Integrated 60-GHz LTCC circularly polarized antenna array

A 60-GHz wideband circular polarized (CP) patch array of 4×4 elements is designed and fabricated in low temperature cofired ceramic (LTCC) technology. By applying a strip line sequential rotation feeding scheme this array exhibits wide impedance bandwidth (VSWR<2) and 3-dB axial ratio (AR) bandwidth, both over 8 GHz. In addition, it exhibits a peak gain of 16.8 dBi and a beam-shaped pattern with a 3-dB beam width of 20°. With a grounded co-planar waveguide (GCPW) to strip line (SL) transition added to facilitate the testing, the array performance is not degraded except of a 0.6-dB peak gain penalty. The fabricated antenna sample measures 13×18.7×1.4 mm³. The wireless test is finally conducted to demonstrate the CP characteristic and wide impedance bandwidth over 8 GHz (VSWR<2) of this antenna.