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A low-profile dual U-shaped monopole antenna designed for WLAN, WiMAX, and C-band applications has been implemented in this paper. The proposed antenna has covering frequency ranges of 2.7-3.1 GHz, 4.0-5.2 GHz, and 5.9-6.4 GHz. The compact antenna's antenna size is 24×30×0.8 mm², and the antenna has achieved bandwidths of 13.79%, 26.67%, and 8.1% across the respective bands. This frequency band is achieved as a result of dual inversion to each other in U shape. The low profile of the proposed antenna enables its easy and fast inculcation in modern communication devices. [ABSTRACT FROM AUTHOR]

A novel compact rectangular fractal-shaped antenna for tri-band wireless communication applications is developed in this article. The proposed fractal shaped is achieved by cutting two rectangular slots in the rectangular monopole. Additionally, a stub is introduced in the bottom side of the antenna to enhance the impedance bandwidth of the acquired three bands. The developed antenna has a compact size 22 × 34 × 1.6 mm3. The CST MWS is used to design the antenna and its characteristics including S11, current distribution, radiation characteristics are exposed and analysed. To demonstrate that the simulation outcomes are reliable, the suggested antenna is manufactured and put through testing on an E5071C VNA. Additionally, the results of the experiments demonstrate that the designed antenna offers three impedance bandwidths 2.25–2.96 GHz, 3.56–4.01 GHz, and 4.6–5.86 GHz, which shields all the LTE, WLAN, WiMAX, and C-band applications. The proposed tri-band fractal antenna also provides good gain at the operating frequencies and an omnidirectional radiation pattern. [ABSTRACT FROM AUTHOR]

This paper presents a novel filter-based analysis for the conventional rectangular patch antenna (RPA) using the Composite Right/Left-Handed Transmission Line (CRLH-TL) theory. We introduce two circuit models for RPA, described by lumped components and transmission line (TL) elements. An RPA is considered a Symmetric CRLH-TL (SCRLH-TL). We validated the analysis by comparing the circuit model and full-wave analysis simulation results. The TL circuit model error in the full-wave analysis was less than 5%. A dual-band Zeroth-Order Resonant (ZOR) antenna is designed and manufactured based on the introduced Lumped element circuit model, which exhibits filtering characteristics in both bands. We obtain the antenna circuit model by incorporating the RPA lump circuit model with LC resonators. We implemented the antenna structure by combining the RPA and complementary split-ring resonators (CSRR) modeled by the LC resonators. We initialized the antenna center frequency bands for WiMAX 2.45 GHz and 3.60 GHz. The CSRRs control the configuration of the center frequencies. The simulation and measured results are in good agreement. The proposed antenna dimensions are 0.66 × 0.66 × 0.012 λ g at 2.45 GHz (43.22 × 43.22 × 0.81 mm3). The measured gains are 3.47 dB and 4.64 dB for 2.45 GHz and 3.60 GHz, respectively. Two radiation nulls were observed at 2.09 GHz and 2.98 GHz for the 2.45 GHz band and one radiation null at 3.45 GHz for the 3.60 GHz band. Also, the fractional bandwidth is 4.03% and 1.39%, respectively. The radiation pattern is nearly omnidirectional. The simulated efficiency is 90% for 2.45 GHz and 87% for 3.60 GHz frequency bands. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a novel filter-based analysis for the conventional rectangular patch antenna (RPA) using the Composite Right/Left-Handed Transmission Line (CRLH-TL) theory. We introduce two circuit models for RPA, described by lumped components and transmission line (TL) elements. An RPA is considered a Symmetric CRLH-TL (SCRLH-TL). We validated the analysis by comparing the circuit model and full-wave analysis simulation results. The TL circuit model error in the full-wave analysis was less than 5%. A dual-band Zeroth-Order Resonant (ZOR) antenna is designed and manufactured based on the introduced Lumped element circuit model, which exhibits filtering characteristics in both bands. We obtain the antenna circuit model by incorporating the RPA lump circuit model with LC resonators. We implemented the antenna structure by combining the RPA and complementary split-ring resonators (CSRR) modeled by the LC resonators. We initialized the antenna center frequency bands for WiMAX 2.45 GHz and 3.60 GHz. The CSRRs control the configuration of the center frequencies. The simulation and measured results are in good agreement. The proposed antenna dimensions are 0.66 $$\times$$ × 0.66 $$\times$$ × 0.012 $$\lambda _g$$ λ g at 2.45 GHz (43.22 $$\times$$ × 43.22 $$\times$$ × 0.81 mm3). The measured gains are 3.47 dB and 4.64 dB for 2.45 GHz and 3.60 GHz, respectively. Two radiation nulls were observed at 2.09 GHz and 2.98 GHz for the 2.45 GHz band and one radiation null at 3.45 GHz for the 3.60 GHz band. Also, the fractional bandwidth is 4.03% and 1.39%, respectively. The radiation pattern is nearly omnidirectional. The simulated efficiency is 90% for 2.45 GHz and 87% for 3.60 GHz frequency bands.

