IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document analyzes the bit error rate (BER) performance of the mobile WiMAX physical layer under different communication channels and modulation techniques. It simulates BER and signal-to-noise ratio (SNR) using the Stanford University Interim (SUI) channel models, which model six different channel conditions for varying terrain types. The performance is evaluated for different data rates and modulation schemes like BPSK and OFDMA under the SUI channel models.
Field-flow fractionation (AF4) is a separation technique that uses an external cross-flow to fractionate samples based on differences in size, shape, or density. In AF4, an analyte mixture is injected into a thin channel and separated under the influence of a perpendicular laminar flow. Smaller analytes are eluted faster than larger ones. AF4 coupled with detectors like multi-angle light scattering (MALS) and fluorescence allows characterization of size, shape, and structure of macromolecules, nanoparticles, viruses, liposomes, and protein aggregates with high resolution.
Research Inventy : International Journal of Engineering and Science is publis...researchinventy
A multiple C-shaped microstrip patch antenna system is presented to provide wide coverage for wireless applications. The system consists of five C-shaped patch antennas fed by a coplanar waveguide network. The antennas and feeding network are fabricated on an FR4 substrate that is 1.6mm thick with a relative permittivity of 4.4. Modeling and simulation using HFSS electromagnetic simulator shows the system provides multiple resonance frequencies at 2.4GHz for applications such as DCS, MCS, WLAN, and WiMAX. Simulation results demonstrate return losses of 20dB at 6.7GHz, 10dB at 4.4GHz and 14dB at 1.8GHz, obtaining frequency bands of 1.7-
non inclined slotted waveguide array with various shapes of irisesINFOGAIN PUBLICATION
Non-inclined narrow wall slotted waveguide with iris reduces the cross polarization. In this paper non inclined slotted waveguide array with iris is compared with inclined narrow wall slotted waveguide array to demonstrate the huge reduction in cross polarization. Analysis of various shapes of iris is done to compare their effects on co polarization and cross polarization.
IOSR Journal of Electronics and Communication Engineering(IOSR-JECE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of electronics and communication engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electronics and communication engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document analyzes the bit error rate (BER) performance of the mobile WiMAX physical layer under different communication channels and modulation techniques. It simulates BER and signal-to-noise ratio (SNR) using the Stanford University Interim (SUI) channel models, which model six different channel conditions for varying terrain types. The performance is evaluated for different data rates and modulation schemes like BPSK and OFDMA under the SUI channel models.
Field-flow fractionation (AF4) is a separation technique that uses an external cross-flow to fractionate samples based on differences in size, shape, or density. In AF4, an analyte mixture is injected into a thin channel and separated under the influence of a perpendicular laminar flow. Smaller analytes are eluted faster than larger ones. AF4 coupled with detectors like multi-angle light scattering (MALS) and fluorescence allows characterization of size, shape, and structure of macromolecules, nanoparticles, viruses, liposomes, and protein aggregates with high resolution.
Research Inventy : International Journal of Engineering and Science is publis...researchinventy
A multiple C-shaped microstrip patch antenna system is presented to provide wide coverage for wireless applications. The system consists of five C-shaped patch antennas fed by a coplanar waveguide network. The antennas and feeding network are fabricated on an FR4 substrate that is 1.6mm thick with a relative permittivity of 4.4. Modeling and simulation using HFSS electromagnetic simulator shows the system provides multiple resonance frequencies at 2.4GHz for applications such as DCS, MCS, WLAN, and WiMAX. Simulation results demonstrate return losses of 20dB at 6.7GHz, 10dB at 4.4GHz and 14dB at 1.8GHz, obtaining frequency bands of 1.7-
non inclined slotted waveguide array with various shapes of irisesINFOGAIN PUBLICATION
Non-inclined narrow wall slotted waveguide with iris reduces the cross polarization. In this paper non inclined slotted waveguide array with iris is compared with inclined narrow wall slotted waveguide array to demonstrate the huge reduction in cross polarization. Analysis of various shapes of iris is done to compare their effects on co polarization and cross polarization.
This document describes the design and simulation of a dual band patch antenna for WLAN/WiMax applications. Three miniaturized dual band u-slot patch antenna designs are investigated that can operate in both the 2.4 GHz and 5 GHz bands. The second resonant frequency band can be shifted by varying the width of the u-slot. The antennas are simulated using Ansoft HFSS and Antenna Magus software. The antenna parameters such as input impedance, return loss, and polarization are obtained and optimized to meet design requirements.
Propagation Model for Tree Blockage in Mobile Communication Systems using Uni...IJEEE
A deterministic model for spherical wave propagation in microcellular urban environment is presented. This methodis based on ray tracing and uniform theory of diffraction. The various ray contributions includes the diffraction from corner of obstacle, reflection from ground and direct wave. According to the height of transmitting station, different ray paths will be presented in the received signal. Calculation is carried out using hard and soft polarization. Results can be used for the planning of new cellular system.
This document presents a new printed slot antenna design based on the first iteration of the Sierpinski gasket fractal geometry for dual band wireless communication applications. The antenna is fed by a microstrip transmission line and exhibits resonant behavior at 2.4 GHz and 5.2 GHz, making it suitable for dual band WLAN systems. Simulation results show the lower resonant band is determined by the slot size, while the feed length and position of a vertical stub affect the upper band matching and frequency. Parametric studies optimize the antenna for good impedance matching across both bands.
This technical report describes the design of a rectangular microstrip patch antenna using CST simulation software. The key steps included:
1) Calculating the antenna dimensions using standard formulas based on the given parameters of 3GHz frequency, 2.33 permittivity, 0.508mm substrate thickness.
2) Simulating the antenna in CST to analyze the S-parameters, radiation pattern, return loss. The results showed a return loss above -10dB, indicating room for improvement.
3) Etching defected ground structures (DGS) on the patch and ground plane to perturb the current and modify the transmission characteristics.
4) Simulating the modified antenna, which showed significantly improved results with a return
The document compares different parameters of a CPW-fed bowtie antenna designed for wideband applications across S, C, and X bands. Simulation results show that the antenna exhibits the widest bandwidth of 25% for VSWR <1.5 in the 4.9-8.2 GHz band. Return loss is highest at -26.5 dB in this band as well. Gain is highest at 6.03 dB in the same band. The antenna therefore performs best in the C-band frequency range of 4.9-8.2 GHz based on its bandwidth, return loss, and gain performance in the different bands analyzed.
