Design and measurement of a linearly polarized radial line MSA array with U-slot circular MSAs

This paper presents design and measurement of a linearly polarized radial line microstrip antenna array (RL-MSAA) with U-slot circular MSAs (C-MSAs). An circular microstrip antenna with U-shaped slot is used as a radiation element of the RL-MSAA. Radiation phase of the U-slot C-MSA is controlled by tuning a radius of the C-MSA and dimensions of the U-slot on the C-MSA; therefore, the desired phase distribution of the RL-MSAA can be designed. In this paper, a linearly polarized RL-MSAA with three concentric rows of the C-MSAs at a spacing of 0.65 wavelengths is designed and tested at 12 GHz. For uniform phase distribution, U-slot C-MSAs for inner two rows and normal C-MSAs for the termination row are arranged. Validity of the linearly polarized RL-MSAA with the U-slot C-MSAs for radiation phase control is confirmed by simulation and measurement.