Draft:Sarat Kumar Kotamraju

== Sarat K. Kotamraju | K L University | 36 Publications

Other affiliations: Asian Institute of Technology Bio: Sarat K. Kotamraju is an academic researcher from K L University. The author has contributed to research in topics: Patch antenna & Antenna (radio). The author has an hindex of 7, co-authored 33 publications receiving 135 citations. Previous affiliations of Sarat K. Kotamraju include Asian Institute of Technology.

Topics: Patch antenna, Antenna (radio), Side lobe ...read more Papers

More filters Showing all 36 results Journal Article•DOI• Transparent and conformal wheel-shaped fractal antenna for vehicular communication applications B. T. P. Madhav1, T. Anilkumar1, Sarat K. Kotamraju1• 01 Jul 2018-Aeu-international Journal of Electronics and Communications TL;DR: The virtual analysis of platform mounted characteristics of the proposed antenna at two different locations of the vehicle are performed in ANSYS Savant simulation tool and the corresponding far-field radiation performance is characterized.

Abstract: In this article, a low cost, compact conformal antenna is proposed for vehicular communications applications. The concept of fractal geometry is applied in this design to make the model more attractive in its appearance as well as to attain desired bands in the vehicular communication spectrum. It is fabricated on a transparent and flexible poly vinyl chloride material of size 55 mm × 40 mm × 3 mm. The proposed antenna is intended to operate in GSM-1800/1900, Digital Communication System (DCS-1800), Personal Communication Service (PCS-1900), Universal Mobile Telecommunications System (UMTS), Long-Term Evolution (LTE2600), Industrial, Scientific, and Medical radio band (ISM 2.4G), Wireless local area network (WLAN), Bluetooth, World Interoperability for Microwave Access (WiMAX), IEEE802.11p protocol based Vehicle-to-everything, Dedicated short-range communications (DSRC) and Wireless Access in Vehicular Environments (WAVE) communications bands. The prototype of the antenna in its planar and conformal versions exhibit the wideband characteristics and their measured results show good agreement with that of obtained simulation results. The virtual analysis of platform mounted characteristics of the proposed antenna at two different locations of the vehicle (vehicle roof-top and on side-view mirror) are performed in ANSYS Savant simulation tool and the corresponding far-field radiation performance is characterized.

40 citations Journal Article•DOI• Estimating the Performance of Free Space Optical Link Under Adverse Weather Conditions by Using Various Models Govardhani Immadi1, M. Venkata Narayana1, Sarat K. Kotamraju1, A. Sree Madhuri1• 23 May 2018-Wireless Personal Communications TL;DR: The performance analysis of free space optical link in the presence of rain considering the parameters like received optical power its corresponding electrical power, quality factor was extracted with the help of simulation using Opti System software developed by Optiwave.

Abstract: Free space optics (FSO), going to replace the present microwave communications in the future is gaining considerable attention as it supplies fruitful solutions to many complications like the last mile problem. Besides availing many advantages like high bandwidth, data rate, low bit error rate any communication system operating in free space undergoes a significant amount of degradation in its signal strength due to the atmospheric affects in its pathway. Similarly, an optical signal launched into free space will also interfere with its surroundings and may get impaired due to the presence of different climatic conditions like rain, fog, haze, snow, gas molecules etc. As FSO is a perfect line of sight communication it may also undergo the problems of outage due to obstructions (birds, base motion), scattering, beam dispersion etc. Precise prediction of the impairments (atmospheric affects) can result in an efficient and flawless communication system. Supporting the research on free space optics this paper mainly focuses on the performance analysis of free space optical link in the presence of rain considering the parameters like received optical power its corresponding electrical power, quality factor. The analysis was extracted with the help of simulation using Opti System software developed by Optiwave.

