WiMAX Communication Research Articles

A low-cost dual bandpass planar filter for WiMAX and mobile communications

This study proposes a new design of low-cost dual-bandpass filter for worldwide interoperability and microwave access (WiMAX) band at <br /> 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 mm<sup>2</sup>.

A COMPACT HONEYCOMB-STRUCTURED RECONFIGURABLE ANTENNA WITH COPLANAR WAVEGUIDE FEED FOR MULTIBAND WIRELESS APPLICATIONS

The design and implementation of reconfigurable antennas in wireless applications play a tremendous role in minimizing the hardware size of wireless devices. An antenna with the potential to vary its frequency of operation, radiation pattern, and polarization according to the requirement is known as a reconfigurable antenna. Here a novel honeycomb-structured frequency and pattern-reconfigurable monopole antenna has been designed. A honeycomb structure provides better bandwidth as it has multiple edges; angles of the hexagon allow for more efficient radiation and reception of electromagnetic waves and it offers a symmetric radiation pattern. It is compact, with higher packing density. A lowcost FR-4 substrate with a thickness of 1.5 mm and a compact size of 25 mm × 42 mm is used in the design. The antenna can be operated in four modes using two PIN diodes. In mode 0 it can resonate at 2.4 GHz, which is commonly used for Wi-Fi and Bluetooth communication, while in mode 1 it operates at 2.8 GHz and 1.8 GHz for mobile communication. In mode 2 it operates at 2.7 GHz as well as 1.8 GHz, and in mode 3, it works at 1.8 GHz and 3.6 GHz for WiMAX communication. This antenna has a peak gain value of 3.99 dBi. Thus, by changing the geometry/structure, antenna performance can be improved. The proposed design is fabricated on FR-4 substrate material, and the parameters such as return loss (S<sub>11</sub>) and bandwidth are validated. The simulated results and the measured results match well.

A Triband Compact Antenna for Wireless Applications

This paper presents the implementation of a triple band microstrip patch antenna based on modified split ring resonator (SRR) and modified complementary split ring resonator (CSRR) as defected ground plane. The antenna is designed in a FR4 substrate of dielectric constant 4.4 with dimensions as 35 mm × 35 mm × 1.6 mm that comprises a total designed antenna volume of 1960 mm3. Multiband operation is introduced in the antenna through multiple resonators that are introduced in the patch. Impedance matching was provided with the help of partial ground plane and modified SRR in patch. The simulation performance of the antenna is verified using high frequency structural simulator (HFSS) software. The designed antenna resonates at 2.8 GHz, 5.8 GHz, and 6.9 GHz for the application requirements of WiMAX, ISM, and Sub-7 GHz wireless communication. The antenna is fabricated as printed circuit board (PCB) format, and its return loss characteristics are measured using a vector network analyser (VNA). The measurement results of the proposed triband antenna are in good agreement with simulated return loss characteristics.

A tri-band flexible antenna based on tri-band AMC reflector for gain enhancement and SAR reduction

A tri-band wearable antenna fed by coplanar waveguide (CWP) with an artificial magnetic conductor (AMC) reflector is presented in this paper. The radiation patch consists of three open inverted triangles for multiband, and the ground is defected for better impedance matching The AMC unit is composed of three concentric nested regular octagonal rings. And to improve the performance of gain, the unit achieves three reflection zero phases at 1.8, 2.45 and 3.5 GHz corresponding to the three bands of the antenna. The proposed antenna based on AMC has been fabricated and measured. The working frequency bands are 1.34–1.67 GHz, 2.33–2.47 GHz and 3.55–3.7 GHz. The measured gain has increased by 3.4, 1.8, 4 dBi at 1.8, 2.45 and 3.5 GHz, respectively. The scenario that the antenna is placed on the human arm is also considered and experimented for wearable applications. The results are in good agreement with the simulation data and verify that the antenna has good robustness. When the antenna is conformal with the human tissue, the specific absorption rate (SAR) is calculated and reduced by about 99.8% after adding AMC reflector. Hence the proposed antenna has excellent wearable safety and is compatible with LTE 1800, WLAN, WiMAX communication systems.

