WiMAX Bands Research Articles

On-Body Low-Profile Compact AMC-Integrated Wideband Antenna for Body Area Network Applications

This communication presents a wideband and a low-profile flexible wearable antenna intended to operate at a 2.45 GHz WBAN band. The suggested antenna comprises a CPW-fed monopole antenna backed by an artificial magnetic conductor (AMC) to act as a reflector. The latest AMC-integrated design uses R03003 as a dielectric substrate. The suggested design features an impedance bandwidth of 71.03% (1.87–3.93 GHz) with a gain value of 3.62 dBi and has a compact footprint of 40 × 40 mm2. The incorporation of wideband AMC with a monopole antenna leads to bandwidth enhancement and covers the 3.5 GHz WiMAX band. Simulation and experimental studies provide evidence that in the case of structural deformities and human body loading, the suggested AMC-integrated antenna is stable and shows superior efficiency relative to the traditional monopole antenna. Furthermore, numerical analysis demonstrates that the amount of radiation AMC-integrated antenna decreases tremendously in terms of specific absorption rate for various bodily attachment scenarios. Three body templates with various compositions and forms were used to study the effects of the antenna on bodily attachment. Extensive experiments on human body phantoms and bodily attachment are also conducted and the results are presented. The suggested AMC-integrated design thus confirms a promising contender for portable wearable wireless applications.

Polyimide-based Flexible Antenna for Telemedicine and Wireless Applications

Background: The era of flexible antennas started long ago because they are cost-effective while offering several advantages, such as good flexibility, stretchability, and compactness. Although several synthetic and natural polymers with good flexibility are available, the first flexible antenna is designed with polyimide materials (polymers), often known as engineering plastics. Objective: To fabricate a compact antenna with a higher gain than other existing ones and the bending loss of the proposed antenna is lower than other existing ones, this study proposes an ideal antenna. Methods: A polyimide (PI)-based flexible antenna with a defected ground structure is proposed for telemedicine and wireless applications, and we implement this antenna using microstrip feeding. The proposed antenna consists of a polyimide substrate with a thickness of 0.1 mm, a relative permittivity of 3.15, a loss factor of 0.0013, and a compact overall size of 25 x 32 x 0.1 mm3. Results: The proposed antenna operates on three frequencies, including 2.4 GHz (ISM or telemedicine application), 5.5 GHz (WiMAX band), and 7.5 GHz (wireless radio band). The proposed antenna produces impedance bandwidths of 10.16%, 14.54%, and 5.33% at frequencies of 2.4 GHz, 5.5 GHz, and 7.5 GHz, with gains of 4.9 dB, 5.1 dB, and 5 dB. Conclusion: The proposed antenna is simulated using Ansys High-Frequency Structure Simulator (HFSS) software. A good agreement is found between the measured and simulated results.

Triple-Band Notched Ultra-Wideband Microstrip MIMO Antenna with Bluetooth Band.

In this paper, a novel ultra-wideband UWB antenna element with triple-band notches is proposed. The proposed UWB radiator element operates from 2.03 GHz up to 15.04 GHz with triple rejected bands at the WiMAX band (3.28-3.8 GHz), WLAN band (5.05-5.9 GHz), and X-band (7.78-8.51 GHz). In addition, the radiator supports the Bluetooth band (2.4-2.483 GHz). Three different techniques were utilized to obtain the triple-band notches. An alpha-shaped coupled line with a stub-loaded resonator (SLR) band stop filter was inserted along the main feeding line before the radiator to obtain a WiMAX band notch characteristic. Two identical U-shaped slots were etched on the proposed UWB radiator to achieve WLAN band notch characteristics with a very high degree of selectivity. Two identical metallic frames of an octagon-shaped electromagnetic band gap structure (EBG) were placed along the main feeding line to achieve the notch characteristic with X-band satellite communication with high sharpness edges. A novel UWB multiple-input multiple-output (MIMO) radiator is proposed. The proposed UWB-MIMO radiator was fabricated on FR-4 substrate material and measured. The isolation between every two adjacent ports was below -20 dB over the FCC-UWB spectrum and the Bluetooth band for the four MIMO antennas. The envelope correlation coefficient (ECC) between the proposed antennas in MIMO does not exceed 0.05. The diversity gains (DG) for all the radiators are greater than 9.98 dB.