IEEE 802.16 can be seen as a compelling replacement for conventional broadband technologies because its primary goal is to provide Broadband Wireless Access (BWA). The variable and uncertain nature of wireless networks makes it much more challenging to ensure QoS in this network. WiMAX Technology is used to support various quality of services which includes UGS, rtps, nrtps, ertps, and Best Effort. This study employs an IEEE 802.16 network simulator, which offers adaptable and reliable features for assessing a particular QoS parameters for rtps. Achieving better internet performance in real time services is currently a challenge, and it is in need of a present scenario. This work emphasized better internet service, with good quality of service using rtps with Relay Station and Without Relay Station. In this work the CBR packet size, CBR data rate, and data rate with rtps service are fine-tuned for achieving better performance with good quality of service. When comparing uplink connections in rtps with and without relay station, it is found that the throughput in the uplink is 200% greater when using a relay station. The throughput and goodput are evaluated in uploading and downloading with single and multiple subscriber stations and we observed that the multiple subscriber stations in downloading give better performance, as compared to single subscriber stations. The throughput and goodput in single subscriber stations is better than multiple subscriber stations in uploading. The academic researchers and commercial developers can use this analysis to validate different WiMAX Network implementation mechanisms and parameters. [ABSTRACT FROM AUTHOR]

In this paper, a CPW-fed compact antenna with tri-band reject characteristics is presented and experimentally verified. A curved ground plane is introduced to enhance the bandwidth to 250 MHz. The sectoral patch antenna has a T-strip and Y-slot to reject WLAN (4.78 ∼ 5.68 GHz) and WiMAX (3.385 ∼ 3.97 GHz), respectively. L-strips are placed in the ground plane to increase the bandwidth as well as the plane to reject uplink satellite frequency in the X-band (7.93 ∼ 8.74 GHz). In all notch bands, high VSWR values are observed. The structure is compact with a size of 15 × 12 × 0.8 mm3. To study the effect of strip/slot on VSWR, parametric analysis is done. The notch frequency is theoretically calculated by an empirical formula. The measured result validates the simulated and calculated notch frequencies. [ABSTRACT FROM AUTHOR]

In this article, an F-shaped four-port multiple-input multiple-output (MIMO) antenna is designed and analyzed. In the designed antenna for achieving high isolation, we introduced a novel isolation technique that appears like plus-shaped wall placed in between the antenna elements. The antenna is designed on a low-cost FR-4 epoxy substrate with total dimensions of 0.61 $ \lambda _{0}\times 0.61\lambda _{0}\times 0.03\lambda _{0} $ λ 0 × 0.61 λ 0 × 0.03 λ 0 (31 mm × 31 mm × 1.58 mm) where $ \lambda _{0} $ λ 0 is the free space wavelength at 5.8 GHz and experimentally verified. This MIMO antenna design covers operating the range of frequencies 5.47–6.20 GHz ( $ |S_{11}| \lt - $ | S 11 | < − 10 dB) which provides a bandwidth of 730 MHz. In terms of performance, the proposed antenna achieves high isolation of $ \lt -45.52 $ < − 45.52 dB with an improved reflection coefficient of $ -30.44 $ − 30.44 dB, a peak gain of 3.77 dBi and a radiation efficiency more than 82% across the entire operating band. Moreover, the achieved MIMO diversity parameters of the proposed antenna are envelope correlation coefficient < 0.005, diversity gain $ \lt 9.99 $ < 9.99 dB, mean effective gain $ \lt -3 $ < − 3 dB and total active reflection coefficient $ \lt -10 $ < − 10 dB in the operating band of frequency. The simulated and measured results show a good agreement between them. Finally, after analyzing the performance of the proposed MIMO configuration, we can say that this antenna is suitable for C-band, WiMAX, Wireless-Fidelity (Wi-Fi), Wireless Local-Area Network (WLAN), Bluetooth and Industrial, Scientific, & Medical (ISM) bands applications. [ABSTRACT FROM AUTHOR]

