Authors:
Diego Dupleich;Eric Schäfer;Giovanni Del Galdo;Reiner Thomä;
Pages: 2200 - 2206 Abstract: Hybrid, mixed analogue/digital beam-forming architectures are a central research topic for the development of mm-wave communication for fifth generation. Most approaches are based on phase shifters in the analogue part, which are inherently narrowband. In this study, the authors evaluate the effects and performance of narrowband beam-steering on wideband signals using two different modelling approaches: spatial-narrowband model, in which the inter-antenna element delays are neglected, and spatial-wideband model, in which the inter-antenna element delays are considered. They show that neglecting the spatial-wideband effects on channel models overestimates the focusing of beam-forming, the expected delay spread reduction, and achievable data-rate with an increasing number of antennas and bandwidth. These effects are quantised by simulations using a realistic ray-tracing scenario at 60 GHz. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Thomas Jost;Wei Wang;Martin Schwinzerl;Fernando Pérez-Fontán;Michael Schönhuber;Nicolas Floury;Svilen Dimitrov;
Pages: 2207 - 2215 Abstract: Wireless radio transmission from a satellite-based emitter to a receiver located on an aircraft is of interest for many applications such as internet access for passengers, air traffic management or positioning by global navigation satellite systems especially when a worldwide service shall be granted. In particular, the last two mentioned applications are related to the safety of life requiring realistic and accurate channel models for software-based system testing. State-of-the-art channel models for the satellite-to-aircraft case lack of accuracy in terms of modelling all propagation impairments. In this contribution, the authors describe airborne propagation experiments using Global Positioning System signals for channel sounding, the data evaluation and the derived channel model. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Thomas Blazek;Golsa Ghiaasi;Christian Backfrieder;Gerald Ostermayer;Christoph F. Mecklenbräuker;
Pages: 2216 - 2223 Abstract: All too often, the performance of vehicular communications is benchmarked merely for a single link. A major challenge for benchmarking the performance of multiple interacting vehicles is the definition of repeatable vehicular scenarios. In this study, the authors propose and discuss an approach for performance analysis of the IEEE 802.11p standard in urban interference channels, by linking network simulations to a Software Defined Radio (SDR) setup. This approach provides communication performance measurements in the worst-case interference scenario caused by an urban traffic jam. They do this by starting out with vehicular traffic flow simulations and continue to model the medium access. They furthermore introduce an algorithm to reduce the complexity of the communication network while retaining its properties. Finally, they use a setup of SDR encompassing the communication nodes and channel emulators that emulate urban channels to measure the packet level performance as a function of signal-to-interference ratio and distance to a receiver under urban traffic conditions. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Maria Garcia-Fernandez;Yuri Alvarez Lopez;Fernando Las-Heras Andres;
Pages: 2224 - 2231 Abstract: This contribution analyses the performance of an unmanned aerial system for antenna measurement (UASAM) for different kinds of measurement scenarios. UASAM is conceived for antenna diagnostics and characterisation at the operational location of the antenna under test (AUT). The system measures the amplitude of the near field radiated by the AUT. Then, these measurements are post-processed using phase retrieval techniques and equivalent currents methods to obtain an electromagnetic model of the AUT. This model can be used for antenna diagnostics and for evaluating the far field pattern. Similar to antenna measurement systems in anechoic chamber, UASAM allows defining different acquisition grids depending on the type of AUT (planar, cylindrical, arc cylindrical), which also influences the flight time. In addition to this, the capability to measure circularly polarised antennas from amplitude-only measurements is presented, discussing the limitations found during the tests, and comparing the results with those from measurements at a spherical range in an anechoic chamber. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Josef Knapp;Jonas Kornprobst;Thomas F. Eibert;
