A Compact High Isolation Co-Linearly Polarized Microstrip Patch Antenna for Full-Duplex Integrated Sensing and Communication

In this paper, a compact co-linearly polarized microstrip patch antenna (MPA) with high isolation is proposed for full-duplex (FD) integrated sensing and communication (ISAC) at the ISM band. With an extremely closely edge-to-edge distance of $1 \mathrm{~mm}\left(0.019 \lambda_{0}\right)$ between $T x$ and $R x$ aperture-coupled MPAs, high $T x / R x$ isolation is realized by a novel dualdecoupling scheme composed of a modified single spindle-type defected ground structure and a coplanar decoupled structure. The prototype of the proposed FD-MPA is simulated, fabricated, and measured to validate the proposed design scheme. The results confirm that a good $T x / R x$ isolation is achieved to 54 dB around 5.8 GHz, which proves the potential applications of employing for FD-ISAC.