Hyperspectral imaging and its applications: A review.

Hyperspectral imaging has emerged as an effective powerful tool in plentiful military, environmental, and civil applications over the last three decades. The modern remote sensing approaches are adequate for covering huge earth surfaces with phenomenal temporal, spectral, and spatial resolutions. These features make HSI more effective in various applications of remote sensing depending upon the physical estimation of identical material identification and manifold composite surfaces having accomplished spectral resolutions. Recently, HSI has attained immense significance in the research on safety and quality assessment of food, medical analysis, and agriculture applications. This review focuses on HSI fundamentals and its applications like safety and quality assessment of food, medical analysis, agriculture, water resources, plant stress identification, weed & crop discrimination, and flood management. Various investigators have promising solutions for automatic systems depending upon HSI. Future research may use this review as a baseline and future advancement analysis.

8-port MIMO antenna at 27 GHz for n261 band and exploring for body centric communication.

This paper presents a compact 5G wideband antenna designed for body-centric networks (BCN. The single element antenna design includes a simple T-shaped radiator patch with ring shaped ground plane and transformer impedance feedline. First, the antenna was simulated in free-space, and its resonant frequency is found to be 27 GHz, falling within 5G's n261 band. The proposed single radiator antenna has a size of 23.375 mm3, and it offers a wide impedance bandwidth of 2.0 GHz (26-28 GHz). Parametric studies demonstrated that by increasing the length of slots in patch, the antenna frequency can be reduced further. Single radiator antenna is used as 8-element MIMO structure. Parallel adjacent antenna in X-direction has minimal coupling effect, whereas antenna placed in Y-direction has high coupling effect. Thus, coupling is reduced by etching a wall of slots in ground plane. It alters the surface current interference in Y-direction and limits the coupling effect. The antenna is investigated to use in body area network applications. To evaluate its on-body performance, an equivalent body model is virtually developed. The on-body performance is assessed by placing the antenna in close proximity to body model. Stable and robust performance is achieved for the on-body operation. At the resonant point, the antenna exhibits a reflection coefficient of -30 dB (free space) and -40 dB (on-body), high isolation of above 20 dB between adjacent radiators and above 30 dB for other radiators. Antenna has stable performance for different body tissues and on the non-planar structures. Bidirectional radiation pattern with gain of 2.53 dB and broadside type orientations with gain of 4.64 dB are achieved for free space and on body operations respectively. low specific absorption rate makes antenna safe for health care devices. Further, diversity performance is measured in terms of envelope correlation coefficient (ECC), and diversity gain (DG). Maximum Value of ECC is 0.005 and minimum value DG is 9.97 at 27 GHz which confirms the excellence of antenna for MIMO applications.

Design and performance analysis of an L-shaped radiator and defected ground antenna for enhancing wireless connectivity in brain implants.

Brain implantable wireless microsystems has potential to treat neurological diseases and maintain the quality of life. Highly efficient miniaturized antenna is the fundamental part of BID (brain implantable device) for reliable signaling of data through dissipative intracranial material. In this paper, a patch antenna with L-shaped defected ground is demonstrated. L-shaped radiator contributed to achieve the resonance at 2.45 GHz industrial scientific and medical (ISM) band. Antenna size is reduced to 10 × 10 × 0.25 mm3. The proposed L-shaped ground plane geometry is contributing in improving the radiation performance. |S11| value shifts from 15 dB to 30 dB after modifying the ground plane. Proposed structure attained the gain of -14 dBi when located between the Dura and CSF layers at the depth of 12 mm in human brain model. Full wave simulated antenna prototype is fabricated and measured for performance verification. Impedance bandwidth of 270 MHz and broadside radiation pattern (for transferring maximum electromagnetic energy away from tissue) are maintained by the proposed antenna. Brain tissue safety is ensured by specific absorption rate which is 0.709 W/kg and in compliance with the safety limits of 1.6 W/kg for 1-g averaged tissue. Proposed antenna structure is the promising candidate for medical implant technology.