Design UWB antenna with notch band for WiMAX application

ABSTRACT


INTRODUCTION
Wireless technology has allowed ultra-wide band (UWB) to coexist with nearby communication systems in its radio environment.The simplicity, compact size, low cost, lightweight, low complexity and high data rate of UWB technology make it a popular choice [1], [2].UWB signals often have a large absolute or relative bandwidth (bandwidth divided by carrier frequency).Use of wide transmission bandwidths, such as better barrier penetration and covert operation as well as interference rejection and coexistence with narrow bandwidth (NB) systems may provide several benefits.In fact, there are significant challenges in UWB signal production, transmission, propagation, processing, and system architecture that need more research.High data rates (up to 500 mbps) and short-range transmission (G 10 m) are only two of the numerous uses of UWB technology [3]- [5], low-rate communications with accurate geolocation and vacillation and systems of radar, which offer extraordinarily high spatial resolution and the ability to overcome barriers, such as wireless "USB" such as infrastructures between computer components or wireless links among components of operating systems [6]- [8].
The Federal government has approved the commercial usage of ultrawideband technology in the frequent range of 3.1 GHz to 10.6 GHz [2] in the United States.Otherwise, neighboring WiMAX communication systems (which run at frequencies ranging from 3.2 to 3.8 GHz) create interference with the UWB system since they operate at frequencies higher than the UWB system's designed bandwidth [9], [10].Because of this, notched features on the UWB antenna are required in order to reduce interference from other In order to establish frequency notched band characteristics on a UWB antenna, an appropriate structure may be etched into the antenna [11]- [13].
The antenna in question rejects just one band of the UWB spectrum, and it is a limited band at that.WiMAX technology has just been shown to be used by the network.Slot antennas for ultra-wideband communications may only be capable of functioning in a single notch band [14]- [16].A rectangular UWB monopole antenna with a π-shaped slots resonator is installed within it for WiMAX band rejection [16], and the resonator is tuned to the frequency of the WiMAX band.
UWB range of 3.1 GHz to 10.6 GHz as shown by the simulation's, the antenna is capable of avoiding the interference caused by the WiMAX.The H-plane of the antenna provides an omnidirectional patterrn over the whole bandwidth of the antenna [17]- [21].Some of research which suggest the same problem is listed as: a.An individual patch of a radiating patch has dimensions of 11.86 mm (L) x 8.96 mm (W), or 5.43 mm x 7.43 (L2) for the combination of a pair of monopoles lengthwise and widthwise, according to [22].The substrate is 16 mm (L) x 20 mm (W) x 1.6 mm thick.This antenna arrangement has been used to mimic the 10 GHz resonance frequency.Dielectric constant   =2.2 e was achieved using Duroid as the substrate material.Two monopoles with a partial ground plane and steps at the bottom of the patch were employed for the required broad bandwidth.At the same time, to avoid interference with other frequency bands included inside the passband, the center bottom of the radiating patch was fitted with a strip bar.b.The proposed antenna for Dhakar's antenna design in 2015 [23] is printed on an FRP substrate 1.6 mm thick and has a 4.4 V permittivity and a 0.25 V loss tangent.The primary structural components of this proposed antenna are as follows: a square radiating patch with W-and O-shaped slots carved into it, a 50 Ω microstrip feed line printed on the substrate, a partial ground plane with a pair of U-shaped slots printed on the opposite side of the substrate.For achieving a characteristic impedance of 50 Ω over the whole frequency range of 3.05-14.1GHz, the square patch has dimensions of 8 mm by 8 mm and the width Wf of the microstrip feed line has been fixed at 2 mm.c.While Kumar and Kamatham [24] suggested a coplanar beveled feed in 2019, they advocated dual bandrejection.Antenna for ultra-wideband FR-4 substrate (permittivity 4.4, tan=0.02)with overall dimensions of 20x14x1.6 mm 3 is used to print the antenna's twin fork radiating element loaded with a pair of inverted L-shaped stub resonators.A rectangular ground plane symmetrically surrounds the 50 Ω CPW feed.It has a ground plane of 5.5x4.5 mm 2 and 2 mm in the width feed line.It is possible to acquire dual notched bands to cover the WiMAX and WLAN operating bands with enhanced impedance matching (3.4-3.8GHz and 4.5-5.5 GHz) (2.6 GHz -11.6 GHz).d.In 2019, Zhong et al. [25] operated in the 2.7 to 10.7 GHz frequency range; its radiating patch is in the form of a gradient curve, and its ground plane is asymmetrical.In order to construct unwanted bands at C-band (3.60-4.32)GHz, "WLAN" bands (5.17-5.32)GHz and (5.80-5.93)GHz, and ITU band (7.8-8.2) GHz, respectively, four different slots, consisting a two meandering slots, cap-shaped slot, and a split-ring, are working.
In this paper we would propose the antenna design in two sections first is the design of an UWB antenna and its simulation results, and in the second part we explain the design of antenna with inserting the pi shaped resonator and its simulated results.

