International Journal of Applied Sciences, Engineering and Management ISSN , Vol. 04, No. 06, November 2015, pp

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1 Compact UWB Array Antenna for Wireless Personal Area Networks Dudla Sirisha 1, P. Balakrishna 2 1 M. Tech Student, Vikas Group of Institutions, Nunna, Vijayawada, A.P, India. 2 Assistnat Professor, Dept.of ECE, Vikas Group of Institutions, Nunna, Vijayawada, A.P., India. Corresponding Author mail id: dsirisha23@gmail.com Abstract : UWB (ultra wide Band width) brings the convenience and mobility of wireless communications to high speed interconnects in devices throughout the digital home and office. UWB differs from other wireless architectures in that it is not restricted to using a single waveband. It transmits streams of extremely short energy pulses, typically around 10 to 1000 picoseconds, which can be spread across a broad range of frequencies. The power levels needed for UWB are very low, even lower than those for mobile phones, which is a real advantage when it comes to mobility and battery life. FCC (Federal Communications commission) declares the GHz frequency as unlicensed Band. In this project work designing a compact UWB array antenna for wireless personal area network applications. The designed antenna will cover the frequency bandwidth of GHz frequency range in free space. The antenna will satisfy the design parameters for achieving good return loss, VSWR, radiation pattern and gain. Here a tapered micros trip feeding is used to enhance the antenna matching. Keywords: UWB Array Antenna, Micro strip Feed. 1. Introduction UWB brings the convenience and mobility of wireless communications to high speed interconnects in devices throughout the digital home and office. UWB differs from other wireless architectures in that it is not restricted to using a single waveband. It transmits streams of extremely short energy pulses, typically around 10 to 1,000 picoseconds, which can be spread across a broad range of frequencies The power levels needed for UWB are very low, even lower than those for mobile phones, which is a real advantage when it comes to mobility and battery life. Added to which the broad frequency spread makes UWB very resistant to interference. It can also carry a huge amount of data potential bandwidth is quoted in hundreds of mega bits per second, making it a lot faster than Bluetooth at 2 Mbit/s, and the latest 54 Mbit/s Wi-Fi standards. Security is less of a problem with UWB as the short pulses are far harder to intercept, but range remains an issue. Signals can travel no more than around 10 to 20 meters, which effectively rules UWB out as a rival to the WLAN technologies. With the rapid development of wireless communications, the requirement of compact and planar antennas are increasingly stringent due to their attractive features such as low cost, simple structure, ease of fabrication, wide bandwidth, and omnidirectional radiation pattern have, which received great attention for UWB systems. In recent years, many people are committed to the research of planar broadband antennas for UWB applications using wide variety of antenna configurations [1] [6]. These antennas have their own advantages respectively, but there are common limitations on them that it is difficult to obtain an antenna that is small in size, yet still satisfies the bandwidth requirements for UWB applications, which is unable to meet needs of the development of modern wireless communications. Compared with the three dimensional type of antenna, flat type UWB antenna printed onto a piece of printed circuit board is a good option for many applications because it can be easily embedded into wireless devices or integrated with other microwave integrated circuits. Ultrawideband is a leading candidate for short-range, wireless personal area networks, or WPANs. With this technology, people will be sharing photos, music, video, data and voice among networked consumer electronics, PCs and mobile devices throughout the home and even remotely. For example, users will be able to stream video content from a PC or consumer electronics (CE) device, such as a camcorder, DVD player or personal video recorder, to a flat screen HDTV (high-definition television) display without the use of any wires. In this application, a wireless universal series bus (WUSB) is required to replace cables and build up high speed wireless link between personal computers and other devices. The W-USB has strong demands for highperformance UWB antennas which will be facing three most challenging issues namely miniaturized size, reduced ground plane reliance, and enhanced diversity performance. For applications in portable systems, compact, radiation efficient and printed antennas are desired. Slot antennas satisfy these requirements where wide bandwidth can be obtained by different techniques. Owing to a balanced structure, a large L and T shape slots for size reduction are used for bandwidth enhancement. A CPW fed tapered ring slot antenna which can achieve a relatively large bandwidth is introduced in [8]. The wide band slot antenna [9] uses a large aperture and a modified microstrip feed to create multiple resonances. In another technique, a rotated slot is proposed in [10], wherein two modes of closed resonances are excited by a microstrip feed line. A tapered slot feeding structure is used to transform the guided waves to free space waves in [11]. IJAEM SRC. 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2 Compact UWB Array Antenna for Wireless Personal Area Networks In this paper, a design of printed antenna fed by microstrip line is proposed. It is printed on FR4 dielectric substrate and fed by a 50 Ω microstrip line with an U-shaped tuning stub on the opposite side of the substrate. The major parameters affect the antenna operation are analyzed using 3D EM simulation software. The paper is organized in three sections; literature overview is introduced in the first section followed by antenna design and parametric study then results are concluded. 2. EXISTING Antenna Design Figure 1 shows the basic antenna stuctrue. The antenna is structured as a U-shape radiator fed with a tapered microstrip line to improve the matching between the mean radiator and the feeding line. An elliptical slot with a long diameter A and short diameter B is created within the ground plane underneath the patch for widening the antenna operating frequency range. The designed antenna is printed on an FR4 microwave dielectric substrate with a thickness of 0.75 mm and a relative permittivity ε r of 4.4. The major parameters controlling the antenna bandwidth and affecting its performance are optimized using the EM simulators. The final the antenna dimensions are given in Table 1. The overall size of the antenna is 30 mm 30 mm. Figure - 1: Antenna Basic Structure The figure 2 shows the antenna Design using Three Dimensional Electro Magnetic Simulator. In order to validate the antenna design here S-Paremetres and radiation patterns are calculated. Figure 3 shows the back view simulated design. Figure 4 and 5 shows the simulated Return loss and VSWR of the existing antenna. Fig 6 and 7 shows the raditaion patterns at 7GHz frequency in 3 Dimensional and 2 Dimensional respectively. Table - 1: Antenna Parameters of the basic Stucture Figure - 2: Basic antenna structure front View designed in 3D EM Solver

