[ADS] Smith chart & Impedance matching

EE316 Microwave Engineering

Lab 3: Introduction to Advanced Design System

记录微波作业，从我做起????
这个主要搞了一下史密斯图的用法，匹配阻抗啥的。

Part 1: Introduction.

• Advanced Design System (ADS) is an electronic design automation software system . It provides an integrated design environment to designers of RF electronic products such as mobile phones,pagers, wireless networks, satellite communications, radar systems, and high-speed data links.

• In this lab, we will use ADS to solve Example 5 and draw a smith chart correspondingly.

• Example 5 is given below:

  

Part 2: Process & Result.

1. Draw the schematic of the circuit and set the simulation parameters.

Fig.1 Circuit schematic

2. Draw the smith chart to match the load (which is shown in Fig. 2), which could be split up into four steps:
   • Find the admittance point Y L , n = 1 Z L , n = 1 2 + j 2 = 0.25 − 0.25 j Y_{L,n}=\frac{1}{Z_{L,n}}=\frac{1}{2+j2}=0.25-0.25j YL,n​=ZL,n​1​=2+j21​=0.25−0.25j in the smith chart.
   • Draw two V S W R VSWR VSWR circles which respectively have radius of 0.25 0.25 0.25 and 1 1 1.
   • Find the intersection point of these two circle and choose the shortest transmission line.
   • Match the imaginary part.

Fig.2 Smith Chart

3. Simulate the program, and draw the rectangular plot of S ( 1 , 1 ) S(1,1) S(1,1). The below running result show that the load was matched at 1 G H z 1GHz 1GHz.

Fig.3 Rectangular Plot

4. The electrical length of l s l_s ls​ and d d d is shown below that l s = 32.08 l_s=32.08 ls​=32.08 and d = 79.14 d=79.14 d=79.14, where the reference frequency for Electrical length is 1 G H z 1GHz 1GHz.

   

Fig.4 Running Result

Part 3: Experience.

• ADS could easily calculate some relative parameters of a certain circuit, which could save us a lot of efforts.
• There are various options for ADS. For example, we can draw a smith chart or a rectangular plot simply in the display window.