Four port MIMO antenna for IoT applications in public safety band and sub-6 GHz TDD 5G band

Abstract

This paper proposes a Multi Input Multi Output (MIMO) antenna specifically developed for Internet of Things (IoT) Applications in Public Safety 4.9 GHz (4940–4990 MHz) band and Sub-6 GHz TDD 5G band (4800–4990 MHz). The proposed MIMO antenna consists of Koch fractal element, and it is introduced in four port configuration. HFSS is used to design, analyze, and optimize the performance parameters of the introduced MIMO antenna. To achieve optimum performance in terms of isolation, initially all two radiating elements of 1 × 2 MIMO configuration with varying orientations have been evaluated, which are positioned on top of a cost-effective FR4 substrate. Later on 2 × 2 and 1 × 4 MIMO configurations are evaluated; and 1 × 4 configuration is fabricated and tested in lab for the verification of simulated results. The MIMO antenna demonstrates resonance at 4.97 GHz, offering a bandwidth of 320 MHz (4795–5115 MHz). It exhibits excellent performance with Envelope Correlation Coefficient (EC-C) < 0.4, Diversity Gain (D-G) > 9.8, Mean Effective Gain (ME-G) < 3 dB, Total Active Refection Coefficient (TAR-C) < −14 dB, Channel Capacity Loss (CC-L) < 0.4 bits/s/Hz, and Isolation < −20 dB across the entire operating frequency range. The proposed MIMO antenna has a maximum gain of 1.2 dBi and radiation efficiency (η) of 80%. This proposed antenna offers several advantages over traditional ones, including high efficiency (η), low CC-L, and significant isolation, even without the use of special techniques to achieve isolation.