Circularly polarized ultra–wide band filtering antenna with controllable band-notch for wireless communication system

doi:10.1016/j.aeue.2021.153738

AEU - International Journal of Electronics and Communications

Volume 135, June 2021, 153738

https://doi.org/10.1016/j.aeue.2021.153738 Get rights and content

Abstract

A UWB filtering antenna (or filtenna) with a band-notched characteristic has been proposed in this paper. A square-shaped-stepped patch UWB antenna and an inverted T--shaped bandpass filter based integrated filtering antenna (IFA) with band-notch characteristic has been designed and fabricated. The size of the proposed filtenna is the same as the UWB patch antenna. The UWB patch antenna has a bandwidth from 3 GHz to more than 14 GHz. A UWB filter having a notched band is proposed and integrated with the primarily offered square-shaped--stepped patch antenna to design an IFA for UWB wireless communication system. The filter is placed on the feeding position of the patch antenna, and the output of the filter is coupled with the radiating patch to achieved the desired result. Proposed filtenna achieves circular polarization, minimum of 14 dB out of band gain rejection, and a notched band from 5.55 to 6.98 GHz, which avoids the interference from Dedicated Short Range Communication (DSRC) applications. A wide axial-ratio bandwidth (AXBW) from 3.1 to 5.5 GHz and 7–9.8 GHz along with a maximum gain of 6.8 dBi within the operating frequency range of the proposed filtenna has been achieved.

Introduction

Filters and antennas are among the essential elements of an ultra-wideband (UWB) wireless communication device. Modern UWB antennas should have a small size to make them suitable for small portable devices. Planar microstrip antennas printed on the circuit board are a better option for many wireless communications. Microstrip antennas are ideal for UWB applications because they are featured with a low profile, lightweight, inexpensive, and ease of fabrication. Planar antennas with different shapes and different types are widely reported as they demonstrate the fundamental features related to UWB technology [1].

There are chances to receive undesired adjacent frequency components by the antenna, which will affect the receiver performance. A bandpass filter with notch band characteristic is needed to suppress the unwanted signals. On the other hand, it is increasingly popular to integrate the bandpass filter and antenna into a single module to reduce the insertion loss as well as the size of the system. As a result, some filtering antennas are reported having a filter-like frequency response [2], [3], [4], [5]. The microstrip antenna is integrated vertically with differential resonators [2], open stubs, and parasitic strips [3], shorting vias [4], and the multi stub feed [5] for creating band-notch characteristics. Microstrip patch filtering antennas [6], [7], [8], [9], filtering horn antennas [10], [11], filtering planar ultra-wideband (UWB) antennas [12], [13], [14], substrate integrated waveguide (SIW) filtennas [15], [16], and filtering slot antennas [17] are reported in the existing literature. In some cases filter based on stub-loaded open-loop resonator [18], [19] have been used to create multi-band and band-notches. These designs are based on the filter synthesis approach. This method can provide a satisfying filtering response, but antenna gain and radiation of antenna degraded due to the interference and insertion loss of the filter. Another approach is to design the filtering antenna by introducing simple parasitic elements or resonators into the radiator or its feeding circuit. Since there is no requirement of other specific filtering circuits, the resultant designs have lower insertion loss and a more compact size. Many filtering antennas are designed using this approach, but most of them are unidirectional, and no out of band gain rejection characteristic.

This paper proposes an ultra-wideband filtering antenna having band-notched characteristics and an omnidirectional radiation pattern. To avoid the interference between the dedicated short-range communications (5.9 GHz is assigned for DSRC applications) and UWB systems, a notch band filter in UWB systems is necessary. However, the use of filters in the UWB system increases the complexity and overall size. A choice to overcome this problem is to create a band-notched in the UWB antenna. But it cannot provide an out of band gain rejection and circular polarization. Thus for out of band gain rejection and circular polarization, proposed a band-notched filtering antenna. A band-notched filter is used by replacing the feed line of the proposed square--shaped stepped patch UWB antenna. The size of the proposed filtenna is the same as the square--shaped stepped patch UWB antenna. This paper is organized in four sections. Section--2 includes the design of a square-shaped stepped patch UWB antenna. In this section, the fabrication of antenna and measured results are also presented. In section--3, an inverted T-shaped notch band UWB filter [20] and their results are discussed and presented. In section--4, we proposed a UWB filtering antenna with a notched band by integrating the UWB antenna to the notch band filter. Simulated and measured results of the proposed filtering antenna with a notched band are discussed and presented. In the last section, the conclusion of the paper is presented.