Pages: 2232 - 2241 Abstract: Measurement errors due to echoes are a major challenge for accurate antenna pattern measurements. In particular in highly-reflective measurement environments, the echo contribution can easily have more influence on the measurement signal than the desired line-of-sight contribution between the antenna under test and the measurement probe. A large number of redundant measurement samples at different locations and for different frequencies is used together with appropriate post-processing techniques to mitigate the echo influences on the measurements. The frequency diversity is used for time gating. A virtual array, less sensitive to the undesired echo fields, is formed using probe diversity. In this work, the common time gating technique is enhanced and the impact of different probe configurations for creating a virtual array is investigated. The utilised time gating method extends the measured frequency domain signal to mitigate the Gibbs phenomenon. Processing measurements in a quasi-metallic room, the signal contributions at the edges of the measured bandwidth do not suffer from distortions with the enhanced time gating method. Combining up to 115 probes to form a virtual array, it is found that the results improve with an increasing number of probes as long as the probes are distant enough from the walls. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Reuven Ianconescu;Vladimir Vulfin;
Pages: 2242 - 2255 Abstract: This work derives exact expressions for the radiation from two conductors non-isolated transverse electromagnetic (TEM) transmission lines of any small electric size cross-section in free space. The cases of infinite, semi infinite and finite transmission lines are covered and it is shown that while an infinite transmission line does not radiate, there is a smooth transition between the radiation from a finite to a semi-infinite transmission line. The present analysis is in the frequency domain and the authors consider transmission lines carrying any combination of forward and backward waves. The analytic results are validated by successful comparison with ANSYS commercial software simulation results, and successful comparisons with other published results. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Qing Liu;Dongfang Zhou;Dalong Lv;Dewei Zhang;Yi Zhang;
Pages: 2256 - 2263 Abstract: A novel basic quasi-elliptic response bandpass filter in quadruplet based on coupled TE101-mode-based eighth-mode substrate integrated waveguide (EMSIW) cavities is proposed and analysed firstly. The negative cross coupling is achieved by the nature of coupled fringe electric-field components of the first and fourth cavities. Then, based on the proposed basic quadruplet structure, two methods using a step-impedance resonator and meandered feeding lines, respectively, are introduced and analysed to realise S-L coupling to improve the upper stopband performance further. Finally, two possible structures with quasi-inline and quasi-folded layouts, respectively, are proposed to realise sixth-order EMSIW filters. Five EMSIW filters are designed, fabricated, and measured to demonstrate and verify the proposed structures. The proposed filters have the advantages of compact size, good out-of-band rejection and realisation of higher-order filtering function. The size of the realised 4th-/6th-order filter is less than $0.13/0.17lambda _g^2 $0.13/0.17λg2. The out-of-band rejection higher than 28 dB can reach 2.32f0. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Omar Jibreel;Nihad Dib;Khair Al Shamaileh;
Pages: 2264 - 2271 Abstract: In this study, general design equations for 3-way unequal-split Bagley power dividers (BPDs) are systematically derived. The proposed design procedure allows for obtaining power dividers with the same split ratio but with different solutions for design parameters. Conditions are firstly derived to achieve a perfect input port matching, then, taken into consideration to divide the power unequally between the output ports. A technique to compensate the resulting impractical high-impedance transmission lines is presented, where such lines are replaced by their equivalent single- and dual-frequency T-shaped sections. To validate the derived equations, different dividers with different split ratios, specifically, 1:3:1, 1:10:1, 3:1:3 and 10:1:10 are designed and simulated. Furthermore, 3-way dual-band 10:1:10 BPDs are designed, fabricated and tested. Very good agreement between simulated, theoretical and experimental results is found. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Yanwen Hu;Yu Wang;Qiong Xu;Zhongming Yan;Hongcheng Zhou;Wenying Zhou;