20 citations Journal Article•DOI• Precipitation and other propagation impairments effects at microwave and millimeter wave bands: a mini survey Sarat K. Kotamraju1, Ch Sri Kavya Korada1• 01 Apr 2019-Acta Geophysica TL;DR: In this article, a survey article abridges all outcomes related to propagation impairments and attenuation aspects at microwave and millimeter wave frequencies covering the studies of various researchers in last three decades, and few of the models developed by various researchers were listed along with model parameters which are useful for the propagation engineers and others who are interested in this specialization.

Abstract: The current past has seen a sensational increment in the utilization of satellites for the applications like navigation, entertainment, media transmission, remote sensing, mobile communications, weather forecasting, defense and other purposes. These applications are assigned in the microwave and millimeter wave bands, which offer higher information transfer possibility in lesser time and use very small antennas and devices by ensuring secured and effective communications. However, beyond the 10 GHz range of frequencies these applications are generally subjected to signal losses due to various atmospheric parameters like rain, clouds, fog, hail ice and other applicable phenomena. The main factor for the signal degradation is the rainfall. The attenuation caused by rain increases with frequency, as there is increased absorption of the RF energy at higher frequencies due to water drops present along the path of the transmission; hence, the signal attenuation is more in higher-frequency bands. The other factors that induce losses in the signal are the clouds, gases present in the lower atmosphere and the different layers in the atmosphere that cause scintillation and the system losses and cable losses. This survey article abridges all outcomes related to propagation impairments and attenuation aspects at microwave and millimeter wave frequencies covering the studies of various researchers in last three decades. In addition, few of the models developed by various researchers were listed along with model parameters which are useful for the propagation engineers and others who are interested in this specialization.

15 citations Journal Article•DOI• Characteristics of ionospheric scintillation climatology over Indian low-latitude region during the 24th solar maximum period K. Sahithi, M. Sridhar, Sarat K. Kotamraju, K. Ch. Sri Kavya 01 Mar 2019-Geodesy and Geodynamics TL;DR: In this article, the amplitude and phase of L-band satellite signals are fluctuated randomly due to small scale electron density irregularity structures in the ionosphere which result in fleeting variations, known as ‘ionospheric scintillations’.

Abstract: The amplitude and phase of L-band satellite signals are fluctuated randomly due to small scale electron density irregularity structures in the ionosphere which result in fleeting variations, known as ‘ionospheric scintillations’. The Global Navigation Satellite System (GNSS) is a profound remote sensing tool to monitor, model and forecast the ionospheric weather conditions. In this paper, the GNSS amplitude scintillation data has been analyzed during the year 2013 at Bengaluru (12.9°N, 77.59°E) and Lucknow (26.8467°N, 80.9462°E) stations to reinforce climatology of ionospheric scintillation over Indian low-latitude region. The probability of scintillation occurrence and their variations over equatorial and Equatorial Ionization Anomaly (EIA) regions in India are analyzed during various geomagnetic quiet and disturbed days, months and seasons. The annual occurrence of amplitude scintillations are mapped with the function of local time. It is observed from the experimental results that the probability of scintillations occurrences is higher over EIA region than over the equatorial region. The probability of scintillations is higher during March equinox and December solstice, and lowest during June solstice. Distribution of scintillations is intense during post–sunset period. The maximum percentage of scintillation occurrences at the two stations are recorded in November. Moreover, the highest percentage of scintillation occurrences took place on storm day (March 17, 2013) at the two stations. This work would be helpful for understanding the features of GNSS amplitude scintillations over Southern and Northern Indian regions. Moreover, these kinds of investigations are helpful for developing new algorithms to nowcast and forecast ionospheric scintillations over Indian Sub-continent.