A Multi-Frequency Omnidirectional Antenna Based on a Ring-Shaped Structure.

A multi-frequency microstrip antenna loaded with a ring-like structure has been proposed. The radiating patch on the antenna surface consists of three split-ring resonator structures, and the ground plate consists of a bottom metal strip and three ring-shaped metals with regular cuts to form a defective ground structure. The proposed antenna works in six different frequency bands covering 1.10, 1.33, 1.63, 1.97, 2.08, and 2.69 GHz and works entirely when connected to 5G NR (FR1, 0.45-3 GHz), 4GLTE (1.6265-1.6605 GHz), Personal Communication System (1.85-1.99 GHz), Universal Mobile Telecommunications System (1.92-2.176 GHz), WiMAX (2.5-2.69 GHz), and other communications frequency bands. Moreover, such antennas also have stable omnidirectional radiation properties across different operating frequency bands. This antenna meets the needs of portable multi-frequency mobile devices and provides a theoretical approach for the development of multi-frequency antennas.

A four-port wideband filtering monopole MIMO array for sub-6 GHz 5G communications

AbstractThis communication presents the significance of a four-port 2×2 multiple input multiple output antenna operating in mid-band frequency for 5G handheld device application. A microstrip-fed reference truncated decagonal monopole antenna operating at 3.9 GHz and a modified split-ring resonator (SRR)-based low-pass filter that excites at a cut-off frequency of 6.5 GHz are designed. On introducing a stub line in the SRR structure, the proposed filter shows a good out-of-band rejection beyond 6.5 GHz. By integrating the filter into the reference monopole, a wideband filtering monopole with improved stopband performance is obtained. A four-port MIMO array is constructed by orthogonally positioning the antenna with a center-to-center separation of 0.25λ0. To improve isolation, a pair of inverted L-stubs of varying lengths is introduced. The closed loop formed by the interconnection of stubs enhances isolation within the frequency range of 3–3.5 GHz. The fabricated prototype fosters an impedance bandwidth of 66.67%, isolation >18.5 dB, an average suppression of 15 dB, an average peak gain >3.7 dB, envelope correlation coefficient < 0.015, Actual Diversity Gain (ADG) > 9.9 dB, Effective Diversity Gain (EDG) > 8.8 dB, and efficiency >88%. The proposed design is suitable for 5G sub-6 GHz applications such as n48, n77, n78, n79 bands, WiMAX, and LTE bands 42, 43, 46, 47, 48.

A CPW-fed dual band four-port MIMO antenna based on liquid crystal polymer for flexible IoT applications

AbstractA 2 × 2 dual band MIMO flexible antenna with a low profile and CPW feeding is designed for Internet of Things (IoT) domains, operating in 5G (3.3–3.6/4.8–5.0 GHz), WiMAX (5.25–5.85 GHz) and WLAN (5.15–5.35/5.725–5.825 GHz) bands. Two resonant frequencies are generated by L-shaped branches and a rectangular monopole. The mentioned MIMO antenna comprises four elements arranged vertically. With the addition of an orthogonal branch, significant isolation is attained, which exceeds 21 dB in the entire bands. The four-element MIMO antenna is fabricated and experimented to analyze the performance. According to the measurement, the antenna can operate bandwidth covering 3.156–3.84 GHz (19.55%) and 4.638–6.348 GHz (31.13%). Furthermore, the provided four-element MIMO antenna possesses a number of advantageous properties, such as ECC, DG, and TARC, indicating its suitability for 5G/WiMAX/WLAN applications. In accordance with the results of bending measurement and human body influence, it is evident that the presented liquid crystal polymer antenna could be an ideal candidate for integrating into wearable 5G/WiMAX/WLAN devices.

