GSM Bands Research Articles

HARVESTING MICROWAVE SIGNAL POWER FROM THE AMBIENT ENVIRONMENT

To harvest microwave frequencies in the ambient environment and convert into DC is presented in this paper. The RF harvester replaces a dedicated RF source which is used in an applications like wireless sensor networks to battery operated wireless handheld devices. The focus of work is divided into two parts. The first is to design a compact planar prototype microstrip patch antenna using HFSS for the frequencies of 900&1800MHz (GSM band), 1575MHz (GPS band) and 2.4GHz (ISM band). Antenna is fabricated using MITS PCB prototype machine and tested in VNA. Results obtained from the VNA indicates -30dB and -35dB for GSM 900& 1800 MHz, -15dB for GPS 1575 MHz band and -28dB for ISM 2.4GHz band. Second part consists of RF circuit model includes matching and rectification unit which determines the RF to DC conversion efficiency up to 60%. Voltage doubler RF rectification circuit using schottky diode is designed in ADS and it is tested practically. A lumped T type matching network is implemented to provide a proper impedance match

A novel RF energy harvesting cube based on air dielectric antenna arrays

In this article, a new 2 × 2 circular microstrip antenna array with air dielectric layer for ambient RF energy harvesting has been proposed. Two pairs of arc-shaped slots located close to the boundary of the circular microstrip patch have been designed for achieving dual-band response and extending the frequency bandwidth. The antenna has a frequency bandwidth from 1.85 to 1.93 GHz and from 2.0 to 2.1 GHz which can cover GSM-1800 and UMTS-2100 bands. At the frequency of 1.89 and 2.05 GHz, the measured gain is 5.3 and 6.6 dBi, respectively, and high gain of 3.8-9.3 dBi has been achieved over the whole band. Also, a broadband rectifier that can cover all the bandwidths of the antenna array is designed for the rectenna, which has the maximum rectifying efficiency of 53.6%. Finally, a cube device formed of four antenna and four rectifiers is designed to harvest RF energy, whose maximum output DC voltage is 2.3 V and the maximum output power is 4 mW that can drive four LEDs and an electronic watch.

A modified Hilbert fractal resonator based rectenna design for GSM900 band RF energy harvesting applications

This article proposes a novel rectenna design based on modified Hilbert fractal shaped microstrip antenna and Villard voltage doubler rectifying circuit for RF energy harvesting applications operating at Global System for Mobile Communications (GSM) 900 MHz band. The energy harvesting antenna is numerically optimized and fabricated on a Rogers RO4003 substrate of thickness 1.52 mm with a compact overall physical sizes of 80 mm × 82 mm (λ0/4.16 × λ0/4.06). Various geometric parameters and circuit component values of the proposed energy harvesting system are optimized in order to achieve a matched input impedance with good radiation performance of high gain for the input power level less than −20 dBm. The numerical and experimental results point out the technical potential of the proposed rectenna design to be utilized in DC power supply modules of low voltage, low power electronic devices.

Design Analysis of Integrated Passive Device-Based Balun Devices With High Selectivity for Mobile Application

This paper presents highly selective, low-loss, and miniaturized balun devices fabricated using the integrated passive device (IPD) technique for the GSM band (900/1800 MHz) and the WiFi band (2400 MHz) in mobile applications. Balun devices were fabricated on a gallium arsenide (GaAs) substrate using the IPD fabrication process to reduce the overall size (0.05λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</sub> × 0.036λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</sub> at 900 MHz). Each device is the combination of lattice lumped structure with a low-pass filter and a high-pass filter configuration. This structural formation of lumped elements helps to reduce the phase mismatch error in the balun devices. For all the balun devices, the measured results indicated a minimum amplitude imbalance (<;0.47 dB) and low phase imbalance (180 ± 2.6°). Mathematically calculated, calculated after considering parasitic effects, simulated and measured results exhibited a good correlation. The return loss is below 18 dB and insertion loss is below 0.25 dB for the entire fabricated devices. A balun device with a center frequency of 900 MHz has given the best results amongst all fabricated devices.

