# report代做 | project作业 | oop代写 – Design Project #1: Coupled Line Couplers

### Design Project #1: Coupled Line Couplers

report代做 | project作业 | oop代写 – 这是一个report面向对象设计的practice, 考察report的理解, 涵盖了report等程序代做方面, 这个项目是project代写的代写题目

### Due date: March 28 th, 2022

##### project SCOPE

Design a coupled-line coupler with the following specifications: Number of sections 3& 5 Center frequency 1 GHz Coupling -1 2 dB Port impedance 50 Frequency response Maximally Flat PROJECT TASKS:

``````A. Design
``````

1) Determine the odd and even mode impedances for each of the 3/ 5 sections. The coupling coefficients for each section of this multi-section coupler are: 3 – sections coupler 5 – sections coupler

#### c^5 =^

The odd and even mode impedances of each section are thus: 3 – sections coupler 5 – sections coupler

section (^) () () 1 2 3 section (^) () ()

#### 5

``````B. Implementation Based on Ideal Coupled Lines
``````

2) Implement both designs (3 and 5 sections) in Keysight ADS. We will start with the ideal behavior using ideal coupled lines (CLIN). Instructions on how to use ADS is at the end of this document.

3) Plot S 11 , S 21 , S 31 and S 41 (in dB) from 0 to 2 GHz, using a vertical scale from – 50 dB to 0 dB for both couplers for plotting S 21 & S 31 , and a vertical scale of – dB to -300dB for S 11 and S 41.

``````(Insert figures here)
``````

Q1: Do these results indicate that your design is correct? Explain why you think so. Give specific numerical examples from each plot.

4) Use the markers to determine the bandwidth of your design, given that the coupling must be numerically less than 15 dB to satisfy specifications (i.e., a 3 dB bandwidth).

The bandwidth of this coupler has been determined in ADS to be:

``````Coupler Bandwidth = (Insert value here) GHz
``````
``````(Attach accompanying figure(s) here)
``````

C. Signal Flow Graph Analysis 5) Draw an exact signal flow graph of this (4-port) directional coupler. In other words, a signal flow graph of the form below, where c is the specific coupling coefficient of this coupler at the design frequency.

``````(Write signal flow graph here)
``````

6) Reduce this signal flow graph for the case where ports 2, 3, and 4 are terminated in matched loads ( L2 = L3 = L4 ) and determine in decibels the numeric values of S 11 , S 21 , S 31 and S 41 , at the design frequency.

The reduced signal flow graph for this coupler circuit at the design frequency of 1 GHz is:

``````(Show reduced signal flow graph here)
``````

From these results, the values of S 11 , S 21 , S 31 and S 41 (at 1 GHz) were determined to be (in decibels):

Q2: Do these values precisely match those provided by the ADS analysis? Why or why not?

``````(Give your explicit, detailed answer here)
``````

7) Now attach a short circuit ( L4 = – 1 ) to port 4 of the coupler signal flow graph (with ports 2 and 3 again terminated in matched loads). Reduce this graph and determine in decibels the numeric values of |S 11 |^2 , |S 21 |^2 , |S 31 |^2 , at the design frequency.

The reduced signal flow graph for this coupler circuit at the design frequency of 1 GHz is:

``````S 11 (dB)=
S 21 (dB)=
S 31 (dB)=
S 41 (dB)=
``````

(Show reduced signal flow graph here)

From these results, the values of S 11 , S 21 , and S 31 (at 1 GHz) were determined to be (in decibels):

8) Likewise place a short circuit on port 4 of your ADS designyou now have a 3-port device! Replot S 11 , S 21 , and S 31 (in dB) from 0 to 2 GHz, using the same vertical scale as before. Do not plot S 41!

``````(Attach accompanying figure(s) here)
``````

Q3: How do these new results compare to the case where port 4 is terminated in a matched load (i.e., tasks 2 and 5)? Use your knowledge of the physical behavior of coupled-line couplersincluding any physical insight provided by the signal flow graph of task 7to explain why you get this result. What physically happens to a wave incident on port 1, once it is inside the coupler?

``````(Provide your specific, detailed answer here)
``````

9) Now attach a short circuit ( L2 = – 1 ) to port 2 of the coupler signal flow graph (with ports 2 and 4 terminated in matched loads). Reduce this graph and determine in decibels the numeric values of S 11 , S 31 , S 41 , at the design frequency.

The reduced signal flow graph for this coupler circuit at the design frequency of 1 GHz is:

``````(Show reduced signal flow graph here)
``````
``````S 11 (dB)=
S 21 (dB)=
S 31 (dB)=
``````

From these results, the values of S 11 , S 31 and S 41 (at 1 GHz) were determined to be (in decibels):

10) Likewise place a short circuit on port 2 of your ADS designyou now have a 3-port device! Replot S 11 , S 31 and S 41 (in dB) from 0 to 2 GHz, using the same vertical scale as before. Do not plot S 21

``````(Attach accompanying figure(s) here)
``````

Q4: How do these new results compare to the case where port 2 is terminated in a matched load (i.e., tasks 2 and 5)? Use your knowledge of the physical behavior of coupled-line couplersincluding any physical insight provided by the signal flow graph of task 9to explain why you get this result. What physically happens to a wave incident on port 1, once it is inside the coupler?

``````(Provide your specific, detailed answer here)
``````
``````D. Actual Microstrip Implementation
****Please watch the educational video using the following link

``````

D.1) Using ADS, implement the 3 sections and 5 sections coupler using microstrip coupled lines (MCLIN). Please note that several steps might be needed to achieve convergence when using linecalc since the line spacing might be small to converge. Also note that to connect different pairs of coupled lines, you will need to use some forms of bends or tapers, these can be found in the library as (MSOBND_MDS; MTAPER; MCURVE2)

``````S 11 (dB) =
S 31 (dB) =
S 41 (dB) =
``````

For board material, assume FR Thickness: H =1.57mm Relative Dielectric Const. r= 4.4 (note: r has frequency dependence) Relative Permeability: Mur= Dielectric loss Tangent: TanD=0. Copper Conductivity: 6e7 s/m Metal Thickness: T: 17.5um (for oz copper)

D.2) Discuss the design challenges of the 5 sections compared to the 3 sections? Please note that in the implementation, when you add transitions going from one section to the other, these transitions will change your design parameters. You should be able to see that during EM simulations. Build the whole design using the layout tool and perform full electromagnetic simulations on the structure.