International Journal of Electrical Engineering and Technology (IJEET), INTERNATIONAL JOURNAL OF Issue 2, March – April (2013), ©ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, ELECTRICAL ENGINEERING IAEME & TECHNOLOGY (IJEET) ISSN 0976 – 6545(Print) ISSN 0976 – 6553(Online) Volume 4, Issue 2, March – April (2013), pp. 105-111 IJEET © IAEME: www.iaeme.com/ijeet.asp Journal Impact Factor (2013): 5.5028 (Calculated by GISI) ©IAEME www.jifactor.com FEASIBILITY STUDIES OF WIRELESS SENSOR NETWORK AND ITS IMPLICATIONS S.R.Shankara, Dr.G.Kalivarathanb a Research Scholar, CMJ University, Meghalaya, Shillong. b Principal/ PSN Institute of Technology and Science, Tirunelveli, Tamilnadu, Supervisor, CMJ University, Shillong. Email:email@example.com ABSTRACT WSNs provide endless opportunities, but at the same time pose formidable challenges. One of the key challenges of wireless sensing applications is that the information collected by these applications is incomplete. In particular, the amount of usable quality information collected by the wireless sensing applications is constrained by various limiting characteristics of the host network. High Temperature Superconductors (HTS) are more and more present in RF and microwave applications. HTS thin film technology can be used for high Q resonators and very selective multi-pole filters with very low insertion-loss. In order to prove the HTS devices feasibility for RF and microwave applications, HTS microstrip resonators and HTS antennas have been investigated experimentally. The work described is limited to a few preliminary studies. This is due to the lack of further funding. Most of the research results performed for this thesis refer to cellular systems, which are the most prevalent part of terrestrial radio communications. The terrestrial communications include also cordless telephony, paging, professional mobile radio (PMR). The radio link in a cellular system is subjected to the specific propagation laws of the radio waves. There is a significant contrast between a transmission channel of a wired communication path and a radio mobile channel. Since the former is almost constant in time, the latter is random and undergoes shadowing and multipath fading. Even when a mobile user is stationary, ambient motion in the vicinity of the base station can produce fading. Keywords: High Temperature Superconductors, Professional mobile radio, Finite-Difference Time-Domain, GSM 900 receivers, 105 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 2, March – April (2013), © IAEME 1.0 INTRODUCTION A 3-D Finite-Difference Time-Domain (FDTD) method for planar microwave devices was developed. Various microstrip circuits on substrates with different thickness and dielectric constants have been analyzed in order to test the method. The method was validated by a very good matching between simulated data and measurements, literature data or, for simple cases, comparisons with commercial software. Coupling between rings have been realized by using capacitive gaps. The lines between rings and coupling elements provide appropriate transformations from the gaps or in/out structures as well as a spatial separation between rings. In addition, the filter response is very sensitive to the input and output couplings. The final rejection of the four-pole filter could not be measured accurately due to the limitation in the network analyser dynamic range. 2.0 HTS THIN FILM FABRICATION Thin Flim HTS prepared off-axis thin films by using single target RF magnetron sputtering. The superconducting. YBa2Cu3O7-δ thin films were deposited on Lanthanum Aluminate (LaAlO3) and on Yttria Stabilized Zirconia (YSZ) substrates. Both “in situ” and “ex situ” methods have been used. “In situ” method was used for deposition on both sides of the substrates. Standard ceramic technique was used to produce the target. The raw materials were ground and calcined at 900°C for 12 h. Sintering was carried out in oxygen at 930°C for 20h. The target size was 50 mm in diameter and 4 mm thick. When the “in situ” method was used, the substrates were glued on a heated stainless steel piece by using silver paste The actual substrate temperature was measured using a Chromel-Alumel thermocouple. The substrate was heated during the deposition. The sputtering gas was a mixture of 50%Ar and 50%O2 at 20 Pa sputtering pressure. The sputtering power was 40 W and the deposition rate was 100 nm/h. The typical film thickness was in the range of 250-300 nm. oxygen atmosphere. When the temperature was decreased to 450°C, the oxygen pressure was increased to 104Pa. The films were additionally kept for 1h at 450°C. Finally the films were cooled at a rate of 100°C/h down to room temperature. When using the ex-situ method, the deposition was carried out at room temperature and followed by post annealing. The post annealing was achieved in a gas flow consisting of a mixture of N2 and 29 Pa O2 for 3.5 h at 750oC. Next, the films were cooled from 750°C to 450°C at a rate of 3°C/min, in pure oxygen atmosphere at a pressure increasing from 29 Pa to 104 Pa at a rate of 100 Pa/min. The films were further kept at 450°C for 1h in order to provide them with the necessary amount of oxygen required by stoichiometry. The films were next cooled at a rate of 100C°/h back to room temperature. 