Page 264 - 2024-Vol20-Issue2

260 | Majeed
(a)
band-notching techniques shouldn’t require the current an-
tenna to be any bigger or function any differently [7].
This work presented a small-size UWB patch antenna with an
elliptical radiating patch on the substrate’s front side and an
ellipse-shaped slot etched on the substrate’s back side. The
dimensions of both elliptical shape patch and ground plane
elliptical slot were selected to provide the possibility for more
bandwidth. The proposed antenna includes two rejected bands
4.89–5.79GHz (WLAN) and the 7.2–8.45GHz (X-band satel-
lite system) in order to avoid interfering with these systems.
In order to reject these two frequency bands, a radiating patch
is etched with two slots, an inverted U shape slot and a U
shape slot. Since the extra two slots are integrated into the
radiating patch, they provide the necessary band-notching
without requiring any additional space, allowing the antenna
to remain the same size. Section II. provides an explanation
of the antenna’s design mythology, Section III. presents the
experimental results of the manufactured prototypes, and Sec-
tion IV. lists the final conclusions.

II. DESIGN MYTHOLOGY

A. The Fundamental Antenna (b)

The elliptical patch utilized as the active antenna, with major Fig. 1. The proposed fundamental antenna geometry, (a)
and minor radii of a and b, respectively, is seen in Fig. 1. This Front view, (b) Back view.
design, which will undergo band-notching in later stages of the
design process, is referred to as the fundamental antenna and 1) The Single Rejection Band Phase:
it should provide UWB characteristics in addition to sufficient
gain. The ground plane is etched with a slot of elliptical By etching slots of a specific length in a radiating patch or
shape with a upper radius slx and lower radius sly. In order to in a feed line, a specific band rejection can be accomplished
enhance bandwidth, an elliptical shape was chosen for both [11–13]. As seen in Fig. 4, this design entails etching an
of patch and ground plane slot. The antenna is mounted on a inverted U-shaped slot in the radiating patch. By adjusting the
FR4 substrate with a permittivity of er = 4.3 and thickness of slot’s length to half of its effective wavelength, it can be used
1.43 mm. The substrate’s final dimensions are 24.5 × 24.5 × as a two short-circuited ends resonator. This is the second step
1.43 mm3 to achieve a small antenna. A 50 ? micro strip line of design, and the achieved antenna is called a single rejection
is used to feed the antenna; its width is determined by applying band antenna. The rejected band is significantly influenced by
the widely recognized micro strip line design formulae [10]. the slot’s length. To calculate the notch frequency, use [6]:
The micro strip feed line dimensions are 2.82 mm in width
and 7.2 mm in length. = c (1)
fnotch v
The CST microwave studio version 2020 is used to de- 2Lslot ee
sign and simulate the construction of the proposed antenna. f f
For the intended antenna to provide the necessary extremely
wide bandwidth, every design parameter has been optimized. where c is the speed of light in free space,Ltotal is the inverted
The parameters (a, b, slx, sly) are carefully optimized in this U slot total length and ee f f is the effective permittivity.
instance. The simulation results for the realized gain and
reflection coefficient obtained for the fundamental antenna
are displayed in Figs. 2 and 3. These figures show that the
fundamental antenna has a maximum gain of 4.11 dBi and
covering UWB from 3.168 GHz to over 15 GHz, or 131% of
the relative bandwidth.