Compact Antenna for 4G/5G Metal Frame Mobile Phone Applications Using a Tuning Line

A compact antenna with a 6 mm ground clearance for 4G and 5G metal frame mobile phones is proposed in this paper. The proposed antenna consists of a coupled line, a ground branch, a monopole branch, and a tuning line. The ground branch and the coupled line are used to obtain the lower band (698–960 MHz), the monopole branch is used to improve the match at the lower band and obtain the higher band (1710–2690, 3400–3800 MHz), and the tuning line is used to improve the match at the higher band. The novelty of the proposed antenna is that more modes are excited and work together to obtain multiple working bands, by using the coupled line and the folded branches with the help of the tuning line, and then nine bands are obtained under the conditions of a 6 mm, only, ground clearance and a metal frame environment. A prototype has been fabricated and measured. The measured −6 dB impedance bandwidths are 345 MHz (0.685–1.03 GHz) and 2.16 GHz (1.67–3.83 GHz) at the lower and higher bands, respectively. The LTE700, GSM850, GSM900, DCS, PCS, UMTS, LTE2300, and LTE2500 bands for 2G, 3G, 4G, and the 3.5 GHz band that is possible for 5G are covered. The measured efficiencies and patterns are also presented.

Primary user characterization for cognitive radio wireless networks using long short-term memory

Cognitive radio is a paradigm that proposes managing the radio electric spectrum dynamically by integrating the spectrum sensing, decision-making, sharing, and mobility stages. In the decision-making stage, the best available channel is selected for transmitting secondary user data in an opportunistic fashion, and the success of that stage depends on the efficiency of the primary user characterization model. Use of the long short-term memory technique based on the deep learning concept is proposed in order to reduce the forecasting error present in the future estimation of primary users in the GSM and WiFi frequency bands. The results show that long short-term memory has the capacity needed to improve channel use forecasting significantly more than other methods such as multilayer perceptron neural networks, Bayesian networks, and adaptive neuro-fuzzy inference systems (ANFIS-Grid). It is concluded that although long short-term memory exhibits better performance generating forecasts for time series, computing complexity is higher due to the existence of input, forget, and output gates within the neural structure; therefore, implementation is feasible in cognitive radio networks based on centralized network topologies.

Learning‐based predictive dynamic spectrum access framework: a practical perspective for enhanced QoE of secondary users

In a cognitive radio environment, the optimality in channel selection by a secondary user (SU) is directly dependent on its spectrum-sensing efficiency, and quality of experience (QoE) in terms of the channel-switching frequency (CSF) and the interference caused to the primary users (PUs). Modelling the spectrum through statistical methods becomes, sometimes, difficult due to the lack of a-priori information of the PU activity. This work proposes a framework for learning-based prediction of the future idle times of the PUs thereby opportunistically allocating the channel with enhanced QoE of SUs. The idea is to minimise the spectrum-sensing energy requirement by sensing only if the channel is predicted to be idle, thereby reducing the CSF and mitigating the SU–PU interference. Initially, the authors have tested the accuracy of the prediction approach in various traffic scenarios for a single PU channel case. Later, it is extended to the multiple channel case for a particular data traffic. Furthermore, a practical scenario has been considered where the efficacy of the proposed framework is validated for PU data traffic in GSM and ISM bands. The results highlight the practicability of prediction-based opportunistic dynamic spectrum access with improvement in the SU QoE over random channel selection.

