Question 3-64J4

A half-wave antenna is a resonant structure where standing waves of current and voltage exist along its length. These waves are 90 degrees out of phase with each other. At the ends of a half-wave antenna, the impedance is very high, approaching that of an open circuit. In an open-circuit condition, the voltage potential reaches its maximum amplitude, while the current approaches its minimum (ideally zero). This is because the free electrons have nowhere to flow beyond the physical end of the conductor. Conversely, at the center of a half-wave antenna (where it is typically fed), the impedance is low, resulting in maximum current and minimum voltage. Therefore, at the ends, you will find maximum voltage and minimum current.