This paper introduces two miniaturized antennas for either omnidirectional or unidirectional radiation. These two antenna designs are based on the manipulation of two electric and magnetic radiators. First, omnidirectional CP antennas have broad radiation coverage and can avoid the polarization mismatch problem, which are suitable for device-to-device (D2D) and satellite communications. Two horizontally placed electric and magnetic radiators excited with equal amplitude and 90 degree phase difference can produce omnidirectional CP pattern. This paper will present a 28 GHz compact wheel-shaped omnidirectional CP antenna. The entire antenna is printed on a dielectric disk with the diameter of only 4 mm. It has broad bandwidth and good electrical characteristics, which is ideal for compact 5G mobile terminals. Second, unidirectional CP antennas have high directivity and can avoid polarization mismatch problem, which have been widely used in satellite mobile terminals. Two orthogonally placed electric and magnetic radiators excited with equal amplitude and phase produce unidirectional cardioid-shaped radiation pattern. This paper will introduce an electrically small unidirectional CP antenna, which organically combines two metamaterial-inspired electric and magnetic radiator into a compact entity. This antenna is ideal for satellite communication and wireless power transfer applications.