Dual-band pattern diversity liquid antenna with passive beam-steering of the broadside modes

A dual-band liquid cylindrical dielectric resonator antenna with pattern diversity at two different frequency bands is proposed using the lower order and higher order modes of the HEM and TM modes namely HEM11 delta, HEM12 delta+1, HEM31 delta+1, HEM13 delta, TM01 delta, and TM02 delta. The proposed antenna is designed to cover the GPS L2 band and the lower Wi-Fi band at 1.227 and 2.4 GHz frequencies, respectively. The HEM modes which constitute the primary radiating modes achieved around 20.84% and 19.35% impedance bandwidth at lower and higher bands, respectively. In the later stage, beam-steering is performed, whereby the realised broadside HEM modes at both lower and higher bands were passively steered with simple physical re-orientation of the antenna structure. For this, the liquid's natural fluidic property of adhering to gravity is taken as an advantage which makes the proposed antenna adaptively steer its radiation pattern always towards the sky, irrespective of the tilt angle of the antenna. This concept of passively steering two modes at two different frequency bands without the use of any mechanical, electrical, or other associated components is presented for the first time. The authors propose a low profile dual-band pattern diversity antenna with liquids as the main radiating materials for GPS L2 band and Wi-Fi band around 2.4 GHz. Pattern diversity at both lower and higher bands is achieved using the lower and higher order HEM (broadside) and TM (omnidirectional) modes. Later stage, passive beamforming of the broadside modes is demonstrated through which the radiation pattern is retained even for different physical orientations of the antenna.image