Monopole antenna
![Mast radiator monopole antenna used for broadcasting. AM radio station WARE, Warren, Massachusetts, USA.](/Images/godic/202412/24/Transmitter_site_of_Ware,_Massachusetts_radio_station_WARE_on_Coy_Hill_in_Warren,_Massachusetts,_USA4357.jpg")
![Showing the monopole antenna has the same radiation pattern over perfect ground as a dipole in free space with twice the voltage](/Images/godic/202412/24/Monopole_and_image_antenna.svg4357.png")
![Radiation pattern of 3/2 wavelength monopole. Monopole antennas up to 1/4 wavelength long have a single](/Images/godic/202412/24/Vpol_dual_band_blade_antenna_blade_L1_3D4358.jpg")
![VHF ground plane antenna, a type of monopole antenna used at high frequencies. The three conductors projecting downward are the ground plane](/Images/godic/202412/24/Antenne_gp_vhf_34358.jpg")
A monopole antenna is a class of radio antenna consisting of a straight rod-shaped conductor, often mounted perpendicularly over some type of conductive surface, called a ground plane. The driving signal from the transmitter is applied, or for receiving antennas the output signal to the receiver is taken, between the lower end of the monopole and the ground plane. One side of the antenna feedline is attached to the lower end of the monopole, and the other side is attached to the ground plane, which is often the Earth. This contrasts with a dipole antenna which consists of two identical rod conductors, with the signal from the transmitter applied between the two halves of the antenna.