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.

MIMO-DRA with triple-band CP & low EM coupling: a methodical design approach

This article presents a methodical approach for designing a circularly polarized multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) with triple frequency bands and low mutual electromagnetic (EM) coupling. The MIMO configuration is composed of two identical circularly polarized DRA elements in an orthogonal arrangement. To achieve circular polarization (CP) radiation, each rectangular DR element is modified and rotated with respect to the feeding-aperture. Meanwhile, the low mutual coupling is obtained by arranging the DRA elements orthogonally, and also by etching a Y-shaped slot on the ground plane. The Y-shaped slot facilitates the increase of the coupling current path, which decreases the inter-port coupling. The simulated outcomes are validated through an experimental test of the fabricated prototype. The proposed concept provides triple impedance bands as well as triple CP bands with low EM coupling ( < −25 dB). This article fills a research gap by developing a circularly polarized triple-band MIMO-DRA that can be used for a variety of wireless applications, including WiMAX, Wi-Fi, WLAN, and satellite communication.

Design and Fabrication of Compact, Multiband, High Gain, High Isolation, Metamaterial-Based MIMO Antennas for Wireless Communication Systems

We proposed a novel approach based on a complementary split-ring resonator metamaterial in a two-port MIMO antenna, giving high gain, multiband results with miniature size. We have also analyzed a circular disk metasurface design. The designs are also defected using ground structure by reducing the width of the ground plane to 8 mm and etching all other parts of the ground plane. The electric length of the proposed design is 0.5λ × 0.35λ × 0.02λ. The design results are also investigated for a different variation of complementary split-ring resonator ring sizes. The inner and outer ring diameters are varied to find the optimized solution for enhanced output performance parameters. Good isolation is also achieved for both bands. The gain and directivity results are also presented. The results are compared for isolation, gain, structure size, and the number of ports. The compact, multiband, high gain and high isolation design can apply to WiMAX, WLAN, and satellite communication applications.

Four-Port Dual-Band Multiple-Input Multiple-Output Dielectric Resonator Antenna for Sub-6 GHz 5G Communication Applications.

A four-port dielectric resonator (DR)-based multiple-input multiple-output (MIMO) antenna is presented for sub-6 GHz MIMO communication. The dielectric resonator was fed through aperture feeding to achieve dual-band resonance. The DRA has the operating modes of TE01δ and TE10δ&amp;nbsp;at 3.3 GHz and 3.9 GHz, respectively. The engineered antenna has port isolation of higher than 20 dB at the target frequencies without the employment of an extra isolation mechanism. Full-wave high-frequency simulation software was employed for the simulation computation. The antenna has a peak gain of 5.8 dBi and 6.2 dBi, and an efficiency of 88.6% and 90.2% at 3.3 GHz and 3.9 GHz, respectively. The proposed resonator has good MIMO diversity parameters. The optimal envelope correlation coefficient (ECC) is 0.01, channel capacity loss (CCL) is 0.1 bits/sec/Hz, and the total active reflection coefficient (TARC) is -22.46. The DRA elements are aligned orthogonally with adequate displacement for achieving polarization diversity and spatial diversity. The antenna delivers its applications in Sub-6 GHz 5G and WiMAX communications.

