T/R modules are the key parts of the active phased array radar.Their design decides the cost

feasibility and the system performance of the whole radar.As the designer usually didn't attach much importance to the stability of the module system

this paper firstly brought forward the stability design of the loop in T/R module system

then its theoretic analysis is made in the case of noise power and the design function to meet the system stability is deduced

finally

several system design methods to solve the problem are suggested.