Printed UWB Circular and Modified Circular Disc Monopole AntennasIDES Editor
The document summarizes the simulation of two types of printed ultra-wideband (UWB) monopole antennas: circular and modified circular disk monopole antennas. The circular disk antenna operated from 2.1 to 12.4 GHz while the modified circular antenna operated from 2.3 to 11.3 GHz. Both antennas had omnidirectional radiation patterns, with the E-plane patterns becoming distorted at higher frequencies. The gap between the patch and ground plane was a crucial parameter for achieving broad bandwidth. The modified circular antenna had slightly higher efficiency but a reduced bandwidth compared to the circular disk antenna.
The document describes the design of three complementary-symmetry microstrip patch antennas with slots for wideband operation: a V-slot corner truncated square microstrip antenna (VCCSMA) that operates over two bands, an extended V-slot corner truncated square microstrip antenna (ECCSMA) that operates over three bands, and a W-slot corner truncated square microstrip antenna (WCCSMA) that merges the three bands into a single wide band. Experimental results show the VCCSMA achieves 11.16% and 36.01% bandwidth, the ECCSMA achieves 11.30%, 42.51%, and 8.70% bandwidth, and the WCCSMA achieves the highest bandwidth of 85.37%.
Atmospheric aberrations in coherent laser systemswtyru1989
The document discusses atmospheric effects on coherent laser systems and compensation methods. It presents:
1) Simulations of atmospheric propagation using phase screens and analyzing phase distortion, beam wander, spreading, and scintillation.
2) Techniques for compensating atmospheric effects in coherent measurements, including phase compensation receivers and adaptive optics.
3) Modeling of beam projection in coherent lidars and analyzing compensation of speckle averaging using non-conjugated adaptive optics.
This document discusses waveguide to suspended stripline transition techniques at 94 GHz. It describes two types of probe transitions that were designed and simulated. Type I uses a top excitation and rectangular probe on a 5 mil RT Duroid substrate. Type II uses side excitation and a rectangular probe. The best results were achieved with Type II, which has been used to realize bandpass filters, couplers, and crossbar mixers operating at 94 GHz. Both transitions were fabricated and tested, with the probe shape, depth and shorting plane optimized using electromagnetic simulation software.
Research Inventy : International Journal of Engineering and Science is publis...researchinventy
This document summarizes the design and development of a switchable fractal patch antenna for GPS applications. The antenna uses a stacked fractal patch design to reduce size and mitigate interference. Two fractal patch antennas with different radiation patterns are stacked and selected using diode switching. Simulation results show the stacked fractal patch antenna achieves a return loss of -29.01 dB, VSWR of 1.30, and size reduction of up to 62.4% compared to a basic patch antenna design through the use of fractal iterations. The stacked fractal patch design provides a compact antenna that can directly replace existing antennas for GPS applications.
The document discusses placement algorithms used in circuit design. It describes the min-cut placement algorithm which partitions the layout surface and circuit into halves recursively to minimize wirelength. Terminal propagation is discussed to address limitations of min-cut by considering terminal pin positions. Placement by simulated annealing is also summarized, using neighborhood structures and cost functions to iteratively improve placement quality as temperature decreases.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document discusses applications of fiber optics and holography. It covers fiber optics topics like types of optical fibers, numerical aperture, acceptance angle, and attenuation in optical fibers. For holography, it discusses the basic principles, construction and reconstruction of holograms, and applications like holographic data storage, digital holography, use in banknotes, and holographic art.
This document discusses the design and testing of a gap-coupled broadband microstrip antenna for GPS applications. A basic rectangular microstrip patch antenna was first designed with a bandwidth of 26 MHz at 1.57 GHz. The bandwidth was increased to 35.5 MHz by adding two parasitic patches along the radiating edges of the main patch. Both antenna configurations were simulated and experimentally tested, with the gap-coupled design showing around a 36% increase in bandwidth. The effects of a finite versus infinite ground plane were also studied, with the finite ground plane design achieving around a 33% size reduction.
2008 IEEE AP-S-Internal Wideband Monopole Antenna For MIMO Access-Point Appli...Saou-Wen Su
A three-antenna MIMO system capable of generating a wide operating bandwidth of 2400-5850 MHz for access-point applications is introduced. The proposed design is based on a bent metal-plate monopole antenna with a compact size of 20 × 20 × 14 mm3. The three antennas are equally spaced along the perimeter of a circular ground and all generate a wide bandwidth of larger than 4 GHz. With the antenna short-circuiting facing the center of the ground, not only the overall antenna size is reduced but also good isolation of less than -20 dB can easily be obtained. Calculated envelope correlation is also less than 0.002 across the operating band.
Printed Omnidirectional Access-Point Antenna for 2.4/5-GHz WLAN OperationSaou-Wen Su
A new design of the printed omnidirectional antenna for applications in 2.4/5-GHz dual-WLAN-band access points is proposed. The antenna consists of a conventional collinear antenna for 2.4 GHz operation and two U stubs for 5 GHz operation. The two U stubs are located near the points where the maximum currents at about 5.5 GHz occurring on the strips of the collinear antenna, and arranged back to back in the same phase for achieving better antenna gain. Detailed analyses of the U stub on the impedance matching over the 5 GH band is presented. A prototype with good omnidirectional radiation across the 2.4/5-GHz WLAN bands is demonstrated.
Investigation of Integrated Rectangular SIW Filter and Rectangular Microstrip...IJASCSE
This paper presents an investigation based on the resonant circuit approach to characterize an integrated microwave filter and antenna from a lumped element prototype. This approach is used to design an integrated filter and antenna to reduce the overall size of the physical dimensions of the RF/microwave front-end subsystem. This study focuses on the integration of a rectangular Substrate Integrated Waveguide (SIW) filter with a rectangular microstrip patch antenna to produce a filtering and radiating element in a single device. The physical layouts of the SIW filter and rectangular microstrip patch antenna based on single- and dual-mode will be developed. To prove the concept, the integrated microwave filter and antenna at a center frequency of 2 GHz is demonstrated and validated through simulation and laboratory experiments. The experimental performance yielded promising results that were in good agreement with the simulated results. This study is beneficial for microwave systems, given that the reduction of the complexity of design and physical dimension as well as cost are important for applications such as base stations and multiplexers in wireless communication systems.
