Frequency Reconfigurable MIMO antenna: Previous advancements

¹ LabSTIC, ENSA of Tetouan, Abdelmalek Essaadi University, Tetouan, Morocco
² STIC Laboratory, Faculty of Sciences, Chouaib Doukkali University, El Jadida, Morocco

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 3 August 2026

Abstract

This paper presents a comparative study of six recent publications on frequency-reconfigurable MIMO antennas for wireless communications, covering works published between 2019 and 2023. The reviewed designs span PIN-diode switching, varactor-based continuous tuning, and band-notch reconfiguration strategies, targeting 4G LTE, sub-6 GHz 5G, Ultra-Wideband (UWB), WLAN, WiMAX, and cognitive radio applications. Key performance metrics are systematically compared: gain ranges from 1.15 to 7.7 dBi, radiation efficiency from 60% to over 85%, port isolation from 12 to 30 dB, and Envelope Correlation Coefficient ECC from less than 0.001 to 0.2 Results show that PIN-diode designs dominate current implementations due to their low cost and fast switching speed. Among the reviewed works, reference [1] achieves the best balance of ECC, isolation, fabrication simplicity for sub-6 GHz LTE/5G applications, while reference [2] offers superior isolation (>30 dB) and ultra-low ECC (<0.001) for UWB scenarios. Persistent challenges include switching losses, mutual coupling in compact arrays, and discrete tuning limitations, with future research converging on RF MEMS, AI-driven reconfiguration, and SDR integration.