DESIGN AND ANALYSIS OF MULTI-BAND COMPACT MICROSTRIP ANTENNA IN GSM1900/WLAN/WiMAX/DSRC/X-BAND FREQUENCY BANDS FOR VEHICLE APPLICATIONS

This study focuses the design and analysis of a compact, multi-band microstrip patch antenna for wireless communications operations. The design antenna exhibits distinct quad resonance frequency bands I from 1.879 GHz to 1.986 GHz, II from 3.1 GHz to 3.87 GHz, and III from 4.97 GHz to 6.515 GHz, IV from 7.26 GHz to 8.6 GHz, which covers GSM 1.900 GHz, WLAN (5.2/5.8 GHz), DSRC 5.9 GHz and WiMAX (3.5/5.5 GHz) bands. In addition, it can also support the X-band from 7.26 to 8.6 GHz. The antenna is designed on an inexpensive substrate of FR4 with dimensions of 36(L) × 25(W) mm2 and consists of two branches of curved strips for a quad-band response. The antenna is designed and analyzed using electromagnetic 3D computer simulation software. The designed antenna can provide advantages in GSM/WLAN/WiMAX/DSRC/X-band satellite applications for vehicle communication with four resonant frequency bands, nearly omnidirectional radiation characteristics, and acceptable gain.

A Compact UWB Monopole Antenna with Triple Band Notches

This article presents an ultra-wideband (UWB) monopole antenna with triple band notch characteristics. The proposed antenna consists of an octagonal patch, fed with a 50 Ω line, which occupies a compact size of 40 mm × 29 mm (0.36λ × 0.26λ, λ is computed using 2.7 GHz frequency) and resonances at a relatively low frequency (2.94 GHz). Specifically, an L-shaped stub, an inverted C-shaped slot, and a pair of U-shaped resonating structures are introduced into the design, which allow antenna to generate three band notches at 3.22-3.83 GHz, 4.49-5.05 GHz and 7.49-8.02 GHz, corresponding to WiMAX band, Indian national satellite (INSAT) band, and X-band satellite frequencies, respectively. In the center of the notched band, the antenna has lower efficiency and gain, essentially indicating that the antenna has good interference rejection performance. To evaluate its performance, the proposed antenna has been fabricated and measured, and the relevant functional parameters, such as S-parameters, voltage standing wave ratio (VSWR) and radiation property, have been studied.

Antennas for Licensed Shared Access in 5G Communications with LTE Mid- and High-Band Coverage.

Two novel antennas are presented for mobile devices to enable them to access both licensed shared access (LSA) bands (1452-1492 and 2300-2400 MHz) and all the long-term evolution (LTE) mid (1427-2690 MHz) and high (3400-3800 MHz) bands, together with the GSM1800, GSM1900, UMTS, and 3.3 GHz WiMAX bands. These antennas do not require any passive or active lumped elements for input impedance matching. One of them is a dual-band antenna and the other is a wideband antenna. Both antennas have high efficiency in all the LSA bands, as well as the mid- and high-LTE bands, and nearly omnidirectional radiation patterns in the mid band. In the high band, the radiation patterns of the wideband antenna are less directional than those of the dual-band antenna. The wideband antenna was fabricated and tested and the measurements demonstrated that it had good wideband performance in a wide frequency range from 1.37 to 4 GHz, covering all the above-mentioned bands.

A Christmas Tree-Shaped Quadband Compact Antenna with Triple Slots for Various Wireless Technologies

A compact, coplanar waveguide (CPW)-fed multiband antenna is developed and analyzed in this paper for quad-band applications. Christmas tree-like monopole antennae with three symmetric slots are designed on a low-cost FR4 epoxy substrate with the overall dimensions of 0.312λ 1 × 0.364λ 1 × 0.0083λ 1 where λ 1 is the wavelength corresponding to the lower cut-off frequency. Three rectangular-shaped slots of different dimensions are etched on the three triangular-shaped stacked patches to enhance the current carrying path due to which the proposed antenna resonates at the required frequency bands. Different antenna parameters such as reflection coefficient (S 11), gain, radiation efficiency, surface current, radiation pattern, group delay and magnitude response of transfer function (S 21) are analyzed for inspecting the antenna performance. The quad-band antenna offers measured bandwidths of 3.1–3.9 GHz (22.86%), 5.46–5.98 GHz (9.1%) 9.76–11.74 GHz (18.42%) and 17.55–19.25 GHz (9.24%). The antenna shows nearly omnidirectional radiation patterns in all resonating bands with the highest gain of 4.5 dBi and measured radiation efficiency greater than 70% in all the bands. The antenna also offers stable group delay response and linear S 21 response in its operational spectrums. All these characteristics ensure the antenna’s applicability in IEEE 802.16 WiMAX band, 5.5 GHz Wi-Fi band, 5.8 GHz ISM band, terrestrial broadband, radiolocation and earth explorer satellite applications.

