phased array radar design 360 degree view

#PHASED ARRAY RADAR DESIGN 360 DEGREE VIEW PATCH#
#PHASED ARRAY RADAR DESIGN 360 DEGREE VIEW PORTABLE#

#PHASED ARRAY RADAR DESIGN 360 DEGREE VIEW PORTABLE#

Compactness and directionality are the major concerns in antenna geometry for microwave head imaging as compactness allows more elements within the available volume with portable and deployable features, and directionality ensures the enhancement of the radiated signal strengths by a consequent increase in the received scattered signals without backward signal interference 19, 21, 22, 23. Radar scanning and tomography both are the approaches for image reconstruction, and in both cases, the antenna array is one of the main components as the performances of the antenna array determine the success of the system. This technology is capable of detecting the early cancerous tissues, hemorrhages, and other internal changes in the human head from the variances in electrical properties of head 19, 20. Microwave head imaging is nowadays an emerging technology for the medical diagnostic system that has drawn a significant interest among researchers all over the world because of its cost-effective, nonionizing, non-invasive, and portable features 13, 14, 15, 16, 17, 18.

Hence, a portable, non-ionizing, low-cost, and highly accurate imaging system is urgently needed for the detection of stroke. PET imaging has been used to assess the ischemic penumbra but is not widely utilized 11, 12. Ultrasound imaging can be used to quantify intracranial and extracranial blood vessel anatomy and blood flow but requires expertise and is time-consuming 13. MRI is more expensive and less widely available 11, 12. CT scans have drawbacks concerning exposure to radiation 9, and cancer hazard 10. Time to begin reperfusion is critical for limiting and perhaps reversing neurological disability. Furthermore, these existing imaging systems are very bulky 8. However, according to the World Health Organization (WHO), reliable and affordable medical imaging systems are not accessible to about three-quarters of the World’s population 7. Although these existing technologies are highly sensitive, they are not easily accessible or affordable for patients in rural hospitals and can only be undertaken once the patient has been admitted to the hospital, apart from some centers where CT imaging has been made available through mobile ambulances. Magnetic resonance imaging (MRI) and computed tomography (CT) are the currently available medical diagnostic imaging modalities to detect a stroke. Stroke is classified mainly into two categories: Ischemic stroke (IS) (~ 80%) and Hemorrhagic stroke (~ 20%) 6. Stroke is characterized by acute onset neurological disability due to an underlying disruption of blood flow to the brain 4, 5. In the USA, about 796,000 people suffer a stroke, of which 650,000 are first strokes and 187,000 are recurrent strokes each year 4. It is noteworthy that worldwide each year, approximately 16 million people are affected by stroke, of which 6 million die and another 6 million become disabled 1, 2, 3. Stroke is the 2nd most frequent cause of death and disability in developed countries. The reconstructed images in simulation and experimental environment demonstrate the feasibility of the proposed system as a portable platform to successfully detect and locate the hemorrhages inside the brain. The backscattered signal is collected from different antenna positions and processed by the updated Iterative Correction of Coherence Factor Delay-Multiply-and-Sum beamforming algorithm to reconstruct the hemorrhage images.

To verify the imaging capability of the proposed system, an array of 9 antennas and a realistic three-dimensional tissue-emulating experimental semi-solid head phantom are fabricated and measured. One-dimensional mathematical modelling is analyzed to precisely estimate the power distribution that validates the performance of the proposed antenna. It is also explored to improve radiation efficiency and gain when placed to head proximity. The optimization of MTM unit cell is performed to increase the operational bandwidth, realized gain, and efficiency of the antenna within the frequency regime. The operating frequency of the antenna is 1.95–4.5 GHz.

#PHASED ARRAY RADAR DESIGN 360 DEGREE VIEW PATCH#

The antenna has two slotted dipole elements with finite arrays of MTM unit cell and a folded parasitic patch that attains directional radiation patterns with 80% of fractional bandwidth. A metamaterial (MTM) loaded compact three-dimensional antenna is presented for the portable, low-cost, non-invasive microwave head imaging system.

Phased array radar design 360 degree view