This document analyzes the dose linearity response of thermoluminescence in ternary mixed multiphased crystals of (KCl)x(KBr)y-x(KI)1-y that were prepared by melt method and irradiated with 15MV photon beams. Nine combinations of the crystals were irradiated at doses of 10, 50, 100, and 200Gy. Thermoluminescence glow curves were studied from 50-400°C at a heating rate of 3°C/sec. The (KCl)0.1(KBr)0.8(KI)0.1 composition showed a maximum TL output at 100Gy with a glow peak around 85°C
This document summarizes an experimental study on the use of neem methyl esters as biodiesel in a compression ignition engine. Neem oil was transesterified to produce biodiesel, which was then blended with diesel in ratios of 10%, 20%, and 30% by volume. The blends were tested in a single cylinder diesel engine and performance and emission characteristics were analyzed at varying loads. Results showed that the B20 blend performed better than diesel with lower emissions. Higher blend ratios like B30 saw decreased performance due to higher viscosity negatively impacting combustion. Overall, the study demonstrated the potential of neem biodiesel to replace a portion of diesel fuel.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document summarizes a research paper that proposes a new routing protocol called U-LEACH for wireless sensor networks. U-LEACH aims to prolong the lifetime of sensor networks by uniformly distributing cluster head selection throughout the network, unlike the original LEACH protocol. It describes how LEACH works and its limitations in ensuring uniform cluster head distribution. The proposed U-LEACH protocol incorporates a Uniform Distribution Technique to select cluster heads in a way that ensures each sensor node is within transmission range of a cluster head, extending the overall network lifetime.
This document describes the design and simulation of a dual band patch antenna for WLAN/WiMax applications. Three miniaturized dual band u-slot patch antenna designs are investigated that can operate in both the 2.4 GHz and 5 GHz bands. The second resonant frequency band can be shifted by varying the width of the u-slot. The antennas are simulated using Ansoft HFSS and Antenna Magus software. The antenna parameters such as input impedance, return loss, and polarization are obtained and optimized to meet design requirements.
Propagation Model for Tree Blockage in Mobile Communication Systems using Uni...IJEEE
A deterministic model for spherical wave propagation in microcellular urban environment is presented. This methodis based on ray tracing and uniform theory of diffraction. The various ray contributions includes the diffraction from corner of obstacle, reflection from ground and direct wave. According to the height of transmitting station, different ray paths will be presented in the received signal. Calculation is carried out using hard and soft polarization. Results can be used for the planning of new cellular system.
This document presents a new printed slot antenna design based on the first iteration of the Sierpinski gasket fractal geometry for dual band wireless communication applications. The antenna is fed by a microstrip transmission line and exhibits resonant behavior at 2.4 GHz and 5.2 GHz, making it suitable for dual band WLAN systems. Simulation results show the lower resonant band is determined by the slot size, while the feed length and position of a vertical stub affect the upper band matching and frequency. Parametric studies optimize the antenna for good impedance matching across both bands.
This technical report describes the design of a rectangular microstrip patch antenna using CST simulation software. The key steps included:
1) Calculating the antenna dimensions using standard formulas based on the given parameters of 3GHz frequency, 2.33 permittivity, 0.508mm substrate thickness.
2) Simulating the antenna in CST to analyze the S-parameters, radiation pattern, return loss. The results showed a return loss above -10dB, indicating room for improvement.
3) Etching defected ground structures (DGS) on the patch and ground plane to perturb the current and modify the transmission characteristics.
4) Simulating the modified antenna, which showed significantly improved results with a return
The document compares different parameters of a CPW-fed bowtie antenna designed for wideband applications across S, C, and X bands. Simulation results show that the antenna exhibits the widest bandwidth of 25% for VSWR <1.5 in the 4.9-8.2 GHz band. Return loss is highest at -26.5 dB in this band as well. Gain is highest at 6.03 dB in the same band. The antenna therefore performs best in the C-band frequency range of 4.9-8.2 GHz based on its bandwidth, return loss, and gain performance in the different bands analyzed.
Printed UWB Circular and Modified Circular Disc Monopole AntennasIDES Editor
The document summarizes the simulation of two types of printed ultra-wideband (UWB) monopole antennas: circular and modified circular disk monopole antennas. The circular disk antenna operated from 2.1 to 12.4 GHz while the modified circular antenna operated from 2.3 to 11.3 GHz. Both antennas had omnidirectional radiation patterns, with the E-plane patterns becoming distorted at higher frequencies. The gap between the patch and ground plane was a crucial parameter for achieving broad bandwidth. The modified circular antenna had slightly higher efficiency but a reduced bandwidth compared to the circular disk antenna.
The document describes the design of three complementary-symmetry microstrip patch antennas with slots for wideband operation: a V-slot corner truncated square microstrip antenna (VCCSMA) that operates over two bands, an extended V-slot corner truncated square microstrip antenna (ECCSMA) that operates over three bands, and a W-slot corner truncated square microstrip antenna (WCCSMA) that merges the three bands into a single wide band. Experimental results show the VCCSMA achieves 11.16% and 36.01% bandwidth, the ECCSMA achieves 11.30%, 42.51%, and 8.70% bandwidth, and the WCCSMA achieves the highest bandwidth of 85.37%.
Atmospheric aberrations in coherent laser systemswtyru1989
The document discusses atmospheric effects on coherent laser systems and compensation methods. It presents:
1) Simulations of atmospheric propagation using phase screens and analyzing phase distortion, beam wander, spreading, and scintillation.
2) Techniques for compensating atmospheric effects in coherent measurements, including phase compensation receivers and adaptive optics.
3) Modeling of beam projection in coherent lidars and analyzing compensation of speckle averaging using non-conjugated adaptive optics.
This document discusses waveguide to suspended stripline transition techniques at 94 GHz. It describes two types of probe transitions that were designed and simulated. Type I uses a top excitation and rectangular probe on a 5 mil RT Duroid substrate. Type II uses side excitation and a rectangular probe. The best results were achieved with Type II, which has been used to realize bandpass filters, couplers, and crossbar mixers operating at 94 GHz. Both transitions were fabricated and tested, with the probe shape, depth and shorting plane optimized using electromagnetic simulation software.
Research Inventy : International Journal of Engineering and Science is publis...researchinventy
This document summarizes the design and development of a switchable fractal patch antenna for GPS applications. The antenna uses a stacked fractal patch design to reduce size and mitigate interference. Two fractal patch antennas with different radiation patterns are stacked and selected using diode switching. Simulation results show the stacked fractal patch antenna achieves a return loss of -29.01 dB, VSWR of 1.30, and size reduction of up to 62.4% compared to a basic patch antenna design through the use of fractal iterations. The stacked fractal patch design provides a compact antenna that can directly replace existing antennas for GPS applications.
