The progress in week 3

Third Lab Day

Details for 3rd weeks's activities:

1. We have a group meeting firstly, discussing the content referred to the writing of sustainable design. The whole name of this paper is sustainable development (SD) and ethical aspects of the design, which are divided into four parts: a basic description of our project; the regulatory considerations of actual power divider ("RoHS", "WEEE"); SD/Ethical implications of large scale manufacture and sale; SD/Ethical implications of follow-on products or markets. We will complete this paper before 17th Feb,2014. 
2. Review the inner operation of a four-way power divider which main focus on the part of input reflection. The detailed knowledge of this field can be seen at the log of week 2. The basic equation that used to calculated the input reflection of a four-way power divider can are shown below:
   
   where the calculation of "Sre" and "Sim" are represent as:
   
   
3. According to the equations which show above, we began to use "Matlab" software to coding a function that aimed to calculating the input reflection of a four way power divider, where the value of fundamental frequency (fo) and transmission lines`s length (x) can be setting before each calculation.The detailed code for this part is shown below:
   
   It can be seen from the code that only the "x" and "fo" are independent variables, where the scale of frequency is multiple by [0.4,1.6]. This code can be used as a component of the final interface named "power divider calculator", which is our next target of this project. We used this code to calculating the graph of input reflection for a four way power divider with "x=π" and "x=π/2", the results are shown below:
   
   
   Compared with the simulation results which obtained at week 2, we can figure out that there are existing some error with out calculation because the graph of "x=π/2" is wrong. Meanwhile, there are existing some strange points which can be easier found by change the results from 2D to 3D, eg.fo=1GHz, x=2*pi/2.
   
   We have checked our edited equations and relative paper, no error was founded and our supervisor will check it in later few days. Although there are some error in the calculation of input reflection, it will not influences our next research stage. 
4. Our group began to developing the interface of "power divider calculator" by using the software "Matlab". The operation interface is shown below:
   
   We have built a graphical user interface (GUI) to design our "power divider calculator", there are three input options: number of output;fundamental frequency in GHz and transmission line's length in degree. The graph of input reflection will be shown at the right after input parameters and push "calculate" button. The codes of the GUI are shown below:
   
   The codes which are lighting on are used to linking our previous calculation codes with the GUI. Thus the interface can calculate the results by calling the calculation codes. 
5. After completing the design of "power divider calculator" interface, we began to debugging by several times of calculation. The results show that the codes for the GUI is successful while the calculation results still existing error just like I mentioned previous. We will try to figure out the reason in later days and then modify the original calculation codes. Hence a calculation results will be shown below with "fo=1 GHz" and "x=0 in degree":
   
   It can be found that value of "Number of output" is in blank, the reason is that we just focus on the four way power divider for this week so the default value for outputs number is 4. We will improve this function at next week, aiming at customer can calculate the input reflection for multiple inputs as they want.