Re: question:ku-band LNB
Hi,
Well assuming you are designing a discrete LNA, the main keys controling the NF of the LNA is the choice of the active device, the number of passive resistors, and the DC current consumped.
You need only one transistor as the active part of the LNA, choosing the transistor is a critical issue at this frequency, for instance philips semiconductos has the BFG series with low noise charateristics and high Ft, of course high Ft means better noise figure and gain, passive resistors are used for biasing and feedback, yet careful choice of their values is necessay due to their thermal noise contribution, DC current influences both minimum noise figure and gain of LNA.
The following URL contains a very useful paper on Discrete LNA design, though for 1.9GHz applications, not in the Ku band, but provides useful general design methodology for Discrete LNA design.
**broken link removed**
don't hesitate for any questions.
regards,