Design of compact rectangular SIW-based cavity-backed slot antennas for WiMAX communication in Asia–Pacific regions

Design of compact rectangular SIW-based cavity-backed slot antennas for WiMAX communication in Asia–Pacific regions

Tri-Strip Monopole Antenna for LTE, WLAN and WIMAX Communication Applications

In this study, a Tri-strip monopole antenna for LTE, WLAN, and WiMAX (Worldwide Interoperability for Microwave Access) applications is presented. This is because wireless apps do not need to connect to all working frequencies at once, improving functionality without requiring a larger antenna. For LTE, WLAN, and WIMAX applications, a tiny triple wideband coplanar waveguide-fed patch antenna with a defective ground structure is used. Gain and radiation patterns have improved, return loss has been examined, and parametric analysis has been offered for antenna optimization. Average gain through the band is reported to be 3.5 dB, while radiation efficiency for the model is observed to be 94% on average.

Parasitic Element Based Frequency Reconfigurable Antenna with Dual Wideband Characteristics for Wireless Applications

A Microstrip Frequency Reconfigurable circular patch slot antenna for switchable Bluetooth, WiMAX, WLAN, and satellite communication applications is analyzed and presented in this work. The optimized overall size of 47 mm x40 mmx1.6 mm is utilized in the design, and which can cover wide range of frequencies below 10 GHz. In the initial phase, different monopole antennas are designed with various shapes of same size and later parasitic patch elements has been added to those monopole antennas. The circular monopole driven element and parasitic element are connected with a PIN diode, and which reinforced in achieving frequency reconfigurability. The proposed antenna is resonating at various frequencies of 2.4 GHz, 4 GHz, and 8.4 GHz when the diode in ON condition and resonating at 3 GHz, 5.4 GHz, and 8.4 GHz when the diode is in OFF condition. The performance of the designed antenna prototype is scaled and differentiated with the results of simulation and found good matching with respect to performance characteristics.

Capacitive Coupled Wide-Notch Stepped Impedance Narrow-Band Bandpass Filter for WiMax Application

The development of wireless communication standards necessitates optimal filter design for the selection of appropriate bands of frequencies. In this work, a compact in size pair of parallel coupled symmetric stepped impedance-based resonator is designed with supporting to the WiMAX communication standards. The coupled resonator is tuned to allow the frequency band between 3.4 GHz and 3.8 GHz, which is centered at 3.6 GHz. A parasitic effect of capacitively coupled feed structure is used for exciting the two symmetrical stepped impedance resonators. The bandwidth and selectivity of the filter are enhanced with the change of characteristic impedances and controlling the coupling gap between resonators. This design offers single narrow sharp passband selectivity as well as multiple stopband harmonic suppression arising as a result of multiple transmission zeros. The designed filter operates with a fractional bandwidth (FBW) of 11.47%. The proposed single narrowband bandpass filter provides better suppression in either side of the tuned frequency (3.6 GHz) without degrading the passband performance. Also, this novel filter offers an insertion loss of about −0.08 dB and a return loss of greater than −30 dB in passband. This approach is useful for eliminating unwanted spurious harmonics responses that enter the desired response. The suggested bandpass filter has been simulated using Advanced Design System (ADS) tool, and the measurement has been made using a network analyzer, and the results are reported.

A dual-band miniature uniplanar antenna on epoxy reinforced woven glass material for WiMAX, WLAN, UWB, and X-band applications

In this paper, a dual-band miniature uniplanar antenna is presented. The antenna size is 24.5 mm × 20 mm × 1.6 mm which consists of a modified bow-tie-shaped radiator, an inverted L-shaped ground plane, and an extended inverted U-shaped ground plane, and designed on the single side of a low-cost epoxy matrix reinforced woven glass material with permittivity 4.6. The numerical results confirm that the radiator is effectively coupled with the coplanar ground planes and the investigated antenna can cover dual frequency bands ranging from 3.32 to 10.9 GHz, and 11.88 to 17.77 GHz. The measured results of the prototype in frequency-domain and time-domain are obtained and compared with the simulated results. The results indicate that the proposed antenna demonstrates good performance over the dual impedance bands, which makes it a very potential candidate for WiMAX, WLAN, UWB, X-band, and Ku-band wireless communication applications.