Due to high demand for wireless communication a wideband Microstrip antenna with compact size is designed for 5G Communication. In this paper a wideband patch antenna is designed and simulated using Ansoft HFSS software and modeled for experimental verification. The design is proposed with a Coplanar Waveguide fed and with a modified ground plane for 5G communication. Extending ground plane, the same antenna can be used for multifrequency operation. The proposed wideband antenna provides a bandwidth of 90.4% ranged from 1.28 GHz to 4.4 GHz, which is useful for 5G communication. The second proposed structure provides tetra frequency response with good reflection coefficient of 18.6 dB, -28.1 dB, -29.3 dB and -32.5dB at 3.96 GHz, 6.45 GHz, 8.29 GHz and 10.4 GHz respectively. Both the simulated and experimental results are found in good agreement. [ABSTRACT FROM AUTHOR]

The Next-Generation Networks offer a green environment with demanded data rates with ultra-low latency. Future efforts will be oriented in more degrees of freedom and system complexity with incorporating global optimization in terms of non-linearities, cost-effective, and reduced environmental impacts. The multitone upconverted radio over fibre (RoF) link with an optical modulator as phase modulator as desired alternatives with respect to optimization features and quantum photonic integration. In this paper, a framework has been developed to characterise the upconverted phase modulated signal model based on next-generation networks, in which an analytical model is investigated for single-tone upconverted, two-tone upconverted, and three-tone upconverted. Numerical simulations have been carried out to verify the novel outcomes using OptSIM software. The developed analytical models have a major contribution to the implementation of next-generation networks such as 5G, 6G, WiMAX, Quantum Communication, etc. The fundamentals of harmonics and the intermodulation product terms of third and fifth order via optical link are also evaluated for multitone Phase modulated RoF link with upconversion method. As per the finding outcomes, the proposed link is adaptable with frequency upconversion and long fibre distances. [ABSTRACT FROM AUTHOR]

This research presents an innovative dual-band microstrip patch antenna design enhanced with defected ground structures (DGS) and barium strontium titanate (BST) thin film, tailored for wireless local area network (WLAN) and WiMax applications. The first design phase involved the development of an microstrip patch antenna (MPA) using an flame retardant (FR4) substrate with a permittivity (er1) of 4.3 and a thickness of 1.524 mm, enhanced with DGS. This configuration achieved a single-band resonance at 4.1 GHz, with a bandwidth of 0.82 GHz and a return loss (S11) of -32 dB. The second phase involved the integration of a BST thin film, with a high permittivity(er2) of 250 and a thickness of 0.1 mm, into the DGS-enhanced microstrip patch antenna (MPA). This modification led to a transformation in the antenna's performance, enabling dual-band operation at resonance frequencies of 2.8 GHz and 5.8 GHz. Further, there was a corresponding substantial increase in bandwidth to 1.34 GHz and 1.25 GHz, respectively, an improvement in S11 values to -16.3 dB and -21.4 dB. Moreover, and antenna's size of 14×10×1.524 mm³. The study underscores the critical role of innovative material use and design optimization in advancing antenna technology, offering significant enhancements in bandwidth, and miniaturization, for wireless communication systems. [ABSTRACT FROM AUTHOR]

The development of a compact and straightforward circularly polarized hexagon-microstrip patch antenna with two layers and a single feed is presented. Circular polarization is achieved using two strategies. The first technique incorporates a narrow slot along one vertex of a hexagonal patch's diagonal, opposite the feed line. The second one is based on embedding a complementary split ring resonator on the hexagonal patch. The proposed antenna is excited by an aperture coupling feed, and it is implemented on two substrate materials; the patch substrate is Roger droid/RT-5880, and the second feed substrate is RO 4350. This work compares the performance of the suggested antennas, including their radiation characteristics, axial ratio, and return loss, in two different scenarios. The proposed antenna has overall dimensions of (0.8λ0 - 0.8λ0 - 0.037λ0) at 3.4 GHz. The slot patch antenna has 2.65% bandwidth for its 3-dB axial ratio and 5.71% impedance bandwidth from 3.4 to 3.6 GHz at 3.5 GHz of the center frequency. The proposed patch antenna also demonstrates a maximum gain of 1.2 dBi. High-frequency structure simulation software was used to design and simulate the proposed hexagon configurations.

