In this paper, the systematic design of a multiple antenna system for 5G smartphone operating at 3.5 GHz for multiple-input multiple-output (MIMO) operation in smartphones is proposed. The smartphone is preferred to be lightweight, thin, and attractive, and as a result metal casings have become popular. Using conventional antennas, such as a patch antenna, Inverted-F antennas, or monopole, in proximity to metal casing leads to decreasing its total efficiency and bandwidth. Therefore, a slot antenna embedded in the metal casing can be helpful, with good performance regarding bandwidth and total efficiency. The proposed multiple antenna system adopted the unit open-end slot antenna fed by Inverted-L microstrip with tuning stub. The measured S-parameters results agree fairly with the numerical results. It attains 200 MHz bandwidth at 3.5 GHz with ports isolation of (≤−13 dB) for any two antennas of the system. The influence of the customer’s hand for the proposed multiple antenna system is also considered, and the MIMO channel capacity is computed. The maximum achievable MIMO channel capacity based on the measured result is 31.25 bps/Hz and is about 2.7 times of 2 × 2 MIMO operation.

As a promising optical method used in a variety of applications surface plasmon resonance (SPR) sensors are employed over a wide range of boundaries. This research proposes a highly sensitive SPR based sensor with a novel hybrid structure using transition metal dichalcogenides (e.g. WSe2, PtSe2) along with black phosphorene (BP) through comprehensive numerical study. To analyze and evaluate the performances of the proposed sensor, the widely used transfer matrix method (TMM) was used. The performances of the sensor were measured in terms of reflectivity, sensitivity, detection accuracy (DA), and figure of merit (FOM). The sensor structure was optimized by changing different structural parameters of the hybrid architecture to obtain better performances. The results revealed that insertion of PtSe2 with WSe2 and BP over a gold layer of the conventional structure improved the performance of the sensor and the maximum sensitivity of the sensor was measured as 200 deg/RIU with a FOM of 17.70 RIU-1. As well, the light penetration through the optimized sensor is investigated using the finite element method (FEM) based software. With this kind of high sensing capabilities, it may be convinced that the proposed sensor can be applied in different fields of biosensing to detect liquid biological and biochemical samples or analytes.

A low-profile (0.21 ${\lambda }_g$ × 0.35 ${\lambda }_g$ × 0.02 ${\lambda }_g$ ) and a simply-structured frequency-switchable antenna with eight frequency choices is presented in this paper. The radiating structure (monopole) is printed on a 1.6-mm thicker, commercially-available substrate of FR-4 ( ${ϵ}_r$ = 4.4, tan $\delta$ = 0.020). Specifically, it uses three PIN diodes in the designated places to shift the resonant bands of the antenna. The antenna operates at four different modes depending on the ON and OFF states of the PIN diodes. While in each mode, the antenna covers two unique frequencies (Mode 1 = 1.8 and 3.29 GHz, Mode 2 = 2.23 and 3.9 GHz, Mode 3 = 2.4 and 4.55 GHz, and Mode 4 = 2.78 and 5.54 GHz). The performance results show that the proposed antenna scheme explores significant gain (>1.5 dBi in all modes) and reasonable efficiency (>82% in all modes) for each mode. Using a high-frequency structure simulator (HFSS), the switchable antenna is designed and optimized. The fabricated model along with the PIN diode and biasing network is tested experimentally to validate the simulation results. The proposed antenna may also be combined in compact and heterogeneous radio frequency (RF) front-ends because of its small geometry and efficient utilization of the frequency spectrum.

A numerical illustration of a hybrid design and numerical analysis of graphene-coated fiber-optic surface plasmon resonance (SPR) biosensor for BRCA-1 and BRCA-2 genetic breast cancer detection is provided. Two specific mutations named 916delTT in BRCA-1 gene and 6174delT in BRCA-2 gene are being selected for detection of breast cancer numerically. This sensor is based on attenuated total reflection (ATR) method to detect individual point mutations in BRCA-1 and BRCA-2 genes. Based on the numerically obtained results, a momentous change is present in the SPR angle (minimum 35% more) and surface resonance frequency (SRF) (minimum 36% more) for probe DNA with various concentrations of target DNA corresponding to the mutation of the BRCA-1 and BRCA-2 genes. The variation of the SPR angle and SRF for mismatched DNA strands in BRCA-1 and BRCA-2 genes is quite negligible, whereas that for complementary DNA strands is considerable. This considerable change is essential for proper detection of genetic biomarkers (916delTT and 6174delT) for early breast cancer. To the best of our knowledge, this is the first demonstration of such an adept biosensor for detecting BRCA1 and BRCA2 genetic breast cancer. Here, we used graphene as bimolecular acknowledgement element for improving sensor performance. At the end of the article, the performance in terms of sensitivity is analyzed. Therefore, the proposed biosensor opens a window toward detection of early detection of BRCA-1 and BRCA-2 genetic breast cancers.