106 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 2, March – April (2013), © IAEME Figure1. Microstrip ring and linear resonators patterned of YBa2Cu3O7-δ thin film deposited on Yttria Stabilized Zirconia. An interesting feature of the resonance curves where there are 330 MHz / div, is the presence of second resonance peak at about 70 MHz below than the main peak. The symmetric coupling cannot generate this peak-splitting. The second resonance peak can be caused by the anisotropic nature of the single crystal substrate. The anisotropy can cause a sort of dual mode effect similar to the dual mode effects observed on loop resonators when non- symmetrically coupled 3.0 DEVELOPMENT OF GSM 900 RECEIVERS The research goal was to obtain a good SNR, therefore the RF receiver electronics was positioned right on the back of the microstrip antenna patches. For each antenna element in the array, there were two feed points implementing polarization diversity. The second feed point was also used for calibration. In addition, the IF and RF sections were enclosed in separate metallic boxes for adequate electromagnetic interference (EMI) isolation. Figure2. Connection of the sixteen receivers 107 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 2, March – April (2013), © IAEME Signals from RF and IF local oscillators (LOs) were supplied to all the receivers. The power divider networks for local oscillators signals can be noticed on the back of the antenna. The receivers’ outputs were provided by 50 coaxial cables to analog to digital converters, physically situated together with the digital signal processing (DSP) circuitry. To avoid any spurious noise coupling the DC power was supplied separately for each receiver. The gain of each receiver was controlled using the voltage gain control (VGC). The signals coming from the two antenna feed points (RF INPUT 1 and RF INPUT 2) were fed into the RF inputs LNA IN0 and LNA IN1 of the TQ9203 down-converter. However, the noise reduction research goal required the isolation of the receiver band from the out-of-band interferences, especially from the transmission (downlink) signals, which could saturate the LNAs. This preliminary band selection was performed by preselect SAW filters. The characteristics of the uplink RF SAW filter used for the array receivers, together with the downlink SAW filter used for a mobile station (MS) receiver 4.0 DESIGN OF GSM 900 / DCS 1800 TRANSMITTER A RF transmitter was developed to test the electronics for GSM / GPRS Smart Antenna. The transmitter was aimed to function for both frequency bands GSM 900 and DCS 1800. For testing, no high output power was demanded. Two versions of the transmitter were investigated. The first version was developed on the basis of RF2422 2.5 GHz Direct Quadrature Modulator. Figure 3. Block schematics of the first version of the GSM 900 / DCS 1800 Transmitter 108 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 2, March – April (2013), © IAEME 5.0 TESTING AND VALIDATION The RF electronics developed for GSM / GPRS Smart Antenna was tested using HP 8922S “GSM MS Service Test Set” and a normal GSM mobile telephone. Since the test set provided no auxiliary input, which could be used for DCS 1800, a measurement setup shown in Fig. 6.23, using a MACOM FR11-0003 circulator (1805-1890 MHz ), and dielectric filters LARK ENG SSD1747 (1747 MHz) and SSD1842 (1842 MHz) was prepared. The Bit Error Rate (BER) was found in the limits of the GSM specifications. The RF electronics for GSM / GPRS Smart Antenna was developed to provide adequate signals for further digital processing. The spatial filtering was processed in the baseband. The array main beam was first steered towards the desired mobile phone. The horizontal linear array played an important role in beamforming in the azimuth plane differentiating easily the users transmitting from different locations of the cell. In addition, beamforming in the elevation plane was required especially by the multipath propagation in crowded urban environment. Following the spatial filtering, the digital signal was filtered in time