Ka-band Power Amplifier Research

In the paper, the technique of millimeter-wave power-combining is discussed in detail.The methods of spatial power-combining are presented. According to the theory of electromagnetic, the characteristic of each method is analyzed.Considering our project, the key point is the slotted-waveguide power combining. The design method of the taper is given. It makes the optimization of the magnitude and the phase of the taper respective. And also it excludes the disadvantage of the traditional taper and improves the band-width . This passive circuit exhibits a measured 2dB insert loss and 11dB return loss.Also, the theory of 3dB power splitter is described. The traditional Wilkinson hybrid is improved, so the obtained structure of the circuit is simpler. The power combining amplifier is fabricated. The insert loss of the passive circuit is less than 3.5dB,return loss better than 10dB.The AMMIC5040 is used to drive the TGA1141,and the power is splited into two signals, each of these is to drive TAG4517.At the output port ,the power is 4w. The power combining efficiency reaches 85 %.