Notch Characteristics Research Articles

Proximity-Coupled Graphene-Patch-Based Tunable Single-/Dual-Band Notch Filter for THz Applications

A tunable single-/dual-band notch filter is proposed for THz applications. The filter geometry contains a proximity-coupled graphene patch. The filter structure operates with propagating- and nonpropagating-type transverse magnetic ( $$ {\hbox{TM}} $$ ) modes. Different higher-order $$ {\hbox{TM}}_{mn} $$ (where $$ m $$ and $$ n $$ are integers) modes can be excited in the filter structure by changing the aspect ratio of the graphene patch, thus enabling the filter response to be tuned to obtain single- or dual-band notch characteristics. Appropriate selection of the physical parameters of the filter structure allows the desired response at different frequencies to be obtained. Furthermore, the response of the proposed band notch filter can be tuned over frequency by changing the chemical potential of the graphene.

Design and analysis of triple notch ultrawideband antenna using single slotted electromagnetic bandgap inspired structure

ABSTRACTA microstrip line fed pentagonal printed ultra wideband (UWB) monopole antenna with partial ground plane having triple notches is proposed. The realized antenna has an operating bandwidth (VSWR ≤ 2) ranging from 3.1 GHz and continuing beyond 12 GHz. A novel mushroom-shaped slotted electromagnetic bandgap (EBG) inspired structure is used near the feedline to introduce triple notches at CBRS (3.5–3.7) GHz, WLAN (5.15–5.725) GHz and X-band downlink satellite communication (7.25–7.75) GHz frequencies. The band notch characteristics are demonstrated with current distribution and impedance analysis. Further, the proposed structure has stable radiation patterns, gain and group delay in the UWB range except the notch frequencies. Finally, a prototype of the proposed antenna is fabricated and measured results are in good agreement with the simulated results.

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Rectangular Dielectric Resonator Antenna with Single Band Rejection Characteristics

In this paper, a rectangular dielectric resonator antenna (DRA) suitable for wideband applications is presented and a band notch of WLAN (5.15–5.75) GHz is proposed. The DRA is mainly composed of a 20 × 20 mm rectangular dielectric resonator, coated with metal on the top surface, and a circular monopole excitation patch with an air gap insert. A coaxial line feed is used to excite the circular, planar monopole. An open-ended quarter wavelength C-shaped slot is embedded in the circular patch to create the notched band. The simulated results demonstrate that the proposed design produces an impedance bandwidth of more than 80%, ranging from 3.10 to 7.25 GHz for a reflection coefficient of less than −10 dB and with a band rejection at 5.50 GHz. Band notch characteristics, VSWR, and radiation patterns are studied using the HFSS high-frequency simulator and CST Studio software.

Design of a Compact Ultrawideband U-Shaped Slot Etched on a Circular Patch Antenna with Notch Band Characteristics for Ultrawideband Applications

Interference between ultrawideband (UWB) antennas and other narrowband communication systems has spurred growth in designing UWB antennas with notch characteristics and complicated designs consisting of irregular etched slots and larger physical size. This article presents a simplified notched design method for existing UWB antennas exhibiting four frequency-band-rejecting characteristics. The investigation has been conducted by introducing four semicircular U-shaped slot structures based on a theoretical formulation. The formulation is validated with the equivalent LC lumped parameters responsible for yielding the notched frequency. A novel feature of our approach is that the frequency notch can be adjusted to the desired values by changing the radial length based on the value calculated using a derived formula for each semietched U-slot, which is very simple in structure and design. Additionally, by introducing the rectangular notch at the ground plane, the upper passband spectrum is suppressed while maintaining the wide impedance bandwidth of the antenna applicable for next-generation wireless communications, 5G. The measured result shows that the antenna has a wide impedance bandwidth of 149% from 2.9 to 20 GHz, apart from the four-notched frequencies at 3.49, 3.92, 4.57, and 5.23 GHz for a voltage standing wave ratio (VSWR) of <2 rejecting the Worldwide Interoperability for microwave Access (WiMAX) band at (3.38-3.7 GHz), the European C-band at (3.84-4.29 GHz), the Indian national satellite (INSAT) at (4.47-4.92 GHz), and wireless local area networks (WLANs) at (5.09-5.99 GHz). Measured and simulated experimental results reveal that the antenna exhibits nearly an omnidirectional pattern in the passband, low gain at the stopband, and good radiation efficiency within a frequency range. The LC equivalent notched frequency has been proposed by analyzing the L and C equivalent formula, and it has been validated with simulated and measured results. The measurement and simulated results correspond well at the LC equivalent notch band rejecting the existing narrowband systems.

