A design for antennas with quad-polarization diversity is described. The antenna structure is mainly composed of a reconfigurable crossed dipole fed with coaxial baluns and a switchable feeding network. By controlling the states of pin diodes embedded in the balun feeds, the crossed dipole can generate vertical and horizontal polarization radiations, and the phase of each polarization mode can be switched between 0° and 180°. As for the feeding network, it has four output ports and only two output ports are set to be active to excite the crossed dipole at a time. By integrating the crossed dipole with the feeding network, the resultant antenna can provide four polarization modes, including ±45° linear polarizations and dual orthogonal circular polarizations. Moreover, the overlapped operation bandwidth of the four polarization modes is more than 35 %, and within the bandwidth, the cross polarization level of the linear polarization modes is less than −20 dB and the axial ratio of the circular polarization modes is smaller than 3 dB. Good impedance matching is also achieved for each polarization mode.
All Science Journal Classification (ASJC) codes
- Electrical and Electronic Engineering