Band Notch Research Articles

UWB bandpass filter with tilted square shape ring topology sandwiched in the middle of interdigital structure

ABSTRACT This paper consists of compact novel design and high-performance ultra-wide band (UWB) bandpass filter (BPF) employed with square ring resonator (SRR) sandwiched between an interdigital structure (IDS). The unique combination of these microstrip resonators achieves a good selectivity across the passband with good rejection performance. The proposed structure also achieves less complexity and ease of fabrication. The passband extends from 4.2 GHz to 10.9 GHz with a notch band of 3 dB fractional bandwidth 88% centred at 7.6 GHz. The first passband in UWB BPF has minimum insertion loss as 0.59 dB and maximum return loss as 40.1 dB, whereas second passband has minimum insertion loss as 1.33 dB and maximum return loss as 36.62 dB. The presented filter structure is designed using Keysight Advance Design System (ADS). The simulated s-parameter characteristics performance is found to be in good agreement with the measured result.

Retraction Note: Design and analysis of super wide band antenna and its notch band characteristics

Retraction Note: Design and analysis of super wide band antenna and its notch band characteristics

Generation and tuning of notched bands in wideband THz antennas using graphene/metal strips

Abstract A technique is implemented for obtaining tunable band notch/filtering features in terahertz (THz) monopole wideband antennas. A parasitic metal strip is engraved in the antenna radiator, which creates the band notch characteristics in the wideband response. The tunability of the created notched band can be obtained by engraving a non-resonant U-shaped graphene strip in the radiator. The change in the material properties of the graphene strip alters the nature of field confinement in the antenna structure, enabling tunability in the filtering frequency band. Moreover, multiple notch bands can be obtained by carefully selecting the material of the parasitic element U-shaped graphene strip. Thus, the antenna response can be configured for dual- and triple- band filtering operation by varying the materials used for the strips to obtain band notch operation and a U-shaped graphene sheet.

Ultra-wideband bandpass microstrip filter with electronically tunable notch-band

This paper introduces a compact ultra-wideband (UWB) microstrip filter featuring both a fixed and an electronically tunable notch band. Operating within the frequency range of 3.27 GHz to 5.61 GHz, the filter incorporates a permanent notch at 4.08 GHz and a tunable notch at 4.88 GHz. Utilizing a traditional ground plane and a short-circuited transmission line, we develop a bandpass filter with a stable notch-band positioned and another tunable notch band. Systematic defects are made to the ground plane to increase the coupling between input and output ports leading to UWB response. The stable notch band is created using a rectangular slot resonator, while the tunable notch employs a varactor diode (NXP BB135 Varactor Diode) integrated into a rectangular stub. Operating in the even-mode with symmetrical current distribution, the filter exhibits a -3dB passband bandwidth of 740 MHz, 610 MHz, and 240 MHz across its respective passbands. Notch band attenuation measures at -10 dB and -9 dB, respectively. Experimental results from the prototype demonstrate excellent agreement with simulated results, confirming the efficacy of the design.

CSRR and EBG loaded wideband THz dielectric resonator MIMO antenna for nano communication and bio-sensing applications

