A multilayer K-band patch antenna element featuring polarization multiplexing is presented. It relies on a previously published design providing high polarization purity. The layer stack and, in essence, the geometry are preserved. Left- and right-handed circular polarization (LHCP/RHCP) are realized without hybrid coupler, the two feeds still sharing the same layer. The arrangement is thus very compact. For interpretation, the simulation results are cast into an equivalent circuit model. Measurements performed on a multilayer antenna with vertical transitions confirm the concept.
