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.
The antenna has been fed by a 50 [OHM] microstrip line loaded by a tuning stub
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.
With the given slot perimeter and tuning stub
length, the resonance is obtained at 3.
To design slot antennas with band notch function, one simple and effective way is to incorporate slots (known as half-wave resonant structures) in the antenna's tuning stub
with U-shape , T-shape , C-shape slots [8, 12] etc.
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
In order to compensate of the inductive reactance, the tuning stub
acted like a capacitive reactance is joined to form an open transmission line.
A shorted, variable length tuning stub
was added to the fifth port to provide an extra tuning adjustment.
To design slot antennas with band-notched function, one simple and effective way is to incorporate slots (known as half-wave resonant structures) in the antenna's tuning stub
, such as a U-shaped , V-shaped , C-shaped slots [27, 28], etc.