In this paper, a wideband Graphene-inspired dielectric resonator THz MIMO antenna is designed. The antenna has dimensions of 56 × 56 × 3.6 μm³ and is designed on a Rogers RO3035 substrate with a relative permittivity of 3.6 and loss tangent of 0.0015. This antenna works in the range of 6.0 THz-12.5 THz (70.76 %) with a peak gain of 7.68 dBi and radiation efficiency (>70 %) is suitable for use in medical imaging and THz wireless near-field applications. A CSRR is loaded to obtain band notch characteristic for avoiding interference between nearby wireless devices in the range of 10.6–10.8 THz. EBG was also introduced with a patch antenna to reduce surface wave loss and improve isolation, resulting in a high front-to-back ratio (FBR) in the range of 10–12.5 THz. Without the graphene disk, the silicon-based DRA did not achieve significant gain. At a chemical potential of 0.5 eV and a relaxation time of 0.1 ps, the proposed DRA demonstrated good antenna properties. By varying the chemical potential and relaxation time, frequency agility was easily achieved. A Graphene disk having a height of 3 μm is placed on a Silicon (εr = 11.1) based cylindrical DRA to provide high gain and improve the impedance bandwidth, achieving wide bandwidth from 6.0 THz to 12.5 THz. The proposed two element antenna performance is evaluated by parameters such as gain, return loss, isolation between two antenna elements, and diversity parameters like Envelope correlation coefficient ECC<0.1, Directive Gain >9.5 dB, Total Active reflection Coefficient >10 dB and Avg. Channel capacity loss <0.35bps/Hz so that the proposed antenna is suitable for wideband nano/optical communication in IoT-6G. Furthermore, the antenna is suitable for biological sensing applications due to its average sensitivity and FOM for hemoglobin and urine of 805.33GHz/RIU and 805.55GHz/RIU, respectively, and 3.37 and 10.55.

Super compact and ultra-wideband bandpass filter with three band notches using triple-mode stepped impedance resonator and defected ground structure

A super-compact ultra-wideband (UWB) microstrip band-pass filter (BPF) with triple-notched bands and wide stopband is proposed in this paper. The super-compactness of the proposed filter is achieved by integrating the modified SCRLH-TL UWB-BPF and backbone-shaped defected ground structure (DGS). The equivalent LC circuit models of the DGS and the modified SCRLH-TL UWB-BPF with the DGS are analyzed to validate their numerical simulation results. To introduce the triple notched-bands to mitigate the interference the two triple-mode SIRs are designed and loaded on the modified UWB-BPF without increasing the circuit size. The proposed filter was fabricated by using a conventional PCB process with the substrate of FR4. The measured 3-dB passband ranges from 2.8 through 10.2 GHz with the fractional bandwidth (FBW) of about 114%. The triple-notched bands with attenuation of more than 15 dB are measured at 4.4, 5.3 and 8.2 GHz, respectively. The filter exhibits a high selectivity with steep skirt property and has a wide upper stopband with an out-of-band rejection of −10 dB at 11.8−20 GHz. Its total dimension, including the rectangular substrate with feed lines, occupies only 16mm × 8 mm.

Triple notched MIMO antenna for S and C band applications

ABSTRACT A hexagon-shaped fractal multiple-input multiple-output (MIMO) antenna for WLAN, WiMax, and C band applications is proposed. The antenna consists of two hexagon-shaped self-similar fractal structures placed at a 6 mm gap with a reduced ground plane along with a ground stub at the centre. The proposed design covers the 2.37–7.82 GHz band with band rejections at 2.54–2.87 GHz, 3.56–3.83 GHz and 6.26–7.13 GHz. The notches are introduced to avoid interference between different application bands. The parametrically optimised reduced height of the ground plane and the strategical placement of a stub at the centre of this ground plane provide notch bands and reduce the mutual coupling below −17 dB throughout the operating bands. The proposed antenna gain varies between 2–3 dBi in the operating bands. The diversity parameters like envelope correlation coefficient (ECC) and diversity gain, channel capacity loss (CCL) and Total Active Reflection Coefficient (TARC) are calculated and found to be well below the acceptable range. A prototype of the proposed design is fabricated and measured. The measurement results are in good agreement with their simulated counterparts.