A CPW-fed UWB MIMO antenna with integrated GSM band and dual band notches

This article presents a coplanar waveguide fed global system for mobile communications band integrated ultra wide band (UWB) multiple input multiple output (MIMO) antenna with single and dual notch band characteristics. The novelty of the antenna lies in its design as all the unit cells of the proposed UWB MIMO antenna structure are orthogonal to each other therefore the additional isolation elements responsible for achieving high isolation are not required consequently making proposed antenna design simple and easy to fabricate. In this context, 2 MIMO systems have been designed. The first MIMO system is consisting of a dual port antenna whereas the second MIMO system is a printed quad port antenna; further single and dual notch band are achieved in the proposed multi-port MIMO antenna. The antenna shows pattern diversity throughout the impedance bandwidth range. The gain of the antenna varies from 4 to 8.48 dBi. The 2 band notches are achieved at 4.8 and 7.7 GHz in the UWB range. The proposed antenna is fabricated and it is found measured results are in good agreement with simulated results.

Design of a T-Shaped Antenna Based on Characteristic Mode Manipulation for Metal-Framed Handset Application

Recently, metal-framed handset antennas have aroused much attention due to their fantastic appearance and superior robustness. In this paper, a T-shaped antenna suitable for integration with a USB connector is proposed for metal-framed handset application by utilizing the theory of characteristic modes (TCM). Five eigenmodes, one for the lower band and four for the higher band, were merged by a T-shaped metal frame, a feed point, and two shorting pins, as well as three radio frequency (RF) switches so as to broaden the antenna’s operating bandwidth. A prototype was fabricated in order to verify the design concept. Experimental results showed that the proposed antenna was able to cover bandwidths of 0.824–0.960 GHz (GSM band) and 1.710–2.690 GHz (DCS, PCS, UMTS, and LTE bands) with an acceptable radiation efficiency of up to 50% and satisfactory radiation patterns.

Dual-Band Compact Metamaterial-Inspired Absorber with Wide Incidence Angle and Polarization Insensitivity for GSM and ISM Band Applications

Dual-Band Compact Metamaterial-Inspired Absorber with Wide Incidence Angle and Polarization Insensitivity for GSM and ISM Band Applications

An Antenna With a Stair-Like Ground Branch for Octa-Band Narrow-Frame Mobile Phone

An antenna with a small nonground portion (56 × 5 mm2) for 5.7 in octa-band mobile phones is presented in this letter. Owing to the stair-like ground branch, the width of the nonground portion is 5 mm (0.013 λg at frequency 0.8 GHz), and the area of ground clearance is only 280 mm2 . By utilizing the space with a small value of the electric field, the antenna's size can be reduced without worsening the performance. The optimized structure can generate the high band that covers GSM1800, GSM1900, UMTS, LTE2300, and LTE2500 bands (1710–2690 MHz). Moreover, a double-resonant mode is generated in the low band for LTE700, GSM850, and GSM900 bands (704–960 MHz). A prototype is fabricated, and the measured −6 dB impedance bandwidths are 310 MHz (690–1000 MHz) and 1270 MHz (1680–2950 MHz). Meanwhile, the measured patterns, efficiencies, and gains are also obtained. This antenna is promising to utilize in the future.

A Compact Dual-Band Rectenna for GSM900 and GSM1800 Energy Harvesting

This paper presents a compact dual-band rectenna for GSM900 and GSM1800 energy harvesting. The monopole antenna consists of a longer bent Koch fractal element for GSM900 band and a shorter radiation element for GSM1800. The rectifier is composed of a multisection dual-band matching network, two rectifying branches, and filter networks. Measured peak efficiency of the proposed rectenna is 62% at 0.88 GHz 15.9 μW/cm2 and 50% at 1.85 GHz 19.1 μW/cm2, respectively. When the rectenna is 25 m away from a cellular base station, measurement result shows that the harvested power is able to power a batteryless LCD watch and achieve 1.275 V output voltage. The proposed rectenna is compact, efficient, low cost, and easy to fabricate, and it is suitable for RF energy harvesting and various wireless communication scenarios.