Efficient network selection using multi fuzzy criteria for confidential data transmission in wireless body sensor networks

In the last decade, due to wireless technology’s enhancement, the people’s interest is highly increased in Wireless Body Sensor Networks (WBSNs). WBSNs consist of many tiny biosensor nodes that are continuously monitoring diverse physiological signals such as BP (systolic and diastolic), ECG, EMG, SpO2, and activity recognition and transmit these sensed patients’ sensitive information to the central node, which is straight communicate with the controller. To disseminate this sensitive patient information from the controller to remote Medical Server (MS) needs to be prolonged high-speed wireless technology, i.e., LTE, UMTS, WiMAX, WiFi, and satellite communication. It is a challenging task for the controller to choose the optimal network to disseminate various patient vital signs, i.e., emergency data, normal data, and delay-sensitive data. According to the nature of various biosensor nodes in WBSNs, monitor patient vital signs and provide complete intelligent treatment when any abnormality occurs in the human body, i.e., accurate insulin injection when patient sugar level increased. In this paper, first, we select the optimal network from accessible networks using four different fuzzy attribute-based decision-making techniques (Triangular Cubic Hesistent Fuzzy Weighted Averaging Operator, Neutrosophic Linguistic TOPSIS method, Trangualar Cubic Hesistent Fuzzy Hamacher Weighted Averaging Operator and Cubic Grey Relational Analysis) depending upon the quality of service requirement for various application of WBSNs to prolong the human life, enhanced the society’s medical treatment and indorse living qualities of people. Similarly, leakage and misuse of patient data can be a security threat to human life. Thus, confidential data transmission is of great importance. For this purpose, in our proposed scheme, we used HECC for secure key exchange and an AES algorithm to secure patient vital signs to protect patient information from illegal usage. Furthermore, MAC protocol is used for mutual authentication among sensor nodes and Base Stations (BS). Mathematical results show that our scheme is efficient for optimal network selection in such circumstances where conflict arises among diverse QoS requirements for different applications of WBSNs.

Modelling of an Optical Access Network Platform for Radio-Frequency Transmission in the S Band / Modelação de uma Plataforma de Rede de Acesso Óptico para Transmissão de Radiofrequências na Banda S

Microwave transmission in the S Band are used in WiMAX, mobile telephony, air control and satellite communications. Such applications demand the use of wideband optical access networks. In this article, the impact of non-linearities of a fluorescent optical source (FFOS) is analyzed on the performance, at 560 nm, of Discrete-Multitone (DMT) transmissions, using the multicarrier signal-to-noise ratio (SNR mc ) metric. The objective is to provide a model of SNR mc level curves based on empirical measurements by varying the bias current and the amplitude of the input signal in the optical source. The cartography was approximated by fitting ellipses, which allows us to find an approximate optimum point of operation for the setup.

Square Monopole Microstrip Antenna for Quad Band Operation

In this paper the square monopole microstrip antenna with slot on the radiating patch is presented for multiband operation. The antenna has a volume of 80×80×16 mm3. The antenna is fabricated using the modified glass epoxy substrate material. The antenna operates between the frequency range of 2.9 GHz to 10.87 GHz. The radiation characteristic is broadside and the peak gain of about 5.1dB is obtained in its operating frequency. The design details are tabulated and the results are presented and discussed. This antenna may find its applications in WLAN and Wi-max communication applications.