A multiband quasi‐Yagi antenna using stepped driver and slotted ground for 2.4/3.5/5.2 GHz bands applications

AbstractA multiband quasi‐Yagi antenna using a stepped driver and slotted ground for the applications of 2.4/3.5/5.2 GHz bands is presented. The ground plane modifications match impedance and help form the resonances, while the stepped driver parameters allow independent control of resonance frequencies. The antenna shows multiband characteristics and has achieved dB in three different frequency bands of 2.15–2.65, 3.4–4, and 5–5.3 GHz. Furthermore, the antenna shows a stable gain of around 3.9–4.9 dBi and retains its general radiation characteristics for all frequency bands. The simulation and measurement results agree well with each other. The proposed antenna is suitable for applications requiring general quasi‐Yagi antenna characteristics for wireless communications applications for WLAN, WiMAX, ISM, and Bluetooth frequency bands.

Design and Implementation of a Textile-Based Embroidered Frequency Selective Surface

This article presents the design, fabrication and analysis of a textile-based band-stop frequency selective surface (FSS), in GSM, WiFi, LTE and WiMAX bands where the electromagnetic (EM) pollution is intense. The unit cell of the proposed FSS has been designed and simulated via a full-wave EM solver; CST Microwave Studio at the frequency of interest. In contrary to traditional FSS designs, which are printed on solid materials such as PCBs, this study presents an FSS considering a woven fabric as a substrate layer having features such as flexibility and compact weight. Two fabrication techniques have been considered one is conducted with a copper tape having a thickness of 35 µm denoted as CT FSS and the second one is conductive yarn embroidering technique denoted as CY FSS for the conducting pattern. Fabricated samples are evaluated in terms of transmission characteristics and a satisfactory agreement is obtained between CT FSS and CY FSS for both simulations and fabricated prototypes.

Dual‐wideband dipole antenna with symmetrical strips for WiMAX and WLAN application

AbstractA dual‐wideband planar dipole antenna for WLAN and WiMAX applications is proposed. The antenna is mainly composed of a U‐shaped dipole which is fed by a parallel double transmission line. The U‐shaped dipole is employed to generate a wide lower band and a narrow higher band. To expand the higher band, two pairs of strips are used to symmetrically embed in the U‐shaped arms of the dipole. The tested results demonstrate that this antenna achieves two wide bandwidths about 53.6% (2.33–4.02 GHz) and 23.7% (5.04–6.45 GHz) at the higher and lower frequency band, which can satisfy the requirement of the whole 2.4/5.2/5.8‐GHz WLAN and 2.5/3.5/5.5‐GHz WiMAX bands.

Design of three multibranch microstrip antennas compatible with WiMAX/WiFi/4G/5G NR for coal mine applications

AbstractIn this letter, three microstrip antennas are designed and fabricated for coal mine applications, each of which can be compatible with WiMAX, WiFi, 4G, and 5G NR bands. The first one is the Pentagon antenna, which is realized by optimizing the sizes and positions of five branches. The second one is designed by adding a passive inverted L‐shaped branch on the top of a trident antenna. And the third one is designed by loading an inverted L‐shaped structure in the ground of the trident antenna. The simulated and measured results showed that each of the three proposed antennas can cover the frequency bands of 2.51–2.68, 3.40–3.60, and 4.80–4.90 GHz for commercial 5G NR of coal mines, 1.88–2.66 GHz for China Mobile/Unicom/Telecom full‐band of 4G, 2.40–2.484 GHz for WiFi, and 2.50–2.69 GHz for WiMAX. Good agreements between the simulated and measured results confirm the practical feasibility of the proposed multiband antennas.

