Isolation Enhancement between Indoor Repeater Antennas with Chip Resistor Embedded FSS

The isolation enhancement between the donor antenna and the service antenna for indoor repeater systems is presented by using a frequency-selective surface (FSS). A unit cell of the proposed FSS consists of a quarter-wavelength resonator, a chip resistor, an FR4 substrate, and a ground plane. Applying the unit cells of the proposed FSS embedded a chip resistor on the side walls of each reflector for indoor WCDMA repeater antennas and aligning them along with the cross-polarization of each antenna, the isolation is improved by about 13 dB at the WCDMA band.