Dual band notched superwideband MIMO antenna for 5G and 6G applications

In this article, a compact super wideband multiple input multiple output (MIMO) antenna with dual band elimination feature is presented. The antenna element comprises of modified square shaped radiating element and coplanar waveguide (CPW) with asymmetric ground planes. A dual-port MIMO configuration is proposed for spatial diversity. It has compact size of dimensions 18 × 37.5 × 1.6 mm3. It has frequency band of impedance matching (VSWR < 2) from 3.9– > 150 GHz (%BW > 189.86 %). The radiator and feedline are loadedwith modified M- and U-shaped slots to achieve a band notch at 5.5 GHz (WLAN) and 7.5 GHz (X-band satellite communication), respectively. A modified staircase shaped structure is used between the two ports to achieve an intraport isolation of > 20 dB at maximum frequencies. The MIMO antenna has envelope correlation coefficient based on scattering parameters < 0.005, envelope correlation coefficient based on farfield parameters < 0.08, peak gain of 8.63dBi, Mean Effective Gain (MEG) < -3dB, multiplexing efficiency > -4.0 dB, channel capacity loss (CCL) < 0.4bits/sec/Hz to signify its suitability for MIMO applications. The measured and the simulated outcomes are found to be close to each other. The proposed antenna element and MIMO antenna structure will be suitable for Internet of Things (IoT), 5G, and 6G due to their superwideband (SWB) bandwidth, desirable radiation properties and diversity performance.

Compact High-Performance Balanced Wideband BPF With a Notch Band and Multiple Transmission Zeros

Compact High-Performance Balanced Wideband BPF With a Notch Band and Multiple Transmission Zeros

INVESTIGATION OF BROADER BANDWIDTH ELLIPTICAL DIPOLE ANTENNA PERFORMANCE PARAMETERS FOR 5G, KU AND KA-BAND APPLICATIONS: DIELECTRIC CONSTANT EFFECTS

This study presents an examination of the design and evaluation process of an elliptical dipole antenna operating at the design frequency of 5 GHz. Initially based on conventional dipole antenna principles, the antenna's design is iteratively refined through bandwidth enhancement techniques, resulting in the emergence of ultra-wideband characteristics. Notably, the modified antenna design features a distinctive notch band spanning from 4.21 to 10.06 GHz, positioning it as a versatile solution suitable for applications across the mid-band of 5G, as well as the full Ku and partial Ka bands, encompassing frequencies from 27 GHz to 31 GHz. Furthermore, this study investigates the impact of varying dielectric constants on antenna parameters, shedding light on a critical aspect often overlooked in conventional dipole antenna calculations. Through systematic analysis, it is revealed that a dielectric constant of 4.3, aligned with the commonly used low-cost epoxy-based FR-4 material, yields optimal performance. While higher dielectric constants broaden the antenna's characteristics, lower values are found to enhance communication efficiency, thus offering potential benefits in terms of power consumption and cost savings. The detailed examination and findings presented in this study enrich the understanding of antenna design principles and provide valuable guidance for future research and practical applications in the field of wireless communication and antenna engineering.

Circularly polarized dielectric resonator based MIMO antenna for sub-6 GHz 5G cognitive radio applications

A 2-port wideband circular polarized (CP) multiple input multiple output (MIMO) dielectric resonator antenna (DRA) integrated with cognitive radio (CR) application is designed and investigated. This is a novel concept of integrating wideband CP-MIMO antenna based on dielectric resonator (DR), with CR concept. The multi-functional reconfigurable filter is designed within the feedline of the antenna making it applicable for both the operations of CR, namely, underlay and interweave. Rogers RT Duroid 5880 is used as the substrate for the designed CP-MIMO antenna. The antenna shows wide Axial Ratio (AR) bandwidth of 48.14% (2.2–3.50 GHz) and an overlapping bandwidth of 41.85% (2.37–3.50 GHz). The DR based MIMO antenna shows sensing range of 2.37–3.66 GHz. For the interweave operation, the designed CP-MIMO antenna shows narrowband frequency reconfigurability from 2.45–2.83 GHz. For the underlay case, the designed antenna shows band notch tunability between 3.23–3.62 GHz. The proposed antenna can be used effectively in sub-6 GHz band of the 5G communication systems.