DESIGN ULTRA-WIDE BAND ANTENNA
As illustrated in Figures 1(a) and (b), the projected UWB antenna has the dimensions of 20×30 mm.The design relative permittivity was 4.3, and the thickness was 1.6 mm; loss is equivalent to 0.02, and the pattern is printed on FR4.Radiating ground and structure, bottom and top patches are printed on the substrate's surface.Wf (3.137 mm), the microstrip feedline width, serves as a 50 ohm resistor between the end of the feeding strip and the ground plane.Using the staircase patch construction in Figure 1, we may increase the antenna's bandwidth to encompass the UWB spectrum, design's dimensions is shown in Table 1.

Design of band notched ultra-wide band antenna
This section explains the band-notch characteristics of a UWB antenna.A single notched band may be executed by etching a π -configuration notch in the radiating patch of another UWB antenna.Details of the antenna's design may be found in Table 1.It is possible to compute the notched frequency's dimensions using (1) [10]: Where C is the speed of light, L is the length of the resonator, and   is the effective dielectric constant.
Figure 2 represented  11 of the UWB antenna while Figure 3 represented VSWR of the UWB antenna.Table 1 lists the ideal parameters for simulating the suggested antenna, which is represented in Figures 4(a

RESULTS AND DISCUSSION
For the purpose of covering the whole UWB band, this antenna has been developed to have wideband performance ranging from 3.10 to 10.60 GHz with an S11 of less than 10 dB.An antenna's abii to focus radiated power in a given direction, or the antenna's ability to absorb incoming radiation, is referred to as its gain."The ratio of highest voltage or current to lowest voltage or current at each site it investigates as a measure of mismatch between the line and the load" is how VSWR is described in electrical engineering.Figure 5 displays the simulated reflection coefficients, while Figures 6 and 7 illustrate the voltage standing wave ratio and the antenna's actual gain.It's clear that things are looking up.
For VSWR<2, the antenna covers the whole UWB range, with single-notch bands of 3.3-3.8GHz having VSWR>2.If one looks at Figure 8, one can see that the surface current distributions are more concentrated in one direction and cancel each other out at the notch frequency.For frequency rejection, the π-shaped filter structure of the UWB antenna has a considerable impact.In order to generate a frequency notch band, the antenna does not emit at this particular frequency.Because of this, we may infer from the present distributions that the frequency-notch functions result from the π-shaped filter structure [11]- [13].

Surface current distribution
The surface current pattern at 3.5 GHz frequencies is shown in Figure 8.The colors on the scale are arranged in decreasing order by the scale's current value.Regions in red have better current distribution than those marked in yellow, green, and so on.

CONCLUSION
This paper detailed planar UWB antennas that are fed by microstrips, which are intended to avoid interference between the WiMAX and other UWB bands from occurring.An UWB monopole antenna's radiating patch is embossed with a π-shaped resonator in order to produce the desired notch band.The suggested antenna has a VSWR of 2 from 3.1 GHz to 10.6 GHz, which covers the whole UWB range, with the exception of a notch band from 3.3 GHz to 3.7 GHz (WiMAX).

Figure 1 .
Figure 2 represented  11 of the UWB antenna while Figure 3 represented VSWR of the UWB antenna.Table 1 lists the ideal parameters for simulating the suggested antenna, which is represented in Figures 4(a)-(c) where (a) is the designed antenna, (b) and (c) are the dimensions of the antenna.

Figure 8 .
Figure 8. Frequency (3.5 Ghz) surface current distribution in notch band resonant

Figures 9 (
a) and (b) depicts the 3, and 3.5 GHz observed radiation patterns for the UWB antenna.Single-band UWB antenna's measured radiation pattern at (a) 3 GHz and (b) 3.7 GHz.The E-plane and Hplane are both represented by antennas that are printed in the x-y plane.It may be considered that the Eradiation plane's pattern is monopole-related, and the H-radiation plane's pattern is practically Omnidirectional except in the notched frequency range.The comparison with previous literature is shown in Table 2 .

Table 1 .
Dimensions of the planned antenna (mm)

Table 2 .
Comparison with published work