A low profile circularly polarized UWB antenna with integrated GSM band for wireless communication

A novel monopole antenna with wide impedance bandwidth and axial ratio bandwidth (ARBW) is presented. The proposed structure is consisting of a wide slot hexagonal shape with an L-shaped radiator coupled inside the slot. Further, two inverted L-shaped strips are protruded on the opposite corners of the hexagonal patch for better radiation capability. The radiating patch is fed by a semi hexagonal ring feed mechanism followed by a tapered line coplanar waveguide (CPW) for improving antenna performance. The proposed structure is supported by a triangular shaped ground plane. An extremely wide -10 dB impedance bandwidth of around 195% and 3-dB axial ratio bandwidth of 32.5% is achieved. The designed antenna has stable radiation characteristics within the operating band. Proposed antenna is fabricated on FR4 epoxy substrate by means of standard photolithography process and measured results are found in a good match with simulated.

Compact Multiband Wireless Energy Harvesting Based Battery-Free Body Area Networks Sensor for Mobile Healthcare

This paper demonstrates a prototype of a self-sustained body area networks (BAN) sensor, which consists of the electrically small triple-band rectenna, the direct current (dc) energy management and storage module, the microcontroller, and the sensing and communication module. The proposed antenna is composed of corrugated metal-insulator-metal plasmonic structures, which covers triple frequency bands, including GSM-900, UTMS-2100, and TD-LTE bands. Its electrical size is only ${\text{0.21}}\,\lambda \times {\text{0.2}}\,\lambda $ at 900 MHz. The gains reach 1 dBi, 2.64 dBi, and −0.19 dBi at 0.9 GHz, 2.025 GHz, and 2.36 GHz, respectively. A triple-band rectifier for low power application is designed to convert the harvested radio frequency (RF) power into dc power. The maximum RF to dc conversion efficiency of the rectifier reaches 59% when the input power is −10 dBm. The proposed compact BAN sensor based on multiband wireless energy harvesting is suitable for human body self-monitoring and mobile healthcare.

Advancement in GSM Network to Access Cloud Services

Cloud services are offering a large number of utilities to the mobile users. Mobile users can share, store, develop, compute and many other services on the cloud. Due to extensive utilization of cloud services by the mobile users, security concerns are also evolving with the same pace. Among different security problems, secure access to the cloud services (cloud data utilization, data storage) is also a difficult and challenging task. This paper highlights the security concerns, particularly addresses the issue of secure access to cloud infrastructure, Such as access the cloud services securely by the mobile users. As Elastic Cloud Computing is valid only for Amazon, MLaden model is theoretical based model and not implemented practically, Wayne model enhances the end user security but not proposed tool for practical implementation. Intention of this paper is to propose mechanism to securely access the cloud services using GSM band. Only defined frequency band of GSM will provide the access to the cloud services. Users will be restricted to use the particular frequency to access the cloud services.

A Circular Disc Microstrip Antenna with Dual Notch Band for GSM/Bluetooth and Extended UWB Applications

A microstrip antenna with a circular disc design and modified ground is proposed in this paper. Circular shapes of different size have been slotted out from the radiating patch for achieving extended ultra wideband (UWB) with GSM/Bluetooth bands with maximum bandwidth of 17.7 GHz (0.88-18.6 GHz). Further, characteristic of dual notch band is achieved, when a combination of T and L-shaped slots are etched into the circular disc and ground plane respectively. Change in length of slots is controlling the notch band characteristics. The proposed antenna has rejection bandwidth of 1.3-2.2 GHz (LTE band), 3.2-3.9 GHz (WiMAX band) and 5.2-6.1 GHz (WLAN band) respectively. It covers the frequency range of 0.88-18.5 GHz with the VSWR of less than 2. Also, an equivalent parallel resonant circuit has been demonstrated for band notched frequencies of the designed antenna. The gain achieved by the proposed antenna is 6.27 dBi. This antenna has been designed, investigated and fabricated for GSM, Bluetooth, UWB, X and Ku band applications. The stable gain including H &amp; E-plane radiation pattern with good directivity and omnidirectional behavior is achieved by the proposed antenna. Measured bandwidths are 0.5 GHz, 0.8 GHz, 1.1 GHz and 11.7 GHz respectively.