5G ДВУХДИАПАЗОННАЯ ПРЯМОУГОЛЬНАЯ МИКРОПОЛОСКОВАЯ АНТЕННА С ДВУМЯ ТРАВЛЕНИЯМИ И ВЕРХНИМ ШЕСТИГРАННЫМ ВЫРЕЗОМ НА КОНЦЕ CPW FED

Around the world, wireless or distant communication has become fundamental and indispensable.Every day, billions of users access calls, the internet, and social media. Many electricalequipment, including the antenna, are used in the sophisticated networks and systems that supportthat massive information interchange. An electrical device known as an antenna sends or receivesinformation across space. The antenna is a key component in many systems, including radio andtelevision transmission, communications receivers, radar, cellular phones, Bluetooth-enabledgadgets, and satellite communications. The rapid expansion of wireless technology and personalcommunication has increased the demand for multiband antennas, which can operate at severalfrequencies and are suited for a variety of applications. Dual-band coplanar waveguide (CPW)fed rectangular microstrip patch antenna for 5G, WiMAX band, ISM Band, and WLAN applicationsis presented in this paper. The proposed antenna is robust, cheap, light weight, and easy tofabricate, resonating at 2.4 GHz in -12.182379 s11 with 205.7 MHz BW and 3.42 GHzin -37.344879 s11 with 464.9 MHz BW whereas gain is 3.85 and 3.41 respectively. Patch elementsare placed on isolation FR408 (loss-free) substrate of relative permittivity 3.75 kept at a substrateheight of 1.6 mm. Results of simulation are presented using CST STUDIO SUITE 2019.

SEMICIRCULAR SLOT BASED UWB MICROSTRIP PATCH ANTENNA FOR VARIABLE BAND NOTCHED APPLICATIONS

The patch antenna with Ultra-Wide Band (UWB) characteristics is a promising candidate for wireless communication. It is a major research problem to mitigate electromagnetic interference (EMI) with narrowband technologies such as 5G lower band, Wi-MAX, WLAN and satellite band, which are all in the UWB region. This study describes a UWB antenna with variable band rejection that can be used to avoid interference with Wi-MAX and 5G lower band applications. The UWB characteristics of a simple rectangle patch antenna with a faulty ground structure has been designed for operational bandwidth (2.7–13) GHz. A novel method semicircular slot (SCS) at the radiation patch creates a band notched from (3.25–3.80) GHz and (3.4–4) GHz. Variable band rejection between (2.95–4.40) GHz can be achieved by adjusting the “Wa” values. When measured over the band rejection frequency, the return loss (S11) and VSWR values are very close to 0 dB and larger than 2. The simulated and measured results such as return loss, VSWR, 2-D polar pattern and gain have almost similar agreement. The design of the suggested antenna is simple, compact and efficient for Wi-MAX application, this is an ideal UWB antenna with the band notch characteristics.

A miniaturized microstrip antenna with tunable double band-notched characteristics for UWB applications

This paper proposes the step-by-step design procedure for obtaining independent dual band-notch performance, which provides a valuable method for designing tunable dual band-notched UWB antenna. The proposed antenna consists of the semicircle ring-like radiating patch with an elliptical-shaped slot and double split ring resonators on the top surface of the substrate and defected ground structure (DGS) on the bottom surface of the substrate. The operating frequencies ranged from 1.3 to 11.6 GHz (S11 < − 10 dB). By loading varactor diodes at the gap of the resonators structure and changing the varactor diode’s reverse bias voltage(0–30 V), a wider band-notched tuning range from 2.47–4.19 to 4.32–5.96 GHz can be achieved, which covers the whole WiMAX band and WLAN band. The experimental results agree well with the simulated results. The notched gain at notched frequency points is about − 5.3 dBi and − 5 dBi, demonstrating that the narrow-band interference signal could be efficiently suppressed. The security of UWB communication systems can be further enhanced. Meanwhile, the selection of varactor diode and DC bias circuit are fully considered. Hence, the accuracy of the experiment results and antenna operating performance have been improved. Furthermore, the proposed antenna only has an electrical size of 0.26λ*0.19λ at 1.3 GHz. Compared to the related reported antennas, the proposed antenna has achieved a simpler structure, low profile, compact size, tunable dual band-notched characteristics, extensive independent tunable range, and good band-notched performance simultaneously, to the best of our knowledge. The proposed antenna is believed to have a valuable prospect in UWB communication, Wireless Body Area Network, Industry Science Medicine, mobile communication applications, etc.

