Contact engines, probe head assemblies, probe systems, and associated methods for on-wafer testing of the wireless operation of a device under test (DUT). A contact engine includes a flexible dielectric membrane having a first surface and a second surface and a plurality of probes supported by the flexible dielectric membrane. The plurality of probes are oriented to contact a plurality of contact locations on the DUT. Each probe in the plurality of probes includes a corresponding probe tip that projects from the second surface of the flexible dielectric membrane and is configured to electrically and physically contact a corresponding contact location of the plurality of contact locations. The contact engine further includes at least one membrane antenna supported by the flexible dielectric membrane. A probe head assembly includes the contact engine. A probe system includes the probe head assembly. Associated methods include methods of utilizing the contact engine.