lna gate inductor problem

Discussion in 'Wireless & RF Design' started by kameliya, Oct 16, 2011.

  1. kameliya

    Thread Starter New Member

    Jan 23, 2011
    I have designed an source inductive degeneration cascode lna for ism band my lna gate inductor(used for input matching) amplify the signal. it's wonderful that voltage gain at the terminals of ind is 18db but the power gain is 0db. and my main transistor has the gain of -2db i.e it attenuates the signal however it's in sat region and has reasonable gm for amplification the cascode one has the same gm and amplify the signal up to14db it affects the linearity of lna at the high level input powers.i alter the size of lna and inductor and matching ckt but the problem is fixed.i have seen at some literatures some l match ckt(inductor) used to amplify the signal befor the passive mixer but not in the case of lna.the amplification of ind decrease up to 3db when i alter the size of cascode transistor up to 1/15 of the main one and the gain drops but the matching has been ruined drastically.
    have any body any idea about this problem?
    thank in advance.