38.1 Transmission lines38.1.1 Primary line constants38.1.2 Propagation constant and characteristic impedance38.1.3 Reflection coefficient, standing waves and return loss38.1.4 Voltage standing wave ratio (VSWR)38.2 Smith’s charts38.3 Waveguides38.3.1 Cut-off frequency, dominant or fundamental and second-order modes38.3.2 Resonant cavities and waveguide couplings38.3.3 Waveguide parameters38.4 Miscellaneous terms38.5 Useful references