The design work presents a triple Y-fed dual substrate aperture coupled microstrip antenna that operates in C, X, and Ku bands. The overall dimension of the antenna is 50*40*1.894 mm. The antenna has four layers with two dissimilar substrates. A unique triple Y-structured feed line connected to a quarter-wave transformer forms the first layer of the design and shows a greater impact on impedance matching. A superimposed modified defected ground structure is sandwiched between two dissimilar substrates, FR4 and RT5880. The FR4 substrate is placed above the triple Y feed structure over which superimposed DGS is placed to obtain enhanced bandwidth. The third layer is formed by placing the second substrate RT5880 above the ground plane. The dielectric constant of the lower substrate is considered higher than the upper substrate to avoid undesired radiations at unwanted frequencies. A patch with three rectangular slots is placed over the RT5880 substrate for having tri-band characteristics. The patch is excited effectively through the slots in the ground plane thereby enhancing the coupling between the patch and the feed resulting in maximum radiation of RF energy. With this, an enhanced bandwidth of 12.66%, 16.67%, and 7.19% in all three bands is attained. Besides, the proposed design has a gain of 3.265 dBi at the C band, 3.305 dBi at the X band, and 4.385 dBi at the Ku band. The fabricated antenna is tested and the results are compared for both simulated and measured values. The results emphasize that a tri-band antenna can be used effectively in operating frequencies including the 5G wireless application band.

This communication presents the significance of a four-port 2×2 multiple input multiple output antenna operating in mid-band frequency for 5G handheld device application. A microstrip-fed reference truncated decagonal monopole antenna operating at 3.9 GHz and a modified split-ring resonator (SRR)-based low-pass filter that excites at a cut-off frequency of 6.5 GHz are designed. On introducing a stub line in the SRR structure, the proposed filter shows a good out-of-band rejection beyond 6.5 GHz. By integrating the filter into the reference monopole, a wideband filtering monopole with improved stopband performance is obtained. A four-port MIMO array is constructed by orthogonally positioning the antenna with a center-to-center separation of 0.25λ0. To improve isolation, a pair of inverted L-stubs of varying lengths is introduced. The closed loop formed by the interconnection of stubs enhances isolation within the frequency range of 3–3.5 GHz. The fabricated prototype fosters an impedance bandwidth of 66.67%, isolation >18.5 dB, an average suppression of 15 dB, an average peak gain >3.7 dB, envelope correlation coefficient < 0.015, Actual Diversity Gain (ADG) > 9.9 dB, Effective Diversity Gain (EDG) > 8.8 dB, and efficiency >88%. The proposed design is suitable for 5G sub-6 GHz applications such as n48, n77, n78, n79 bands, WiMAX, and LTE bands 42, 43, 46, 47, 48.