About Reflection Oscillator design

feedback on transistor

i have add a feedback on transistor,but s(1,1) still can't reach my demand,how should i do next? or the transistor i choosed have problem? how to choose the transistor? thanks

Transistors have 3 terminals. Usually, one of the terminals is commonly connected to ground (either a transistor emitter, a fet source). But that is just normal operation for amplifiers. For reflection oscillator applications, try connecting the base or gate to ground, or the collector or source to ground, and see if s11 magnitude is bigger. (I assume you are trying to make s11 > 1). Try adding some feedback between the device terminal and ground (inductive, capacitive). Often you can get a stubborn transistor to do what you want if you try all the different options.

hi ,biff4,thanks for your hot-heartly reply.
but If i want to adopt a common-emitter structure , how should i choose the transitor parameters to predict that it can agree with design goals.

My VCO works at 800Mhz, its BandWidth is 24MHz,

IF you have some articles (the design example is preferable :))about reflection oscillator design, please give me some one,OK?

thanks you sincerely

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