Modeling and Optimization of the Steering Range of a Phased Array Antenna for Neuromodulation Applications in the Near-Field Region

This paper presents modeling and optimization of the steering range of a microstrip planar phased array antenna to steer the unidirectional near-field focused beam towards a certain direction. This antenna can be implemented in headstage-based neural stimulation system and wireless recording system for optogenetic neuromodulation applications. The proposed phased-array antenna consists of sixteen elements that are designed to provide a uniform power transmission over the
$\mathbf{27}\ \mathbf{cm} \times \mathbf{23}\ \mathbf{cm} \times \mathbf{16}\ \mathbf{cm}$
rat behavioral cage area. The proposed transmitter (TX) antenna implements a near-field-based wireless power transmission system operating at 2.4 GHz frequency. The phased array antenna steers the beam from -30° to 60° in the elevation plane by feeding the individual elements with different phases using four 4-bit phase shifters. A design analysis of the beam-steering approach of the phased array antenna is presented and the corresponding simulation and measurement results are included in this paper.