Electromagnetic interference (EMI) is one of the biggest challenges faced during the production of any electronic device. The effect on the performance of the instrument due to these inevitable interferences must be carefully measured to understand and quantify the electromagnetic compatibility (EMC) of the instrument under test. If the EMI profile of the system does not meet the accepted standards, then it becomes necessary to take measures to reduce the influence of these unwanted interferences so that the equipment can be used in the real world. Unfortunately, research and studies on EMI and EMC have not received their due attention from the scientific community. Moreover, the literature available for this area of research is scattered where different sources provide information on one or more (but not all) aspects of EMI/EMC while ignoring the others. With the objective of encompassing this extremely significant area of research in its entirety, this review presents both EMI measurement techniques and EMI reduction techniques in detail. EMI measurement techniques are presented under two sections that deal with emission testing and immunity testing, respectively. Herein, EMI reduction techniques are presented under four sections, where electromagnetic shielding has been given special attention under which various methods used by the scientific community to measure the shielding effectiveness of a material or microwave absorber and its application in EMI reduction are illustrated. This is followed by EMI filters, circuit topology modification and spread spectrum. This review can help students and young scientists in this area to get an idea of the ways to conduct EMI tests as well as the ways that can be employed to reduce the EMI of the system, depending on the application.

A multi-purpose dual Multiple-Input-Multiple-Output (MIMO) antenna system for 5G mobile systems is presented in this paper. The proposed antenna consists of two sets of MIMO antennas on a single board. The 8-port MIMO antenna, placed on the board, is working over 3.5 GHz (3.4 GHz-3.6 GHz) 5G band with dimensions 150 mm × 70 mm. The 4-port MIMO system, placed on the chasis, is operating over 5.2 GHz WLAN/5.5 GHz WiMAX/5.8 GHz/6 GHz WiFi band with dimensions 20 mm × 7 mm. The prototype is designed and fabricated on FR4 ( r = 4.4 and tan δ = 0.02) substrate with 0.8 mm thickness. The overall design of the entire dual MIMO system is very minimal leaving ample space for other components to be placed on the board. The presence of two separate MIMO antennas in the proposed prototype aids in using the 5G frequencies and 4G frequencies independently. Since no active elements like diodes, switches etc. are involved in the proposed design to switch between different bands, the prototype is free from any ohmic losses. It is also worth noticing that the proposed antenna operates in the highly anticipated next generation WiFi 6E spectrum.

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In this paper, the concept of a novel mechanically reconfigurable antenna with spectral diversity, for internet of things (IoT) applications is presented. The prototype consists of a rectangular microstrip patch antenna placed upon a dielectric slab with four end‐to‐end cavities that are perceived as binary bits. The status of each bit depends on the material filling it. Since four cavities are included in proposed system, a total of 16 combinations, each yielding unique impedance characteristic, are exhibited. Here, FR4 epoxy (εr = 4.4 and tanδ = 0.02) is used as substrate with 2.4 mm thickness. The same material is used to fill the cavities in one case, while, in the second case the cavities are filled with Rogers RT/duroid 6010/6010LM (tm) material that has dielectric constant, 10.2. It is shown that by using a higher dielectric constant material as filler, the range of variation of resonant frequency can be increased. In both cases, the prototype exhibits capability to reconfigure its operating bandwidth from 2.4GHz WLAN (2400‐2480 MHz) to LTE2500 (2496‐2690 MHz). Besides, for some combinations, the prototype covers a frequency span beyond LTE till 3000 MHz for wireless‐sensor‐network based applications. One among the potential application of the proposed design as a chipless RFID tag is also discussed in this work.

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