This paper presents a novel slotted wideband microstrip patch antenna array with 2 decoupling structures that enabled isolation enhancement between 10 and 40 dB throughout the operating bandwidth of 4‐6.5 GHz. Four asymmetrical patches were first used as a unit cell to produce a multiresonance electromagnetic band gap (EBG) structure capable of increasing the isolation between the patch array by about 50 dB within the impedance bandwidth of 5.8‐6.4 GHz. By introducing 3 double F‐shaped etchings in the array ground plane, the isolation bandwidth is extended to 4.0‐6.5 GHz (ie, 48%) with measured isolation improvement of 10‐40 dB over the entire isolation bandwidth. The multiresonance EBG structure mitigates the surface waves propagating in the substrate while the double F‐shaped ground plane reduces the surface waves traveling on the ground plane. The edge‐to‐edge spacing between the 2 patch antennas is 25.2 mm which is equivalent to 0.42 λ0 (λ0 is the free‐space wavelength at the center frequency of 5.0 GHz). After loading the decoupling structures in the antenna array, the gain increased from 5.6 dB to 7 dB. The proposed antenna is fabricated and there is an acceptable agreement between the simulated and measured results. The antenna radiation characteristics are observed to be fairly consistent over the large operating bandwidth of 4‐6.5 GHz. The proposed antenna is a potential candidate for wideband wireless applications in the sub‐6 GHz band.

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This paper proposes a simple novel technique for self-isolating a MIMO antenna for mmwave applications. MIMO antenna elements with inter-element separation of 0.2 mm (0.023λ at 35 GHz) and measured high isolation (> 50 dB) are presented. By observing the concentration of surface waves on the radiating patch, several rigorously optimized slots of different shapes, positions, and dimensions are etched on the patch to enhance the inter-element isolation and increase the bandwidth within 28-37.5 GHz. The circuit models of the reference and proposed antennas have been presented. The coupling is measured by the level of the differences in the output voltage in both antennas. The novel mm-wave antenna exhibits high impedance bandwidth (> 29%), high isolation (> 50 dB), high efficiency (> 90%), and low envelope correlation coefficient (<0.005). Two configurations of MIMO antenna (i.e, 1×2 and 1×4) are fabricated and measured to validate the simulation outcomes. The single reference antenna has dimensions of 10x12 mm 2 while the 1x2 array has dimensions of 19x12 mm 2 . The presented design is the first to exhibit such wideband isolation improvement without any external decoupling structure at the mm-wave frequency range, to the best of the authors' knowledge.INDEX TERMS Self-isolated antenna, mm-waves, multiple-input-multiple-output (MIMO), 5G Antennas, Patch Antenna, Surface Waves, Mutual Coupling.

This paper proposes a novel electromagnetic band gap (EBG) structure based on a duallayer dual-patch unit (DLDP-EBG) cell to improve isolation and decrease envelope correlation between MIMO slot antenna array elements. A wideband MIMO slot antenna array operating in the frequency range of 4.2-6.5 GHz (43%) is deployed. The antenna array is based on slotted rectangular microstrip radiating elements printed on the top surface of two stacked FR4 substrates to widen the array impedance bandwidth. A 2 × 7 dual-layer DLDP-EBG unit cell is inserted between the array elements to reduce the mutual coupling and deflect the individual beams of each antenna in opposite directions. An isolation improvement of up to 56 dB is maintained throughout the working bandwidth of the antenna, when the EBG is inserted. Also, the DLDP-EBG unit cells reduce the envelope correlation coefficient by 5-30 dB across the whole operating bandwidth by deflecting the radiation beams of the individual antenna elements in opposite directions. The MIMO array gain and radiation efficiency have been improved after using the EBG structure due to the reduction in mutual coupling and surface wave mitigation between the array elements. The proposed low-profile MIMO slot antenna array is the first in literature to exhibit such wideband isolation improvement, gain enhancement, and correlation reduction behavior simultaneously.

Recently, more people are showing interest in knowing what the packaged food they buy contains, and not just that, they want to also know the different processes those foods went through, at least to a certain extent. This rising interest can be traced to the rising need for special diets and nutritional requests of certain groups of people who wants to either just live a healthier lifestyle or are made to turn to healthy eating due to health challenges occasioned by illnesses. The importance of the lactic acid bacteria to the food industry cannot be over-emphasized and as such, more awareness about it should be created for informational purpose. Although there are numerous literature on lactic acid bacteria online, mostly dealing with their identification and purification, there is a gap in getting these technical information together in a form that can be understood by anyone who wishes to learn more about lactic acid bacteria. This review article explores the numerous benefits of lactic acid bacteria in the food industry, highlighting its key uses for fermentation and preservation. More so, this review pinpoints the health benefits of certain strains of lactic acid bacteria in form of probiotics in addition to its well-known antimicrobial properties. Lactic acid bacteria confers numerous beneficial characteristics to foods ranging from enhanced taste to provision of healthy probiotics. Lactic acid bacteria may also experience a decrease in viability and functionality when stored while controlling and optimizing their metabolic activity is another major concern in the food industry. Key words: Lactic acid bacteria, probiotics, fermentation, food preservation, antimicrobial, starter cultures.