Not all signals are a good signal! Electromagnetic interference (EMI) is an unwanted electromagnetic signal that often causes problems when it interferes with other electronic equipment. EMI is one of the many challenges in the rapid growth of smart electronic devices that often are placed in plastic cases. The plastic cases provide little to no protection, making it easy for EMI to pass through and cause device malfunctions. To protect against the EMI, EMI shielding was used.

Conventionally EMI shielding uses solid or mesh metal gaskets. However, works on polymers to replace the conventional methods have been on the rise due to the lightweight and flexibility that polymers offer, making it useful in personal electronic devices and the aerospace industry, in which weight, size, and high EMI shielding are essential. EMI shielding comprises two mechanisms: shielding efficiency due to reflection (SER) and shielding efficiency due to absorption (SEA) (figure1). Polymers with high conduction offer higher SER and can be attained by utilizing either ionic conductivity, electron conductivity, or both. The SEA of a polymer can be improved by altering the dielectric and magnetic properties of the polymer. The adjustment to the polymer can be made by chemical modification of the polymer chain or by a mechanical process of inserting selected material as filler into the polymer matrix.

Our current work aims to produce free-standing, flexible and transparent high shielding efficiency polymer. This includes works utilizing various filler ranging from metal ions, carbon, oxide, ferroelectric, magnetic and many more (figure2). The possibility of using hybrid material to increase shielding efficiency further has also been examined. This includes work on a single layer and sandwich polymer. To date, shielding efficiency ranging from 1.5 dB to 34 dB has been recorded from various fillers, correspondence to 29 % to 99.95 % EM energy shield [1-2]. We are working to achieve the industrial standard of 40 dB (99.99 % EM energy shield) requirement. 

Figure 1: EMI shielding mechanisms of a shielding polymer

 

Figure 2: EMI shielding polymer with various fillers

References:

1. Osman, N.H.; Mazu, N.N.; Ying Chyi Liew, J.; Ramli, M.M.; Sandu, A.V.; NabiaÅ‚ek, M.; Abdull Majid, M.A.H.M.; Mazlan, H.I. “Sodium-Based Chitosan Polymer Embedded with Copper Selenide (CuSe) Flexible Film for High Electromagnetic Interference (EMI) Shielding Efficiency”. Magnetochemistry 2021, 7, 102.

 

2. N. Mazu, M. A. H. M. A. Majid, N. H. Osman, J. Y. C. Liew and M. M. Ramli, "Shielding Efficiency Study of Sodium Based Chitosan Polymer with Different Types of Filler," 2020 IEEE International RF and Microwave Conference (RFM), 2020, pp. 1-4.

 

About Author

Nurul Huda Osman (Dr.) Department of Physics, Faculty of Science, Universiti Putra Malaysia Expertise: Microwave Planar Components, Material Characterization, Sensor Design Email: nurulhuda@upm.edu.my

Date of Input: 26/07/2024 | Updated: 26/07/2024 | harithdaniel