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Millimeter-wave antennas are the trend nowadays because of the necessity of higher data rates. Designing a supplementary efficient antenna capable of dealing with dual bands has several challenges. This chapter reports the problematic approaches introduced in the field of a millimeter wave design. Prevailing investigations in millimeter-waves and MIMO antennas have a tendency to emphasize discovering how to increase the data rate without the need of increasing the bandwidth and what type of antenna preferred in the 5G band. However, there is a little indication that researchers have come close to the issue of antenna integration in the mobile handset with the intent of adding multiple antennas with multi-band capability in a small space. Accordingly, the target of this chapter is to offer a summary of how the small-dimensional MIMO antennas with band duality for 5G mobile communications can be intended, designed, sustained and fabricated.

A two-element antenna system is introduced with good isolation in this manuscript. The offered °G antenna gets two resonance frequencies at 28/38 GHz. The offered antenna is designed and simulated using industry-standard software CST MWS program. The elementary antenna is conventional microstrip antennas placed at the end of the mobile handset. The obtained reflection coefficient is -27.908 dB from (26.961 - 29.266) GHz with impedance bandwidth of 8.19 % and -20.58 dB from (36.646 - 40.297) GHz with impedance bandwidth of 6.09%. The two ports are coupled with less than −30 dB. The achieved directivity, far-field gain, and efficiency are 7.581 dB i , 7.182 dB i and 91.24 % at 28 GHz and 9.716 dB i , 9.24 dB i and 89.63 % at 38 GHz, respectively. The size of the Rogers 5880 substrate is 55 × 115 mm2 with h = 0.508 mm and E r =2.2 which is a low-cost substrate and small size patches best suited for miniaturized devices.

A novel dual-band two port Multiple-Input-Multiple-Output (MIMO) antenna at 28/38 GHz bands for the approaching 5G wireless applications is configured and manufactured in this paper. The MIMO antenna takes in identically positioned two rectangular slotted patches with inverted I-shaped slots at the lower border of the mobile substrate. The system has an overall size of 55 x 110 x 0.508 mm3. The antenna works in a 1.0683 (27.58–28.649) GHz bandwidth at 28 GHz and 1.4306 (37.213-38.643) GHz 38 GHz. A defected ground construction (DGS) to raise the isolation among the two ports and magnify the antenna radiation is introduced. The isolation is further desirable than -29.4 dB and -27.3 dB for the higher and lower frequencies, respectively among antenna elements. The MIMO antenna is planned and optimized through CST-MW Studio 2017 simulator as well as by measurement. The results from simulation and measurement are in a good agreement in the meaning of reflection coefficients and mutual coupling of the introduced MIMO antenna.

This manuscript introduces the design and analysis of dual-band air-filled-slotted- loop MIMO antenna which operates at 28 and 38 GHz frequencies for coming fifth-generation 5G for mobile communications. The antenna designed using low-cost FR-4 substrate material that achieving good performance of means of gain and efficiency. The dual-band operation acquired by presenting an air-filled-slotted loop AFSL structures in the radiators. The antenna model contains radiating patch at the upper edge with three AFSLs for 28 GHz and radiating patch at the lower edge with three AFSLs for 38 GHz. The attained results demonstrate that the reflection coefficients for the upper and lower antennas below -10 dB in the frequency bands (27.7 - 28.7) GHz and (37.3 - 38.6) GHz with impedance bandwidths 3.5% for 28 GHz and 7% for 38 GHz which has the quality of covering the 5G band. The introduced antenna is designed and simulated by industry-standard CST 2017 MWS and HFSS programs with substrate size of 55 x 110 mm2with h = 1.6 mm and εr=4.3.

Propofol has a high incidence of pain on injection, particularly when a vein on the back of hand is used. Administration of lidocaine, either before or mixed with propofol remains the most widely used method to attenuate this pain. The use of opioids such as alfentanil and fentanyl has been found to decrease pain induced by propofol injection. The purpose of this study was to evaluate the effects of different doses of remifentanil and alfentanil in minimizing the pain caused by propofol.In this randomized, double-blind, placebo-controlled study, healthy premedicated children between the age group of 5-12 years admitted for adenotonsillectomy were randomly allocated to one of 6 treatment groups. Group I: remifentanil 0.25 microg kg(-1); Group II: remifentanil 0.50 microg kg(-1); Group III: alfentanil 15 microg kg(-1); Group IV: alfentanil 20 microg kg(-1) 60 s prior to propofol mixed with 1 mL of 0.9% normal saline; Group V: lidocaine 1 mL of 1% (10 mg) added to 100 mg of propofol and Group VI: normal saline. During the injection of propofol (3 mg kg(-1)) pain perception was assessed with a four-point behavioural scale: none, mild, moderate, or severe.There were 52 subjects in Group I, 51 in Group II, 49 in Group III, 52 in Group IV, 52 in Group V and 52 in Group VI; 63.46% of patients in Group I, 39.21% in Group II, 38.77% in Group III, 36.53% in Group IV, 38.46% in Group V and 84.61% in Group VI experienced pain. Statistically, Groups II, III, IV and V were significantly better than placebo in the reduction of propofol pain (P0.0001). Groups II, III and IV significantly reduced the pain in comparison with Group I (P0.001).Pretreatment with intravenous remifentanil 0.5 microg kg(-1), alfentanil 15 microg kg(-1) and 20 microg kg(-1) were equally effective in reducing pain associated with propofol injection in children between the age group of 5-12 years.

The paper presents an analytcal investigation of the behavior of reinforced high strength concrete slabs. A plasticity-based concrete model is used for the finite element analysis. The details are described of the study in which a suitable post-cracking tensile model of reinforced high-strength concrete was used based on the fracture energy of high strength concrete recorded from stress-displacement curves. The validity of the model is then established by comparison with the test results of reinforced high strength concrete slabs. The behavior of such slabs is examined through a parametric study. The sensitivity of the material model to different properties and edge restraints is also demonstrated.