Introduction to RF Electronics
Special Topics in ECE: RF Electronics
Laboratory Exercise No. 1
Genesys and Passive Filter Design
Equipment Required: Genesys software. DipTrace software.
Objectives
1. Learn how to use the Genesys software package.
2. Demonstrate the ability to design a passive filter to meet a set of requirements using the
techniques discussed in the textbook/class.
3. Develop the skill to design and analyze passive filters using the Genesys software.
4. Learn how to layout the filter design for PCB fabrication.
Introduction
Filter design is an essential aspect of RF electronics. It is common to see filters used on the receiver
input to limit interference from other services and minimize noise. Filters are also used after the
mixer to select the correct intermediate frequency. In a full-duplex radio system (simultaneous
transmit and receive), a filter is required to prevent the transmitted signal from directly entering
the receiver.
In this lab, we explore passive filter design using both lumped and distributed devices. In
addition to the traditional hand-design of filters from tables, we will utilize computerd-aided design
technique using the Genesys software.
Passive Filter Design By Hand
Use the techniques developed in class to design a bandpass filter by hand. Predict the operating
characteristics of this filter design. Using the schematic drawing portion of Genesys, put your
design into the software and analyze its performance. Compare your predicted performance with
that of the Genesys software. In detail,
• Design a bandpass Butterworth maximally flat with a passband from 420 - 450 MHz. Do not
exceed a third-order design.
• Predict the performance of your design with hand calculations. Specifically, determine the
transfer function of the bandpass filter.
• Put the design into Genesys through the Schematic worksheet.
• Analyze the performance of your filter using the Genesys software and compare it to your
hand calculations. Comment.
• Compare S21 to S12 and comment on the results.
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Introduction to RF Electronics
Special Topics in ECE: RF Electronics
Genesys Passive Filter Synthesis
Use the Passive Filter synthesis section of Genesys to create a filter that meets the requirements in
the first bullet above. Compare the performance of several different filter types (at least three) and
comment on how the performance varies as a function of different filters and different filter orders.
Quantify the performance of the various filters by calculating the filter parameters discussed in
class, e.g., insertion loss, ripple, bandwidth, shape factor, etc.
Genesys S/Filter Synthesis
Do the same calculations as above but using the S/Filter synthesis section of Genesys. In addition,
create a distributed parameter version of the filter and compare its performance to the lumped
version.
Board Layout
Using DipTrace software, design boards to fabricate the lumped as well as the distributed versions
of the bandpass filter.
Graduate Students
Design 3-4 straight transmission lines for analysis in the undergraduate course in Engineering
Electromagnetics (EEMAG). Assume the operating frequency is 500 MHz. Design lines with Z0 =
50Ω, an unknown Z0 , and a line that has an electrical length of λ/8 that could be terminated in a
short or open to act as an inductor or capacitor.
Laboratory Write-up
Content is more important than form. It is important that you explain your results. Handing
in excellent data without explanations is not sufficient. There should be an introduction to the
lab, figures of results, circuit designs with component values, an explanation for each figure, and
a summary of what you learned in the exercise. If you want a specific format, consider using the
IEEE style sets for transaction publications.
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