A Novel Beam Steerable Antenna Employing Tunable High Impedance Surface With Liquid Crystal

Abstract

A novel beam steerable antenna employing tunable high impedance surface with liquid crystal is proposed. This antenna utilizes three microstrip patches as the radiators and a tunable high impedance surface based on liquid crystal as the ground plane. In this design, liquid crystal is deliberately disposed under the two parasitic microstrip patches to reduce the effect of relatively large dielectric loss and to improve the gain and radiation efficiency of the antenna. More importantly, this work explores a tunable high impedance surface based on liquid crystal, which has advantages of simple structure and biasing scheme as compared with other tunable high impedance surfaces based on solid-state devices. It is shown that by tuning the permittivity of liquid crystal, the high impedance surface becomes to support the propagation of TE surface waves to strengthen the mutual coupling between main and parasitic microstrip patches. Consequently, the main lobe can be steered to the desired direction and the scanning range of the antenna is enlarged. To prove this novel concept, a Ka-band prototype is fabricated and tested. Measured results show that the antenna not only has acceptable gain, but also keeps a satisfactory scanning range. In addition, this antenna consumes negligible DC power and thus is a strong antenna competitor for 5G access point applications.

Development of Beam Steerable Reflectarray With Liquid Crystal for Both E-Plane and H-Plane

“…Here a 2-finger structure shown in Figure .1 is used as unit of LC RA. This multi-resonant element appllicaiton in LC RA unit is firstly presented in [28], which can achieve reflection phase change, this structure exhibits excellent performance of reflection phase variation more than 330° within a broad frequency. In this work, Particle Swarm Optimization(PSO) is applied to develop and optimize the parameters of this structure to achieve larger phase shift range over 360° and relative high reflection coefficient, which are two basic indexes for RA element design.…”

Beam Steering Using Active Artificial Magnetic Conductors: A 10-Degree Step Controlled Steering

“…13 represents the AAMC, and the position of each element and the reflection angles in azimuth and elevation. The phase gradients that can be generated in the previously presented structure are defined by Equations (16) to (18).…”

“…In both previous cases the antenna does the beam steering and not the AMC surface. The authors of [16] use an AAMC that is composed with a combination of liquid crystal and substrate to change the reflection phase of the structure, thus steer the radiation pattern of an array of three patch antennas. This work is only suitable for frequencies above 20 GHz due to the thickness limitation of the liquid crystal.…”

“…Another draw back of this work is the high cost. Unlike the method presented in [14] and [15], this contribution generates beam steering by changing the properties of the AAMC, while our technique is cheaper to implement than [16].…”

Design Optimization of Reconfigurable Liquid Crystal Patch Antenna

“…Here, we propose applying a liquid crystal to a frequency tunable patch antenna for a microwave frequency band. This liquid crystal is being actively studied in the field of an antenna for variable frequency [ 16 , 17 , 18 , 19 , 20 ] and an electronic beamforming antenna for the mm-wave frequency band [ 21 , 22 , 23 , 24 , 25 , 26 ]. However, research on technology for securing antenna performance while using an expensive liquid crystal to a minimum is still insufficient [ 27 ].…”