The document discusses placement algorithms used in circuit design. It describes the min-cut placement algorithm which partitions the layout surface and circuit into halves recursively to minimize wirelength. Terminal propagation is discussed to address limitations of min-cut by considering terminal pin positions. Placement by simulated annealing is also summarized, using neighborhood structures and cost functions to iteratively improve placement quality as temperature decreases.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document discusses applications of fiber optics and holography. It covers fiber optics topics like types of optical fibers, numerical aperture, acceptance angle, and attenuation in optical fibers. For holography, it discusses the basic principles, construction and reconstruction of holograms, and applications like holographic data storage, digital holography, use in banknotes, and holographic art.
This document discusses the design and testing of a gap-coupled broadband microstrip antenna for GPS applications. A basic rectangular microstrip patch antenna was first designed with a bandwidth of 26 MHz at 1.57 GHz. The bandwidth was increased to 35.5 MHz by adding two parasitic patches along the radiating edges of the main patch. Both antenna configurations were simulated and experimentally tested, with the gap-coupled design showing around a 36% increase in bandwidth. The effects of a finite versus infinite ground plane were also studied, with the finite ground plane design achieving around a 33% size reduction.
2008 IEEE AP-S-Internal Wideband Monopole Antenna For MIMO Access-Point Appli...Saou-Wen Su
A three-antenna MIMO system capable of generating a wide operating bandwidth of 2400-5850 MHz for access-point applications is introduced. The proposed design is based on a bent metal-plate monopole antenna with a compact size of 20 × 20 × 14 mm3. The three antennas are equally spaced along the perimeter of a circular ground and all generate a wide bandwidth of larger than 4 GHz. With the antenna short-circuiting facing the center of the ground, not only the overall antenna size is reduced but also good isolation of less than -20 dB can easily be obtained. Calculated envelope correlation is also less than 0.002 across the operating band.
Printed Omnidirectional Access-Point Antenna for 2.4/5-GHz WLAN OperationSaou-Wen Su
A new design of the printed omnidirectional antenna for applications in 2.4/5-GHz dual-WLAN-band access points is proposed. The antenna consists of a conventional collinear antenna for 2.4 GHz operation and two U stubs for 5 GHz operation. The two U stubs are located near the points where the maximum currents at about 5.5 GHz occurring on the strips of the collinear antenna, and arranged back to back in the same phase for achieving better antenna gain. Detailed analyses of the U stub on the impedance matching over the 5 GH band is presented. A prototype with good omnidirectional radiation across the 2.4/5-GHz WLAN bands is demonstrated.
Investigation of Integrated Rectangular SIW Filter and Rectangular Microstrip...IJASCSE
This paper presents an investigation based on the resonant circuit approach to characterize an integrated microwave filter and antenna from a lumped element prototype. This approach is used to design an integrated filter and antenna to reduce the overall size of the physical dimensions of the RF/microwave front-end subsystem. This study focuses on the integration of a rectangular Substrate Integrated Waveguide (SIW) filter with a rectangular microstrip patch antenna to produce a filtering and radiating element in a single device. The physical layouts of the SIW filter and rectangular microstrip patch antenna based on single- and dual-mode will be developed. To prove the concept, the integrated microwave filter and antenna at a center frequency of 2 GHz is demonstrated and validated through simulation and laboratory experiments. The experimental performance yielded promising results that were in good agreement with the simulated results. This study is beneficial for microwave systems, given that the reduction of the complexity of design and physical dimension as well as cost are important for applications such as base stations and multiplexers in wireless communication systems.
This document analyzes the dose linearity response of thermoluminescence in ternary mixed multiphased crystals of (KCl)x(KBr)y-x(KI)1-y that were prepared by melt method and irradiated with 15MV photon beams. Nine combinations of the crystals were irradiated at doses of 10, 50, 100, and 200Gy. Thermoluminescence glow curves were studied from 50-400°C at a heating rate of 3°C/sec. The (KCl)0.1(KBr)0.8(KI)0.1 composition showed a maximum TL output at 100Gy with a glow peak around 85°C
This document summarizes an experimental study on the use of neem methyl esters as biodiesel in a compression ignition engine. Neem oil was transesterified to produce biodiesel, which was then blended with diesel in ratios of 10%, 20%, and 30% by volume. The blends were tested in a single cylinder diesel engine and performance and emission characteristics were analyzed at varying loads. Results showed that the B20 blend performed better than diesel with lower emissions. Higher blend ratios like B30 saw decreased performance due to higher viscosity negatively impacting combustion. Overall, the study demonstrated the potential of neem biodiesel to replace a portion of diesel fuel.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document summarizes a research paper that proposes a new routing protocol called U-LEACH for wireless sensor networks. U-LEACH aims to prolong the lifetime of sensor networks by uniformly distributing cluster head selection throughout the network, unlike the original LEACH protocol. It describes how LEACH works and its limitations in ensuring uniform cluster head distribution. The proposed U-LEACH protocol incorporates a Uniform Distribution Technique to select cluster heads in a way that ensures each sensor node is within transmission range of a cluster head, extending the overall network lifetime.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document discusses peak-to-average power ratio (PAPR) reduction techniques for orthogonal frequency division multiplexing (OFDM) systems. It analyzes the PAPR of discrete Hartley transform (DHT) precoded OFDM and compares it to discrete Fourier transform (DFT) precoded, Walsh-Hadamard transform (WHT) precoded, selected mapping (SLM) based, and conventional OFDM systems. Simulation results show that the WHT precoded OFDM system has the highest PAPR, while the DFT precoded OFDM system achieves zero PAPR. The document concludes that DFT precoding is the most effective technique for PAPR reduction analyzed.
This document describes several methods for estimating the speed of an induction motor, including:
1. A conventional MRAS (Model Reference Adaptive System) method using a reference model and adaptive model to estimate rotor flux linkages and speed.
2. An AI-based MRAS method using a two-layer neural network instead of a mathematical model, which provides more accurate estimation and is more robust to parameter variations.
3. An improved AI-based MRAS method with a dynamic reference model that estimates stator resistance online, making the scheme more independent of machine parameters.
