Design and Investigation of Orthogonal Hybrid Dual-Mode Single-CDR-Based MIMO Antenna With High Self-Isolation at 5.8GHz

In this article, a dual-port single-element coaxial probe-fed cylindrical dielectric resonator MIMO antenna is designed and investigated. The high-permittivity dielectric ( ${\varepsilon }_{\mathrm {r}}=15$ ) is composed of barium-titanate-doped polydimethylsiloxane (PDMS) silicone polymer. The orthogonal excited antenna generates orthogonal modes ( $\mathrm {H}\mathrm {E}_{11\delta }^{\mathrm {x}}$ and $\mathrm {H}\mathrm {E}_{11\delta }^{\mathrm {y}}$ ) with high port-to-port self-isolation ( $\lt -21$ dB) without additional mutual coupling reduction structures. The antenna achieved bandwidths are 5.65–5.96 GHz (gain: 8.91 dBi) and 5.62–5.92 GHz (gain: 8.97 dBi) for Port1 and Port2, respectively. It has an axial ratio >26.5 dB, ensuring orthogonal linear polarization characteristics and improved isolation. The antenna attains excellent MIMO parameters; TARC $\lt -10$ dB, VSWR-MIMO <2, ECC <0.24, DG $\sim ~10$ dB, CCL <0.4 bits/sec/Hz, and MEG $\lt \pm 3$ dB in operating bandwidth. The HFSS simulated and investigated performance parameters of the MIMO antenna are found to be in excellent agreement with experimental data, this validates the antenna’s MIMO functionality. The antenna is modeled as a parallel RLC equivalent circuit in ADS using a novel technique based on complex-valued impedance parameters (Zij). This approach demonstrates improved accuracy, validated by both simulations and measurements. The antenna is suitable for ISM (5.725–5.85 GHz), WLAN 5.8 GHz, C-band (5.0–6.0 GHz).