 10 dB impedance bandwidth of this setup ranges from 2.25-3.0 GHz, having low isolation throughout. Impedance matching, bandwidth, and isolation have all been improved with four-line stubs inserted in the upper half on the ground plane. Multi parallel lines serve like a resonator, generating transmission zeros between antenna pairs. The corresponding results reveal that the 10 dB bandwidth varies between 2.25-3.0 GHz. SRR is put on the base plane at the back side of the antenna, while CSRR has been mounted on the radiator patch to reduce signal interference in the ISM band [32-36]. MIMO Antennas for loT and ISM Band 11.4 DISCUSSION AND RESULTS 11.4.1 SCATTERING PARAMETERS FOR MIMO ANTENNAS In the following subsection, the scattering parameters of the proposed Compact 4-Port MIMO antenna construction including the terms reflection coefficient, Z-parameters, and antenna to antenna isolation is discussed in depth. 11.4.1.1 Reflection Coefficient The simulated and measured reflection coefficient plots for the suggested MIMO antennas are shown below. Some parameters of MIMO antennas are altered for isola- tion enhancement; hence MIMO antennas have a slightly different 10dB bandwidth than the suggested single-element antenna. The antennas provide good impedance matching throughout a broad frequency range of 2.0-4.0 GHz, which corresponds to a fractional bandwidth of 15.9% with regard to the central operating frequency. Because all of the antenna elements have symmetrical form and location, the reflec- tion coefficient curves are nearly identical. Due to measurement limitations, there is a small variance in the measured reflection coefficients among the antenna elements. The reflection coefficient (in dB) of the first port is shown in Figure 11.2(a) and the combined result of all the ports is given in Figure 11.2(b). 11.4.1.2 Z-Parameters The Z parameter is used to determine an antenna's quality factor, which can pro- vide information about the available bandwidth. Z(ant) = R+jX, where R = R(rad) + R(Loss), hence the lo