Design of a compact planar dual-band rat-race coupler using improved microwave C-Section

ABSTRACTThis work presents a compact planar dual-band rat-race coupler (RRC) using improved microwave C-section. The difference in even- and odd-mode phase velocity is compensated by using wiggly lines in the structure. The wiggle depth is tuned to obtain a characteristic impedance of 70.7 Ohm and phase of 90° at 2.1 GHz and 5.3 GHz. The size of the proposed structure is 0.42 λg × 0.26 λg. The measured and simulated responses are in good agreement. The 1 dB bandwidth of the first and second bands is 670 MHz and 210 MHz, respectively, covering the GSM and WLAN bands. The structure is compact, simple, single layer, and cheap.

VHF 및 UHF 대역 소형 안테나 매칭성능 개선을 위한 비 포스터 정합회로 설계

Herein, a non-Foster matching circuit is designed to improve the impedance matching characteristics of small antennas in the VHF and UHF bands. The proposed non-Foster circuit is designed to operate with negative capacitance in a wide frequency band from 50 MHz to 1,000 MHz for use in various communication bands. To ensure the stability of the non-Foster circuit with conditional stability, the open-circuit stability condition of Linvill was satisfied, and the circuit was fabricated using the FR-4 substrate. The fabricated non-Foster circuit was combined with a small antenna to verify its performance by measuring the return loss and received power in the FM, DMB, and GSM bands. The measured return loss was improved from −6 dB to −30 dB, and the measured received power was improved from 0.5 dBm to 5.2 dBm.

Multiport Pixel Rectenna for Ambient RF Energy Harvesting

We describe the design of a multiport pixel rectenna for ambient radio-frequency (RF) energy harvesting consisting of an optimized triple-port pixel antenna and a triple-port rectifier with dc combining. The advantages of the multiport pixel approach include enhanced harvested RF power for a given area as well as a reduction in the antenna matching requirements. We formulate the design of the triple-port pixel antenna as a binary optimization problem with an objective function related to harvested RF power in the GSM-1800 band for specified power angular spectrums without the need for antenna matching components. The optimization of the triple-port pixel antenna is obtained by using successive exhaustive Boolean optimization. The design for the triple-port rectifier with dc combining is also provided and a prototype is demonstrated. The rectenna measurement demonstrates that the proposed triple-port pixel antenna has dc output power over double that of single-port-based antennas of similar size. The overall RF-to-dc efficiency of the multiport pixel rectenna is also evaluated and shown to be 19% when the total input RF power is −20 dBm. The effects of nonuniformity in the input RF power across antenna ports are also investigated.

Dual band RF sensor for testing of magnetic properties of materials using meandered line SRR

In this paper, a microwave planar resonant sensor using the meandered line based split ring resonator (MLSRR) is proposed to retrieve the magnetic properties of materials in 3G and 4G GSM bands. The proposed sensor is based on the field perturbation theory, where the permeability of the test sample is determined after placing it on the designed meandered conductive loop. The loading of magnetic test sample on the meandered conductive loop of the split ring resonator perturbs the magnetic field concentrated on it thereby changing the resonant frequency of the sensor, which is recorded for the determination of permeability. The proposed dual band RF sensor is designed using the full wave electromagnetic solver. The equivalent circuit model and the corresponding numerical model of the proposed dual band sensor are discussed. The designed sensor is fabricated using the standard microstrip technology. The resonant frequencies of the proposed sensor are measured using the vector network analyzer (VNA), and are found to be 1.71 GHz and 2.35 GHz corresponding to 3G and 4G bands, respectively. Various standard materials are measured and the relative permeability is estimated using the proposed sensor in combination with the developed numerical model. The measured data are compared with values available in literature, and the typical error is found to be less than 8% for all the samples.