A Novel SWB Antenna with Triple Band-Notches Based on Elliptical Slot and Rectangular Split Ring Resonators

In this paper, a wideband antenna was designed for super-wideband (SWB) applications. The proposed antenna was fed with a rectangular tapered microstrip feed line, which operated over a SWB frequency range (1.42 GHz to 50 GHz). The antenna was implemented at a compact size with electrical dimensions of 0.16 λ × 0.27 λ × 0.0047 λ mm3, where λ was with respect to the lowest resonance frequency. The proposed antenna prototype was fabricated on a F4B substrate, which had a permittivity of 2.65 and 1 mm thickness. The SWB antenna exhibited an impedance bandwidth of 189% and a bandwidth ratio of 35.2:1. Additionally, the proposed antenna design exhibited three band notch characteristics that were necessary to eradicate interference from WLAN, WiMAX, and X bands in the SWB range. One notch was achieved by etching an elliptical split ring resonator (ESRR) in the radiator and the other two notches were achieved by placing rectangular split ring resonators close to the signal line. The first notch was tuned by incorporating a varactor diode into the ESRR. The prototype was experimentally validated with, with notch and without notch characteristics for SWB applications. The experimental results showed good agreement with simulated results.

Enhanced bandwidth reconfigurable single and dual band-notch antenna by using DGS for UWB and KU applications

In this article, a dual band notch reconfigurable antenna for ultra-wide band applications by switchable band notch characteristics is reported. The antenna includes rectangular patch with two L-shaped strips, rectangular and L-shaped slits on the ground sheet. To create much wider impedance bandwidth, slits on the ground sheet have been added. To create dual band notch characteristics, the L shaped strips on the radiating patch are connected using two PIN diodes in order to control the band rejection range. The reconfigurable antenna includes single and dual band notch 4.5–6.5 and 9–10.5 GHz. The presented antenna with final size of 12×18×1.6 mm3 is manufactured on an affordable FR-4 substrate and tested. The measured and simulated results are in good agreement.

Design of an UWB antenna with two slits for 5G/WLAN‐notched bands

AbstractIn this article, we propose a dual notched‐band antenna with 2 slits for ultra‐wideband (UWB) applications. The antenna consists of a circular ground plane and a patch radiator with having 2 slits and a folding arm. The patch with folding arm is used to achieve UWB band while a V‐shaped and a split ring‐shaped slit are used to eliminate the interference from WLAN and 5G band, respectively. The width and length of the slits are optimized to obtain the necessary band notch characteristics. The prototype of the antenna having a total size of 75 × 10 mm2 is fabricated. Simulated and measured results show that the antenna covers the entire UWB frequency ranging from 2.754 to 14.656 GHz (127%) for VSWR < 2 except at notched bands. Moreover, the antenna successfully notched the WLAN band (5.15‐5.825 GHz) and 5G band (3.4‐3.7 GHz) besides of providing a stable gain and radiation patterns.

Compact wideband MIMO antenna for 4G WI-MAX, WLAN and UWB applications

This article proposes a compact wideband MIMO antenna. The antenna comprises of two identical modified P shaped monopole radiators, spatially oriented at 180° to each other with side to side spacing of 0.075λo, where λo is the wavelength corresponding to the lowest operating frequency. To design a compact antenna, a semicircular monopole with a rectangular strip is designed instead of a circular monopole. This P shaped monopole antenna offers same impedance bandwidth with 50% size reduction. To enhance the impedance bandwidth of the antenna, the effective current path length is increased by introducing two semi-circular slots in P shaped monopole antenna. To achieve the desired impedance bandwidth of 2.5–12 GHz, the rectangular strip is corrugated on both sides in the slotted P shaped monopole. Triangular slots and meshed metal strip are introduced in the ground plane to achieve high mutual coupling over wideband. The triangular slots act as variable length capacitance and exhibits wide band notch characteristics. A meshed metal strip acts as decoupling structure for the surface current emerging from the surface waves and also act as reflector for space waves. Those bands which are not rejected by triangular slots, are notched by meshed metal strips. Thus by employing both triangular slots and meshed metal strip, isolation >20 dB is achieved over 2.5–12 GHz. The proposed antenna is a novel design which has smaller dimensions and still offers isolation >20 dB over a wider impedance bandwidth of 2.5 GHz to 12 GHz as compared to state of art antenna structures reported in literature. The band stop characteristics of proposed isolation techniques are analyzed by suspended stripline method. Mutual coupling reduction is also analyzed with the help of vector surface current density and magnetic field distribution. The proposed structure has compact dimensions of 0.25 λ0 × 0.241 λ0. The fabricated prototype antenna exhibits envelope correlation coefficient (ECC) >0.02, diversity gain >9.5 dB and stable radiation patterns. The antenna is suitable for 4G WI-MAX, WLAN and UWB applications.

