Design and Development of Compact Ultra-Wideband Millimeter-Wave Planar Antennas for Next-Generation Wireless Communication Systems: A Comprehensive Review

Abstract

The emerging sixth-generation (6G), beyond-fifth
generation (B5G) and fifth-generation (5G) wireless systems are
rapidly developing, which has led to the need for antennas that are
compact, have wide impedance bandwidth, and have adequate gain
and reliable radiation. The planar antennas are desirable for their
lightweight, low-profile, economical, and printed circuit
manufacturing compatibility. This review reflects recent advances in
planar UWB and mmWave antenna research, with a focus on the
topics of bandwidth extension, miniaturization, gain enhancement,
band-notched, MIMO, wearable applications, choice of substrate,
and the design through Artificial Intelligence (AI). The following are
major methods: Slot loading, defected ground structures (DGS),
coplanar-waveguide (CPW) feeding, parasitic elements, fractal
geometries, engineered electromagnetic surfaces and antenna arrays.
The literature shows that hybrid configurations can yield good
balance in performance, but bandwidth/ gain/efficiency/size/c
Fabrication Tolerance are still interdependent. Key research areas
include low loss and low-cost substrates, optimization that is tolerant
of the substrate, repeatable measurements, multifunctional
integration, and AI models that are more transferable. These
directions are applicable to future communication and sensing
platforms in practice, featuring high-performance antennas.

Keywords-Ultra-Wideband (UWB), millimeter-wave (mm Wave),
planar antenna, DGS, CPW, MIMO, 5G, B5G, 6G, artificial
intelligence.