15 citations

Tapered step cpw-fed antenna for wideband applications B. T. P. Madhav, Sarat K. Kotamraju, K. Narendra, M. R. Kishore 01 Jan 2014 TL;DR: In this article, a CPW-fed tapered step grounded antenna is proposed for wideband applications, where the antenna is prototyped on FR4 substrate with dimensions of 20x20x1.6 mm. Abstract: A novel CPW-fed tapered step grounded antenna is proposed for wideband applications. We observed that there is an enhancement in the bandwidth with the addition of tapered step ground in the geometry of monopole antenna. Antenna is prototyped on FR4 substrate (er =4.4) with dimensions of 20x20x1.6 mm. It has been observed that circular aperture with tapered step grounded model is operating over wide range bandwidth from 5-18 GHz. Good agreement is attained between simulation and measured results. Parametric analysis with change in substrate material is also studied and presented in the current work.

12 citations

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Propagation research in Europe using the OLYMPUS satellite : Propagation effects on sattelite communication links B. R. Arbesser-Rastburg, G. Brussaard 01 Jan 1993 TL;DR: In this paper, the prediction of propagation impairments has been a key element in the design of ground stations for satellite communication systems, and the work in this paper is related to this work. Abstract: Since the inception of commercial satellite communications, the prediction of propagation impairments has been as a key element in the design of ground stations. In the last decade, satellite communication systems started to migrate from trunk telephony using large groundstations towards flexible video, data, and voice communications employing very small apertue terminals (VSAT's) at frequencies between 11 and 30 GHz

35 citations Journal Article•DOI• Circular ring structured ultra‐wideband antenna for wearable applications B. Prudhvi Nadh1, B. T. P. Madhav1, M. Siva Kumar1, M Venkateswara Rao1 • 01 Apr 2019-International Journal of Rf and Microwave Computer-aided Engineering

33 citations Journal Article•DOI• A Compact Conformal Printed Dipole Antenna for 5G Based Vehicular Communication Applications Usha Devi Yalavarthi, M. S. S. Rukmini, and Boddapati Taraka Madhav 01 Jan 2018-Progress in Electromagnetics Research C TL;DR: In this article, a conformal printed dipole antenna with geometrical modifications in ground plane is proposed for 5G based vehicular communications and IoT applications, which yields a better −10 dB impedance bandwidth of 17.65 GHz and 2.24 GHz over the frequency ranges 24.3 to 41.95 GHz and 49.91 to 2.15 GHz.

Abstract: A novel and compact conformal printed dipole antenna with geometrical modifications in ground plane is proposed in this paper for 5G based vehicular communications and IoT applications. The proposed antenna consists of a printed dipole as defected ground structure and a staircase structured offset fed integrated balun to attain wideband operation. It yields a better −10 dB impedance bandwidth of 17.65 GHz and 2.24 GHz over the frequency ranges 24.3 to 41.95 GHz and 49.91 to 2.15 GHz. Antenna projects the peak gain of 6.81 dB with 98.82% of peak radiation efficiency. The measured results of the proposed model are in good agreement with the simulation obtained from HFSS. The conformal models of the proposed antenna are developed to embed the antenna in different curved surfaces on vehicular body. The analyzed conformal characteristics of the antenna support excellent constant reflection coefficient with respect to planar structure of the antenna over the operating band at different angles.

27 citations Journal Article•DOI• Design and Analysis of High-Speed Free Space Optical (FSO) Communication System for Supporting Fifth Generation (5G) Data Services in Diverse Geographical Locations of India Harjeevan Singh1, Nitin Mittal1, Rajan Miglani2, Harbinder Singh1 • 20 Sep 2021-IEEE Photonics Journal TL;DR: In this paper, the authors evaluated the performance of the FSO system for the implementation of 5G technology in diverse geographical locations of India and found that due to weak fog events in coastal areas, effective link range of up to 10.75

