5G mm-Wave Technology: Innovative Design of Integrating mm-Wave Wideband Antenna With a Compact CP Microwave Antenna for Diverse Applications

A compact dual-band antenna with a large frequency ratio and wideband mm-wave capabilities, incorporating multiple input multiple outputs (MIMO) technology, and designed for high isolation proposed for 5G applications. It contains a substrate-integrated waveguide (SIW) fractal Koch surface (FKS) slot antenna and a patch with L-shaped slots. A wideband performance is achieved by incorporating a novel FKS slot in SIW during ka-band operation. An L-shaped slot on a coaxial-fed microstrip patch is analysed to achieve circular polarisation in a sub-7 GHz band. The suggested wideband antenna attains improved diversity performance within MIMO systems. A prototype of the proposed antenna is fabricated. Measured results coincide aptly with simulated data. The low-frequency antenna operates at 4.8 and 6.29 GHz with a gain of 4.35 and 3.8 dBi and radiation efficiency of 85 and 88%, respectively. The mm-wave antenna operates from 27.1 to 33.2 GHz, with a bandwidth of 20.3% with a gain of 8.5 dBi and a peak efficiency of 93%. Isolation of ≥50 and ≥20 dB is achieved at low and high frequencies, respectively. Envelope correlation coefficient (ECC) value ≤ 0.001 and channel capacity loss (CCL) 0.1 bits/sec/Hz. The proposed MIMO systems exhibit lower Bit Error Rate (BER) performance over the AWGN channel. The design shows significant potential for application in mm-wave massive MIMO base station applications.