In Fifth Generation (5G) mobile communication, the system needs low-profile, compact size, low cost, and constant gain antennas for effective communication. Therefore, this paper addresses multi-band patch antennas which are applicable to C-band, X-band, Ku-band, K-band, and Ka-bands of communication. The proposed antenna design can effectively operates at nine different frequency's for various application including 5G communication network. Our proposed method to design multi-band antenna based on the transmission line mode analysis. Moreover, the slot on the radiating part of the antenna and the ground plane is also considered. The designed antenna has small voltage standing wave ratio (VSWR), give omnidirectional radiation patterns, high directivity and gain for different frequencies. Our design considers octagon shaped circular slot on the patch antenna and defect ground structure (DGS) on the ground plane of the circular micro strip monopole antenna for multi band function. It resonates in a range of frequency from 1 to 40 GHz and dimension 20.27 × 16.76 × 1 mm 3 . The proposed antenna system has been designed using Rogers RT Duroid 5880 substrate of dielectric constant 2.2 and thickness's of 1 mm, and is simulated by High Frequency Structure Simulator (HFSS) software. The simulation results show that the proposed antenna system improves bandwidth, gain, and optimum reflection loss for the desired frequency. [ABSTRACT FROM AUTHOR]

This study introduces a cost-effective monopole antenna array and its MIMO configuration. The single element consists of a rectangular patch monopole featuring five circular slots at the center, accompanied by two thin slots at the top, offering a wide bandwidth (2–7.62 GHz) and a peak gain of 3.8 dBi. For gain improvement, a 2 × 1 antenna array is demonstrated. This antenna array exhibits dual-band behavior; spans from 2 to 3.71 GHz and from 5.9 to 7.54 GHz; covers the 2.5 GHz band (2.3–2.7 GHz), a significant portion of the n78 band (3.3–3.71 GHz), and the n96 band (5.925–7.125 GHz); and is assigned to WiMAX, sub-6 GHz, and sub-7 GHz applications, respectively. The antenna array achieves a peak gain of 6.47 dBi. Lastly, a two-element MIMO configuration derived from the 2 × 1 array is designed. Implementing a defected ground structure (DGS) on the ground plane plays a crucial role in enhancing the isolation from 7 dB to 20 dB. The presented MIMO antenna covers the desired frequency bands of 2.5 GHz, n78, and n96 with a peak gain of 7.5 dBi and high radiation efficiency (<99%), which qualifies it for WiMAX, sub-6 GHz, and sub-7 GHz applications. [ABSTRACT FROM AUTHOR]

A miniature multiple input multiple output (MIMO) ultrawide band (UWB) antenna with dual band notched characteristics is proposed. The proposed MIMO UWB antenna has a microstrip feed line, two slotted rectangular radiating structures, and a slotted reduced ground structure. The antenna is constructed on an FR-4 substrate with a 40 × 20 mm2 compact dimension to span the − 10dB bandwidth of 2.5–12 GHz with a fractional bandwidth of 133%. The two notched bands for WiMAX (3.3–3.8 GHz) and WLAN (5–6.5 GHz), respectively, are generated using hook and E-structured stubs etched on patch and defective ground. Over the full operational frequency range, self-isolation of <-15 dB is obtained between two perpendicular radiating patch structures. 4-element MIMO antenna is also designed, studied and analysed. From the determined MIMO parameters, it can be concluded that the recommended antenna is adequate for portable wireless systems. [ABSTRACT FROM AUTHOR]

Research on energy consumption and bandwidth allocation is the basis for achieving the standard of service and fairness requirements for various traffic classes within the integrated optical-wireless access networks. The energy consumption issue is increasingly vital nowadays. The access segment of both optical and wireless networks is well-known for its domination over total network power consumption. In this research paper, the full power consumption and energy efficiency of integrated Ethernet Passive Optical Network (EPON) and two wireless technologies, namely Worldwide Interoperability for Microwave Access (WiMAX) and Long-Term Evolution (LTE) with a unique EPON-based semi-dynamic bandwidth allocation (SD-DBA), are evaluated. A semi-analytical power consumption model is proposed and applied within the simulation process for energy performance evaluation. Furthermore, various issues that will affect the energy performance like split ratio, Femtocell Base Station (FBS) range, analysis of broadcast elements, and modulation schemes are considered. The obtained results prove that the EPON-WiMAX with SD-DBA has better energy efficiency compared to EPON-LTE with SD-DBA that offers the best data rates with an increase of 12% in splitting ratio, 3.846% in FBS range and 8.6957% in broadcast factor. [ABSTRACT FROM AUTHOR]

