Dual‐frequency dual‐polarization antenna of high isolation with embedded mushroom‐like EBG cells

A dual‐frequency dual‐polarization (DFDP) antenna of high isolation between two ports with embedded 2 × 1 mushroom‐like electromagnetic bandgap (EBG) cells is presented. The equivalent circuit of a suspended microstrip line over 2 × 1 EBG cells is introduced. The numerical analysis from the equivalent circuit and measured results show that the microstrip line with embedded EBG cells has a distinctive and sharp rejection band that provides near 0 dB insertion loss outside the rejection band. By embedding the EBG cells under feedlines of a DFDP antenna, the isolation between two ports of the proposed antenna is enhanced by more than 20 dB, when compared with that of a conventional DFDP antenna. The proposed DFDP antenna is fabricated and measured. The simulated and measured results show a good agreement. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1764–1768, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22513