rf schematic tutorial
Hi Cristos,
The objective is not to exceed a specified noise figure values while achieving the highest possible gain. But because maximum power gain and minimum noise figure cannot be achieved simultaneously, in most cases we need to trade off one to achieve our objectives.
LNA design is the last stage in designing an amplifier, if you already selected the proper device the next step is to Bias your device. For most small signal condition linear operation is required and this demand that device operates in class A mode or Bias your device midrange in the IcQ-VceQ characteristic curves. Next is to Measure the S-Parameters of the device at the selected Q-point. The next stage is to check the stability condition at particular frequency, sometimes you need to draw the input and output stability circles and determine the stable region, use Unilateral design if S12=0 or if S12≠0 compute the unilateral figure of merit and find the error range and if big otherwise use the bilateral analysis and design.
Next and the last stage is to design the input and output matching network based on LNA requirement where you define the noise figure or NF, Power Gain and the S-Parameter, you can find all this information from your device datasheets.
I'll be posting few tutorial in the future
Goodluck....