Compact design of MIMO antenna with split ring resonators for UWB applications

In recent times, the Multiple-Input Multiple-Output (MIMO) system has played a vital role in wireless communication. MIMO antenna uses multiple antennas on both the sides of the transmitter and receiver. Mutual coupling occurs between two antenna elements to reduce the performance. The passage of current in the same direction on both neighbouring sides of the antennas increases the rate of mutual coupling. To decrease the mutual coupling, Split Ring Resonators (SRR) are located on the MIMO antenna. In this research paper, a MIMO antenna with SRR for Ultra Wide Band (UWB) applications with different frequency notches is proposed. Also, bandwidth and isolation are considered essential metrics for MIMO antennas. In the proposed 4 × 4 MIMO antenna design, SRR is located at the antenna's two sides, and the defected ground structure is on the bottom portion with a permittivity of 4.4 (FR4 substrate). The defected ground structure is proposed with stubs to enhance the characteristics of bandwidth and create notch bands in the frequency range of 3.1 GHz to 10.6 GHz. Placing SRRs adjacent to the feed line enhances the gain performance. The experimental results show that the ECC of the proposed antenna is less than 0.25, DG is higher than 9.8 dB, and the peak realized gain for 9.38 GHz is 11.3 dB, which is more reliable than other antenna designs. Therefore, experimental outcomes of the proposed antenna design enhance the applicability of band notching for wideband communication.

An Electronically Reconfigurable Highly Selective Stop-Band Ultra-Wideband Antenna Applying Electromagnetic Bandgaps and Positive-Intrinsic-Negative Diodes.

In this article, an ultra-wideband (UWB) antenna featuring two reconfigurable quasi-perfect stop bands at WLAN (5.25-5.75 GHz) and lower 5G (3.4-3.8 GHz) utilizing electromagnetic bandgaps (EBGs) and positive-intrinsic-negative (P-I-N) diodes is proposed. A pair of EBG structures are applied to generate sharp notch bands in the targeted frequency spectrum. Each EBG creates a traditional notch, while two regular notches are combined to make a quasi-perfect, sharp, notch band. Four P-I-N diodes are engraved into the EBG structures to enable notch band reconfigurability. By switching the operational condition of the four diodes, the UWB antenna can dynamically adjust its notching characteristics to enhance its adaptability to various communication standards and applications. The antenna can be reconfigured as a UWB (3-11.6 GHz) without any notch band, a UWB with a single sharp notch (either at WLAN or 5G), or a UWB with two quasi-perfect notch bands. Moreover, the antenna's notch bands can also be switched from a traditional notch to a quasi-perfect notch and vice versa. To confirm the validity of the simulated outcomes, the proposed reconfigurable UWB antenna is fabricated and measured. The experimental findings are aligned closely with simulation results, and the antenna offers notch band reconfigurability. The antenna shows a consistently favorable radiation pattern and gain. The dimension of the presented antenna is 20 × 27 × 1.52 mm3 (0.45 λc × 0.33 λc × 0.025 λc, where λc is the wavelength in free space).

Improvement in notch band characteristics of a hexagonal super wideband antenna by interfering back radiation out of phase with front radiation using frequency selective surface

SummaryA band‐notched super wideband (SWB) planar monopole antenna with improved notch characteristics is proposed in this article. A hexagonal SWB antenna operating in the frequency range from 3.04 to 36 GHz is initially designed on Arlon substrate. The hexagonal patch is then loaded with optimum sized U‐shaped slot to eliminate WLAN band (5.15–5.85 GHz). The notch band's characteristics are further improved by incorporating a frequency selective surface (FSS) of a square array at a specific distance below the antenna to introduce a phase delay of 180° between the back radiation reflected by the FSS with the front radiation at the notched frequency. Improvement of notch band gain, efficiency, and antenna front‐to‐back ratio (FBR) are studied. The antenna without embedding an FSS exhibits working spectrum from 3.1 to 33.6 GHz with notch frequency gain of −2.6 dBi and efficiency 53%. The inclusion of an FSS layer at 25.2 mm behind the antenna results in notch frequency gain of −7.6 dBi with an efficiency of 23%. FBR improvement of about 16 dB is achieved at 8 GHz, and FBR is reduced by about 5 dB at the notch frequency. 169% fractional bandwidth with bandwidth dimension ratio (BDR) of 1622 is achieved in this proposed FSS integrated antenna. The inclusion of FSS to improve the band elimination performance represents the novelty of this proposal. The data are validated by electromagnetic simulation and physical measurement techniques.

