This paper proposes a hybrid decoupling method based on a novel electromagnetic bandgap (EBG) structure and hair-pin shaped defected ground structure (DGS) to obtain high isolation between 2element multiple input multiple output (MIMO) antenna at 5G millimeter wave band over 27.5−28.35 GHz. The proposed EBG designed on stacked dielectric substrates, achieves a wide frequency band-gap between 26.2−32.03 GHz (20 %). A 2  3 array of the EBG is arranged between two electromagnetically coupled radiating patches in order to suppress the surface wave coupling. Substrate integrated waveguide (SIW) feeding network and cavity are strategically incorporated in the antenna design for improving the radiation performance and minimizing the losses from the feed. EBG shows an average isolation improvement of 13.9 dB within 5G band as compared to unloaded MIMO antenna. The additional reduction in coupling is achieved by placing hair-pin DGS (HP-DGS) on the ground plane, resulting into maximum isolation improvement of 47.7 dB at 27.94 GHz. The prototype of the MIMO was fabricated and experimentally verified. Measured peak isolation between the antennas is obtained as 71.9 dB, having a gain of 9 dBi and front to back ratio (FTBR) of 19.8 dB. A good diversity diversity performance is also noticed for the designed MIMO with envelope correlation coefficient (ECC) of 0.00015, diversity gain (DG) of 9.99 and channel capacity loss (CCL) of 0.025 bits/Hz/sec. Later, SIW corporate feed network is designed for 4-element linear array loaded with EBG and HP-DGS to achieve higher gain and narrow beamwidth. The array was fabricated and the measured results are found in good accordance with the simulation results. The peak gain, beamwidth, and FTBR of the array are 13.3 dBi, 16.2, and 19.97 dB respectively.INDEX TERMS Antenna array, defected ground structure (DGS), electromagnetic bandgap (EBG), mutual coupling reduction, multiple input multiple output (MIMO)

Purpose Rubber leaves are the abundant agro-waste and pineapple, the most economically important fruit crop in Tripura. So, in our present study, different amounts of rubber leaf vermicompost have been applied to the soils of pineapple plantation to determine their effects on earthworms-the soil ecosystem engineers, coupled with the vegetative growth and yield of pineapples. Methods During 30 months of field trial (2010-2012) in ICAR regional station, Lembucherra, West Tripura, the control plot (T 0 ) received no fertilizer, while experimental plots were fertilized with four different amounts of vermicompost viz. T 1 (5 tons ha -1 year -1 ), T 2 (10 tons ha -1 year -1 ), T 3 (20 tons ha -1 year -1 ) and T 4 (30 tons ha -1 year -1 ). Results A significant (p \ 0.05) but gradual increase in density (up to T 3 treatment) and biomass (up to T 4 treatment) of earthworms were recorded with the increasing amounts of vermicompost. During the second year, average length and width of leaves, number of leaves per plant, plant girth, fruit weight, fruit yield and fruiting percentage were highest in the T 3 plot compared to other treated plots and control. ConclusionThe present study reveals that crop yield is very much related to the particular concentration of vermicompost, beyond the level of which production declines and increase in vegetative growth, fruit weight and fruiting percentage of pineapple are strongly linked with the soil pH, av. P, av. K, clay content and the earthworm density of soils.

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In this paper, we study ∗-Conformal [Formula: see text]-Ricci soliton on Sasakian manifolds. Here, we discuss some curvature properties on Sasakian manifold admitting ∗-Conformal [Formula: see text]-Ricci soliton. We obtain some significant results on ∗-Conformal [Formula: see text]-Ricci soliton in Sasakian manifolds satisfying [Formula: see text], [Formula: see text], [Formula: see text] [Formula: see text], where [Formula: see text] is Pseudo-projective curvature tensor. The conditions for ∗-Conformal [Formula: see text]-Ricci soliton on [Formula: see text]-conharmonically flat and [Formula: see text]-projectively flat Sasakian manifolds have been obtained in this paper. Lastly we give an example of five-dimensional Sasakian manifolds satisfying ∗-Conformal [Formula: see text]-Ricci soliton.

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The object of the present paper is to study some properties of Kenmotsu manifold whose metric is conformal $\eta$-Einstein soliton. We have studied certain properties of Kenmotsu manifold admitting conformal $\eta$-Einstein soliton. We have also constructed a 3-dimensional Kenmotsu manifold satisfying conformal $\eta$-Einstein soliton.

SummaryThirty-four soils from the Rothamsted Experiments were exhaustively cropped with ryegrass in the glasshouse. The concentration and yield of potassium in ryegrass tops and the potassium intensity in the soil were measured every 4 weeks, after harvesting the grass.The change in K-intensity of soils, rich in potassium, with exhaustion differed from that of ‘poor’ soils. This change was related to the rate of change of the cumulative K-yield. The rate of change of soil K-intensity demarcated periods of intense and limited exhaustion and partial recovery of the soil during cropping.The cumulative K-yield of ryegrass was very significantly related to the K-intensity of the uncropped soil; the ‘16-week’ yield was slightly better related than the ‘60-week’ yield. For Park Grass soils, the relationship was improved by allowing for variations in soil pH.The K-intensity of all soils, with or without manuring, decreased to nearly 10-3 (M)½ in (AR)0 units after 16 weeks cropping, although large differences in K-yield persisted until much later.K-buffer capacity per unit clay content of the soil, measured by a laboratory method, was inversely related to the K-intensity of the uncropped soil. The K-buffer capacities of soils rich in potassium, measured in laboratory and glasshouse experiments, were significantly related, but were unrelated for ‘poor’ soils. The K-buffer capacity (laboratory method) of Rothamsted soils with different manurial treatments was only very approximately related to the cumulative K-yield.Less K was taken up from all Rothamsted soils given nitrogen fertilizer in the field and their K intensities were also smaller than the corresponding soils without ‘N’. Field liming of acid soils decreased their K-intensity and increased their K-buffer capacity, presumably because more potassium was removed by the field crop.A rapid method is suggested for measuring potassium intensities of soils.