Beamforming apparatus and beamforming method using expandable planar array antenna

A beamforming method performed by a beamforming apparatus, the beamforming method comprising:

• in an array antenna in which an Elevation (EL) antenna group configured to perform beam steering in an elevation angle direction and an Azimuth (AZ) antenna group configured to perform beam steering in an azimuth angle direction are disposed on a same plane,
• setting the EL antenna group to a transmission (or reception) operation by a first chip located on a top surface of the array antenna and configured to independently control the beam steering in the elevation angle direction by controlling EL patch antennas included in the EL antenna group, the first chip being directly connected to the EL patch antennas through a first feed line disposed on a same plane as the EL patch antennas;
• setting the AZ antenna group to a reception (or transmission) operation by a second chip located on a bottom surface of the array antenna and configured to independently control the beam steering in the azimuth angle direction by controlling AZ patch antennas included in the AZ antenna group, the second chip being indirectly connected to the AZ patch antennas through a second feed line disposed on a plane opposite to a plane on which the AZ patch antennas are disposed, wherein the indirect connection between the second chip and the AZ patch antennas is made through an aperture formed between the AZ patch antennas and the second feed line to indirectly provide power to the AZ patch antennas;
• obtaining a mutual coupling component between the EL antenna group and the AZ antenna group based on the set operation;
• and
• forming beam patterns for the EL antenna group and the AZ antenna group based on the independent control such that the obtained mutual coupling component is removed,
• wherein each of unit antennas of the EL antenna group included in the array antenna comprises:
• a first substrate in which a corresponding one of the EL patch antennas and the first feed line configured to provide power to the corresponding one of the EL patch antennas are disposed on a same plane;
• a second substrate disposed under the first substrate;
• and
• a ground (GND) layer disposed between the first substrate and the second substrate,
• wherein each of unit antennas of the AZ antenna group included in the array antenna comprises:
• a first substrate in which a corresponding one of the AZ patch antennas is disposed;
• a second substrate disposed under the first substrate, in which the second feed line configured to provide power to the corresponding one of the AZ patch antennas of the first substrate is disposed;
• and
• a ground (GND) layer disposed between the first substrate and the second substrate, wherein the GND layer comprises:
• the aperture formed inside the GND layer to indirectly provide power to the corresponding one of the AZ patch antennas of the first substrate through the second feed line disposed in the second substrate.