To upgrade the bandwidth transmission, the microstrip line is nourished by fork-like tuning stub
3 a vertical tuning stub
(L10 x W2) has been located in the feed structure and the gap between the signal strip and the ground plane is widened at the end.
A printed wide-slot antenna  fed by a microstrip line with a fork-like tuning stub
provided broad bandwidth through the proper parameters of the fork-like tuning stub
The antenna has been fed by a 50 [OHM] microstrip line loaded by a tuning stub
. The combination of hexagonal wide slot and rectangular tail slot is structurally different from the entire existing UWB slot antenna configuration.
A printed monopole antenna with a tuning stub
shaped with one horizontal arm and one vertical arm was proposed in .
Reference Antenna 2--UWB Slot Antenna Excited by Fork-Shaped Tuning Stub
Other annular-slot antennas with strip-loaded [12,13] or different structure of tuning stub
 are proposed for better impedance matching.
In , a slot antenna with a circular tuning stub
and a circular slot has been investigated, which produces a bandwidth of 143.2%.
With the given slot perimeter and tuning stub
length, the resonance is obtained at 3.4 GHz with bandwidth from 3.1 GHz to 3.9 GHz.
Before long, people found that the different designs of wide slot and tuning stub
of the printed antenna have an effective impact on the impedance bandwidth [8-17].
However, the reactance of the second slot must be compensated by a matching network that consists of a simple radial tuning stub
Lin, "Circularly polarized microstrip antenna with a tuning stub