Practically, no. A filter usually has a need for a low insertion loss, flat passband, and defined in-band riple. When you take an ideal prototype and try to make it into an actual real life filter, the Q of the filter elements tends to distort the passband so much that it looks nothing like the prototype prediction.
Now, if allyou want to do is pass a single frequency and reject out of band stuff by as much as possible, and you do not care too much about insertion loss, then yeah, you can make a narrow filter at 12 GHz. A single dielectric resonator puck losely coupled will do the job nicely.
I suppose you could use a saphire resonator or superconductor resonator and end up with superhigh Q elements that could do the filter job, but that is more science fair than engineering.