Background to Requirements

• Increased usage of multichannel radiometers for earth observation

• Current range of frequencies 18.7 to 875 GHz

• Waveguide Components except for horns impractical

• Use Quasi-Optical Network with Frequency Sensitive Surfaces (FSS) as filters

• QON can have between 2 and 8 channels - may include dual polarised channels (use wire grid polariser). This results in many FSSs

• More stringent specification on Xpolar levels