An antenna system, comprising: an antenna having antenna elements; and a control circuit configured to activate a first group of the antenna elements during a first time to cause the antenna to generate a first beam pattern including a first main lobe having a main-lobe direction and having a main-lobe beam width and including a first side lobe having a first side-lobe direction, and to activate a second group of the antenna elements during a second time to cause the antenna to generate a second beam pattern that is different from the first beam pattern, the second beam pattern including a second main lobe having approximately the main-lobe direction and having approximately the main-lobe beam width and including a second side lobe having a second side-lobe direction that is different from the first side-lobe direction, wherein: the antenna includes a transmission medium having a conductor with gaps respectively adjacent to the antenna elements, and the control circuit is configured to activate the first group of antenna elements by reducing a respective impedance between each antenna element in the first group and a respective one of the gaps, and to activate the second group of antenna elements by reducing a respective impedance between each antenna element in the second group and a respective one of the gaps. an antenna having antenna elements; and a control circuit configured to activate a first group of the antenna elements during a first time to cause the antenna to generate a first beam pattern including a first main lobe having a main-lobe direction and having a main-lobe beam width and including a first side lobe having a first side-lobe direction, and to activate a second group of the antenna elements during a second time to cause the antenna to generate a second beam pattern that is different from the first beam pattern, the second beam pattern including a second main lobe having approximately the main-lobe direction and having approximately the main-lobe beam width and including a second side lobe having a second side-lobe direction that is different from the first side-lobe direction, wherein: the antenna includes a transmission medium having a conductor with gaps respectively adjacent to the antenna elements, and the control circuit is configured to activate the first group of antenna elements by reducing a respective impedance between each antenna element in the first group and a respective one of the gaps, and to activate the second group of antenna elements by reducing a respective impedance between each antenna element in the second group and a respective one of the gaps. to activate a first group of the antenna elements during a first time to cause the antenna to generate a first beam pattern including a first main lobe having a main-lobe direction and having a main-lobe beam width and including a first side lobe having a first side-lobe direction, and to activate a second group of the antenna elements during a second time to cause the antenna to generate a second beam pattern that is different from the first beam pattern, the second beam pattern including a second main lobe having approximately the main-lobe direction and having approximately the main-lobe beam width and including a second side lobe having a second side-lobe direction that is different from the first side-lobe direction, wherein: the antenna includes a transmission medium having a conductor with gaps respectively adjacent to the antenna elements, and the control circuit is configured to activate the first group of antenna elements by reducing a respective impedance between each antenna element in the first group and a respective one of the gaps, and to activate the second group of antenna elements by reducing a respective impedance between each antenna element in the second group and a respective one of the gaps. to activate the first group of antenna elements by reducing a respective impedance between each antenna element in the first group and a respective one of the gaps, and to activate the second group of antenna elements by reducing a respective impedance between each antenna element in the second group and a respective one of the gaps.