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 27 cm×23 cm×16 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.
more »
« less
Modeling and Characterization of Electrically Small Ultrawideband Antenna for Headstage Based Wireless Neural Signal Recording System
Diagnosis of neural diseases can be performed using microsystems that record neural signals collected simultaneously after neural simulations. Headstage and homecage-based recording systems can be implanted on small freely-moving animals to test such system which requires miniaturized, lightweight, and high gain antennas in order for the small animals to carry them easily while also decreasing loss during data transmission. This paper proposes a 15×15 mm2 slot antenna with a 50 Ω microstrip excitation line. The slot antenna is created by the addition of slots in the ground plane which is a common miniaturization method as it results in ultrawideband operating frequency. A lumped component-based model along with a 3D EM model of the modified SMA connector used for the measurement and headstage model is also developed to observe the effect on the antenna performance. The antenna achieved an operating frequency of 4.25 - 9.4 GHz and a bidirectional radiation pattern with gain ranging from 2.24 to 4.35 dBi. The proposed antenna is also circularly polarized and achieves 80.6% - 90.8% radiation efficiency over the operating BW. It can transmit a maximum of 20 dBm of power over the operating frequency without exceeding the FCC-imposed SAR limit. Based on the performance, the antenna is suitable for headstage and homecage-based neural signal recording systems with IR-UWB transmitter for high data rate transmission.
more »
« less
- Award ID(s):
- 2309413
- PAR ID:
- 10488873
- Publisher / Repository:
- IEEE
- Date Published:
- Journal Name:
- IEEE Open Journal of Antennas and Propagation
- ISSN:
- 2637-6431
- Page Range / eLocation ID:
- 1 to 1
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
For the treatment of chronic neuropathic diseases, long-term behavior study of the patient is very important. The behavior study is performed using neural stimulation and simultaneously recording the response from the neural cells. Headstage-based neuromodulation device has become one of the popular methods for neural stimulation in recent times. In this work, a wirelessly powered system is presented that provides constant power to a headstage based optogenetic stimulator, which includes a receiver (RX) coil, a rectifier, and an mm-sized light-emitting-diode (LED). A multi-layered transmitter (TX) coil is designed to provide uniform power transmission over the 20.7 cm × 14 cm mouse behavioral cage area. A maximum of ~49% efficiency is achieved using the proposed system at 3 cm distance through the air media at 13.56 MHz operating frequency. The proposed system uses less number of headstage resonators on the 3-D printed light-weight headstage which is able to achieve higher efficiency compared to the other state-of-the-art.more » « less
-
To avoid interruption of experiment and risk of infection, wireless power transfer (WPT) techniques have been used to eliminate the bulky wires and batteries attached to the animals in rodent electrophysiological applications for long-term in-vivo electrophysiological recordings. Headstage-based neuromodulation device has become one of the most popular methods for neural stimulation in recent times. In this work, a wireless power transfer system is designed which provides a constant power to a headstage based optogenetic stimulator. The proposed research is composed of two parts: i) a unidirectional 28 cm × 21 cm phased array transmitter antenna, and ii) an electrically small bi-directional 2.4 cm × 2.4 cm receiver antenna. A phased array transmitter antenna is designed to provide a uniform power transmission over the 27 cm × 23 cm × 16 cm rat behavioral cage area. The proposed WPT scheme utilizes a near-field power transmission scheme at 2.4 GHz frequency. Simulation results show that the transmitter antenna achieves a -24 dB and receiver antenna achieves a −27 dB return loss (S 11 ) at the resonating frequency. The proposed WPT system shows a maximum of 24.5% power transfer efficiency (PTE) when the receiver is in the center position and is 10 cm distance apart from the transmitter, which is much higher compared to the other state-of-the-art works. The transmitter antenna steers beam from −21° to 27° in ϕ axis and −108° to 74° in θ axis which covers the maximum 6.27 cm 2 area of the cage. The preliminary simulation results of the proposed WPT module show a better prospect for future optogenetics based applications.more » « less
-
This paper presents the novel design of a printed, low-cost, dual-port, and dual-polarized slot antenna for microwave biomedical radars. The butterfly shape of the radiating element, with orthogonally positioned arms, enables simultaneous radiation of both vertically and horizontally polarized waves. The antenna is intended for full-duplex in-band applications using two mutually isolated antenna ports, with the CPW port on the same side of the substrate as the slot antenna and the microstrip port positioned orthogonally on the other side of the substrate. Those two ports can be used as transmit and receive ports in a radar transceiver, with a port isolation of 25 dB. Thanks to the bow-tie shape of the slots and an additional coupling region between the butterfly arms, there is more flexibility in simultaneous optimization of the resonant frequency and input impedance at both ports, avoiding the need for a complicated matching network that introduces the attenuation and increases antenna dimensions. The advantage of this design is demonstrated through the modeling of an eight-element dual-port linear array with an extremely simple feed network for high-gain biosensing applications. To validate the simulation results, prototypes of the proposed antenna were fabricated and tested. The measured operating band of the antennas spans from 2.35 GHz to 2.55 GHz, with reflection coefficients of less than—10 dB, a maximum gain of 8.5 dBi, and a front-to-back gain ratio that is greater than 15 dB, which is comparable with other published single dual-port slot antennas. This is the simplest proposed dual-port, dual-polarization antenna that enables straightforward scaling to other frequency bands.more » « less
-
For the diagnosis and treatment of various chronic neurological diseases such as Epilepsy, Seizure and, chronic pain, a long-term electrophysiological recording and stimulation are required for the patients. This type of study can be done through implantable neuromodulation devices. One of the key challenges in designing such implantable medical devices is the size restriction. Even the antennas transmitting the recorded signals must be small, miniaturized, and light-weight in order for the small animals used in the clinical studies to carry it easily. In this paper, two 15mm×15mm antennas are designed which have ultra-wide bandwidths making them suitable for the high data rate electrophysiological recording applications. The proposed antennas are bidirectional and small in size making them suitable to be added to the headstage based electrophysiological recording devices. Both antennas have a similar radiating patches with each ground patch modified by creating two different slots. A comparison of the proposed antenna is presented in the paper where both antennas operate within 4.7 GHz to 8.3 GHz and having average gain above 4.35 dBi. Though the proposed antennas are 40% smaller in size, they have 6% higher gain compared to the state of the arts.more » « less
An official website of the United States government

