Unlike the above antennas, traveling wave antennas are nonresonant so they have inherently broad bandwidth. They are typically wire antennas multiple wavelengths long, through which the voltage and current waves travel in one direction, instead of bouncing back and forth to form standing waves as in resonant antennas. They have linear polarization (except for the helical antenna). Unidirectional traveling wave antennas are terminated by a resistor at one end equal to the antenna's characteristic resistance, to absorb the waves from one direction. This makes them inefficient as transmitting antennas.
What antenna's are nonresonant? How long are the wire antenna's that the voltage and current waves travel in the same direction? What are undirectional traveling wave directions terminated by? What antenna does not have linear polarization? What is the resistor equal to?