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

Abstract

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 HEM_11δ, HEM_12δ+1, HEM_31δ+1, HEM_13δ, TM_01δ, and TM_02δ. 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.