A Low Profile Tilted Beam Single Arm Spiral Antenna On A High Impedance Surface For Beam Steering Applications

This paper presents the extension of the high impedance surface (HIS) idea and its application to the switchable beam single arm spiral antennas proposed in (A. Mehta et al., 2006, 2004) in order to reduce its substrate thickness. A low profile single arm spiral antenna for tilted beam radiation using a small ground plane (0.97 lambda_g) and a practical coax feeding from bottom is presented. As pointed out in (A. Mehta et al., 2006) the spiral antenna generates a tilted beam when the radiation occurs from its first two wavelength loop concurrently. Using switches, as shown in (A. Mehta et al., 2006), the radiation from the second wavelength loop can be altered resulting in steering of the beam in the space. Hence, steering a tilted beam in space is easy with the structure proposed, consequently it helps in achieving an uncomplicated beam swing. Since it is low profile, this antenna is suitable for implementation in small wireless transceivers for beam adaptive applications.