This article presents a compact reconfigurable antenna capable of wide-band, dual-band operation. The proposed antenna is having two closed rings with ELC integration in the inner ring. The entire structure is designed and fabricated on a FR4 substrate with the foot print area of 30 × 31 mm2. Initially, a circular ELC-based monopole antenna operating within the frequency range of 2.4 - 2.7 GHz is described. By integrating two p-i-n diodes between the rings and ELC, distinct operating frequency bands are achieved through toggling the diodes. With one diode active, the antenna functions at 2.4 - 2.7 GHz and 4.2 - 4.3 GHz. Activating both diodes extends the bandwidth, enabling operation within the same frequency ranges. The bandwidth of 3200 and 98 MHz is achived in both the bands respectiveley. The gain of the proposed antenna is maintained above 2.0 dBi in the entire operating frequency range. The antenna's compact design, suitable for WiMAX and WLAN applications, is emphasized, and a comparison with contemporary designs underscores its size efficiency and versatile operational modes.

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 0.312λ1 × 0.364λ1 × 0.0083λ1 where λ1 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 (S11), gain, radiation efficiency, surface current, radiation pattern, group delay and magnitude response of transfer function (S21) 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 S21 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. [ABSTRACT FROM AUTHOR]

This study proposes a new design of low-cost dual-bandpass filter for worldwide interoperability and microwave access (WiMAX) band at 3.50 GHz and mobile communications band at 1.19 GHz. A high pass filter and a stopband filter make up the new dual-bandpass filter structure. Different theoretical studies were carried out for the design of the proposed filter. This filter's base is a RO5880 substrate with a dielectric permittivity constant of 2.2, loss tangent of 0.0009 and 1.6 mm thickness. High mashing density was used to validate the various simulated structures while accounting for two numerical methods: the moment technique and the finite integration method. The final circuit's overall dimensions are 60×178,3 mm². [ABSTRACT FROM AUTHOR]

This paper presents a reconfigurable single-filtenna system with three different modes for cognitive radio applications. The filtenna has three independent ports for Ultra Wideband (UWB), WiMAX narrowband mode, and WLAN narrowband mode, respectively. Three PIN diodes (D1, D2, and D3) are attached within the filtenna system and are used to switch between the three different modes in order to achieve frequency reconfiguration. UWB mode for sensing purposes is produced by a monopole antenna and is excited by port P1, which is controlled by D1. The desired frequencies of the narrowband communication modes are achieved by using two narrowband bandpass filters. The 5.2 GHz WLAN narrowband mode is produced by a U-shaped filter. This mode is excited by port P2 and controlled by D2. The second-order rectangular open loop resonator creates the 3.5 GHz WiMAX narrowband mode, which is excited by port P3 and controlled by D3. The simulated (measured) impedance bandwidth covers the range 2.54-12 GHz (2.54-11 GHz) for the UWB mode, with a gain value of 4.89 dB (4.5 dB). The WLAN mode covers the simulated (measured) range 5-5.36 GHz (5-5.26 GHz) with a gain value of 2.24 dB (1.92 dB), and the simulated (measured) bandwidth coverage of the WiMAX mode is 3.33-3.84 GHz (3.15-3.72 GHz) with a gain value of 3 dB (2.65 dB). The mutual coupling values are less than -22 dB for all three modes. [ABSTRACT FROM AUTHOR]

This letter presents a compact slotted pentaband inset-fed microstrip antenna designed to operate for UMTS, WLAN, WiMAX, C-band and X-band applications. By incorporating equispaced slots of same width and length and also the inset feeding, the antenna generates five bands, allowing for penta-band operation. The antenna is manufactured on an FR4 substrate and is excited by an SMA connector using a microstrip line. With its compact dimensions of 25x25x1.6 mm3, the antenna offers a simple structure. Based on the simulated and measured outcomes, the proposed antenna demonstrates numerous advantages, making it highly suitable for wireless communication systems. These advantages include its ability to operate in multiple bands, its percentage bandwidth, compact size, stable radiation pattern, ease of processing, and costeffectiveness. [ABSTRACT FROM AUTHOR]

