2023 年 12 巻 6 号 p. 282-287
This letter describes a wideband circularly polarized (CP) array antenna with 2 × 2 alignment of sequentially rotated CP patch elements. Each patch element has a diamond-shaped artificial ground structure (DAGS), which extend the 3-dB axial ratio (AR) bandwidth of a CP antenna, and the patch elements in the array are fed with relative phases of 0°, 90°, 180° and 270°. The main purpose of this work is to show the potential of the 3-dB AR bandwidth by a combination of the DAGS and the sequential rotation technique considering the effect of coupling with neighboring elements. The proposed array antenna achieves an overlapped bandwidth of 74.9% (4.30 GHz-9.45 GHz) with the -10-dB |S11|, 3-dB AR and 3-dB gain characteristics. Also, the 3-dB gain bandwidth of this antenna is 54.65% at 5.0 GHz-8.76 GHz. Furthermore, the cross-polarization is sufficiently suppressed in the main beam of 14 dBic. As a result, it is shown that the patch antenna with DAGS can be applied to sequential array technology with sufficiently low coupling, and the AR bandwidth can be broadened.