4. A method to control motor speed using the estimated speed in a feedback loop with SVPWM (Space Vector Pulse Width
This document presents a speech encryption system that aims to enhance security. It uses chaotic maps to generate a polynomial, which is then used to generate a large set of Kasami sequences. These sequences act as the encryption key. The speech signal is divided into segments and encrypted using AES-128 with the Kasami sequences. Evaluation using noise attacks shows the encrypted speech has high distortion measures, indicating low residual intelligibility and therefore high security. Linear prediction analysis, spectral distance, and cepstrum distance are used to analyze the original and encrypted speech signals. Results demonstrate the proposed system encrypts speech effectively while maintaining good audio quality.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document summarizes advances in electronic nose technologies. It discusses the historical development of electronic noses from the 1950s to present. It describes the four main sensor types used in electronic noses: metal oxide semiconductors, metal oxide semiconductor field-effect transistors, conducting polymer sensors, and piezoelectric acoustic sensors. Each sensor type is explained in terms of its sensitive material, detection principle, and factors that influence selectivity and sensitivity. The document provides an overview of electronic nose technologies and the sensor types commonly used.
This document discusses weak isomorphism and isomorphism between fuzzy graphs. Some key points:
1. Weak isomorphism preserves the weights of nodes but not necessarily the weights of edges, while isomorphism preserves weights of both nodes and edges.
2. If two fuzzy graphs are isomorphic, they have the same order (number of nodes) and size (sum of edge weights).
3. Isomorphism between fuzzy graphs is proved to be an equivalence relation as it is reflexive, symmetric and transitive.
4. Weak isomorphism is proved to be a partial order relation as it satisfies reflexivity, anti-symmetry and transitivity.
5. Some properties of self-complement
The document summarizes a research paper that proposes a low density parity check (LDPC) algorithm for insertion/deletion channels. It begins by providing background on LDPC codes and how they are finding increasing use for reliable information transfer over bandwidth-constrained links with noise. It then describes the specific system model of a concatenated coding scheme using an outer error correcting code and inner marker code. The document analyzes the achievable transmission rates using this scheme through both bit-level and symbol-level maximum a posteriori probability (MAP) detection algorithms. It finds that the symbol-level approach confirms an advantage over codes optimized for additive white Gaussian noise channels.
This document describes a hybrid multilevel converter topology combining a neutral point clamped (NPC) converter with floating DC-link cascaded H-bridge converters. The NPC provides the active power while the H-bridges operate as series active filters to improve the voltage waveform quality by handling reactive power. This reduces the need for large passive filters. The document outlines two design challenges: determining the lowest H-bridge DC-link voltage to achieve adequate harmonic compensation, and developing a control algorithm to regulate the floating DC-link voltages at this level. Experimental results are provided to validate the proposed modulation technique and improvement in output waveform quality.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document summarizes a study that analyzes the costs of alternative energy sources for powering a house in Gwalior, India. The authors conducted an energy audit of the house to determine its total energy consumption. They then analyzed the costs and feasibility of using solar panels and inverters as alternative energy sources. The results provided guidance on using methods like selective loading to reduce energy costs by powering parts of the house with these alternative sources. In conclusion, the study evaluated alternative energy options for the house to help address issues with India's unreliable electricity supply.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document discusses the design and CFD simulation of an annular combustion chamber for a 20 kW gas turbine engine using kerosene as fuel. It outlines the design process which involved evaluating reference area based on aerodynamic and chemical considerations. The aerodynamic design aims for ideal constant pressure combustion while the chemical design allows for efficient combustion. CFD simulation was then carried out using ANSYS CFX to analyze temperature distribution within the combustion chamber.
Este documento describe un proyecto para crear nuevos canales de comunicación social para una asociación a través de redes sociales como un blog, Twitter y Flickr. El objetivo era mejorar la comunicación, unificar la imagen y aumentar el impacto mediante la integración de estas plataformas y la formación de su uso. Se estableció una estrategia y se implementaron pasos como crear cuentas, conectar los servicios y ofrecer talleres a empresas asociadas.
O documento discute conceitos de colisão no Unity 3D, incluindo tipos de colisores, componentes de colisão, tratamento de colisão com scripts e ray casting. Também aborda triggers e como ignorar colisões entre objetos específicos.
El documento explica el uso de los principales signos de puntuación en español como la coma, el punto y coma, el punto, los puntos suspensivos, los signos de interrogación y exclamación, y las comillas. Describe cómo cada signo indica pausas y jerarquiza las ideas para estructurar el texto y eliminar ambigüedades.
This paper presents a trifocal Rotman Lens Design
approach. The effects of focal ratio and element spacing on
the performance of Rotman Lens are described. A three beam
prototype feeding 4 element antenna array working in L-band
has been simulated using RLD v1.7 software. Simulated
results show that the simulated lens has a return loss of –
12.4dB at 1.8GHz. Beam to array port phase error variation
with change in the focal ratio and element spacing has also
been investigated.
Design of wideband Rotman lens for wireless applicationsTELKOMNIKA JOURNAL
An electrically steerable beam is an essential standard in the recent wireless application in order
to increase the gain and reduce the interference. However, high performance of amplitude besides low
phase error difficult to achieve without indicators are used to set lens parameters to desired optimum
performance design level. In this paper, the introduced microstrip lens has examined a comprehensive
explanation for parameters and indications amid a full wave structure methodology. Further, Phase and
energy coupling between excited ports and received ports besides phase error and its relation with
the lens parameters design are explained in detailed. A wideband beamforming network based on a
printed microstrip Rotman lens with a ±26o scanning angle was designed in this study. The designed lens
operates at 2.45 GHz with 592 MHz bandwidth. The lens consists of five switchable ports (input ports) with
four output ports that connected to the microstrip patch antennas. The five switchable ports were used to
realize the scanning beams angle in the azimuth plane. The proposed model is simulated by CST
Microwave Studio and fabricated on FR-4 with 1.565 mm thickness and 4.2 permittivity. A good agreement
between simulation and measurement results were achieved.
2009 measurement of focal ratio degradation in optical fibers used in astronomySiddartha Verma
1. The document describes a study that measured the focal ratio degradation (FRD) and throughput of optical fibers used in astronomy.
2. A simple experimental setup was used, involving a light source, lenses, and CCD camera to measure FRD for different input beam speeds. FRD causes the output beam to have a faster speed than the input.
3. The results showed throughput values of 85-90% for input f-numbers between 3-5. Quantifying FRD is important for optimizing astronomical instrumentation performance.
