Radiation Null Compensation and Isolation Enhancement Between Two Orthogonal Magnetic Dipole Antennas

New approaches to tackle the radiation null and enhance the isolation between two magnetic dipole antennas are presented in this letter. By employing metal-via wall, the magnetic dipole and half-mode substrate-integrated waveguide (HMSIW) cavity are formed. Based on the orthogonal configuration of the magnetic dipoles, null compensation contributes to the nonblind point on the radiation pattern of the dipole. Furthermore, a defected surface structure is adopted to be inserted into the HMSIW cavity. The isolation enhancement with 42.6 dB between the antennas is achieved. With high isolation, the orthogonal integration of the magnetic dipoles is realized. The antenna is fabricated and measured to verify the proposed design.