3 Dudla Sirisha, P. Balakrishna Figure - 3: Basic Antenna Structure Back View in simulation software Figure - 4: Simulated Return loss Parameter of the Basic Antenna Figure - 5: Simulated VSWR Parameter of the Basic Antenna Figure - 6: Simulated Three Dimensional Radiation Pattern

4 Compact UWB Array Antenna for Wireless Personal Area Networks 3. Proposed Antenna Design Figure - 7: Simulated 2D Radiation Pattern of The Basic Antenna The figure 8 shows the proposed antenna, it comprises two identical monopoles parallel to each other and the substrate used are FR4 with thickness 1.6 mm with dielectric constant of 4.4. figure 8 and 9 shows the proposed antenna front and rear view in the 3D EM solver. Figure 10 and 11 shows the S parameter and VSWR of the proposed antenna. By the S-Parameters and VSWR the proposed antenna is good agreement of UWB applications. Figure 12 and 13 shows the 2D and 3D radiation patterns of the proposed antenna. By compare to the existing antenna the proposed antenna have more gain and good return loss parameter. Figure - 8: Proposed antenna structure front View designed in 3D EM Solver Figure - 9: Proposed antenna structure Back View designed in 3D EM Solver

5 Dudla Sirisha, P. Balakrishna Figure - 10: Simulated Return loss parameter of proposed antenna Figure - 11: simulated VSWR of the proposed antenna Figure - 12: Simulated 2 D radiation pattern of the proposed antenna Figure - 13: Simulated 3D radiation pattern of the proposed antenna

6 Compact UWB Array Antenna for Wireless Personal Area Networks Conclusion A printed U-shape monopole array antenna fed by tapered microstrip line for UWB WPAN is presented in this paper. The array antenna performance in terms of the radiation pattern and reflection coefficients has been investigated. The major parameters affecting the antenna performance have been extensively analyzed. The simulated array antenna has also been confirmed to be nearly omni-directional over the entire bandwidth. The array antenna with small size (60*30 mm) with good return loss and gain is proposed. REFERENCES [1] P. Thongyoy, P. Rakluea, and T. N. Ayudthaya, "Compact thin-film UWB antenna with round corner rectangular slot and partial circular patch," IEEE ECTI-CON, pp.1-4, [2] J. P. Shinde, R. Kumar, M. D. Uplane, and P. N. Shinde, "Circularly polarized rectangular slot antenna with trapezoidal tuning stub for UWB application," IEEE AEMC, pp.1-4, [3] Z. N. Chen, T. S. P. See, and X. Qing, "Small printed ultrawideband antenna with reduced ground plane effect," IEEE Trans. Antennas Propag., vol. 55, no. 2, pp , February [4] J. R. Verbiest and G. A. E. Vandenbosch, "A novel small-size printed tapered monopole antenna for UWBWBAN," IEEE Antennas Wireless Propag. Lett., vol. 5, pp , [5] S. Radiom, H. Aliakbarian, G. A. E. Vandenbosch, and G. G. E. Gielen, An effective technique for symmetric planar monopole antenna miniaturization, IEEE Trans. Antennas. Propag., vol. 57, no.10, pp , October [6] T. Dissanayake and K. P. Esselle, UWB performance of compact Lshaped wide slot antennas, IEEE Trans. Antennas. Propag., vol. 56, no. 4, pp , April [7] S. I. Latif, L. Shafai, S. K. Sharma, "Bandwidth enhancement and size reduction of microstrip slot antennas," IEEE Trans Antennas Propag, vol. 53, pp , [8] T. G. Ma and C. H. Tseng, "An ultra wide band coplanar waveguide-fed tapered ring slot antenna," IEEE Trans Antennas Propag, vol. 54, pp , [9] N. Behdad and K. Sarabandi, "A multiresonant single element wideband slot antenna," IEEE Antennas & wireless propag. Lets., vol. 3, pp. 5 8, [10] J. Y. Jan and J. W. Su, "Band width enhancement of a printed wide slot antenna with a rotated slot," IEEE Trans Antennas Propag, vol. 53, pp , [11] T. G. Ma and S. K. Jeng, "Planar miniature tapered slot fed annular slot antennas for ultra wide band radios," IEEE Trans Antennas Propag, vol.53, pp , [12] IDS Space Labrtory, [13] Ansoft Corporation, HFSS,