A Compact Reconfigurable Dual Band-Notched Ultra-Wideband Antenna using Varactor Diodes

In this paper, a reconfigurable dual band-notched ultra-wideband (UWB) antenna is presented. The antenna design consists of a circular shape with two pairs of the L-resonator. To realize the notch characteristics in WLAN at 5.2 GHz and 5.8 GHz bands, the half wavelength of the L-resonator is introduced in the design. The T-shaped notch is etched in the ground to enhance the bandwidth which covers the UWB operating frequency range from 3.219 – 10.863 GHz. The proposed reconfigurable dual band-notched UWB antenna shows good impedance matching for the simulated in the physical layout. Furthermore, the proposed antenna has a compact size of 37.6 x 28 mm2. This proposed reconfigurable design can provide an alternative solution for the wireless system in the designing of a band-notched antenna with a good tuning capability.

Inverted-A based UWB MIMO antenna with triple-band notch and improved isolation for WBAN applications

A compact ultra wideband multiple–input multiple-output (UWB-MIMO) antenna with inverted-A monopole and band notch characteristics of LTE-A 43 band (3.8 GHz), C-band (3.9–4.2 GHz) and the IEEE 802.11ac band (5.1–5.85 GHz) with microstrip line feeding is proposed. The suppression of the inevitable mutual coupling for improved isolation is achieved by using a combination of techniques like orthogonal polarization, defected ground structure (DGS). The antenna has wideband impedance matching with S11 < −10 dB in the UWB frequency range from 3.1 to 10.6 GHz and has a low mutual coupling with |S21| < −17 dB which can be inferred from the simulated and measured results. The antenna has a fractional bandwidth of 109.48%, envelope correlation coefficient of 0.035 and capacity loss of 0.358, which proves the diversity characteristics of proposed MIMO antenna.

Design of wideband antenna with band notch characteristics based on single notching element

In this article, a coplanar waveguide (CPW) fed planner monopole antenna with a compact size of 0.32λ × 0.30λ × 0.0056λ mm3 is presented. The radiator is fed with 50 Ω CPW feed line that provides impedance matching from 1.7 to 30 GHz for VSWR ≤2. In addition, three narrow bands are filtered out in the ultra-wideband (UWB) range. The narrow notched bands are filtered for WiMAX (3.52-4.2 GHz), WLAN (5.04-5.40 GHz), and X band (8.22-9.10 GHz) application. The rejecting bands are achieved by loading a single tri-square ring resonator (SRR) on the backside of the feed line. The dimensions of SRR control the notch resonance frequencies. A single-, dual-, and tri-notch frequencies have been achieved by using single-, dual-, and tri-SRR, respectively. The measured results of antenna structures in the absence and presence of the SRR are compared with the simulations. The measured results validate the proposed design.

A compact ultra wide band bandpass filter with dual band notch designed based on composite right/left‐handed transmission line unit cell

In this article, we propose an ultra wide band (UWB) bandpass filter with dual notch characteristics. The proposed filter is designed based on composite right/left handed (CRLH) transmission lines. The filter is having a compact size of 2.4 mm × 8.78 mm and printed on FR4 material with relative permittivity 4.4 with thickness 1.6 mm. The filter is constructed by series of strip lines, which forms interdigital capacitance and shunt inductors allowing both low and high frequencies of the UWB to pass. The selectivity in lower and higher parts of the UWB is achieved by the slots etched from the ground plane. The dual band notch is obtained at 4 GHz and 7 GHz using the L-shaped strip lines on both sides of the filter. The comparative analysis of the proposed UWB band pass filter without and with notch characteristics is presented with the help of the S11 and S21 curves.

Superwideband Triple Notch Monopole Antenna for Multiple Wireless Applications

In this paper a CPW-fed triple band notch characteristics superwideband antenna is presented for multiple wireless applications. Proposed antenna consists of elliptical guitar shaped radiating patch and modified rectangular ground plane for better impedance matching. Radiating patch consist of inverted T-shaped stub which is responsible for filtering WiMAX band and two elliptical slots which removes interfering WLAN and satellite downlink system. Proposed antenna covers superwideband of bandwidth 2.76–39.53 GHz with ratio bandwidth of 14.32:1 for Voltage Standing Wave Ratio ≤ 2. Proposed antenna is printed on Rogers RT Duroid5880 substrate with antenna dimension 27 × 32 × 0.787 mm3. A prototype antenna is fabricated and measured results shows good agreement with simulated results.

