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Rochester Institute of Technology
Electrical Engineering
Jared P. Burdick
February 2012
Senior Design Project Proposal – RF/Microwave Mixer Evaluation
Overview
The project being proposed is to meet the Senior Design Project II (4 credit hours) requirement for completion
of my BSEE.
This project has been developed with the cooperation of my current employer, Dielectric Labs (DLI) of
Cazenovia, NY. DLI is a leading supplier of high performance RF ceramic chip capacitors, RF filters and custom
thin-film ceramic substrates. This project has the full support of DLI and my supervisor, Mr. Steve Randall (R&D
Manager), who will provide technical support and guidance. I may also seek additional support from another
local company, Anaren, who has competence with this product and will ultimately supply test resources
(equipment) to complete the electrical evaluation. My father is President of Anaren’s Wireless Group and has
committed that support. Anaren is a leading supplier of RF/Microwave components and subsystems to the
Wireless, Space, and Defense markets.
RF mixers are key functional blocks of most communication, radar, and radio applications. They allow
conversion of high frequency signals (Input Signal or RF) to much lower frequencies (Output Signal or “IF”) which
are then suitable for subsequent processing of the information (e.g. sampling by an A/D). Similar products,
called modulators are used for the reverse function, to convert the IF back to RF for transmission. This is
accomplished by use of a fixed (generally) signal (Local Oscillator or “LO”) which is connected to the RF signal
using one or more diodes (mixer configuration dependant). The diodes supply the non-linear element required
to produce the RF-LO and RF+LO outputs, plus numerous harmonic tones referred (inter-modulation products).
(RF)
Typical Mixer
Representation
(IF)
(LO)
This project will evaluate several mixer configurations. Those configurations will be determined later, as a key
element of the project is research and study of the trade-offs between different types (Single-balanced, doublebalanced, Quadrature IF as examples) as well as physical implementations.
Project progress will be provided to RIT as required and final submission will consist of a full report including
theory of operation, design decisions (trade-offs), simulated performance, actual measured performance and
discussion of results. It is expected that this project will take 3 to 4 months to complete.
Project Objectives
1. Research, design, simulate, manufacture and evaluate several implementations of RF mixers, used for
frequency conversion applications.
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2. Understand performance trade-offs for different mixer configurations, physical implementations and
manufacturing tolerances). Use this information to make intelligent decisions relative to the final designs.
3. Evaluate several configurations and/or implementations and provide a comparison against theoretical &
simulated performance as well as comparing and contrasting the performance of the chosen
configurations/implementations.
4. Develop competency for design and simulation of RF components using various CAE tools (primarily Sonnet
and Ansoft HFSS).
Key Tasks
1. Conduct research on mixers; including theory of operation, applications, configurations, and major design
trade-offs. This will consist of technical papers, industry articles, and manufacturer’s application notes, etc.
2. Define mixer configurations (2 or 3) to be evaluated - which offer specific advantages for optimization of key
parameters (e.g. image rejection vs. conversion loss).
3. Finalize Mixer electrical and package requirements for each implementation.
4. Research candidate materials (substrates, diodes, connectors, etc.) and manufacturing requirements and
capabilities/limitations:
o Ceramic processing capabilities available: dielectric constants, thicknesses, metal make-ups, linewidths and gaps, etc.
o Soft-board (PTFE-based) process capabilities: dielectric constants, thicknesses, etched line-widths
and gaps, etc.
o Manufacturing capabilities: wire- or wedge- bonding, soldering, etc.
o Diodes available: performance, package style conducive to manufacturing process (i.e. wirebonding or soldering).
o Other components: RF connectors, passive components vs. printed, etc.
5. Evaluate potential implementations against available materials/capabilities and finalize designs to be
evaluated.
6. Design and simulate all selected configurations using available CAE tools. Optimize the designs as much as
possible (iterate as needed) to maximize performance of each configuration.
7. Develop a test plan for the prototypes – includes mechanical and electrical measurements.
8. Characterize any components independently, if possible (e.g. diodes).
9. Manufacture the prototypes. Compare the physical units against the design assumptions to determine any
significant differences (i.e. circuit-trace dimensions, component locations, wire-bond lengths, etc.).
10. Perform electrical performance measurements. Process the data and present it in easily understandable
formats (e.g. plots vs. frequency, or power levels, etc.).
11. Analyze the data against simulated performance. Understand significant differences and modify design or
repair prototype as needed – insure that the performance is as expected and not due to an error in
manufacturing. If necessary, re-simulate performance with actual physical dimensions to seek correlation.
12. Prepare a final report detailing the entire process, with summaries of theory, design process, simulations,
measured results and a discussion of the actual vs. expected performance. Compare and contrast the
implementations and their impact on the various performance parameters. Submit the prototype devices
with the report.
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