A photopaper‐based low‐cost, wideband wearable antenna for wireless body area network applications

This study presents a low-cost, compact, flexible, and wideband wearable antenna for different wireless body area network (WBAN) band applications, covering medical body area network band of 2.4 GHz, industrial, scientific, and medical band of 2.45 GHz, WiMAX band of 3.5 GHz, and wireless local area network band of 5.2 GHz. The final antenna topology is obtained by hexagonal microstrip radiator patch fabricated on commercially available low-cost photo paper substrate and defected ground plane below the feed line acting as a partial ground to achieve a conformable structure wideband operation. The overall size of the fabricated antenna is 30 × 40 mm2 and yields a wide-bandwidth of 3 GHz (2.30–5.30 GHz), radiation efficiency of 84.35%, and the highest gain of 3.48 dBi at the centre frequency of 5.2 GHz, and minimum gain of 1.91 dBi at 2.45 GHz. Furthermore, our detailed numerical and experimental investigations involving specific absorption rate performance assessment and bending analysis revealed the proposed design's excellent robustness to both human body loading and structural deformation scenarios. Therefore, simulated and measured results strongly advocate that the proposed design has profound implications for flexible and body-worn devices in WBAN applications.

Compact Quad Band MIMO Antenna Design with Enhanced Gain for Wireless Communications.

In this paper, a novel microstrip line-fed meander-line-based four-elements quad band Multiple Input and Multiple Output (MIMO) antenna is proposed with a gain enhancement technique. The proposed structure resonates at four bands simultaneously, that is, 1.23, 2.45, 3.5 and 4.9 GHz, which resemble GPS L2, Wi-Fi, Wi-MAX and WLAN wireless application bands, respectively. The unit element is extended to four elements MIMO antenna structure exhibiting isolation of more than 22 dB between the adjacent elements without disturbing the resonant frequencies. In order to enhance the gain, two orthogonal microstrip lines are incorporated between the antenna elements which result in significant gain improvement over all the four resonances. Furthermore, the diversity performance of the MIMO structure is analyzed. The Envelope Co-Relation Coefficient (ECC), Diversity Gain (DG), Channel Capacity Loss (CCL), Mean Effective Gain (MEG) and Multiplexing Efficiency are obtained as 0.003, 10 dB, 0.0025 bps/Hz, −3 dB (almost) and 0.64 (min.), respectively, which are competent and compatible with practical wireless applications. The Total Active Reflection Coefficient (TARC) resembles the characteristic of the individual antenna elements. The layout area of the overall MIMO antenna is 0.33 λ × 0.29 λ, where λ is the free-space wavelength corresponding to the lowest resonance. The advantage of the proposed structure has been assessed by comparing it with previously reported MIMO structures based on number of antenna elements, isolation, gain, CCL and compactness. A prototype of the proposed MIMO structure is fabricated, and the measured results are found to be aligned with the simulated results.

Design of multimode broadband circularly polarized antenna using characteristics mode analysis

In this article, as low-profile fish-shaped monopole antenna is proposed for circular polarization radiation. The modal characteristics of the proposed antenna were analyzed and manipulated using characteristic mode analysis technique. Four characteristic modes with different resonant frequencies and current distributions were chosen as operating modes. In addition, a suitable position excited the desired modes, which achieve broadband circular polarization performance and dual-band performance. Based on the above analysis, a prototype of the proposed antenna was fabricated with dimensions of 60 mm × 60 mm × 1.5 mm to validate simulated results. Measured results show that the 3-dB axial ratio bandwidth (ARBW) of the proposed antenna is 40.7% (4.9–7.4 GHz) and the antenna broadside peak gain is 4.2 dBic within usable bandwidth. In addition, the measured impedance bandwidths of the proposed antenna are 12.2% (2.3–2.6 GHz) and 53.7% (4.5–7.8 GHz). Compared to other designs, the proposed circularly polarized antenna is a promising design operating in WiMAX band and industrial, scientific, and medical bands.