In this proposed Filtenna an UWB antenna has been integrated with notched band UWB bandpass filter based on inverted T-shaped Multiple Mode Resonator (MMR) to achieve controllable one band-notched characteristics along with an added advantage of circular polarization unlike many others proposed antenna on a single integrated platform.

Section snippets

Proposed a square-shaped stepped patch UWB antenna without integration of BPF

The design structure of the proposed antenna is shown in Fig. 1. The printed circuit board of Rogers 4350 having $ε_{r}$ = 3.38 and tan $δ$ = 0.0037 is used to design the antenna, where $ε_{r}$ is relative dielectric constant and tan $δ$ is loss tangent of the material. The thickness of the substrate material is 1.524 mm. The size of the antenna is 32 $\times$ 27 $\times$ 1.524 mm³. ANSYS HFSSv15 [21] software is used to simulate and analyze the antenna. The proposed design consists of the microstrip-fed square-shaped stepped

UWB bandpass filter based on inverted T-shaped multiple mode resonator (MMR)

An inverted T-shaped ultra-wideband bandpass filter based on multiple mode resonator is proposed and discussed in this section [20]. The proposed filter has a controllable notch-band characteristic. This filter is integrated with the square-shaped-stepped patch UWB antenna to make filtering antenna (or filtenna). The design process and results of the UWB bandpass filter are presented in this section. The filter bandwidth is from 3.145 to 11.01 GHz with a frequency notch band from 5.74 to

Integration of inverted T-shaped UWB bandpass filter with square-shaped-stepped patch UWB antenna

A square-shaped-stepped patch UWB antenna with inverted T-shaped ultra-wideband bandpass filter, called IFA or filtenna having notch-band characteristic is proposed. Fig. 15 shows the design layout of the proposed filtenna, and Fig. 16 shows the fabricated view of the filtenna. A square-shaped-stepped patch is used as a radiating element. Proposed inverted T-shaped UWB filter replaces the feed line of square-shaped-stepped patch UWB antenna and output port of the filter is directly connected to

Conclusion

A square-shaped-stepped patch antenna for UWB band and an inverted T-shaped bandpass filter based IFA or filtenna with notched band characteristics are designed and fabricated. The proposed IFA design is straightforward and compact. Proposed filtenna covers the entire range of the UWB band, excluding a notched band. Circularly polarized radiation patterns are achieved in E-plane and H-plane. High peak gain up to 6.8 dBi (measured) is obtained. The gain of proposed IFA is reduced drastically at

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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Regular paperCircularly polarized ultra–wide band filtering antenna with controllable band-notch for wireless communication system

Abstract

Introduction

Section snippets

Proposed a square-shaped stepped patch UWB antenna without integration of BPF

UWB bandpass filter based on inverted T-shaped multiple mode resonator (MMR)

Integration of inverted T-shaped UWB bandpass filter with square-shaped-stepped patch UWB antenna

Conclusion

Declaration of Competing Interest

Int J Electron Commun (AEU)

Synthesis and design of a new printed filtering antenna

IEEE Trans Antennas Propag

A compact filtering dielectric resonator antenna with wide bandwidth and high gain

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IEEE Access

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IEEE Trans Antennas Propag

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IEEE Antennas Wirel Propag Lett

An integrated approach to RF antenna-filter co-design

IEEE Antennas Wirel Propag Lett

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IET Microw Antennas Propag

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Regular paper
Circularly polarized ultra–wide band filtering antenna with controllable band-notch for wireless communication system