This document discusses different types of lenses used in fiber optic communications. It describes thin lenses and how their focal length is determined based on the radii of curvature. Cylindrical lenses are used to collimate light from a line source so the rays emerge parallel to the lens axis. Graded index rod lenses have a refractive index that decreases from the axis radially, causing ray paths inside to follow sinusoidal paths. GRIN rod lenses are commonly used to collimate or focus light beams coupling between fibers.
Design and implementation of microstrip rotman lens for ISM band applicationsjournalBEEI
This work presents the design and implementation of Rotman lens as a beam steering device for Industrial, Scientific, and Medical (ISM) applications. 2.45 GHz is considered as a center frequency design with (2-6) GHz frequency bandwidth. The beam steering is examined to cover ±21o scan angle with maximum main lobe magnitude 10.1 dBi, rectangular patch antennas are used as radiation elements to beam the output far field. The work is extended to compare between the tapered line which is used for matching between 50-Ω ports and lens cavity. CST microwave simulation studio results show that the rectangular taper line can yield 2 dB return loss less than linear taper line with a little bit shifting in responses for same input and load impedance.
This technical report discusses the components and system design of radar systems. It describes some key subsystems including antennas, duplexers, and the radio frequency subsystem. It also discusses digital waveform generators and frequency synthesizers/oscillators. Antennas are the interface between the radar system and free space, transmitting energy in beams and collecting echo signals. Duplexers use circulators to switch the radar between transmit and receive modes. The radio frequency subsystem includes antennas, duplexers, and filters to transmit signals and filter received signals. Digital waveform generators store and output signals using digital memories and D/A converters. Frequency synthesizers and oscillators generate the radio frequencies used.
This document summarizes a research paper on a surface plasmon resonance (SPR) fiber optic sensor with an enhanced U-shaped design. The researchers modeled how decreasing the bending radius of the U-shaped fiber probe increases the sensitivity of the sensor by up to 25 times compared to a straight fiber probe. They found an optimal bending radius of 1.0 cm provided the best performance by maximizing the interaction between light in the fiber core and surface plasmons excited on the metallic coating. The theoretical analysis considered light propagation in two dimensions within the bent plane and calculated transmitted power through the probe to determine sensitivity based on resonance conditions between incident light and surface plasmons.
Performance of DCO-OFDM in Optical Wireless Communication SystemAM Publications
OFDM scheme is widely adopted as it has high data rate and good performance under various channel conditions. In this paper, a number of unipolar optical OFDM scheme has been used for IM/DD system using simulink. To develop such a complex system, this paper proposes MATLAB as the platform for its implementation. The modeling of block diagram is done using Fast Fourier Transform and Hermitian symmetry. The concept of Optical OFDM uses LED at the transmitter and Photodiode at the receiver to demonstrate the optical characteristics of the system. The model has been implemented using different modulation techniques and under various channels. The paper suggests that using QPSK modulation in white Gaussian noise with 5dB SNR gives best result in terms of BER. Similarly, DBPSK modulation technique performs better with the increase in fading frequency. Thus, the complete model description suggests novelty in the modulation schemes that can be accepted for channels applicable in optical OFDM communication.
Performance of DCO-OFDM in Optical Wireless Communication SystemAM Publications
OFDM scheme is widely adopted as it has high data rate and good performance under various channel conditions. In this paper, a number of unipolar optical OFDM scheme has been used for IM/DD system using simulink. To develop such a complex system, this paper proposes MATLAB as the platform for its implementation. The modeling of block diagram is done using Fast Fourier Transform and Hermitian symmetry. The concept of Optical OFDM uses LED at the transmitter and Photodiode at the receiver to demonstrate the optical characteristics of the system. The model has been implemented using different modulation techniques and under various channels. The paper suggests that using QPSK modulation in white Gaussian noise with 5dB SNR gives best result in terms of BER. Similarly, DBPSK modulation technique performs better with the increase in fading frequency. Thus, the complete model description suggests novelty in the modulation schemes that can be accepted for channels applicable in optical OFDM communication.
What is Antenna.List it functions
Antenna Applications
Types of Antennas
Antenna Parameters
Field Regions
(a) reactivenear-field,
(b) radiating near-field (Fresnel) and
(c) far-field (Fraunhofer) regions .
Typical changes of antenna amplitude pattern shape from reactive near field toward the far field
Radian and Steradian
Challenges of Antenna Design.
softwares available for Antenna Design
Reflector antennas use reflecting surfaces and a feed antenna to achieve high gains for long-distance radio communications. The simplest design uses a single parabolic reflector with the feed at the focal point, while more complex dual-reflector designs position a secondary reflector at the focal point. Parabolic reflectors collimate rays from the feed into a directional beam, with path lengths from the feed equalizing phase. Dual reflectors like the Cassegrain design position the feed at the main reflector's apex for a more robust structure. The gain of reflector antennas depends on the aperture efficiency accounting for losses from tapering, spillover, surface errors and phase deviations reducing the directivity.
This document discusses an algorithm for estimating radar cross section (RCS). RCS is a measure of how detectable an object is by radar. The algorithm takes in data about a target like its material, size, distance from radar, and angle, and uses the radar equation to calculate the RCS. The algorithm was tested on different target types and showed varying RCS values, with aircraft generally higher than humans or insects. Calculating RCS allows analysis of radar system performance independent of specific system parameters.
Designing geometric parameters of axisymmetrical cassegrain antenna and corru...Editor Jacotech
Early detection of faults occurring in three-phase induction motors can appreciably reduce the costs of maintenance, which could otherwise be too much costly to repair. Internal faults in three phase induction motors can result in significant performance degradation and eventual system failures. Artificial intelligence techniques have numerous advantages over conventional Model-based and Signal Processing fault diagnostic approaches; therefore, in this paper, a soft-computing system was studied through Neural Network Analysis to detect and diagnose the stator and rotor faults. The fault diagnostic system for three-phase induction motors samples the fault symptoms and then uses a Neural Network model to first train and then identify the fault which gives fast accurate diagnostics. This approach can also be extended to other applications.
This document summarizes the numerical analysis of a 4x1 microstrip patch antenna array operating at 10 GHz. It presents the equations for the E-field and H-field of a single patch element and the 4-element array. Radiation patterns generated in MATLAB are presented for both the single element and array. The E-field pattern of the array is more concentrated than the single element, indicating increased gain and directivity due to the additional elements. In conclusion, increasing the number of patches enhances antenna performance.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document discusses improving the signal-to-noise ratio (SNR) in biaxial lidar systems through optimizing the receiver aperture geometry. Simulations were conducted to examine the overlap function between the transmitter and receiver fields of view for a vertically pointing lidar across four ranges. Results show that varying the receiver aperture shape, position, and size to fully capture return signals while minimizing background noise can maximize lidar SNR. Proposed aperture designs for each range show improvements to the geometric factor and thus the attainable lidar range compared to a standard small round aperture.
