Future manned missions to the Moon would require an uplink channel significantly broader in frequency than the ones presently used in S and X band. For this reason, the European Space Agency is considering to upgrade its 35-m deep space antennas to include an uplink channel also in K-Band (22.55-23.15 GHz). This paper addresses a solution where dichroic mirrors are used to accomplish this task. In particular, two solutions based on different manufacturing technologies are thoroughly compared taking into account different perspectives. Mirror designs and simulated results, for both dichroic mirrors and Beam Waveguide optics, are presented.