This article reports the Modified Microstrip Feed Hybrid Rectangular Dielectric Resonator Antenna (RDRA). The proposed structure has a ground plane with a plus-shaped slot on an FR4 substrate with a height of 1.6 mm and dimensions of 38 mm x 35 mm. The proposed Dielectric resonator antenna is made of a material with 10 as its dielectric constant, and the dimensions of the DR are 19 x 20 x 18 mm3. The DR is connected to a modified microstrip feed with an octagonal ring through the plus-shaped slot in the ground. The proposed structure operates in frequencies from 2.60 GHz - 2.74 GHz, 3.12 GHz - 3.37 GHz, and 4.25 GHz - 4.37 GHz. The resonant frequency of the final proposed RDRA is 2.68 GHz, 3.26 GHz, and 4.31 GHz, which covers WLAN, WIMAX and Wireless Avionics Intra-Communications (WAIC) applications, respectively. The entire structure was simulated using the CST microwave studio. The simulated results agree with the measured results and both are presented. The compact size, stable radiation pattern and reasonable gain make this antenna suitable for the proposed applications.

The Non Line of Sight (NLOS) broadband wireless access provided by Worldwide Interoperability for Microwave Access (WiMAX) operating in 2-11 GHz frequency is susceptible to the effects of multipath propagation, diffraction fading, vegetation attenuation, shadowing loss etc. In order to overcome these effects effective fade mitigation techniques, have to be implemented. The Orthogonal Frequency Division Multiplexing- Multiple Input Multiple Output (OFDM-MIMO) is an efficient method that helps in combatting the fading and providing higher SNR to the WiMAX system. According to the IEEE 802.16 specification, for QPSK modulation, a threshold SNR of 6 dB is required for the link to operate. In the present work the use of OFDM-MIMO achieves a SNR above this operating threshold.

A compact single-layer, polarization-insensitive, and angularly stable frequency selective surface (FSS) based multi-stop band filter is reported for shielding three useful frequency bands covering 1.82–2.86 GHz Industrial, scientific, and medical (ISM), 3.52–4.06 GHz Worldwide Interoperability for Microwave Access (WiMAX), and 7.42–8.72 GHz (satellite downlink), centered at 2.4 GHz, 3.6 GHz, and 8.1 GHz, respectively. The proposed unit cell (15 mm × 15 mm) contains four equal-sized square-headed dumbbell (SHD) shaped resonators surrounded by two square ring resonators. The outer and inner square rings offer the first and second stop bands, while the SHD resonators provide the third stop band. A highly polarization-insensitive response is realized owing to the four-fold symmetry in the proposed structure. The unique arrangements of the SHD resonators help to realize higher angular stability under transverse electric (TE), transverse magnetic (TM), and diagonally polarized incident electromagnetic (EM) waves for incidence angles up to 80°, 80°, and 70°, respectively. A detailed analysis in terms of equivalent circuit and parametric variation is carried out to illustrate the higher to lower frequency band ratio. A prototype is fabricated and tested through a proper measurement setup to validate its performance, and it shows good agreement with the simulated results. The proposed FSS unit cell offers better angular stability under diagonally polarised incident waves, attenuation level, minimum higher to lower frequency band ratio, good fractional bandwidth, and compactness. So the designed multi-stopband FSS can be considered a potential candidate for shielding EM radiation across the useful bands

In a wireless communication chain, filters play a critical role in ensuring the efficiency, reliability, and overall performance of the system. In fact, filters are essential for selecting specific frequency bands. They can narrow or widen the bandwidth, depending on the requirements of the communication protocol. Appropriate bandwidth management is crucial for optimizing data transmission rates and accommodating multiple channels within the available spectrum. This article describes the design of a compact bandpass filter with two identical rectangular open-loop resonators. The proposed filter frequency response covers the 3.5 GHz global interoperability for microwave access (WiMAX) and fifth generation (5G) applications. The structure of this filter uses the Rogers RO6010 substrate, which has a dielectric constant of 10.2, thickness of 1.27 mm, and tangent loss of 0.0023. The proposed device is intended for wireless communication systems operating at 3.5 GHz. The filter offers a wide bandwidth of 1.21 GHz with a small size of (5.72 × 12.34) mm2, and a low insertion loss of −0.16 dB. The suggested filter offers effective utilization across various applications including fifth-generation (5G), sub-6G, and WiMAX. Simulation and optimization of the proposed design are conducted utilizing the HFSS (High Frequency Structure Simulator) software. To corroborate the results from HFSS, the ADS (Advanced Design System) software is employed. The simulation outcomes obtained from both HFSS and ADS simulators demonstrate close resemblance.