The document presents a modal analysis of a new type of non-conventional optical waveguide with a trapezoidal cross-section and metallic cladding. It derives the characteristic equations using Goell's point matching method under the weak-guidance approximation. It obtains the dispersion curves for different cases of the proposed trapezoidal waveguide and compares them to those of a standard square waveguide with metallic cladding. The analysis shows that distorting a square waveguide into a trapezoidal shape with metallic cladding shifts the lowest cut-off value to a higher value and increases the number of modes.
This document discusses the picosecond dispersive properties of Fabry-Pérot interferometers. It begins with an introduction to Fabry-Pérot interferometers and their basic structure and properties. It then discusses parameters that define Fabry-Pérot interferometers such as finesse and free spectral range. The document uses coupled mode theory to simulate and analyze the dispersion of Fabry-Pérot interferometers. Simulation results are presented that show the transmittance function, finesse, delay, and dispersion versus wavelength. The results demonstrate the relationship between factors like reflectivity and finesse.
This document discusses the simulation and analysis of Fabry-Pérot interferometers using coupled mode theory. It begins with an introduction to Fabry-Pérot interferometers and their basic structure and properties. It then describes using coupled mode equations to model the Fabry-Pérot cavity and study picosecond dispersion. Simulation results are presented on transmittance, finesse, contrast factor, amplitude transmission, power transmission, delay, and dispersion as functions of variables like interference order and mirror reflectivity. Plots demonstrate the relationships between various Fabry-Pérot parameters. The document analyzes the dispersive properties of the Fabry-Pérot interferometer using coupled mode theory and transfer matrix methods.
This document describes the design and simulation of a fractal coplanar waveguide fed multiband antenna. Five iterations of a fractal antenna design are created using FR4 epoxy substrate. The antenna is simulated using HFSS software. The results show the antenna operates at multiple bands in the L, C, and X bands with suitable return loss and VSWR across the bands. The fractal design approach allows the antenna to achieve multiband operation while maintaining a small size.
1. Shruti Vashist, Umesh Dutta, Dr.M.K.Soni / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue4, July-August 2012, pp.1792-1795
Design And Performance Analysis Of Rotman Lens
Shruti Vashist1, Umesh Dutta2, Dr.M.K.Soni3
Department of Electronics and Communication Engineering, , Manav Rachna International University,
Faridabad, India
Abstract
This paper presents a trifocal Rotman In this paper Rotman lens is proposed which is
lens antenna design approach. A three beam capable of scanning at an angle of 45 and has a
prototype feeding an 8-element antenna array medium of dielectric constant of 4.6 in between the
working at C band has been simulated using RLD two contours.The center frequency of lens is 4.6GHz
v1.7 software.Simulation results show that the which lies in the C band and the design of the lens is
designed lens shows good performance in the adapted from the formulas found in [1] and [4].
operating frequency band of (4-5GHz). Simulations were carried out using RLD 1.7 designer
software and various performance analysis
Keywords— Array factor, beam ports, array parameters such as array factor, insertion loss, S-
ports, scanning angle, focal ratio. parameters and phase error are analysed to prove the
effectiveness of the proposed Rotman lens design at
I. INTRODUCTION such a high frequency.
Due to the advancements in wireless
communication technology, smart antenna arrays This paper is organized as follows: Section
which support multi beams and are capable of II presents lens design approach in which trifocal
providing wide angle scanning over a broad Rotman lens design equations and its important
frequency range have become an obvious choice in design parameters are discussed.Section III presents a
numerous cutting edge applications. In order to design example of Rotman lens. In section IV
achieve reliable ,low cost, multi beam phased arrays, simulation results of the designed Rotamn lens are
the Rotman lens is an attractive beam-forming presented and finally in section V conclusions are
network. Rotman lens is widely used in applications drawn.
such as ECM, Radar systems, automotive adaptive
cruise control (ACC) systems and satellite II. LENS DESIGN APPROACH
communication systems. The popularity of Rotman Fig.1 shows a schematic diagram of a
lens for many electronic scanning applications is due trifocal Rotman lens. Input ports lie on contour C1
to its simple design and compact size. W.Rotman and and the output ports lie on contour C2. C1 is known
R.Turner first proposed the Rotman lens which as beam contour and C2 is known as array contour.
consist of air filled parallel conducting plates fed by There are three focal points namely F1, F2 and F3.
co-axial probes [1]. D.Archer [2] gave a modified F1 is located on the central axis while F2 and F3 are
design of Rotman lens in which a dielectric material symmetrically located on the array contour at an
is filled between parallel conducting plates fed by angle of +α and – α respectively. It is quite clear from
microstrip lines. Rotman lens provides linear phase Fig.1 that the co-ordinates of two off-axis focal
shifts at the output ports by utilizing different points F2, F3 and on one axis focal point F1 are (-
propagation paths within the lens structure. At high f2cosα, f2sinα), (-f2cosα, -f2sinα ) and (-f1, 0)
microwave frequencies the losses increase due to respectively.
increase in surface resistance as-
f
Rs
1
Rs
Where , , , f , and represents conductivity,
skin depth , frequency and permeability respectively
[3].
Design of physical structure at high
microwave frequencies is challenging issue. Also at
low frequencies the Rotman lens realization becomes
quite larger and so it is difficult to integrate it in
compact transceiver designs.
Fig.1 Trifocal Rotman Lens Schematic Diagram.
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2. Shruti Vashist, Umesh Dutta, Dr.M.K.Soni / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue4, July-August 2012, pp.1792-1795
where
r 2
f1 -On axis focal length a. .W b r .W c 0 ----------------(7)
e e
f 2 -Off axis focal length
Where-
-Off center focal angle
(1 ) 2 2
-Scanning angle a 1 i 2
(1 C ) 2 r
sin
- beam angle to ray angle ratio given as
2 i 2 (1 ) 2 S 2 (1 ) i
sin b 2 2
ratio of sine of their angles. r 1 cos (1 C ) 2 r
r -Permittivity of medium in between the lens
2S 2 2S 4 i
contour c 2
(1 C ) 4(1 C ) r
e - Permittivity of medium of transmission line
W -Normalized relative transmission line length
i -Permittivity of medium of radiating element
w wo
f and is given as W ( ).
