An antenna with electrical length equal to half the wavelength is called what?

An antenna with electrical length equal to half the wavelength is called what?

• A. Quarter-wave
• B. Half-wave
• C. Full-wave
• D. Dipole

Answer: (B)

An antenna that is one-half of a wavelength long forms a standing-wave current distribution with a maximum at the center and zeros at the ends. This resonance makes it an efficient radiator, and when fed in the middle, it behaves as a half-wave dipole with a practical input impedance (around 70–75 ohms in free space) and a broad pattern perpendicular to its axis. Because its electrical length is exactly one-half of a wavelength, the proper name for this type of antenna is a half-wave antenna.

An antenna that is one-half of a wavelength long forms a standing-wave current distribution with a maximum at the center and zeros at the ends. This resonance makes it an efficient radiator, and when fed in the middle, it behaves as a half-wave dipole with a practical input impedance (around 70–75 ohms in free space) and a broad pattern perpendicular to its axis. Because its electrical length is exactly one-half of a wavelength, the proper name for this type of antenna is a half-wave antenna.