An HIS-Based Spiral Antenna for Pattern Reconfigurable Applications

Single arm rectangular spiral antenna with four open circuit switches over a high-impedance surface (HIS) is proposed for pattern reconfigurable applications. The HIS plane without vias is utilized to achieve a low-profile antenna design with a net thickness of 5.08 mm. This is equivalent to ~ lambda_o/17 for the intended operating frequency of 3.3 GHz. By using the possible sixteen switching combinations a near 360deg beam steering is achieved, and the switched beams do not have a polarization variation from one pattern to another. The realized pattern reconfigurable antenna has both the tilted (thetas_max ges 25deg) and axial (5deg < thetas_max < 10deg) beams, which have an average directivity of 6.9 dBi.