Pages: 2272 - 2278 Abstract: A new method is proposed to design monofocal and bifocal lenses with the function of polarisation conversion based on chiral metamaterial (CMM). The phase distribution of lenses can be calculated more precise by the new numerical simulation method compared to the hyperbolic principle. The complete 360° transmission phase coverage at 1° phase intervals can be achieved by using the metallic split ring resonator and its two deformation structures. Monofocal lens can be realised by the hyperbolic method at microwave frequencies, but it is difficult to realise bifocal lens. The bifocal lens can be easily designed by the new method proposed in this study. The monofocal and bifocal high-gain lens antennas are designed to verify the effectiveness of the new method. The performance of the single-patch lens antenna designed by the new method is improved especially for its axial ratio, compared with the performance of the one designed by hyperbolic principle. The simulation peak gains of the two lens antennas designed by the new method are 18.1 and 18.7 dB at 9 GHz, respectively. The CMM-based lens antennas are fabricated, and the measured results are in good agreement with the simulation results. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Thuy T. Nguyen;Kohei Fujii;Anh-Vu Pham;
Pages: 2279 - 2283 Abstract: This study presents the first fully integrated, push–pull, high power distributed amplifier (DA) for wideband applications in 0.25 µm Gallium arsenide (GaAs) pseudomorphic high electron mobility transistor process. A triple-stacked field-effect transistor cell is employed for each stage of the DA along with the non-uniform distributed power amplifier topology to maximise the output power. The experimental results show that the amplifier exhibits from 7 to 10 dB gain with vi30–32 dBm output power at 1 dB compression (P1 dB) and 32–35.4 dBm saturated output power (Psat) covering a frequency bandwidth from 4 to 20 GHz. The measured second harmonic suppression is>33 dBc from 8 to 40 GHz at the P1 dB operating condition. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Farid Shokouhi;Zaker Hossein Firouzeh;
Pages: 2284 - 2289 Abstract: The design of a dual-polarised series-fed microstrip array antenna for wireless applications, especially in the 5150–5750 MHz band, is delineated in this study, which consists of 12 dielectric rods, fed by circular slots. The rod height can be exploited to improve antenna gain and control its azimuth beamwidth. Using circular slot elements with a central crossing point improves port isolation and cross polarisation. The array elements are fed via two series-fed six-element arms having 25 dB Taylor distribution in each polarisation. The given arms are fed from the centre. Regarding H-polarisation, the arms are fed with a 180° phase shift to improve isolation between the ports as well as the cross polarisation. Additionally, a reflector plane is placed behind the array to suppress back-lobe radiation. A prototype of the array antenna is fabricated and measured. The return loss of the antenna is over 10 dB, varying from 5.1 to 5.8 GHz, and the isolation exceeds 30 dB over the bandwidth. The measured and simulated patterns are presented for both polarisations. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Tianyi Zhou;Fazhong Shen;Qingyang Meng;Huan Li;Kuiwen Xu;Dexin Ye;Jiangtao Huangfu;Shiwei Dong;Tayeb Ahmed Denidni;Lixin Ran;
Pages: 2290 - 2296 Abstract: Although significant progress has been made in microwave imaging, real-time imaging, especially for objects behind walls or closed obstacles, remains a technical challenge. In this work, highly efficient imaging for complex-structured objects surrounded by a closed obstacle was experimentally demonstrated. The imaging equations are derived based on a combination of the inverse-scattering problem and the concept of compressed sensing. Making use of the spatial sparsity of objects and obstacles, the compressed imaging can be implemented using a time-division multi-antenna setup with reduced transmitting antennas. Owing to the spatial compressed sensing applied to the sparse imaging region and objects, the imaging time can be reduced by two orders of magnitude compared with the conventional twofold subspace-based optimisation method with a comparable imaging quality. Taking advantage of the sparsity of the entire imaging area, objects with larger relative permittivity can also be reconstructed. The proposed method can be potentially used in applications such as security examination through boxes. It also provides a new clue for solving the practicability difficulty faced by existing microwave imaging systems. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Rohit Mathur;Santanu Dwari;
