Which type of losses are common in two-wire and coaxial lines, but are reduced in waveguides?

In two-wire and coaxial lines, Copper (I²R) losses are prevalent due to the resistance of the conductors through which electrical current flows. These losses manifest as heat, which occurs when current passes through a conductor and encounters resistance, causing a reduction in signal strength and efficiency over longer distances.

Waveguides, on the other hand, are designed to transmit electromagnetic waves with minimal loss. They operate under the principle of guiding waves along certain paths and do not have the same electrical resistance issues as traditional conductors. Because waveguides rely more on the transmission of electromagnetic waves rather than current flow through a material, the resistive losses associated with the conductor material are significantly reduced.

This difference in operating principle and physical structure accounts for the decrease in resistive losses within waveguides compared to two-wire and coaxial systems. In waveguides, energy is transferred by means of the electric and magnetic fields rather than by the physical flow of electrons, making them more efficient for high-frequency applications.