A state-of-art review on band-notch characteristics in UWB antennas

Ultra-wideband technology has experienced a rapid growth over the last decade for its contribution in different sectors of human society. Printed antennas are considered as preferred platform for implementing this technology because of its alluring characteristics like light weight, low cost, ease of fabrication, integration capability with other systems, etc. Antennas developed for ultra-wideband applications are desired to have notch characteristics for avoiding interference with other existing radio communication systems. The techniques related to design and developments of printed band-notched antennas are continuously upgraded for improving the antenna performance. In this article, a comprehensive review has been carried out on ultra-wideband antennas with band notch characteristics proposed in around last decade. The band notched UWB antennas available in the literature have broadly been classified into five different categories based on their notch characteristics like single band-notch, dual band-notch, triple band-notch, quad/multiple band-notch, and reconfigurable/tunable band-notch, respectively. This review exercise may be helpful for beginners working on ultra-wideband band-notched antennas and also such a review process is not available in the open literature to the best of author's knowledge.

Compact CPW‐fed ultra‐wideband printed antennas with controllable notch characteristics

AbstractIn this paper, a series of compact and miniaturized UWB‐printed antennas with a controllable notch function are proposed. The CPW structure is adopted to feed the proposed antenna, where the overall dimension is as compact as 15 mm × 15 mm × 0.5 mm. From 2.8GHz to 12GHz, the antennas proposed have a superior performance with approximate 2:1 VSWR, except the rejection frequency band. In addition, the main feature of the proposed antennas are their controllable notch frequency, notch amplitude, and notch orders, which are determined by the size of the circular U‐shaped slit, the position of the connecting line, and the number of slits, respectively. Moreover, the measured results are in reasonably good with the simulated results.

Parametric study and Analysis of Band Stop Characteristics for a Compact UWB Antenna with Tri-band notches

In this article, equivalent circuit modeling with study and analysis of band notch characteristics for a triple band notched UWB antenna has been discussed to develop a better understanding of the antenna functioning and its behavior. Â A small square ultra wideband antenna having overall size of 24 x 31 mm 2 with tri- band rejections is designed and simulated using HFSS software. Very narrow band notching is accomplished by placing C slots and inverted C slot of different dimensions on the radiating patch which makes maximum space utilization without performance deterioration. The antenna operates from 3.1 to 14 GHz (VSWR 2) of 3.3- 3.7 GHz (WiMAX), 5.1 - 5.4 GHz (Lower WLAN and HIPERLAN/2) and 5.7 6 GHz (Upper WLAN) as shown by the simulated and measured results (VSWR<2) of the UWB antenna, with and without the presence of triple notches, thus utilizing the maximum UWB bandwidth. The radiation pattern plots for simulated and measured results are also presented to validate the working of the antenna. This antenna can be a respectable candidate for future European and USA high capacity UWB applications. The group delay and peak gain plots are also found to be stable in the range of operation of the antenna. The study and analysis of the band notching is discoursed in terms of current distribution and impedance plots to provide a greater and better perception into the working of the antenna and hence an equivalent circuit for the tri-band notched UWB antenna has been proposed.

Phi Shape UWB Antenna with Band Notch Characteristics

Phi Shape UWB Antenna with Band Notch Characteristics

Phi Shape UWB Antenna with Band Notch Characteristics

In this paper a novel band notch antenna in UWB frequency range is designed using split rings. Split rings are overlapped with designed monopole to give phi shape. The slit gap gives band-notch operation from 5.1GHz to 6.29GHz and from 4.94GHz to 5.91GHz for SPSSR and SPSCR antennas respectively. Simulated and measured results are in good agreement.

A compact quasi-self-complementary dual band notched UWB MIMO antenna with enhanced isolation using Hilbert fractal slot

A compact ultrawideband multiple input multiple output antenna with dual band notch characteristics is proposed. The design utilizes the property of quasi-self-complementary monopoles to achieve a bandwidth that ranges from 2.2 GHz to 11 GHz. The design has a compact size of 30 mm × 41 mm × 1.59 mm. Two quasi-self complementary half circular monopoles are symmetrically arranged to obtain MIMO antenna. Bandnotch characteristics are obtained by adding parasitic strips of Levy's Fractal shape near the feed line. A Hilbert Fractal shaped slot is etched in the ground plane to enhance the isolation (|S21| < −20 dB) throughout the operational bandwidth. The measured and simulated radiation patterns are in good agreement and is found to be stable throughout the ultrawideband. Moreover, the measured peak gain is found to be 4 dBi.