A novel calibration network for patch antennas is proposed. We introduce magnetically coupled in-situ probes, which excite the fundamental patch mode. In that way, finite array effects and mutual coupling are taken into account, providing the opportunity for accurate online calibration of active antenna terminals. The specific advantages of the approach are demonstrated for linearly polarized patch antennas. Realization aspects of the multilayer antenna are discussed and the effect of some fabrication imperfections are investigated. Measured S-parameters as well as radiation simulation results of a single patch with the integrated probes are presented. Based on simulation of antenna arrays with in-situ probes the calibration accuracy is given in theory.
