Microstrip antennas on various Uniplane Compact Photonic BandGap (UC-PBG) substrates are investigated. Particularly, anisotropic characteristics of UC-PBG is studied and applied to the design of microstrip diplexer antennas. Moreover, an Embedded UC-PBG (EUC-PBG) scheme is presented to overcome the strong backward radiation caused by the conventional UC-PBG antennas. Such antennas demonstrate the improved radiation properties over the conventional UC-PBG antennas, and the evidence on surface wave suppression is also demonstrated. Experimental results show very good agreement with theoretical predictions.