Pages: 2297 - 2302 Abstract: In this study, an 8-port multibeam ultrawideband multi-input–multi-output (UWB-MIMO) antenna having pattern and polarisation diversity is investigated for Wireless Personal-Area Network access points. The proposed antenna consists of two different types of slot radiators, each of them provides four directive beams. The novelty of the proposed design is the achievement of a compact 8-port UWB-MIMO antenna using a common ground plane. Eight additional grounded slits are used in this design to enhance isolation. Antenna elements are placed in such a way that two adjacent antennas contribute different patterns. Results show that all the eight antenna elements cover complete UWB (3.1 to 10.6 GHz) with port isolation better than 15 dB. Proposed design offers gain better than 2 dB with envelop correlation coefficient lower than 0.1 from all ports. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Yu-Ming Wu;Sai-Wai Wong;Jing-Yu Lin;Yang Yang;Long Zhang;Wai-Wa Choi;Lei Zhu;Yejun He;
Pages: 2303 - 2309 Abstract: A class of triple-band and triplex cavity-backed slot antenna is proposed by using three fundamental modes in a single metal cavity: TE011, TE101, and TM110 modes, simultaneously. These three resonant modes can be excited by changing the position of the feeding slot without any extra components configured inside the cavity. By opening a single radiation slot, a single band triple-mode cavity-backed slot antenna is achieved. By opening three slots at three side walls of the cavity, a triple-band cavity-backed slot antenna is realised with three different radiation directions at three different operation frequencies. Moreover, a triplex triple-band antenna can be formed by combining a single slot antenna and three input ports in the proposed rectangular cavity. Finally, a triple-band multi-directional cavity-backed slot antenna prototype and a triplex triple-band cavity-backed single slot antenna prototype are fabricated and tested. The tested results are in good agreement with the simulated results, which indicates the feasibility of the proposed design methodology. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Anil Kumar Gautam;Mohd. Farhan;Niraj Agrawal;Karumudi Rambabu;
Pages: 2310 - 2314 Abstract: In this study, a novel design and packaging of miniaturised planar microstrip antenna with circular polarisation (CP) that is suitable for 2.45-GHz radio-frequency identification (RFID) applications is proposed. The circular polarisation is realised by truncating the corners of the left to right diagonal and 76% of miniaturisation is achieved by incorporating two slots in each of the four directions and one at the centre of the square-shaped radiator. This type of miniaturisation method is known in the literature but combining with CP radiation is a novel approach. The radiator of the designed antenna has a compact size of 19.6 × 19.6 mm2 with an overall size of the antenna 30 × 30 × 1.6 mm3, and this technique offers 76% miniaturisation in antenna size. Finally, a prototype antenna is fabricated and experimentally characterised to verify the design concept as well as to validate the simulation results. The designed antenna achieves measured return loss bandwidth of around 80 MHz (2.42– 2.5 GHz) and axial ratio bandwidth of 21 MHz (2.447–2.468 GHz). The proposed antenna is a good candidate for RFID mobile reader applications as it shows a good radiation performance, when it is installed in various types of housing. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Glaucio L. Ramos;Gustavo F. Rodrigues;Franz M. Camilo;Cássio G. Rego;
Pages: 2315 - 2318 Abstract: We present a comparison of statistical and principal component analyses (PCA) for reducing the amount of near-field data required as an input to a time-domain spherical-multipole near-to-far-field transformation. Such transformations are necessary for finite-difference time-domain (FDTD) simulations that typically only model the near-field. The authors demonstrate their approach for the case of far-fields scattered by a dielectric sphere. For a threshold value of $10^6$106, the PCA technique reduced the data required by 32%, using 12 components. A similar compression was achieved with statistical analysis, when the threshold is set at $10^{ - 7}sigma $10−7σ. Their work shows that the proposed statistical compression is preferable because it has simpler implementation and low-cost processing, when implemented together with the NFF transformation code. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Guoping Gao;Ruifeng Zhang;Chen Yang;Huijia Meng;Wenfei Geng;Bin Hu;