This study aims to build a wireless computer network for a large company or university to enhance mobility and allow university users to stay connected at any time or place, which is achieved by applying the Universal Interoperability for Microwave Access (WiMax) technology. WiMax is based on the 802.16 sets of standards and has the most efficient and advanced hardware capabilities to meet the demands of teachers and students to browse the web or download files quickly. OPNET Modeler version 14.5 was used to determine the quality of service parameters of WiMax. [ABSTRACT FROM AUTHOR]

Internet connectivity in WiMAX networks, along with various applications, is increasing rapidly, so the connectivity of internet and data transfer speed are always challenges for effective data transmission in wireless networks. Several factors affect the performance of networks. One important factor is to choose a suitable frame period for effective data transmissions. The performance of different frame periods with Round Robin and Strict Priority is evaluated in this work. A frame period in Round Robin performs better than a Strict Priority in terms of throughput, but a Strict Priority performs better in terms of drop rates. This paper also demonstrates that an effective frame period, when combined with a proper bandwidth allocation algorithm, yields better results. This work gives the analysis that Round Robin performs 83.8847% better while Strict Priority performs 86.0020% better than the earliest deadline first algorithms for 10 subscriber stations in terms of throughput. This work is helpful to researchers and industrialists for actual implementations in WiMAX networks. [ABSTRACT FROM AUTHOR]

A single-substrate-layer Frequency Selective Surface (FSS) is designed with a 1.6 mm thick FR4 substrate for triple band-stop frequency filtering applications, that are for Bluetooth, WLAN, WiMAX, and X-band. The proposed FSS unit cell consists of two polygon loops on the front side and a square loop with four annular rings attached to its corners on the backside. The offered design covers three frequency bands: 2.3-4 GHz, 5-6 GHz, and 8-12 GHz. There are three resonances at 3.3, 5.6, and 9.9 GHz. The equivalent circuit model of the proposed structure and the formulas of the LC parameters are presented. A prototype of this structure was manufactured in size of 26 × 26 cm2 and experimentally verified in the antenna and microwave laboratory. The software used for design and simulation is HFSS from Ansys, which uses the finite element method. A comparison with similar structures was performed to demonstrate the performance of the proposed structure. The advantages of the proposed filter include adequate bandwidth, simple structure, as well as small size. In addition, it is unaffected by variant angles of incidence for TE polarization and TM polarization. Furthermore, due to its symmetrical design, it shows a polarization-independent feature. Experimental results for both polarizations verify the merits of the proposed approach, as shown before in the simulation results as well. [ABSTRACT FROM AUTHOR]

This research presents a coplanar waveguide fed elliptical-based second iterative antenna for dual-broadband applications. The antenna radiator is formed after implementing two iterations of an elliptical-shaped patch in a tree-shaped manner and a modified semi-elliptical CPW plane. The antenna provides a bandwidth of 1.87 GHz (2.49–4.36 GHz) in the lower resonating band and 1.96 GHz (7.96–9.92 GHz) in the upper resonating band with peak gains of 2.84 and 6.15 dBi, respectively. An augmented gain of 9.48 dBi is obtained by implementing a single-layer FSS (frequency selective surface) beneath the designed antenna. The simulated and experimental results of the antenna with and without FSS are very similar regarding gain, impedance bandwidth, and directional radiation patterns. The antenna described in this article is simple, inexpensive, and low profile in nature. It can be used for Wi-MAX, lower sub-6 GHz 5G (n78), and x-band applications. [ABSTRACT FROM AUTHOR]

Summary: An electromagnetic band gap (EBG) coupled miniaturized tri‐notched printed ultra‐wideband (UWB) monopole microstrip antenna having dimensions of 22 mm × 26 mm × 1.6 mm loaded with a slot in radiating patch and a parasitic strip in the ground plane has been presented. The proposed structure incorporates a square‐shaped metallic radiating patch with a square EBG structure adjacent to the microstrip feed line, a U‐shaped meandered slot over the radiating element, and a U‐shaped parasitic resonator at the ground plane beneath the radiating element, to reject the C‐band satellite downlink (3.7 to 4.2 GHz), WLAN frequency band (5.15 to 5.85 GHz), and X‐band satellite downlink (7.25 to 7.75 GHz) frequency bands, respectively. The designed antenna operates in the frequency range from 3 to 11.1 GHz, with an impedance bandwidth of 8.1 GHz and a percentage bandwidth of 114%. Modification steps incorporating into the reference antenna to achieve the desired design objectives have been discussed, along with parametric studies. The proposed design has been simulated using Ansys HFSS, and measurement has been taken using standard measurement technique and compared with the simulated results. [ABSTRACT FROM AUTHOR]