using the constant modulus algorithm (CM). Figure4. Antenna pattern with the main beam steered toward the user's DOA Figure5. Normalized CIR for punctual sources (dotted line) and sources with angular spread of 11o 109 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 2, March – April (2013), © IAEME Figure6. The radiation pattern versus angle (degrees) of the microstrip antenna on 6 dielectric constant substrate at the frequency 7.5 GHz. 6.0 CONCLUSION The layout effect on some parameters was also taken into account. It was experimentally proven, that some parameters of the RF down converters, such as the off- isolation or the LO buffer tuning frequency, were very sensitive to the layout. Furthermore, an appropriate out-of-band isolation of the IF SAW filters could be obtained only if suitable design techniques were applied to eliminate the spurious cross couplings between filter ports. Low noise receivers for GSM 900 uplink, GSM 900 downlink and for DCS 1800 frequency bands were achieved. A transmitter for both frequency bands was developed in order to test the system parameters. Sixteen uplink GSM receivers, developed on noise minimization basis, provided gain uniformity and adequate output signals in order to allow digital processing of the baseband signals, required by the spatial and time filtering. In spite of the later rapid evolution of the technological research for HTS thin film deposition, the developed HTS microstrip resonators constitute an important step towards the realization of multi-pole, low-loss selective filters. This makes HTS technology very attractive for an increasingly crowded radio frequency spectrum. The design and fabrication preamble of a microstrip HTS antenna is presented. A slot coupled feeding was chosen as a promising configuration for microstrip antenna arrays. Preliminary measurements on disk slot coupled antennas designed on different substrates and for different frequencies are presented. HTS antennas were manufactured on YBCO thin films and the antenna design is presented. REFERENCES  M. J. Lancaster, “Passive Microwave Applications of High-Temperature Superconductors”, Cambridge University Press, 1997 110 International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print), ISSN 0976 – 6553(Online) Volume 4, Issue 2, March – April (2013), © IAEME  Z.-Y. Shen, “High Temperature Superconducting Microwave Circuits”, Artech, Boston, 1994  M. Hein, “High Temperature-Superconductor Thin Films at Microwave Frequencies”, Springer, Berlin Heidelberg, 1999  R. Ramer, M. G. Banciu, C. Constantin, G. J. Russell, T. B. Vu, “Superconducting Thin Films for Microwave Resonators”, Proceedings of the Asia Pacific Microwave Conference, APMC ’97, December 2-5 1997, pp. 121-123  M. G. Banciu, M. S. Pham, R. Ramer, T. B. Vu, “Preliminary Design and Fabrication of Microstrip HTS Antenna”, Proceedings of the 3rd Asia-Pacific Conference on Communications, APCC’97, December 7-10, 1997, pp. 902-905  R. Ramer, M. G. Banciu, “High Temperature Superconducting Thin Films for Microwave Devices”, Proceedings of the XV-th International Conference on Microwave Ferrites, Rokosowo, Poland, September 2000, pp. 120-123  M. G. Banciu, P. Rapajic, R. Ramer, “RF Electronics for GSM/GPRS Smart Antenna”, Proceedings of the 25th Edition of the International Semiconductor Conference, CAS 2002, (IEEE Romania Section), Sinaia, Romania, 2002, vol. 1, pp. 45-48  B. Xu, T. B. Vu, G. Jonas, “Implementation of a Smart Antenna Using TMS320C80 DSPs for Mobile Communications”, Proceedings of ICSP’ 98, 355-358  Thomas H. Lee, “The Design of CMOS Radio-Frequency Integrated Circuits”, Cambridge University Press, Cambridge, UK, 1998  Joyashree Das and Dr. Rup Narayan Ray, “Investigation of the Performance of Hysteresis Motor With High Temperature Superconducting Element in the Rotor Using Comsol Multiphysics” International Journal of Electrical Engineering & Technology (IJEET), Volume 3, Issue 1, 2012, pp. 344 - 352, ISSN Print : 0976-6545, ISSN Online: 0976-6553  Neeraj Tiwari, Rahul Anshumali and Prabal Pratap Singh, “Wireless Sensor Networks: Limitation, Layerwise Security Threats, Intruder Detection”, International journal of Electronics and Communication Engineering & Technology (IJECET), Volume 3, Issue 2, 2012, pp. 22 - 31, ISSN Print: 0976- 6464, ISSN Online: 0976 –6472  R.Rajasree and Dr.G.Kalivarathan, “Analysis of Programming Aspects of Wireless Sensor Networks and Non Uniformity Issues-A Feasible Study”, International journal of Electronics and Communication Engineering & Technology (IJECET), Volume 3, Issue 3, 2012, pp. 219 - 226, ISSN Print: 0976- 6464, ISSN Online: 0976 –6472  111
"FEASIBILITY STUDIES OF WIRELESS SENSOR NETWORK AND ITS IMPLICATIONS"