代做ENG5056 Lab 3 Sheet – Impedance Matching and Multi-Port Networks代写C/C++编程

ENG5056 Lab 3 Sheet – Impedance Matching and Multi-Port Networks

Measurement and Simulation

Lab Assignment 3: Filters, Matching Network Design, and Resonant Circuits Characterisation

In the previous labs, you have modelled transmission lines which were mostly matched and are theoretically frequency-independent.  This lab focuses on the design and analysis of frequency-dependent and resonant components including basic resonators, matching networks, and filters.

You will learn:

1.    How to design matching networks for complex impedance loads.

2.    Observe the frequency limitations of different matching topologies.

3.    Design and understand the operation limits of filters, particularly in practical systems.

The scheduled lab sessions are an opportunity to familiarise yourself with the software and ask questions. You should spend time outside the lab carrying out the exercise and writing your report.

Refer to lab 1 for software installation and getting started instructions.

1. Assignment Tasks:

Your test PCBs included non-50 Ohm transmission lines, e.g. Line 2 and Line 4. In addition, Line 3 exhibits a periodic behaviour with filtering properties.

You will work with the modelled and measured s-parameters of these devices to design matching networks and filters. In the labs, you can start by measuring Line 3 on your PCB and observing the provided touchstone files on Moodle.

Start  by  measuring  the  response  of Line 3,  and  compare your  NanoVNA  measurements  to the provided s-parameters

Present the following in your report and discussions:

Matching Networks Design:

1.    Impedance matching design:

a.    Design an input matching network for the CPW line on your board (line 2) to achieve an input impedance of 50 Ohms at 550 MHz. Use both the ADS CPW model and the provided measured s-parameters on Moodle.

i.    Present an LC matching network design.

ii.    Implement a practical version of this matching network using real L/C parts.

1.    You are free to import or use whichever model is available for the LC elements,  but  the  parasitic  values  must  be  discussed,  and  the accuracy of this approach should be critically evaluated.

iii.    Present the S11 and S21 response of the line before and after your matching network is included.

1.    Present the results for both the closed-form. model and the measured touchstones files.

b.    Repeat your design process for 5 GHz.

i.    Present the s-parameters of your newly matched line.

ii.    In your report, compare and discuss the differences between the matching network design at 550 MHz and 5 GHz.

1.    Useful points to consider include the fractional bandwidth, matching quality |S11|, component values.

Multi-Port Devices Design:

Exploiting the periodic behaviour in Line 3 could be used to realise very basic band-stop filters. Building upon your models from lab 1:

1.    Using the microstrip line models, in the same PCB process as your test boards, design a two- way balanced power divider with a centre frequency of 1 GHz.

a.    Present the  input and output  matching parameters including the  10 dB return loss bandwidth of the power divider.

i.       Make sure to clearly show the insertion losses and isolation.

ii.       Include the dimensions of your lines and explain how they were calculated.

iii.       Discuss any deviations from the expected line length in order to achieve a

1.5 GHz power splitter.

b.    Compare the isolation between the output ports with and without resistors.

Another common example of multi-port devices is adiplexer:

2.    Use your knowledge of the band-stop filters to design a two-way diplexer with the following specifications:

a.    The input needs to maintain an VSWR<3.

b.   The output ports need to pass signals (with under -3 dB) loss, at 1 and 2 GHz, each.

c.    The out-of-band rejection for the other signal should be over 20 dB.

d.    Hint: refer to Line 3 on your board for an example of a band-stop filter.

Conclusions and Discussions:

Justify the component choice in your matching network, comment on practical layout considerations, and  discuss  alternative  technologies  for   implementing  the   matching   network.  You   should  also comment  on  the  suitability  of   measured  vs.   modelled  s-parameter  files  in  designing   matching networks. For the passive multi-port network design, you should discuss the practical limitations of your model, design error sources,  potential discrepancies  between simulation and  measurements (using Line 3 on your PCB), and highlight the limits governing the specifications for filters, dividers, and diplexers. The impact of the performance of such devices in a microwave frontend (including active devices such as PAs/LNAs) should be discussed. Careful discussions area large part of this assignment and you should make use of external references and resources to present a complete discussion.

3. Assignment Submission and Deliverables:

You need to submit a report on Moodle detailing the results of the simulation tasks in this document, and commentary on the measurements (see the Moodle page for the submission deadline). Refer to the Assignment Tasks section marking scheme (Appendix A) for the exact tasks that must be included in the report.

For this report, present your results as follows:

•    Present any data files in a figure with a detailed caption.

•    Your report should be no longer than 8 A4 pages.

o Any overlength content will result in a penalty and may not be marked.

o If using MS Word, adhere to: font size 11, calibri/arial font, and >1 line spacing.

o If using Latex, you can use the standard report template, or an IEEE Paper template (which is often more space efficient).

•    It is advisable to use the marking scheme headings to structure your report, to ensure you do not miss any key criteria.

Appendix A: Marking Scheme.

Assessment	Excellent	Good	Poor	Absent
EDA tool use
Model parameters and part choice for the LC matching circuits		1	0.5	0
S-parameter setup for 3-port device simulations		1	0.5	0
Results – Matching
Achieved return loss  and insertion   loss, using both simulated and measured s-parameters, at 500 MHz.	3	2	0.5	0
Achieved matching performance at 5 GHz	2	1.5	0.5	0
Comparison of ideal vs. practical matching at 500 MHz using      LC      components      including      the layout considerations	3	2	0.5	0
Results – Multi-Port Device Design
Achieved  return  loss and  insertion  loss of the  power splitter, including port isolation comparisons	3	2	0.5	0
Achieved diplexer performance across both frequency bands.	3	2	0.5	0
Analysis and discussion
Discussion   of the   limitations   of   lumped   elements matching and    its suitability for    microwave    and mmWave circuits.	3	2	0.5	0
Discussion of multi-port network design challenges and inaccuracies.  You  should list  at least 3 well-justified parameters.	3	2	0.5	0
Conclusions: general commentary on the limitations of the EDA    tool     used,    the     design methodology, comparison   with   industry/research-standard   design processes for complex passive components.	3	1.5	0.5	0
Total (out of 25)

The total  mark for this  report  is  worth  10%  of the  course’s  assessment.  Unless  you are enjoying yourself, you should try not to spend more than 20 hours on this assignment.