A planar antenna apparatus comprising: a first radiation unit configured to transmit a signal; a first feed unit configured to feed a current to the first radiation unit and to apply the signal to be transmitted to the first radiation unit; a first radio frequency, RF, ground; a substrate of a conductive metal pattern; and a via that connects the first radiation unit to the first RF ground across the substrate; and wherein all of the first radiation unit, the first feed unit, the first RF ground, the via and the substrate are disposed on a first plane; wherein a separation distance between the first feed unit and the first radiation unit is configured to provide a serial capacitance value between the first radiation unit and the first feed unit; wherein a length and a width of the first radiation unit are configured to provide a parallel inductance value of the first radiation unit; wherein the serial capacitance value and the parallel inductance value are determined as values that cause a resonant frequency in a predetermined frequency band to be a preset value to radiate the signal in a direction parallel to the first plane; and wherein the planar antenna apparatus further comprises: a second RF ground disposed on a second plane existing in a position parallel to the first plane; and a connection unit configured to connect the first RF ground to the second RF ground, the connection unit being disposed on a third plane connecting the first plane to the second plane; wherein a radiation pattern is configured to vary depending on a position of the connection unit disposed on the third plane. a first radiation unit configured to transmit a signal; a first feed unit configured to feed a current to the first radiation unit and to apply the signal to be transmitted to the first radiation unit; a first radio frequency, RF, ground; a substrate of a conductive metal pattern; and a via that connects the first radiation unit to the first RF ground across the substrate; and wherein all of the first radiation unit, the first feed unit, the first RF ground, the via and the substrate are disposed on a first plane; wherein a separation distance between the first feed unit and the first radiation unit is configured to provide a serial capacitance value between the first radiation unit and the first feed unit; wherein a length and a width of the first radiation unit are configured to provide a parallel inductance value of the first radiation unit; wherein the serial capacitance value and the parallel inductance value are determined as values that cause a resonant frequency in a predetermined frequency band to be a preset value to radiate the signal in a direction parallel to the first plane; and wherein the planar antenna apparatus further comprises: a second RF ground disposed on a second plane existing in a position parallel to the first plane; and a connection unit configured to connect the first RF ground to the second RF ground, the connection unit being disposed on a third plane connecting the first plane to the second plane; wherein a radiation pattern is configured to vary depending on a position of the connection unit disposed on the third plane. a second RF ground disposed on a second plane existing in a position parallel to the first plane; and a connection unit configured to connect the first RF ground to the second RF ground, the connection unit being disposed on a third plane connecting the first plane to the second plane; wherein a radiation pattern is configured to vary depending on a position of the connection unit disposed on the third plane.