Explain Resistive loss and Dielectric loss in detail.
1 Answer


Resistive loss:

  • Resistive losses within the coax cable arise from the resistance of the conductors and the current flowing in the conductor results in heat being dissipated.

  • The actual area through which the current flows in the conductor is limited by the skin effect, which becomes progressively more apparent as the frequency rises.

  • To help overcome this multi-stranded conductors are often used.

  • To reduce the level of loss due to the coax cable, the conductive area must be increased and this results in low-loss coax cables being made larger.

  • However, it is found that the resistive losses increase as the square root of the frequency.

Dielectric loss:

  • The dielectric loss represents another of the major losses arising in most coax cables.

  • Again the power is lost as dielectric loss is dissipated as heat.

  • It is found that the dielectric loss is independent of the size of the RF cable, but it does increase linearly with frequency.

  • This means that resistive losses normally dominate at lower frequencies.

  • However as resistive losses increase as the square root of frequency, and dielectric losses increase linearly, the dielectric losses dominate at higher frequencies.

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