An Ultra-Wideband Antenna with Triple Band-Notched Characteristics for Wearable Application

This work presents a compact UWB antenna with triple band-notched at WiMAX (3.2 GHz to 3.7 GHz), C-band (3.7 GHz to 4.2 GHz) and WLAN (5.15 GHz to 5.35 GHz) for wearable applications. The UWB antenna is fabricated on a semi-flexible thin FR-4 substrate. In order to reduce the complexity, only two slots are introduced on the radiating patch instead of three slots to reject each narrow band frequency. In this case, one slot rejects a combination of WiMAX and C-band and the other slot rejects the WLAN frequency band. The UWB antenna on the thin FR-4 material has an overall size of 21×16 mm2, which is very compact and thus, suitable for wearable applications without causing discomfort when worn on-body. Although the antenna is small in size, the performance is not compromised. The UWB antenna has the frequency range from 2.51 GHz to 12.09 GHz, maximum radiation efficiency of 100% and maximum gain of 4 dBi. Nevertheless, the antenna is able to reject the WiMAX and C-band as well as the WLAN band. The simulated specific absorption rate (SAR) results show that the antenna complies with the SAR limit Federal Communication Commission (FCC) and International Commission of Non-Ionizing Radiation Protections (ICNIRP) standards for 1 mW input power. Bending investigations performed on different diameters of Styrofoam cylinders shows that the frequency range and the notch bands are not very much affected.

Notch band characteristics improvement of a printed ultra wideband antenna by embedding frequency Selective Surface

Excellent improvement on band notched characteristics of a circular ultra-wideband (UWB) printed antenna by embedding Frequency Selective Surface (FSS) at proper position in the far field is presented in this article. A square shaped mushroom Electromagnetic Band Gap (EBG) structure is placed beside the feeding line to achieve an elimination band of 3.7–4.2 GHz over the ultra-wideband range of 2.9–14 GHz showing fractional bandwidth of 131 %. The proposed antenna's electrical dimension is 0.29λ×0.367λ×0.015λ. After embedding the properly designed FSS at optimal position along with the antenna the maximum gain of the radiating frequency increases from 7.1 dBi to 8.1 dBi and notch frequency gain reduces to −7.9 dBi from −5 dBi. Radiation efficiency at notch frequency also reduces from 31 % to 17 %. More than 10 dB Front to Back lobe Ratio (FBR) is obtained at 4.5 GHz. With the aid of Advanced Design Software (ADS), an equivalent circuit for the suggested antenna is created and its response is contrasted with measured and simulated outcomes. The proposed antenna is useful in UWB range with band rejection for C band satellite downlink.

Design of a Reconfigurable Band-notched Wideband Antenna using EBG Structures

A compact WLAN band-notched reconfigurable wideband antenna using two mushroom-like electromagnetic band-gap (EBG) structures is proposed in this paper. It is designed based on a dual wideband microstrip feed patch antenna with operating frequency bands of 2.2-3.7 GHz and 4.8-6 GHz. One of the EBG cells is positioned alongside the feed line, while the other EBG cell is laid on the back of the substrate. The patch or ground of the two EBG units are fed with a stronger current through a ground slot and a parasitic stub respectively, and the connections between the EBG structures and the antenna are controlled by loading a PIN diode with two 56 pF DC blocking capacitors. The advantage of this proposed design is that the antenna and the EBG unit can be designed independently. The proposed antenna has an overall size of 35×46×1.6 mm3. When testing the S11 of the antenna, the influence of the bias circuit on the antenna is also considered. The measured results show that the proposed antenna can generate two notched bands of 2.3-2.49 GHz and 5.11-5.51 GHz of WLAN, and the realized gain in the notch bands can be reduced to -2.65 dBi and -4.55 dBi, respectively, demonstrating its anti-interference characteristics, and can be applied in band notch broadband communication systems or anti-interference communication equipments such as unmanned aerial vehicles and radars.