Pages: 2319 - 2323 Abstract: A microstrip monopole antenna backed with a novel uniplanar compact electromagnetic bandgap (UC-EBG) structure for 2.4 GHz wireless body area network applications is proposed here. The proposed antenna has a size reduction of 50% when the number of EBG array is optimised from 3 × 4 to 2× 3, while the radiation performance is almost invariable at the same time. The operating frequency band under different conditions has the capability of covering the 2.4–2.4835 GHz industrial, scientific, and medical band. Due to the addition of 2×3 UC-EBG on the back, the radiation patterns become unidirectional, and the measured average gain increases from 2.1 to 5.6 dB. Meanwhile, the cross-polarisation of the monopole antenna can be suppressed prominently by the EBG array. The simulated specific absorption rate values are 0.0536 W/kg under 1 g standard and 0.0296 W/kg under 10 g standard, which are far below the limitation of USA and Europe. These results can manifest the reliable wearable performance of the proposed antenna. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Haifeng Song;Wei Wu;Hairong Dong;Eckehard Schnieder;
Pages: 2324 - 2329 Abstract: Smart railway transportation systems aim to make the trains operate in a more intelligent and flexible manner. Reliable train-to-train communication, which can increase the efficiency and safety of the train operation, is getting more concern in recent researches, and different communication solutions can be applied to carry out the data communication. However, its propagation and safety analysis is not systematically put forward. In this work, the structure and working principle of a train-to-train communication system are proposed. In order to have a better performance, multi-communication channels are involved. Three different modems are applied to make sure that the system can implement the communication task in different situations. What is more, the long-range communication modem provides not only long distance communication but also distance measurement between two trains. The propagation analysis based on different carrier waves and application scenarios is discussed. The system safety is evaluated by means of Petri nets, and the analysis procedure can be reused for analysing different system structures. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Siat Ling Jong;Carlo Riva;Jafri Din;Michele D'Amico;Hong Yin Lam;
Pages: 2330 - 2335 Abstract: Heavy precipitation severely degrades the performance of satellite communication systems operating at frequencies higher than 10 GHz. For the implementation of effective countermeasures, rain attenuation statistics are needed, second order statistics in particular. Here, the characteristics of rain fade slope are extensively investigated, exploiting one year of Ku-band attenuation measurements collected in Malaysia. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Snehasish Saha;Nurnihar Begam;Ayan Chatterjee;Sushanta Biswas;Partha Pratim Sarkar;
Pages: 2336 - 2341 Abstract: The authors presented a reconfigurable frequency selective surface (FSS), loaded with light-dependent resistors (LDRs). In this proposed FSS, no biasing circuit is used to control the transmission characteristics. Variation in intensities of the light that falls upon is used as the control parameter for variation of resistance values of LDRs. Thus tunable transmission characteristics of the FSS are achieved. The simulated results show that in the absence of atmospheric light, the FSS has band stop properties at the frequency range of lower S-band (2–3 GHz) and band pass properties at the frequency range of C-band (4–8 GHz). On the other hand, in the presence of full bright light, it has stop band properties at the frequency range of C-band (4–8 GHz). Experimental results are in good agreement with the simulated results. Another novelty about the proposed FSS is the polarisation-independent (TE and TM polarisation) transmission behaviour. The proposed FSS also has a stable transmission behaviour for variation in the incidence angle up to 30°. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Maria Antonia Maisto;Raffaele Solimene;Rocco Pierri;
Pages: 2342 - 2348 Abstract: Planar near-field antenna measurement techniques are addressed with particular reference to the error in the radiation pattern estimation due to the finiteness of the observation aperture. The valid angle (VA) concept is a commonly used rule-of-thumb for predicting the region of validity of the calculated far-field pattern according to observation domain, the aperture antenna size and the distance between the two. However, it is based on simple asymptotic arguments which often lead to erroneous estimations. In this contribution, a new VA criterion and related radiation pattern representation are derived by exploiting the singular value decomposition of the radiation operator. Numerical examples show the goodness of the new VA criterion and the greatest stability of the proposed radiation pattern estimation compared to the classical Fourier transform. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Ratikanta Sahoo;Damera Vakula;
