Ka-band Gaas Phemt Monolithic Low Noise Amplifier Research

With the rapid development of millimeter wave technology, more and more communications and radar systems are designed to work in the millimeter wave band,so there are many demands on the millimeter-wave integrated receiving front-ends as well as the millimeter-wave monolithic integrated circuit (MMIC). The millimeter-wave low noise amplifier is the key device in the millimeter-wave integrated receiving front-ends, It's noise performance play a critical roles for the whole noise performance of the modules. So the task of this dissertation is to research on the Ka-band MMIC LNA.A Ka-band MMIC LNA based on 0.15μm low noise GaAs PHEMT process is designed. It utilizes the four-stage common source topology to obtain high-gain performance, and each stage is designed with the input/output matching networks of T-type for different design tasks. In order to achieve good performance, the project is designed skillfully with some characteristics as follows:1.Utilize four-stages amplification topology to realize a 26.5±2dB gain millimeter-wave MMIC LNA.2.Source feedback microtrip line is adopted in each stage to achieve optimal noise match and conjugate match simultaneously, which enhances the gain and stability and reduce the noise.3.The technology of self-bias power supply is adopted to decrease the number of power supply, so only the Vds is necessary; also the bias circuit and the matching circuit is implemented simultaneously by a parallel branch line, so reduce the chip area and cost.4.Utilize a balanced structure with two Lange couplers to enhance the stability, improve the chip's VSWR and maximum output power.The chip size is 3.85mm×1.9mm。Tests shows that ,In 33.5-36.5GHz, it achieves a high again of 26.5±2dB, a low noise figure of less than 3.5dB, as well as good input/output return loss of less than -8 dB.