UWB TAPERED-SLOT PATCH ANTENNA WITH RECONFIGURABLE DUAL BAND-NOTCHES CHARACTERISTICS

An ultra-wideband patch antenna (UWB) that makes use of tapered slot technology is designed and analyzed in this article. Coplanar waveguide feeds the projected antenna. The presented antenna displayed superior UWB performances with -10 dB return-loss bandwidth, ranging from 1.9 to 12 GHz. The projected slot antenna has another benefit of minimizing the interference effect of the narrow band communications conducted by two notch bands operating at 3.3–3.8 GHz (WiMAX) and 5.1-6 GHz (WLAN and HIPERLAN/2), respectively. The Dual-Bands rejection is generated by etching out a complementary split ring resonator (CSRR) from the patch and placing a trapezoidal split ring resonator (TSRR). Adaptable single or dual-band rejection characteristics have been added to the behavior of the UWB antenna, by mounting electronic switching across SRR and CSRR. Furthermore, the presented UWB slot antenna is printed on an FR4-epoxy substrate (εr = 4.4) and it has an overall size of . 55x48x1.5 mm3

Dual-Notched UWB Orthogonal MIMO Antenna with Improved Gain Characteristics Using Frequency Selective Surfaces for Wireless Communication Applications

In this paper, a complementary split ring resonator (CSRR) loaded compact CPW-fed circular shaped monopole UWB antenna with dual band notch characteristics is designed on an FR-4 substrate. The propounded band-notched UWB antenna is integrated with two frequency selective surface layers referred as bandpass frequency selective surface (FSS-1) and reflector (FSS-2) to offer enhanced radiation performance. Bandpass FSS-1 enhances the gain of the antenna by improving directivity and reflector FSS-2 reflects back the backside radiation of the proposed antenna towards the forward direction thereby increasing gain and directivity of the proposed antenna. Furthermore, a two-element orthogonal MIMO antenna is proposed with improved gain using two FSS layers. The complete configuration of the proposed two-element MIMO antenna consists of CSRR-based radiating patches, monopole ground planes and two integrated FSS layers. The proposed MIMO antenna operates in UWB range from 3.46[Formula: see text]GHz to 16.02[Formula: see text]GHz with dual notches at 3.9[Formula: see text]GHz and 7.2[Formula: see text]GHz. Isolation between MIMO elements is greater than 23 dB. Both antennas are fabricated and investigated at 5.9[Formula: see text]GHz for vehicular communications. Maximum gain improvements of 8 dB and 6.4 dB are observed in case of the presented single element and MIMO antenna within the entire operating band due to the integration of dual FSS layers. The diversity performance of the suggested MIMO antenna is investigated by analyzing mean effective gain, envelope correlation coefficient, channel capacity loss and diversity gain parameters. The proposed MIMO antenna is a suitable candidate for vehicular and UWB wireless communication applications.

Design of a superconducting UWB bandpass filter with tunable notch band

By studying the principles of ultra-wideband (UWB) and band-stop, a novel band-pass filter with adjustable band-stop characteristics is proposed. The filter achieves 3.1-10.6 GHz UWB bandpass characteristics through an improved multi-mode resonator. An L-shape λ/2 notch resonator loaded with a 2-bit reconfigurable interdigital capacitor (IDC) array is coupled to the multiple-mode resonator and generates a tunable notch band to reject any undesired signal that may interfere with the UWB passband. By connecting the IDC to the ground or not, the capacitance of each IDC and the corresponding notch frequency can be adjusted. After design and optimization, the final size of the superconducting filter is 20.0 mm × 6.9 mm, and the test results and simulation results are highly consistent.