Pages: 2349 - 2359 Abstract: In this study, a novel metamaterial inspired compact cylindrical conformal dual-band antenna with a shunt fractal inductor and bottom patch is proposed. The conformal antenna consists of three meander lines type unit cells of composite right/left-handed metamaterials for modification and compactness. To improve the operating bandwidth in the first band i.e at 2.45 GHz, a shunt fractal inductor with large inductance is proposed. A similar patch with a slot along the bottom side is additionally used for better impedance matching. The second band at 3.5 GHz is obtained due to the loading of two meander line unit cells on the patch as parasitic elements. The proposed conformal antenna is placed on a 15 mm radius cylinder whose equivalent planar dimension is 0.48λg × 0.36λg (where λg is the guided wavelength). Asymmetrical coplanar waveguide feed is implemented. Measurement results showed that the proposed cylindrical conformal antenna achieves a wideband −10 dB fractional bandwidth of 44.5% and a gain of 1.26 dBi at the operating frequency of 2.45 GHz and 4.5% of bandwidth and a gain of 2.2 dBi at the 3.5 GHz. The radiation efficiency is 70 and 86% at the said frequencies respectively. There is good agreement between measured and simulation data. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Qi Zheng;Chenjiang Guo;Jun Ding;Guy A.E. Vandenbosch;
Pages: 2360 - 2364 Abstract: A single-feed dual-band circularly polarised (CP) patch antenna is proposed. The antenna consists of a corner-truncated square patch antenna and a superstrate composed of a lattice of 2 × 2 metallic patches surrounded by parasitic elements. The driven patch generates one resonant mode. The metasurface with parasitic elements excites two additional resonant modes (TM10 and TM20). The combined resonances result in minimum axial ratio points, and a good dual-band CP operation is achieved. Simulations show that the antenna has a CP operating bandwidth of 40 MHz centred at 3.72 GHz (1.07%), and a CP operating bandwidth from 5.37 to 6.05 GHz (11.9%). The simulated gain is ∼7.05–7.1 dBic for the low-frequency band and 4.17–6.07 dBic for the high-frequency band, respectively. Measurements and simulations are in good agreement. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Ravi Dutt Gupta;Manoj Singh Parihar;
Pages: 2365 - 2371 Abstract: A wideband differential Fabry–Perot cavity antenna (FPCA) is presented. Unlike the mostly used patch antennas, a rectangular dielectric resonator antenna (DRA) has been investigated as primary radiation source. A compact partially reflective surface (PRS) is proposed and used as superstrate layer over the DRA for wideband gain enhancement. Measurements show that the antenna exhibits a wide impedance bandwidth (for S11 PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Maksud Alam;Mainuddin Siddique;Binod K. Kanaujia;Mirza T. Beg;Sachin Kumar;Karumudi Rambabu;
Pages: 2372 - 2379 Abstract: This study proposes a new hepta-band antenna that consists of an inductive ground plane and slots loaded patch for the multiband body-worn scenario. The phase distribution is optimised by considering a 7 × 7 array of periodic square patches on the metallic ground-backed substrate in such a way that resonant modes of patch slots interact with the resonant modes of meta-resonators of inductive ground to achieve hepta-band behaviour with desired radiation characteristics. Each unit cell corresponds to a phase shift of 3.6° out of available phase distribution of 180°. The seven bands are targeted at 1.8, 2.45, 2.96, 3.5, 3.8, 4.2, and 4.5 GHz which supports GSM (1.8 GHz), WLAN (2.4 GHz), LTE (2.5 GHz), Wi-MAX (3.5 GHz), sub-6 GHz 5G band (3.4-4.2 GHz), navigation (2.96 GHz), and satellite (4.5 GHz) applications. It is also demonstrated that an inductive ground plane can be used to get reduced SAR and increased FBR, making antenna useful for wearable applications. The proposed antenna has a patch size of 28.84 × 28.84 mm upon a 0.4 mm thick substrate of permittivity 4.3. Inductive ground is made of via-free periodic square patches each of size 5 × 5 mm on the 2.6 mm thick metallic ground-backed substrate. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Chan H. See;Jamal Kosha;Widad A. Mshwat;Raed A. Abd-Alhameed;Felicia L.C. Ong;Neil J. McEwan;Peter S. Excell;
