At the ends of a half-wave antenna, compared to the remainder of the antenna, what are the voltage and current?

Get ready for the FCC General Radiotelephone Operator License (GROL) exam. Study with flashcards and multiple choice questions, each with hints and detailed explanations. Prepare effectively for your licensing test!

Multiple Choice

At the ends of a half-wave antenna, compared to the remainder of the antenna, what are the voltage and current?

A half-wave dipole supports a standing wave along its length, with the current distribution peaking at the center and dropping to zero at the ends. Because the ends are open to free space, current cannot flow out, so the boundary condition forces the current to be minimal there. To satisfy the standing-wave pattern, the voltage must reach a maximum where the current is minimal, creating voltage antinodes at the ends. In contrast, the center is where the current is greatest and the voltage is smallest. So at the ends you observe the highest voltage and the lowest current.

A half-wave dipole supports a standing wave along its length, with the current distribution peaking at the center and dropping to zero at the ends. Because the ends are open to free space, current cannot flow out, so the boundary condition forces the current to be minimal there. To satisfy the standing-wave pattern, the voltage must reach a maximum where the current is minimal, creating voltage antinodes at the ends. In contrast, the center is where the current is greatest and the voltage is smallest. So at the ends you observe the highest voltage and the lowest current.

More practice questions