The results of this study indicate that the caustic insert in broadband matching 3 GHz lowpass is less than 1.

To solve the coupled network problem of the communication system, this paper takes an example of designing the lossless equlizer which bases on lowpass Butterworth 20 MHz filter, and use broadband matching to equlize the resistance signal source and frequency dependent load , to get the transducer power gain character which was fixed in advance.

The linear variable gain controlling, input wideband matching and noise optimization methods are analyzed in detail.

A difforent frequency generation of nonlinear optical crystals of AgGaSe_2 and AgGaS_2 has been analyzed based on the three-wave coupled equation and energy consesrvation in the phase-matching of type-Ⅰand type-Ⅱ.

Based on the calculation and discussion on the phase-matching,walk-off angle,acceptance angle and effective nonlinear coefficient for the KTP crystal,and on the numerical simulations of the angle-tuning curve and gain curve,the tuning spectrum and cutting angle of the KTP was finally established as 1.

Energy conversion process and spatial distribution of forward-propagating signal wave and backward-propagating wave of sum frequency under phase-matching condition were investigated.