Abstract: A single-layer capacitive feeding mechanism which radiating patch and feeding patch is located on the same layeris used to design a wideband millimeter wave microstrip antenna. The wideband is obtained by applying two-layers substrates. Asthe purpose of obtaining suited impedance, the radiating patch is fed by coupling of the feeding element which compensates theadditional inductance of using probe-fed. The bandwidth(VSWR<2)of the designed antenna is 44.64%(26.1GHz～41.1GHz).Theaffect of size of feeding patch and the distance between the feeding element and the radiating element to the impedance and Vswrof the antenna is also discussed.