High port isolation co-located patch antenna

To fulfill co-located dual-polarized directional radiation, a dual-port patch antenna is presented. Constructed on a microwave PCB, the patch element is a foursquare of two open slots. The designed antenna can radiate the patch antenna mode while fed by the coaxial line (port 1), and the folded dipole mode while fed by the coplanar stripe (port 2). The experimental results show that the operating bandwidth defined by S
11
or S
22
less than −10 dB is 2.38–2.48 GHz for port 1, and 2.41–2.47 GHz for port 2. Over the operating band the S
21
or S
12
parameters are less than −23 dB.