Abstract: Free space optical (FSO) communication has established a reputation for itself as a next-generation network capable of delivering high-speed data services. In light of the upcoming launch of 5G services, this paper aims to evaluate the performance of the FSO system for the implementation of 5G technology in diverse geographical locations of India. The proposed 16 × 10 $\text{Gbps}$ wavelength division multiplexing (WDM) based FSO link uses orthogonal frequency division multiplexing (OFDM) and digital signal processing (DSP) module to mitigate channel-induced limitations. Additionally, the proposed FSO design also employs Erbium-doped fiber amplifier (EDFA) with optimized gain characteristics. Using the data sourced from the Meteorological Department of India, the link analysis reveals that due to weak fog events in coastal areas effective link range of up to 10.75 $\text{km}$ can be achieved while maintaining bit error rate of $10^{-9}$ . Despite dominant foggy conditions in hilly, plains and desert areas, the proposed FSO link significantly limits the degrading effects of channel. Hence, in pursuit of futuristic smart city models, a heterogeneous combination of FSO and 5G infrastructure can conveniently cover diverse geographical locations of India to support high-speed data connectivity.

26 citations

What is a wind tunnel Charmein Johnson : Msfc 01 Jan 2008 TL;DR: A video showing how wind tunnels work so well, aircraft are not built or flown unless they are first tested in a wind tunnel is shown in this article, where the authors show how wind tunnel works so well. Abstract: A video showing how wind tunnels work so well, aircraft are not built or flown unless they are first tested in a wind tunnel. 117.221.82.152 (talk) 05:17, 3 December 2023 (UTC)

Journal Article•DOI• Novel miniatured wide band annular slot monopole antenna P. Syam Sunder, Sarat K. Kotamraju, T. V. Ramakrishna, B. T. P. Madhav +4 more 11 Jun 2015-Far East Journal of Electronics and Communications Go to Paper 12 citations

Journal Article•DOI• Improve the Performance of a Novel Capacitive Shunt RF MEMS Switch by Beam and Dielectric Materials S. Girish Gandhi1, I. Govardhani1, Sarat K. Kotamraju1, Sarat K. Kotamraju2 +4 more•Institutions (2) 01 Feb 2020-Transactions on Electrical and Electronic Materials TL;DR: In this paper, the design and simulation of RF MEMS Shunt type switch having non-uniform meanders has been discussed and optimized and done various electromechanical and RF performance analysis in the COMSOL multiphysics and HFSS tools. ...read more Abstract: This paper deals with design and simulation of RF MEMS Shunt type switch having non-uniform meanders. The device is optimized and done various electromechanical and RF performance analysis in the COMSOL multiphysics and HFSS tools. By varying the thickness of beam, gap and changing the beam materials such as Gold, Copper, Nickel, we done simulation and calculation of spring constant, pull-in voltage, capacitance analysis of the proposed switch. Out of all these different materials, Gold is best by its material properties. The pull-in voltage of proposed switch is 16.9 V, the switch have fast switching time i.e. 1.2 µs. The capacitance analysis like Up state and down state capacitance of the proposed switch is 7.46 fF and 1.25 pF. The RF-Performance of the proposed switch exhibits at low frequencies (2–12 GHz). The return and insertion loss are carried out by proposed switch is − 41.55 dB, − 0.0865 dB respectively. The switch having good isolation is − 47.70 dB at 5 GHz. The proposed shunt type switch is used for low frequencies such as microphones, radar and satellite applications. ...read more Go to Paper 8 citations

