A High-Order EMSIW MIMO Antenna for Space-Constrained 5G Smartphone

This paper proposes a high-order MIMO antenna operating at 3.5 GHz for a 5G new radio. Using an eighth-mode substrate integrated waveguide (EMSIW) cavity and considering a typical smartphone scenario, a two-element MIMO antenna is developed and extended to a twelve-element MIMO. These MIMO elements are closely spaced, and by employing multiple diversity techniques, high isolation is achieved without using a decoupling network. The asymmetric EMSIW structures resulted in radiation pattern diversity, and their orthogonal placement provides polarization diversity. The radiation characteristics and diversity performance are parametrically optimized for a two-element MIMO antenna. The experimental results exhibited 6.0 dB and 10.0 dB bandwidths of 250 and 100 MHz, respectively. The measured and simulated radiation patterns are closely matched with a peak gain of 3.4 dBi and isolation ≥36 dB. Encouraged with these results, higher-order MIMO, namely, four- and twelve-element MIMO are investigated, and isolation ≥35 and ≥22 dB are achieved, respectively. The channel capacity is found equal to 56.37 bps/Hz for twelve-element MIMO, which is nearly 6.25 times higher than the two-element counterpart. The hand and head proximity analysis reveal that the proposed antenna performances are within the acceptable limit. A detailed comparison with the previous works demonstrates that the proposed antenna offers a simple, low-cost, and compact MIMO antenna design solution with a high diversity performance.

Effects of Differently Located Clearance on the Dynamic Responses of a Two-Degree-of-Freedom Vibration System

The mechanical model of a two-degree-of-freedom forced harmonic vibration system with multiclearance rigid constraints is established, considering the location schemes of symmetrical both-sided clearance and asymmetrical multiple clearance. Existence domains, correlative distributions, and bifurcation scenarios of periodic vibrations are analyzed using multiparameter and multiperformance cosimulation. Pattern diversity, distribution, and occurrence mechanism of the subharmonic impact motion sequences in the tongue-shaped transition regions among the neighboring fundamental periodic motions of the vibration systems are investigated. The emergent behavior of sticking process of fundamental periodic vibration, the occurrence law of chattering-impact motion, and the interaction of different modes of sticking are discussed. According to the sampling ranges of parameters, three multiple heterogeneous constraint conditions are explored; the effects of differently clearance location and values on the dynamic responses and the transition region of fundamental periodic vibrations and subharmonic motions are particularly analyzed. Hence, the reasonable clearance arrangement scheme and numerical optimization combination are determined and the ideal parameter domain of the vibration system is obtained.

Distribution Pattern and Phytosociological Study of Agroforestry Trees in Poonch District of Jammu and Kashmir, India

This study focuses on distribution pattern, diversity and phytosociology of tree species associated with traditional agroforestry in Poonch district of Jammu and Kashmir, India. Data was collected from fifty quadrats (10×10m) sized thrown randomly in agriculture fields. Twenty six tree species belonging to 16 families and 21 genera were encountered. Grewia optiva, Pyrus persica and Celtis australis were the dominant tree species. Grewia optiva was the most dense tree species 3.88 stem/ha followed by Pyrus persica with 3.74 stem/ha. Buxus wallichiana was recorded as the least dense species (0.82 stem/ha). The study revealed that the area has vast potential sites for the plantation of various agroforestry tree species to solve fuel, fodder and timber. J. Biodivers. Conserv. Bioresour. Manag. 2020, 6(2): 77-82

Capturing and analyzing pattern diversity: an example using the melanistic spotted patterns of leopard geckos

Animal color patterns are widely studied in ecology, evolution, and through mathematical modeling. Patterns may vary among distinct body parts such as the head, trunk or tail. As large amounts of photographic data is becoming more easily available, there is a growing need for general quantitative methods for capturing and analyzing the full complexity and details of pattern variation. Detailed information on variation in color pattern elements is necessary to understand how patterns are produced and established during development, and which evolutionary forces may constrain such a variation. Here, we develop an approach to capture and analyze variation in melanistic color pattern elements in leopard geckos. We use this data to study the variation among different body parts of leopard geckos and to draw inferences about their development. We compare patterns using 14 different indices such as the ratio of melanistic versus total area, the ellipticity of spots, and the size of spots and use these to define a composite distance between two patterns. Pattern presence/absence among the different body parts indicates a clear pathway of pattern establishment from the head to the back legs. Together with weak within-individual correlation between leg patterns and main body patterns, this suggests that pattern establishment in the head and tail may be independent from the rest of the body. We found that patterns vary greatest in size and density of the spots among body parts and individuals, but little in their average shapes. We also found a correlation between the melanistic patterns of the two front legs, as well as the two back legs, and also between the head, tail and trunk, especially for the density and size of the spots, but not their shape or inter-spot distance. Our data collection and analysis approach can be applied to other organisms to study variation in color patterns between body parts and to address questions on pattern formation and establishment in animals.