Novel Four Cross Slot Radiator With Tuning Vias for Circularly Polarized SIW Linear Array

A substrate integrated waveguide (SIW) linear array is presented with a new circularly polarized (CP) element. The single radiator consists of four cross tilted slots. In addition, a pair of tuning metallic vias is included to improve the reflection of longest slots. A 16-element antenna prototype with -26-dB Taylor distribution and 1.5% residual power was designed, manufactured and measured to verify the new slot performance in an array configuration. A 17-dB peak gain, 1.86-dB axial ratio and 80% radiation efficiency were experimentally achieved at 17 GHz. A 3% usable bandwidth was obtained owing to frequency main beam tilt dispersion.