利用图解和CAD方法设计低噪声放大器

提出一种依据Smith圆图和CAD软件设计低噪声放大器的新方法。为了设计匹配电路的需要,首先给出了稳定性判别条件及其圆方程、噪声系数及其圆方程和资用功率增益及其圆方程,用图解的方法将三种参量标注在同一源反射平面内。然后利用圆图和CAD软件分别按照最佳噪声和输入匹配原理,设计了输入匹配电路;按照共轭匹配原理设计了输出匹配电路。最后利用CAD软件对所设计的电路进行了仿真并制作了实际电路。仿真结果和测试结果表明,利用图解和CAD相结合的方法能够方便、有效地进行电路设计,提高设计效率。

Design Low Noise Amplifier Using Graphic and CAD Method

A kind of novel method is presented to design Low Noise Amplifier based on Smith Chart and CAD software. In order to satisfy the design demand, above all, stability condition with it' s circle equation, noise figure with it' s circle equation, and avail- able gain with it' s circle equation are given out. In succession, input matching circuit is designed based on simultaneous optimum noise and input matching principle and output matching circuit is designed as well based on conjugate matching principle respectively by using Smith chart and CAD method.Lastly,the designed circuit is simulated by utilizing CAD software and practical circuit is also made up.The simulation and test results show that the hybrid method of Graphic and CAD is able to design circuit efficiently and easily, save development time and enhance design efficiency.