This paper presents a 60 GHz Antenna-on-Chip (AoC) designed using 0.18 um CMOS process. AoC performance is enhanced using asymmetric Artificial Magnetic Conductor (AMC). As asymmetric AMC shields AoC from the lossy CMOS substrate, gain and efficiency of 0.8dBi and 49%, respectively, are achieved. Asymmetric AMC has similar properties to the conventional Perfect Electric Conductor (PEC) allowing for reduced feeding circuit loss than symmetric AMCs. The asymmetric AMC saves about 2dB/mm at 60GHz of insertion loss than symmetric AMC.