Course detail

High Frequency Techniques

FEKT-BPC-VFTAcad. year: 2023/2024

The course is focused on design basics of passive and active high frequency circuits working up to approx. 3 GHz. First part is dedicated to passive circuits: resonant circuits and matching networks, attenuators, splitters, combiners and HF switches. Second part is focused on amplifiers, mixers, oscillators and frequency synthesizers.

Language of instruction


Number of ECTS credits


Mode of study

Not applicable.

Entry knowledge

The student should be able to:
- explain basics of electronic circuits and electromagnetic waves and transmission lines (inductance, capacitance, impedance, reflection coefficient, Smith chart, standing wave ratio)
- analyze basic electronic circuits with passive components
- calculate with complex numbers and logarithms

Rules for evaluation and completion of the course

- measurements in laboratory: 20 points (5 exercises x 4 pts)
- written tests: 1x14 points
- final exam: 66 points
The final exam consists of 2 parts: 30 points in theoretical part, 36 points in numerical examples. The student must get min. half points of each part to pass the exam successfully.
In the case of forced online teaching, the attendance parts would be suplemented by distance online alternatives.
Evaluation of activities is specified by a regulation, which is issued by the lecturer responsible for the course annually.


The aim of the course is to make students familiar with basics of passive and active high frequency circuits.
After successful passing the final exam, the student should be able to:
- calculate power, voltage and current levels in decibels
- describe important electrical parameters of wire, coil and capacitor from the high frequency point of view
- explain behavior and electrical parameters of series and parallel resonant circuit as well as coupled resonant circuits
- explain principle and show examples of lumped element filters
- using the Smith chart, explain principle of impedance transformation with parallel resonant circuit, L-network, T-network and PI-network
- explain principle and describe important parameters of attenuator, HF power combiner and switch
- explain terms: stability and gain of linearized amplifier
- explain and calculate with important parameter of amplifier (dynamic range, intercept point, 1dB compression, noise figure)
- explain terms: mixer and its output spectrum, conversion loss, conversion gain, image frequency and draw basic mixer schematics
- explain principle of feedback oscillators and draw basic schematics of LC and crystal oscillators
- explain terms: phase noise and stability of HF signal
- draw basic schematics of PLL and DDS syntehsizers
- explain principle and important parameters of PLL and DDS systems

Study aids

Not applicable.

Prerequisites and corequisites

Not applicable.

Basic literature

VÁGNER, P. Vysokofrekvenční technika. Skripta [online]. 2013 [cit. 2017-08-12]. Dostupné z elearningových stránek předmětu. (CS)
VÁGNER, P. Vysokofrekvenční technika. Skripta FEKT VUT, 2013. (CS)

Recommended reading

RADMANESH, M., M. RF & Microwave Design Essentials. AuthorHouse 2007. (EN)
RADMANESH, M., M. Advanced RF & Microwave Circuit Design. AuthorHouse 2010. (EN)
HANUS, S., SVAČINA, J. Vysokofrekvenční a mikrovlnná technika. Skripta FEKT VUT v Brně, 2002, ISBN: 80-214-2222-X (CS)
ŽALUD, V. Moderní radioelektronika. Vydavatelství BEN, Praha 2000 (CS)


Classification of course in study plans

  • Programme BPC-MET Bachelor's, any year of study, winter semester, elective
  • Programme BPC-EKT Bachelor's, 3. year of study, winter semester, compulsory

Type of course unit



26 hours, optionally

Teacher / Lecturer


1. Gain and signal level. Series and parallel resonant circuit
2. Impedance transformation using parallel resonant circuit
3. Coupled resonant circuits. Power and impedance matching using RLC circuits
4. Power splitters and combiners, attenuators and HF switches
5. Linearized transistor model. S-parameters
6. Stability, stability circles, gain, constant gain circles
7. Noise in circuits. Noise temperature, noise figure. Noise matching
8. Narrowband and broadband amplifier. Low noise amplifier
9. Large signal amplifier. Operating classes, main parameters
10. Mixer and its output spectrum, mixer parameters. Mixer schematics
11. Transistor oscillators, fixed and tunable oscillators
12. Phase locked loop. PLL synthesizers
13. Direct digital synthesis DDS

Laboratory exercise

13 hours, compulsory

Teacher / Lecturer


Nonlinear amplifier
Linear amplifier
Resonant circuits
Double balanced mixer
PLL synthesizer