Pages: 2380 - 2385 Abstract: This study presents an underground subsurface wireless sensor for drainage infrastructure water level monitoring. It operates from 800 to 2170 MHz to cover the required GSM850/900, GSM1800/1900 and Universal Mobile Telecommunications System (UMTS) bands. The system consists of a wideband antenna, transceiver, data acquisition unit and an ultrasonic sensor. The proposed antenna is a three-dimensional inverted double F antenna and has an envelope size of 90 × 63.5 × 32 mm3, which is acceptably small for a cramped subsurface passageway environment. The antenna design was developed using software simulation to optimise its key parameters of return loss and radiation pattern, these were evaluated both in free space and in the partially underground environment. The design developed was then realised in hardware and tested in a representative subsurface location: a utility manhole chamber. It was found that the location of the antenna in the chamber had a significant effect on its performance, but a location that was acceptable for operational purposes was found by experiment. The overall system, including a transceiver, was demonstrated to operate satisfactorily for utility monitoring purposes, including acceptable levels of path loss for communication with mobile communication base stations. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Rafael P. Torres;Jesús R. Pérez;José Basterrechea;Marta Domingo;Luis Valle;Jorge González;Lorenzo Rubio;Vicent M. Rodrigo;Juan Reig;
Pages: 2386 - 2390 Abstract: This study presents an analysis of the capabilities of using multi-user multiple input multiple output (MU-MIMO) in indoor environments at the 3–4 GHz band through an empirical characterisation of the MU-MIMO channel, obtaining a statistical description of the degree to which this specific multi-user channel verifies the condition of ‘favourable propagation’. Different metrics have been considered to measure the degree of orthogonality between the channels, such as the orthogonality coefficient or the condition number. In addition, in order to obtain a direct measure of the goodness of the channel in terms of the achievable spectral efficiency, the capacity of the channel has been calculated for different numbers of users and base station antennas and compared with theoretical i.i.d. Rayleigh channels. PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Zahra Ghattan Kashani;Seyed Amin Izadi Avanji;
Pages: 2391 - 2395 Abstract: This study presents the design of a fully integrated fractional-N phase-locked loop (FNPLL) for the Global Navigation Satellite System (GNSS) applications. A new linearisation technique is presented for a charge pump (CP) circuit to improve the mismatch between the charging and discharging currents. The linearised currents help to reduce the static phase offset and the reference spurs of the FNPLL and the constant current helps to control the PLL dynamics precisely. The presented FNPLL is designed in a 0.18 µm CMOS technology. The simulation result reveals that the linearity of the CP is enhanced greatly when the technique is enabled and the current mismatch is PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Authors:
Lydia Chioukh;Tarek Djerafi;Dominic Deslandes;Ke Wu;
Pages: 2396 - 2404 Abstract: A harmonically driven bio-radar based on the technique of a multiport interferometer (six-port) technique is proposed and studied in order to improve the performance of vital signs monitoring. The feasibility of estimating cardiopulmonary parametric signatures by deploying a harmonic multiport interferometer radar is presented. This scheme is helpful to reduce the noise floor and the effects of undesirable parasitic harmonics of breathing and intermodulation. A theoretical analysis is developed to explain why a better heart-beat detection using the proposed harmonic six-port radar architecture can be achieved. The well-known null point problem usually encountered in such radar detections of heart-beating signs is alleviated by the insertion of a fixed 45° phase shift between the two different frequencies in the six-port discriminator without an actual phase-shifter. Simulations are carried out to investigate detection accuracy and sensitivity issues for monitoring the vital signs by cancelling the breathing harmonics and intermodulation products. The concept is then validated by the measured results of an experimental prototype using the proposed harmonic six-port radar platform operating at 12 GHz (fundamental) and 24 GHz (harmonic). PubDate:
10 30 2019
Issue No:Vol. 13, No. 13 (2019)
Hybrid journal (It can contain Open Access articles)
