ENGINEERING TRIPOS PART IIA –
Module 3B1 – Radio Frequency
Modern communication products such as radios, mobile ‘phones and GPS
receivers utilise circuitry which operates at very high frequencies. This course aims to give an introduction to
circuit architecture, operation and design techniques used for signals ranging
from the audio range up to microwave frequencies ie. kHz – GHz. Also included is some material on antenna
operation and design, a key part of radio systems.
Transistor characteristics and circuit design: JFET,
MOSFET and Bipolar devices. High
frequency performance and the Miller Effect, input and output impedances.
Multiple transistor circuits: cascaded amplifiers,
current sources and differential amplifiers.
Filters: operational amplifier VCVS filters, resonant
circuits, gyrators, ceramic.
Oscillators: relaxation, Wein Bridge, resonant –
negative impedance, Colpitts, quartz crystal, voltage controlled oscillators,
phase locked loop.
Impedance matching: LC circuits, transformers,
Radio architecture: ‘crystal set’, Superhet, digital
Mixer circuits: simple diode, Gilbert cell, diode ring,
dual gate MOSFET.
Modulation and demodulation schemes: AM, FM, PSK, FSK
and circuits: F®V,
diodes, multipliers, PLL.
Microwave circuit techniques: microstrip and stripline,
characteristic impedance, s & z parameters, Smith chart.
Antenna principles and design: dipole, microstrip
patch, helical, array antennas.
On completion of the course students should be able to:-
Understand the various characteristics of transistors
including high frequency effects and circuit techniques which exploit them.
Explain the Miller effect and how it influences the
Design basic multiple transistor circuits and to
calculate their output and input impedances.
Know the disadvantages and advantages of positive
Explain how to make single and variable frequency
Design simple RF impedance matching circuits including
the use of Smith charts.
Understand the architecture and circuits used in radio
applications and be able to design simple functional blocks.
Know the basic theory and design principles of
microstrip, stripline and antenna structures.
The module is accompanied by the lab experiment: ‘Superhet radio’ situated
in the Electrical and Information Engineering Teaching Laboratory (EIETL).
Please see the Booklist for Part IIA Courses for references for this module.
Last updated: June 2012