Array Pattern Synthesis for ETC Applications

Abstract

The problem of antenna array synthesis for radiation pattern defined on a planar surface will be considered in this chapter. This situation could happen when the electric field r-decay factor effect cannot be neglected, for example, an antenna array mechanically tilted and a pattern defined in terms of Cartesian coordinates, as in the electronic toll collection (ETC) scenario. Two possible approaches will be presented: the first one aims at the precise synthesis of the pattern in the case both a constant power-bounded area and a sidelobe suppression region are defined and required to be synthesized. The second approach instead devotes at stretching the coverage area toward the travel length (without considering a precise definition of the communication area) to increase the available identification time with an iterative methodology. For the latter, an antenna prototype has been fabricated, and measurement results have confirmed the approach validity.

Geometrical Study of Millimeter-Wave Communication Area Covered by an Antenna Array

“…Any respective vectors R in OXYZ and r in oxyz satisfy the relation R = R x (θ rot )r + T XY Z , where R x (θ rot ) denotes a rotation matrix around the x-axis, θ rot indicates the UPA boresight direction relative to the Z-axis, T XY Z = (0, 0, H) T is the translation vector, and H is the antenna height relative to the user equipment (UE) height Z = 0. This situation is similar to the one assumed in [10] except for the orientations of the xand y-axes. Then, R on Z = 0 corresponding to the position vector P (X, Y, 0) on the ground plane is expressed as follows:…”

“…Since the coverage area size is less than approximately a few meters in radius for a single beam emission by a uniform planar array (UPA) antenna [10], a wider area should be covered by beam sweeping or switching by controlling the excitation phase of each element. Here, we describe the required minimum communication area of 1000 m 2 covered by a radio unit (RU) with an antenna array as a "nano-area" [9].…”