Performance enhancement of relays used for next generation wireless communication networks

&lt;p&gt;Relaying is one of the latest communication technologies developed for wireless networks like WiMAX, LTE Advanced and 5G Ultra Reliable Low Latency Communication (URLLC) networks to provide coverage extension as well as higher bitrates for cell edge users. Thus they are included in the design of next generation wireless communication systems to provide performance improvement in terms of coverage and capacity over their predecessors. Other promising features of this technology include easy to implement and reduction in deployment cost. The objective of this paper is to analyze both cooperative and non-cooperative relaying techniques in the Infinite Block length regime and findout the benefits of Relay implementation. A single Amplify and Forward (A&amp;amp;F) Relay is used for this purpose. Reduction in power requirement for Simple Relay is shown in comparison to the direct transmission, using experimental analysis with Matlab simulation. SER (Symbol error rate) is calculated at the receiver for no relay, simple Relay and Cooperative Relaying scenario to show the improvements of cooperative Relaying implementation.The performance enhancement of the Relay is then carried out using Particle Swam Optimization (PSO) optimization technique where allocation of power between Base station and Relay Node is effectively distributed for optimum performance.&lt;/p&gt;

A Compact Dual Notch Frequency Reconfigurable Antenna for WIMAX,DSRC, RADAR and Ku band Communication Applications

A frequency reconfigurable ultra-wide band antenna with dual notch bands is proposed in this paper. PIN diodes are located on ultra-wide band monopole antenna and are investigated for frequency reconfigurable characteristic of the proposed antenna. Multi-bands and narrow bands have been achieved by different combinations. Proposed antenna is fabricated on FR-4 substrate of dimensions 37 x 40 x 0.8mm3. For the successful combinations, antenna performance parameters like S11 characteristics, surface current distribution, peak gain, radiation efficiency and 2D radiation patterns are analyzed and illustrated in the paper. Peak gain of 4.83dB is obtained in operating band for D1, D2= 0, 1 combination. Radiation efficiency is not less than 70% in the entire operating bands. Results are analyzed experimentally for validating proposed antenna. Simulation based results and measured results are in good agreement.

Design of a triple band notched polarization independent compact FSS at UWB frequency range

The design of a compact triple band notched Frequency Selective surface (FSS) at Ultra-Wide-Band (UWB) frequency range is presented. To make the proposed FSS polarization insensitive, on the upper part of the substrate a single metallic square loop (SL) and four identical rotational symmetric square split ring resonators (SSRR1) are placed, whereas at the bottom part another four identical rotational symmetric SSRR loops (SSRR2) are printed. Here each SSRR is rotated in 90°clockwise direction over a single layered FR4 substrate. Triple band notches are obtained at WiMAX and Satellite communication downlink C-band (3.3-4.2 GHz), WLAN (5.1-5.9 GHz) and Satellite communication X-band (7.2-8.4 GHz) for both TE and TM polarizations. Angular stability is achieved until 70° and attenuation of more than 25 dB is observed at resonance. The passband is obtained at 4.37 and 6.22 GHz. The proposed structure separates the closely spaced frequency bands by a ratio of 1.44 and 1.39 at the stop band and 1.42 at the pass band. The dimensions of the proposed FSS unit cell are 0.13λ0 × 0.13λ0 × 0.020 λ0, where λ0 represents the free space wavelength at the lowest resonance frequency. Good agreement between modeled and measured results is obtained.

Analysis and design of a simple and compact bandstop Frequency Selective Surface at mobile WiMAX and satellite communication X-band

This article presents a dual notched Frequency Selective Surface (FSS) using a compact structure. Four sub-cell square split ring resonators (SSRRs) are imprinted over 8×8 mm2 FR-4 substrate in a 90° clockwise rotational symmetric manner. Dual resonant bands are obtained at 3.08 GHz ranging from 2.5 to 3.6 GHz and 10.2 GHz ranging from 7.95 GHz to 12.3 GHz. The proposed FSS covers the WiMAX band ranging from 2.5 to 2.7 GHz and 3.3 to 3.6 GHz and entire X-band ranging from 8 to 12 GHz. The structure presents a good angular response for both TE and TM incident polarized wave for normal and oblique angles. The pass band from 4.3 GHz to 5 GHz frequency with resonant dip at 4.6 GHz is obtained. The maximum relative deviation in between transmission zero frequency and angularly incident frequency is 1.2% and 4.2% at 70° TM and TE polarized wave, respectively.