Transmission lines are arrangements of conductors whose purpose is the transfer of power or information from a source to a load, both of which should be viewed as generic. That is, the source may well be a generator but it can equally be the output of a device such as a transmitter, a receiving antenna, or an amplifier, whereas the load can be any device or system that receives the power or information such as a resistor, a transmitting antenna, or an actuator. Transmission lines differ from the common circuit theory approach to transfer of power. In circuits, we usually assume a lumped parameter model, that is, a line, connecting two points in a circuit has some resistance, capacitance, inductance, and conductance that depend on the type of line, materials, and dimensions, but these are the total values for the whole line.