in order to improve retrievals of wet-tropospheric delay in coastal areas and to increase the potential for over-land retrievals.

Solid state power amplifier and travelling wave tube amplifier additive phase noise characterization at Ka-band operation

Abstract: A Ka-band (31–36GHz) solid state power amplifier (SSPA) capable of producing more than 50 W of output power was developed by the Jet Propulsion Laboratory (JPL) using a novel 32-way combiner/splitter and 32 2W GaAs PHEMT MMIC modules [1]. Additionally, a 200 W travelling wave tube amplifier (TWTA) manufactured by L3 Communications was acquired and characterized. While these devices are typically not the primary sources of origin for phase noise in transponders, they will contribute phase noise and may add to system phase noise differently. Because information on Ka-band tube and solid-state amplifier additive phase noise performance was not available for these high-power Ka-band amplifiers, an investigation into the phase noise of the SSPA and TWTA was launched. Results indicate that the tested SSPA may have a lower close-in phase noise than the tested TWTA.