# ECE 488

## Microwave Engineering II: Active Circuit Design

**Usually offered:**Spring

**Required course:** No

### Course Level

### Units

### Instructor(s)

### Prerequisite(s)

### Course Texts

Microwave and RF Design – A System Approach, Michael Steer, SciTech Publishing.

Suggested Readings:

- Microwave Transistor Amplifiers 2nd Edition, Guillermo Gonzales, Prentice-Hall, 1997.
- Nonlinear Microwave Circuits, Stephan Maas, IEEE Press.

Class Web-site: D2L

### Schedule

### Course Description

**Specific Course Information:****2021-2022 Catalog Data: **Planar active microwave circuits, diode and transistor characteristics, mixers, amps, oscillators, and frequency multipliers. Students will design circuits with CAD tools, fabricate in clean room, and measure performance in the lab.

### Learning Outcomes

**Specific Goals for the Course:****Outcomes of Instruction:** By the end of this course the student will be able to:

- Understand various modulation schemes; basics of wireless transmitters & receivers; basics of Antennas & wireless link; fundamentals of RF systems.
- Design lumped element matching networks; Design single and double stub matching networks for various loads; Create all active circuit designs in microstrip form.
- Apply single / double stub matching network designs for circuits in microstrip form.
- Identify the diode equation and the small signal model and equivalent circuit.
- Explain the role and operation of the depletion and diffusion capacitance.
- Describe the operation of a Schottky barrier diode and Explain how diodes can be used for RF/microwave signal detection and mixing.
- Identify the various types of microwave mixers, as well as parameters used for the evaluation of their performance. Design a single diode microwave mixer, a balanced microwave mixer, a sub- harmonic microwave mixer, and a microstrip mixer.
- Determine the type of diode needs to be used for a specific microwave mixer design; Describe the characteristics of Bipolar and FET microwave transistors.
- Identify the small-signal electric models of microwave transistors; Apply the transistor model to evaluate its S-parameters; Explain how the S-parameters of a transistor can be measured.
- Apply signal flow graphs to evaluate scattering and other parameters of microwave circuits.
- Identify the different power gain expressions of microwave amplifier circuits.
- Calculate power gain expressions of a microwave amplifier from S-parameters.
- Calculate the input and output VSWR of a microwave amplifier.
- Determine the stability of an amplifier from the transistor, matching networks, and terminations; Explain when a two-part network is unilateral.
- Outline the procedure for drawing the constant G circles for the unconditionally stable & potentially unstable cases; Identify & evaluate the unilateral figure of merit.
- Design a microwave amplifier with a) maximum transducer power gain and b) for a specific operating power gain both for an unconditionally stable and potentially unstable cases and c) for a specific available power gain and with a specific gain and input/output VSWR.
- Plot power gain circles for a two-port network.
- Design a DC bias network for a microwave amplifier.
- Calculate noise parameters in microwave circuits and systems; Design a low-noise microwave amplifier using constant noise figure circles.
- Design a microwave amplifier with good ac performance (noise figure, available power gain, power output and input/output VSWR) and a broadband microwave amplifier and a feedback microwave amplifier.
- Distinguish between class A, B, and C microwave amplifiers.
- Design a microwave power amplifier; Identify intermodulation distortion.
- Evaluate the dynamic range of a microwave amplifier; Design a two-stage microwave amplifier; List and describe oscillation conditions.
- Describe and Design the operation of one-port and two-port negative resistance oscillators.
- Apply the Nyquist test to determine conditions for unstable operations of a given circuit;
- Identify different commonly used oscillator configurations; Explain the operation of varactor frequency multiplier; Design a balanced microwave multiplier.
- Determine which active microwave circuit to use depending on the application.
- Perform microwave measurements for the active circuit of the design project.
- Propose solutions to meet specific design goals if those were not met at first design iteration.

### Course Topics

**Brief list of topics to be covered:**

Introduction of Modulation Techniques; Digital Modulation I and II; Receivers, Modulators and Demodulators; Antennas; Radio Link and Systems; Cellular Radio: 1G – 3G and Beyond 3G and Radar; Matching Networks; Microstrip Matching Networks; Microwave Transistors; Scattering Parameters and Signal Flow Graphs; Power Gain Expressions and VSWR Calculations; Stability Considerations; Constant Gain Circles; Simultaneous Conjugate Match; Operating Power Gain Circles; Available Power Gain Circles; VSWR Circles and DC Bias Networks; Noise in Microwave Systems; Constant Noise Figure Circles; Design of Low-Noise Amplifier; Broad- Band Amplifier Design; High-Power Amplifier Design; Two-Stage Amplifier Design; Oscillation Condition.

### Relationship to Student Outcomes

ECE 488 contributes directly to the following specific electrical and computer engineering student outcomes of the ECE department:

1. An ability to identify, formulate, and solve complex engineering problems by applying principles of engineering, science, and mathematics.

3. An ability to communicate effectively with a range of audiences.

6. An ability to develop and conduct appropriate experimentation, analyze and interpret data, and use engineering judgment to draw conclusions