Stub-Loaded Compact Patch Antenna for 5G Sub-6 Ghz and Wi-Fi 6E Application

Abstract

A small stub-loaded monopole antenna using a co-planar waveguide (CPW) transmission line
is proposed and implemented in the present study. The antenna offers (i) a wide bandwidth
characteristics and (ii) high efficiency with appropriate gain. The measured reflection
coefficient (S11 < -10dB) covers 2.4-2.55 GHz (bandwidth 150 MHz) and 3.24-7.28 GHz
(bandwidth 4 GHz) bands. The antenna's overall electrical dimensions are
0.16λL×0.24λL×0.0128λL, where λL is free space wavelength at 2.45 GHz, corresponding to
the lowest resonating frequency. Inverted L-type stubs are attached with the radiating element
and in the vicinity of the wide slot of the main radiating element to cover the 2.45 and 5.6
GHz WLAN and 2.5 GHz and 5.2 GHz Wi-Fi 6E wireless standards. A pentagonal ring is
optimised to cover the 3.7 GHz Sub-6 5G frequency band. A prototype antenna is developed
using an affordable, cheap, low-profile, 1.6 mm thick FR-4 substrate having relative
permittivity (εr= 4.4). The simulated efficiency for all the frequency bands is more than 80%.
Average gain ranges from 2 to 5 dB. The simulated results are validated with measured
experimental results, which approve radiation pattern, impedance bandwidth, efficiency and
steady gain throughout the operating bands. The discussed and proposed antenna is compact,
efficient, without vias, and easy to fabricate with improved performance.