Journal Article•DOI• Rain rate intensity model for communication link design across the Indian region Aravind Kilaru1, Sarat K. Kotamraju1, Nicholas Avlonitis2, K. Ch. Sri Kavya1•Institutions (2) 01 Jul 2016-Journal of Atmospheric and Solar-Terrestrial Physics TL;DR: In this paper, a study on rain statistical parameters such as one minute rain intensity, possible number of minute occurrences with respective percentage of time in a year has been evaluated for the purpose of communication link design at Ka, Q, V bands as well as at Free-Space Optical communication links (FSO). ...read more Abstract: A study on rain statistical parameters such as one minute rain intensity, possible number of minute occurrences with respective percentage of time in a year has been evaluated for the purpose of communication link design at Ka, Q, V bands as well as at Free-Space Optical communication links (FSO). To understand possible outage period of a communication links due to rainfall and to investigate rainfall pattern, Automatic Weather Station (AWS) rainfall data is analysed due its ample presence across India. The climates of the examined AWS regions vary from desert to cold climate, heavy rainfall to variable rainfall regions, cyclone effective regions, mountain and coastal regions. In this way a complete and unbiased picture of the rainfall statistics for Indian region is evaluated. The analysed AWS data gives insight into yearly accumulated rainfall, maximum hourly accumulated rainfall, mean hourly accumulated rainfall, number of rainy days and number of rainy hours from 668 AWS locations. Using probability density function the one minute rainfall measurements at KL University is integrated with AWS measurements for estimating number of rain occurrences in terms of one minute rain intensity for annual rainfall accumulated between 100 mm and 5000 mm to give an insight into possible one minute accumulation pattern in an hour for comprehensive analysis of rainfall influence on a communication link for design engineers. So that low availability communications links at higher frequencies can be transformed into a reliable and economically feasible communication links for implementing High Throughput Services (HTS). ...read more Go to Paper 7 citations

Journal Article•DOI• High gain flexible liquid crystal polymer based 8‐element printed antenna for millimetric wave applications Tirunagari Anil Kumar1, Yalavarthi Usha Devi1, B. T. P. Madhav1, Sarat K. Kotamraju1 +1 more•Institutions (1) 01 Jul 2019-International Journal of Rf and Microwave Computer-aided Engineering Go to Paper 7 citations

Measurement of rain attenuation for ku band satellite signal in tropical environment using dah, sam models Sarat K. Kotamraju1, M. Venkata Narayana, K. Rajkamal, Habibulla Khan +2 more•Institutions (1) 01 Jan 2015 TL;DR: In this article, three sophisticated models (ITU-R, DAH and SAM) have been explained to calculate rain attenuation, i.e., DAH stands for Dissanayake-Allnutt-Haidara Model and SAM stands for Simple Attenuation Model. ...read more Abstract: Nowadays Telecommunications and broadcasting services are in a rapid phase of expansion. There is an increasing demand for the multimedia services such as high-speed internet, on demand digital TV services, video conferencing and tele-education etc., which need high-speed data rates to cope with the demand whilst guaranteeing a high quality of service. The current microwave frequency spectrum allocated for telecommunication and broadcast services has become packed as the proposed broadband systems requires higher bandwidths. However, the attenuation due to atmospheric gases, clouds and rain increases significantly, for the frequencies above Ku- band. Though the attenuation is due to clouds and gases frequently, it is rain that causes the largest attenuation. In this paper three sophisticated models (ITU-R, DAH and SAM) have been explained to calculate rain attenuation. ITU-R model is the most widely accepted model by the international propagation community and is used for estimating long term statistics of rain attenuation at high frequencies in most of the regions. DAH stands for Dissanayake-Allnutt-Haidara Model. This is similar to and an extension of the ITU-R model. This model is also used at high frequencies. SAM stands for Simple Attenuation Model, which is suitable for tropical climate and heavy rainfall regions to calculate attenuation at point rainfall. ...read more Go to Paper 5 citations

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Showing all 175 results Propagation research in Europe using the OLYMPUS satellite : Propagation effects on sattelite communication links B. R. Arbesser-Rastburg, G. Brussaard 01 Jan 1993 TL;DR: In this paper, the prediction of propagation impairments has been a key element in the design of ground stations for satellite communication systems, and the work in this paper is related to this work. Abstract: Since the inception of commercial satellite communications, the prediction of propagation impairments has been as a key element in the design of ground stations. In the last decade, satellite communication systems started to migrate from trunk telephony using large groundstations towards flexible video, data, and voice communications employing very small apertue terminals (VSAT's) at frequencies between 11 and 30 GHz ...read more Go to Paper 35 citations