= 2 -Focal ratio f1
f1 S=sinα and C=cosα
It is important to note that the number of
beams, number of elements, maximum beam angle
wo - Transmission line length between axis point and element spacing are known from the system
„O‟and radiating element. requirement and so the task is to select the optimum
w -Transmission line length between point „P‟and values of , , γ and f1 /λ [4].
radiating element. Element spacing d is also very critical as it controls
FiP-It is the physical distance from focal point Fi to the appearance of grating lobes. The spacing that just
P. admits a grating lobe is given by-
d 1
ξ is another important parameter that relates the ------------------------(8)
distance Y3 of any point on the array contour from the 2 sin m
axis, to f1 . ξ controls the portion of phase and where Ψm is the maximum beam angle.
amplitude error curves that the lens experiences [4].
Y3
It is given by- . III. DESIGN EXAMPLE
f1 The Rotman lens is designed in microstrip
If we assume that the ideal focal points are configuration to meet the following specifications:
located at θ = ± α and 0, and their corresponding Angular coverage= +45◦, number of antenna
radiation angles are Ψ = ± Ψα and Ψ = 0, given Ψα is elements=8, number of input beams = 3, central
a known angle, simultaneous equations 1-3 are frequency = 4.6GHz. The lens structure is fabricated
satisfied: in a microstrip version on a substrate of thickness
1.2mm and dielectric constant of 4.6. The loss
tangent is 0.0012. In order to guarantee a correct
F2 P r w e Y3 i sin f2 r wo e (1) operation of the lens, reflections within the lens must
be avoided. In microstrip configuration this is
F3P r w e Y3 i sin f2 r wo e (2) obtained by employing dummy ports.
F1P r w e f1 r wo e (3)
Also we have-
F2P2 = (-f2 cos -X)2 + (-f2 sin +Y)2 ------------(4)
F3P2 = (-f2 cos -X)2 + (-f2 sin -Y)2 ------------(5)
F1P2 = (f1 +X)2 + (Y)2------------------------------(6)
By algebraic manipulation of the above
equations we can obtain geometric lens equation
which is quadratic in nature and is given by-
Fig.2 Simulated Rotman Lens.
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3. Shruti Vashist, Umesh Dutta, Dr.M.K.Soni / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue4, July-August 2012, pp.1792-1795
IV.SIMULATION RESULTS Fig.5 shows the array ports amplitude distribution
The Rotman lens with the specifications for beam port2 excitation at 4.6GHz. It is observable
mentioned in section III is designed and simulated that for array port 7 and 8 beam to array coupling
using RLDv1.7 software. The radiation pattern are amplitude is of the order of -11.9dB, which shows
shown in Fig.3 and from this it is quite clear that good coupling condition.
good results are obtained in terms of both the side
lobe level and main lobe direction. There are three
main lobes for the three beam port excitation. For
plotting the radiation pattern all the beam ports are
excited with equal amplitude and phase.
Fig.5 Amplitude distribution of array ports.
Fig.6 and Fig.7 shows the variation of S-
parameters with frequency for port2 excitation. It is
observable that within the operating frequency band
of 4-5GHz S-parameter values are better than -10dB.
Fig.3 Array factor plot.
The phase distribution across the aperture is
shown in Fig.4. Phase error across the aperture takes
place for each beam port excitation. The curve in
Fig.4 is for port2 excitation at 4.6GHz. It is
observable that the highest phase error of the trifocal
occurs at the edge receiving ports. Averagely low
phase errors have been maintained across the array
aperture. Port 4 and Port11 have exhibited the highest
phase error of upto 0.35◦ for the given lens.
Fig.5 S-parameter(S2_2 to S2_7) magnitude vs.
frequency.
Fig.4 Phase distribution of Rotman Lens.
Fig.6 S-parameter(S2_8 to S2_11) magnitude vs.
frequency.
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4. Shruti Vashist, Umesh Dutta, Dr.M.K.Soni / International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue4, July-August 2012, pp.1792-1795
V.CONCLUSIONS
A design approach for the trifocal Rotman
Lens has been presented. A C-band lens prototype
with three beam ports feeding eight-element array has
been simulated. The simulated lens has shown very
good performance in terms of radiation pattern and S-
parameter values, beam port to array port coupling
magnitude and also exhibits low phase errors. Future
work will focus on further reducing the phase error,
return loss and also enhancing the scanning capability
of the Rotman lens.
ACKNOWLEDGMENT
The authors thank Prof. M.K. Soni
(Executive Director-FET, MRIU) for his kind help
and encouragement.
REFERENCES
[1] W. Rotman and R. F. Turner, “Wide angle
microwave lens for line source application”,
IEEE Trans. 1963, pp. 623-630.
[2] D.H.Archer,”Lens-fed multiple beam
arrays”,Microwave J,.PP.171-
95,Sept1984.
[3] J.Kim and F.S.Barns”Dielectric slab Rotman
lens with tapered slot antenna array”,IEEE
prop-Microwave Antenna
Prop.vol.152,no.6,PP.557- 562,Dec 2005.
[4] R.C.Hansen,”Design trades for Rotman
lenses”,IEEE Trans Antennas prop
vol.39,no.4,April 1991,PP.464-472
[5] P. K. Singhal, P.C. Sharma, and R. D.
Gupta, “Rotman lens with equal height of
array and feed contours”, IEEE Transaction
on Antennas and Propagation, vol. 51,
Issue 8, pp. 2048-2056, Aug. 2003.
[6] P. C. Sharma et al., “Two-dimensional field
analysis for CAD of Rotman-type beam-
forming lenses,” Int. J. Microw. Millim.-
Wave CAD Eng., vol. 2, no. 2, pp. 90–97,
1992.
[7] E. O. Rausch, A. F. Peterson, W. Wiebach:
Electronically Scanned Millimeter Wave
Antenna Using A Rotman Lens. Radar 97,
pp 374-379, October 1997, Publication No.
449
[8] Fuchs H.-H.; Nüßler D.: Design of Rotman
lens for Beam-Steering of 94 GHz Antenna
Array, Electronic Letters 27th May 1999
Vol. 35 No.11.
[9] L. Musa and M. S. Smith, “Microstrip port
design and sidewall absorption for printed
Rotman lens”, Microwaves, Antennas and
Propagation, IEE Proceding, vol. 136, Issue
1, pp. 53-58, Feb. 1989.
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