Isolation enhancement of a capacitively-fed MIMO antenna using a quasi-fractal parasitic element and defected ground structure

Syed Naheel Raza Rizvi; Md Abu Sufian; Niamat Hussain; Yangbae Chun; Seong-Gyoon Park; Sunggoo Kim; Nam Kim

doi:10.1016/j.heliyon.2024.e39228

Isolation enhancement of a capacitively-fed MIMO antenna using a quasi-fractal parasitic element and defected ground structure

Heliyon. 2024 Oct 12;10(20):e39228. doi: 10.1016/j.heliyon.2024.e39228. eCollection 2024 Oct 30.

Authors

Syed Naheel Raza Rizvi¹, Md Abu Sufian¹, Niamat Hussain², Yangbae Chun¹, Seong-Gyoon Park³, Sunggoo Kim¹, Nam Kim¹

Affiliations

¹ Department of Information and Communication Engineering, Chungbuk National University, Cheongju, 28644, South Korea.
² Department of Intelligent Mechatronics Engineering, Sejong University, Seoul, 05006, South Korea.
³ Department of Information and Communication Engineering, Kongju National University, Gongju, 314701, South Korea.

Abstract

Vehicular Internet of Things (IoT) is facilitated by efficient RF front ends with suppressed mutual coupling for enhanced spatial diversity and increased channel capacity. This paper presents a mutual coupling suppressed MIMO antenna with a hybrid decoupling technique for Vehicle-to-Everything (V2X) communications, enabling IoT in automotive systems. The single elements consist of a radiating patch with a cleaving circular slot to introduce a capacitive effect on the radiating structure. Afterwards, the single-unit design is further extrapolated to a 2 × 2 MIMO antenna. The mutual coupling is suppressed between antenna elements by introducing a quasi-fractal parasitic element and a defected ground structure (DGS). The MIMO antenna is designed to conform to the requirements posed by V2X systems in Dedicated Short-Range Communications (DSRC) and Intelligent transportation system (ITS) scenarios. The proposed MIMO antenna offers measured |S₁₁| < -10 dB of 200 MHz, ranging from 5.77 GHz to 5.97 GHz, fully covering the spectrum guided by the IEEE 802.11p standard. A physical prototype is fabricated and placed on a car roof to assess the congruency between measured and simulated results. The MIMO antenna exhibits exceptional diversity properties, such as enhanced isolation (>28 dB) between its individual elements, a diversity gain (DG) close to the ideal value of 10 dB (9.99 dB), peak realized gain of 6.5 dBi, an ECC below 0.001, and a beam coverage area of 180° in azimuthal and elevation plane by dynamic port switching. Thus, the proposed MIMO antenna module is a considerable candidate for future V2X communication paradigms.

Keywords: DSRC; ITS; Internet of things (IoT) antenna; MIMO antenna; Vehicle-to-everything (V2X) communications; Vehicular internet of things.