Main Lobe Control of a Beam Tilting Antenna Array Laid on a Deformable Surface

Giulia Mansutti,Muhammad S Khan,Sajid M Asif,Andrea Galtarossa,Francesco Rigobello,Antonio-D Capobianco

doi:10.1155/2018/2521953

Giulia Mansutti, Muhammad S Khan + Show 4 more

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https://doi.org/10.1155/2018/2521953

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Abstract

The projection method (PM) is a simple and low-cost pattern recovery technique that already proved its effectiveness in retrieving the radiation properties of different types of arrays that change shape in time. However, when dealing with deformable beam-tilting arrays, this method requires to compute new compensating phase shifts every time that the main lobe is steered, since these shifts depend on both the deformation geometry and the steering angle. This tight requirement causes additional signal processing and complicates the prediction of the array behavior, especially if the deformation geometry is not a priori known: this can be an issue since the PM is mainly used for simple and low-cost systems. In this letter, we propose a simplification of this technique for beam-tilting arrays that requires only basic signal processing. In fact the phase shifts that we use are the sum of two components: one can be directly extracted from strain sensor data that measure surface deformation and the other one can be precomputed according to basic antenna theory. The effectiveness of our approach has been tested on two antennas: a 4 × 4 array (trough full-wave simulations and measurements) and on an 8 × 8 array (trough full-wave simulations) placed on a doubly wedge-shaped surface with a beam tilt up to 40 degrees.

Highlights

Many wireless communication systems have raised the need of developing antenna arrays capable of adapting to surfaces that change shape in time: this can be the case of simple wearable devices that monitor health and fitness parameters and that are placed on body parts that move and bend
The projection method effectiveness was thoroughly studied for many types of antennas, as, for example, 1 × 4 and 1 × 6 linear arrays placed on surfaces that change shape in time [5,6,7] and planar arrays subject to cylindrical [8], spherical [9], and asymmetrical [10] surface deformations
We proposed a simplification of the projection method to retrieve the radiation pattern of beam-tilting antennas

Summary

Introduction

Many wireless communication systems have raised the need of developing antenna arrays capable of adapting to surfaces that change shape in time: this can be the case of simple wearable devices that monitor health and fitness parameters and that are placed on body parts that move and bend (e.g., wrists, ankles, and knees). We will focus on this second class of techniques that is appealing for simple and cheap wearable devices whose main requirement is to keep the product cost as low as possible. Among these pattern recovery techniques, a popular one is the projection method (PM) that exploits only strain sensors and phase shifters to retrieve the main radiation properties of deformable arrays [1], avoiding the use of extensive signal processing, narrow-band correction algorithms, and potentially complex sensor networks that are instead required by more accurate and expensive solutions (e.g., mechanical [2] and electrical [3, 4] compensation).

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