Journal Article•DOI• Circular ring structured ultra‐wideband antenna for wearable applications B. Prudhvi Nadh1, B. T. P. Madhav1, M. Siva Kumar1, M Venkateswara Rao1 +1 more•Institutions (1) 01 Apr 2019-International Journal of Rf and Microwave Computer-aided Engineering Go to Paper 33 citations

Journal Article•DOI• A Compact Conformal Printed Dipole Antenna for 5G Based Vehicular Communication Applications Usha Devi Yalavarthi, M. S. S. Rukmini, and Boddapati Taraka Madhav 01 Jan 2018-Progress in Electromagnetics Research C TL;DR: In this article, a conformal printed dipole antenna with geometrical modifications in ground plane is proposed for 5G based vehicular communications and IoT applications, which yields a better −10 dB impedance bandwidth of 17.65 GHz and 2.24 GHz over the frequency ranges 24.3 to 41.95 GHz and 49.91 to 2.15 GHz. ...read more Abstract: A novel and compact conformal printed dipole antenna with geometrical modifications in ground plane is proposed in this paper for 5G based vehicular communications and IoT applications. The proposed antenna consists of a printed dipole as defected ground structure and a staircase structured offset fed integrated balun to attain wideband operation. It yields a better −10 dB impedance bandwidth of 17.65 GHz and 2.24 GHz over the frequency ranges 24.3 to 41.95 GHz and 49.91 to 2.15 GHz. Antenna projects the peak gain of 6.81 dB with 98.82% of peak radiation efficiency. The measured results of the proposed model are in good agreement with the simulation obtained from HFSS. The conformal models of the proposed antenna are developed to embed the antenna in different curved surfaces on vehicular body. The analyzed conformal characteristics of the antenna support excellent constant reflection coefficient with respect to planar structure of the antenna over the operating band at different angles. ...read more Full-text Go to Paper 27 citations

Journal Article•DOI• Design and Analysis of High-Speed Free Space Optical (FSO) Communication System for Supporting Fifth Generation (5G) Data Services in Diverse Geographical Locations of India Harjeevan Singh1, Nitin Mittal1, Rajan Miglani2, Harbinder Singh1 +2 more•Institutions (2) 20 Sep 2021-IEEE Photonics Journal TL;DR: In this paper, the authors evaluated the performance of the FSO system for the implementation of 5G technology in diverse geographical locations of India and found that due to weak fog events in coastal areas, effective link range of up to 10.75 ...read more Abstract: Free space optical (FSO) communication has established a reputation for itself as a next-generation network capable of delivering high-speed data services. In light of the upcoming launch of 5G services, this paper aims to evaluate the performance of the FSO system for the implementation of 5G technology in diverse geographical locations of India. The proposed 16 × 10 $\text{Gbps}$ wavelength division multiplexing (WDM) based FSO link uses orthogonal frequency division multiplexing (OFDM) and digital signal processing (DSP) module to mitigate channel-induced limitations. Additionally, the proposed FSO design also employs Erbium-doped fiber amplifier (EDFA) with optimized gain characteristics. Using the data sourced from the Meteorological Department of India, the link analysis reveals that due to weak fog events in coastal areas effective link range of up to 10.75 $\text{km}$ can be achieved while maintaining bit error rate of $10^{-9}$ . Despite dominant foggy conditions in hilly, plains and desert areas, the proposed FSO link significantly limits the degrading effects of channel. Hence, in pursuit of futuristic smart city models, a heterogeneous combination of FSO and 5G infrastructure can conveniently cover diverse geographical locations of India to support high-speed data connectivity. ...read more Full-text Go to Paper 26 citations

What is a wind tunnel Charmein Johnson : Msfc 01 Jan 2008 TL;DR: A video showing how wind tunnels work so well, aircraft are not built or flown unless they are first tested in a wind tunnel is shown in this article, where the authors show how wind tunnel works so well. Abstract: A video showing how wind tunnels work so well, aircraft are not built or flown unless they are first tested in a wind tunnel. Go to Paper