Basics of RF Engineering, 5 cr

Core content

• TRANSMISSION LINE (TL) THEORY. Typical use of TLs and practical cables and planar structures. Basic TL concepts and parameters e.g. distributed circuit parameters, Telegrapher's equations, propagation constant, characteristic impedance, phase velocity, wavelength, input impedance, reflection at impedance discontinuity, return loss, reflection (mismatch) loss, and properties of lossy transmission lines. Replacing inductors and capacitors with transmission line elements. Their effective capacitance and inductance, respectively. Properties of quarter wave and half wave lines. Generator properties: Thévenin equivalent and available power.
• SMITH CHART (SC). Normalized impedance. Drawing and reading impedances and reflection coefficients and other related parameters on the SC. Normalized admittance. Impedance locus as a function of frequency. Use of SC in designing simple impedance matching circuits.

• IMPEDANCE MATCHING. The advantages of impedance matching. Simple impedance matching techniques: lumped element matching, distributed element matching, resistive vs. reactive matching. Use of simulation tools (e.g. ADS) in analysis of simple RF circuits.
• SCATTERING (S) PARAMETERS AND GAIN CONCEPTS. Definition of S-parameters, reasons for using S-parameters. Applications of S-parameters. Determination of S-parameters of simple (and arbitrary) S-networks. Gain definitions: power gain, available power gain, transducer power gain; and their relation to S-parameters.
  

Complementary knowledge

• Wave trap (bandstop filter). Effective dielectric constant of microstrip line and its relation to the wavelength in this media.
• How the Smith chart is made? Mathematics behind it.
• Bandwidth of impedance matching. Free-ware design tools.
• Unilateral transducer power gain (Gtu), maximum Gtu. Stability of two-ports, Mu-test and use of stability factors and stability circles.