Fig. 5

The absorption results of the present ultra-broadband PMA with different angles of theta and phi. a Absorption results of the PMA with different angles of phi from 1 to 30 GHz (theta = 0 deg). b Absorption results of the PMA with different angles of theta from 1 to 30 GHz (phi = 0°). c Absorption results at 5.13 GHz with − 90° < theta< 90° and 0° < phi< 360°. d Absorption results at 14.49 GHz with − 90° < theta< 90° and 0° < phi< 360°. e Absorption results at 19.05 GHz with − 90° < theta< 90° and 0° < phi< 360°. f Absorption results at 20.77 GHz with − 90° < theta< 90° and 0° < phi< 360°. g Absorption results at 25.42GHz with − 90° < theta < 90° and 0° < phi< 360°