Ka-band Full Polarization Reconfigurable 1D Beam Steering Staggered Butterfly Phased Array Antenna

A novel full-polarization reconfigurable 8 x 12 Butterfly phased array antenna with wide-angle 1D beam steering performance is proposed at Ka-band (28 GHz) for increased system capacity of 5G communications. The butterfly unit cell of the proposed array is a novel sequentially-rotated series-fed microstrip patch antenna with simple, versatile, and adequate radiation performance characteristics. The proposed staggered planar array configuration reduces the spacing between the adjacent series-fed linear array to 0.45 lambda(0), where lambda(0) is the free-space wavelength at 28 GHz. This reduced spacing can enable larger beam steering angle radiation performance without any grating lobes. The 16-channel Analog devices ADMV4821 RFIC Ka-band beamformer is used to provide excitation weights for achieving the desired beam steering, full- polarization reconfiguration, and reduced sidelobe level. The ADMV4821 beamformer chip is characterized; the average measured phase imbalance is less than 10 degrees, and the average measured channel gain imbalance is less than 1 dB. The proposed Butterfly staggered phased array antenna is being prototyped and integrated with the beamformer board to verify the analysis and simulation results experimentally.