58532 - Microwaves L-A

Learning outcomes

The students will acquire the knowledge of the main aspects regarding the design of RF/microwave circuits. They will also reach the capability of using a typical program for microwave CAD.

Course contents

A. General background on Microwaves: Definitions. Applications of microwaves. From waveguides to hybrid integrated circuits.

B. Impedance matching: Transmission lines. Smith Chart. Stub matching networks. Quarter-wave matching network. Impedance matching with lumped elements.

C. Circuit matrices: Impedance, admittance and chain (ABCD) matrices. Scattering matrix and its properties.

D. Microwave CAD: Circuit simulation and design. Numerical optimization and algorithms.

E. Transmission lines for planar circuits: TEM propagation. The stripline. Quasi-TEM propagation. The microstrip. Dispersion in microstrip. Equivalent-guide model for microstrip.

F. Microwave filters: Ideal filters. Prototype filters. Frequency transformations. Synthesis of lumped-element filters. Design formulas. Transmission line filters: Variable line width filters and stub filters. Filters with impedance inverters. End-coupled filters.

G. Low-noise amplifiers: Semiconductor devices for microwave applications. MESFET: basic principles. Small-signal amplifiers: stability, gain and noise. Graphic design.

H. Directional couplers: Ideal and real couplers. Definitions, properties and applications.

I. Selected topics in microwave CAD: Monolithic microwave integrated circuits. CAD requirements for MMICs. Discontinuities in microwave integrated circuits. Distributed topologies. Electromagnetic simulation. Nonlinear microwave circuits. Harmonic-balance method. Introduction to power amplifiers

Laboratory activities:

- Introduction to a commercial software tool for RF/microwave-circuits CAD

- Computer-aided synthesis of the main classes of matching networks

- Computer-aided synthesis of planar transmission lines

- Numerical optimization of a wide-band matching network

- Synthesis and simulation of lumped-element filters

- Design of transmission-line filters. Numerical optimization

- Small-signal simulation of a microwave MESFET

- Narrow-band design of a low-noise amplifier. Wide-band numerical optimization

- Introduction of discontinuities in the designed circuits. Performance optimization.

Readings/Bibliography

V. Rizzoli, A. Lipparini, Propagazione elettromagnetica guidata, Esculapio

Fred Gardiol, Introduction to Microwaves, Artech House

R.E. Collin, Foundations for Microwave Engineering, 2 ed. McGraw-Hill

Teaching methods

The course proposes to yield the basic knowledge for the study and the design of RF/microwave circuits for telecommunications. The lessons illustrate the operating principles of the planar transmission lines and the of mostly used active devices. Some fundamental circuit functions are presented (matching, filtering, amplifying). The theoretical subjects are complemented by laboratory exercises based on the use of a typical commercial software package for RF/microwave circuit design.

Assessment methods

The examination consists of a laboratory test including exercises of the same kind as those developed during the course, and an oral discussion.

Teaching tools

Lection notes. Commercial software package for RF/microwave CAD: Ansoft Designer SV (Student Version, available to the students in the same configuration as used in the laboratory).

Office hours

See the website of Andrea Neri