The Non Line of Sight (NLOS) broadband wireless access provided by Worldwide Interoperability for Microwave Access (WiMAX) operating in 2-11 GHz frequency is susceptible to the effects of multipath propagation, diffraction fading, vegetation attenuation, shadowing loss etc. In order to overcome these effects effective fade mitigation techniques, have to be implemented. The Orthogonal Frequency Division Multiplexing-Multiple Input Multiple Output (OFDM-MIMO) is an efficient method that helps in combatting the fading and providing higher SNR to the WiMAX system. According to the IEEE 802.16 specification, for QPSK modulation, a threshold SNR of 6 dB is required for the link to operate. In the present work the use of OFDM-MIMO achieves a SNR above this operating threshold. [ABSTRACT FROM AUTHOR]

Abstract In smart grid, the neighborhood area network (NAN) serves as a bridge connecting smart meters and meter data management system (MDMS) and is one of the most important components of the smart grid communication network. In this work, we study the energy-efficient data transmissions from NAN gateways (i.e., routers) to the concentrator that connects the MDMS. Particularly, to assure that each router associated with diverse number of associated smart meters can achieve a required data rate, a set of proportional rate fairness constraints are imposed into the optimization problem. In this case, an optimization problem that balances energy efficiency and fairness is formulated. Due to the fractional form of objective function, the combinatorial constraints on channel allocation variables, and the proportional rate fairness requirements, the formulated energy-efficient data transmission problem is non-convex and extremely computationally complex. In order to solve the problem efficiently, firstly, a subtractive transformation is introduced to handle the objective function, and an iterative algorithm based on Dinkelbach method is proposed; then for the inner loop optimization problem in each iteration, a low-complexity suboptimal algorithm that separates channel allocation and power distribution is developed. Finally, numerical results demonstrate that the proposed algorithm converges in a few steps and achieves a near-optimal energy efficiency performance.

In this paper, on-demand rejection of interfering bands with operating band intended for UWB-X band applications utilizing a diversity antenna with a dimension of 24 × 48 mm2 has been reported. Two sharp rejecting bands, WiMAX and WLAN are obtained by using an anchor-shaped stub embedded within a slotted radiating patch and externally connected C-type stub. MIMO antenna configuration offers isolation of more the 30 db in both measured and simulation environments. The designed MIMO antenna offers good time-domain characteristics and is characterized utilizing various parameters including S-parameters, radiation efficiency, far-field gain, radiation pattern, ECC, DG, TARC, and CCL. [ABSTRACT FROM AUTHOR]

A compact single-layer, polarization-insensitive, and angularly stable frequency selective surface (FSS) based multi-stop band filter is reported for shielding three useful frequency bands covering 1.82-2.86 GHz Industrial, scientific, and medical (ISM), 3.52-4.06 GHz Worldwide Interoperability for Microwave Access (WiMAX), and 7.42-8.72 GHz (satellite downlink), centered at 2.4 GHz, 3.6 GHz, and 8.1 GHz, respectively. The proposed unit cell (15 mm x 15 mm) contains four equal-sized square-headed dumbbell (SHD) shaped resonators surrounded by two square ring resonators. The outer and inner square rings offer the first and second stop bands, while the SHD resonators provide the third stop band. A highly polarization-insensitive response is realized owing to the four-fold symmetry in the proposed structure. The unique arrangements of the SHD resonators help to realize higher angular stability under transverse electric (TE), transverse magnetic (TM), and diagonally polarized incident electromagnetic (EM) waves for incidence angles up to 80°, 80°, and 70°, respectively. A detailed analysis in terms of equivalent circuit and parametric variation is carried out to illustrate the higher to lower frequency band ratio. A prototype is fabricated and tested through a proper measurement setup to validate its performance, and it shows good agreement with the simulated results. The proposed FSS unit cell offers better angular stability under diagonally polarised incident waves, attenuation level, minimum higher to lower frequency band ratio, good fractional bandwidth, and compactness. So the designed multi-stopband FSS can be considered a potential candidate for shielding EM radiation across the useful bands. [ABSTRACT FROM AUTHOR]