A patch antenna is provided to transmit and receive an ultrahigh frequency signal by being attached to a wave guide without forming a separate feeding pad. In a patch antenna, an antenna pattern(310) is formed on a front surface of a dielectric substrate(300). A ground pattern(320) is formed on a rear surface of the dielectric substrate(300). An etching unit(330) enables the front and rear surfaces of the dielectric substrate(300) to transmit an ultrahigh frequency signal by etching the ground pattern(320). The ground pattern(320) is made of a metal material. The etching unit(320) etches a middle part of the dielectric substrate(300) by the metal material to be exposed. A size of the etching unit(330) is varied according to a frequency of the ultrahigh frequency signal to transmit and receive.
