System Maintenance:
There may be intermittent impact on performance while updates are in progress. We apologize for the inconvenience.
By Topic

Date 18-22 Dec. 2011

Filter Results

Displaying Results 1 - 25 of 55
  • Design of planar monopole antenna fed by asymmetric coplanar strip for WLAN applications

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (622 KB)  

    The design of a compact asymmetric coplanar strip (ACS)-fed dual-band monopole antenna is presented for Wireless Local Area Network. The proposed antenna consists of a rectangular patch loaded with a slit and folded branch line strips at top of the patch. Prototypes of the obtained optimized proposed antenna have been designed, simulated and fabricated. The simulated results validate the proposed antenna design. In addition, a parametric study is conducted to describe the design and optimization process. Stable radiation patterns across the operating bandwidth are observed with good antenna gain over the desired band. The peak gain of the proposed antenna is 5.12 dBi at 6 GHz frequency band. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An ultra-wideband antenna using Hilbert slots with dual band rejection characteristics

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1007 KB)  

    A planar ultrawideband antenna with dual band rejection characteristics is presented in this paper. A rejection band, located at 5.5GHz WLAN band, is created using a Hilbert slot at the centre of the antenna patch and the other notched band located at 8.1GHz satellite communication band is achieved by a pair of Hilbert slots in the ground plane. The slots occupy less space compared to other slotted structures. The proposed antenna yields an impedance bandwidth of 3.1-10.6GHz with VSWR<;2 except at the two notched bands. The antenna gain varies from 2.8 dBi to 6.5 dBi over the band with dips at the rejection band. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Circularly polarized hexagonal microstrip antenna for Bluetooth application

    Publication Year: 2011 , Page(s): 1 - 3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (338 KB)  

    Hexagonal microstrip antenna (HMSA) with a single feed has been proposed for circular polarization. The configuration has been realized by inserting perturbations along two opposite vertices of a diagonal of hexagonal patch. Smith chart, axial ratio, impedance and radiation characteristics are presented and discussed. From the results, it has been observed that the impedance bandwidth, defined by 10 dB return loss, can reach an operating bandwidth of 40 MHz with an average center operating frequency of 2.45 GHz. The axial ratio band width of 10 MHz has been achieved for HMSA. The gain and directivity of studied antenna is also observed with peak gain of about 6 dB and directivity of 7.3 dB respectively. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • UWB antenna with single notch-band for WLAN environment

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (526 KB)  

    A CPW-fed planar antenna for ultra-wideband application is presented. The proposed antenna consists of a beveled rectangular patch and a modified rectangular slotted ground. By cutting a half-wave resonant structure in the radiating patch, a notch band centered at 5.6 GHz for band rejection of IEEE 802.11a wireless local area network (WLAN) is achieved. Experimental results show that the proposed antenna yields an impedance band of 2.8-12 GHz with S11<; -10 dB. The antenna also exhibits stable radiation patterns over the operating band with a reasonable gain. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Compact broadband toploaded planar monopole antenna for low frequency applications

    Publication Year: 2011 , Page(s): 1 - 3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (494 KB)  

    A simple compact microstrip fed broad band antenna for low frequency application is presented. The proposed antenna consisting of a toploaded monopole and a truncated rectangular ground plane has a 2:1 VSWR bandwidth of 52% from 765 MHz-1.3GHz. Bandwidth of the antenna is again improved by incorporating a stub. The modified design provides 2:1 VSWR bandwidth of 97% from 780 MHz-2.25 GHz. This antenna occupies overall dimension of 55 × 30 × 1.6mm3 when printed on a substrate of dielectric constant 4.4. Low cost, compact, wide frequency range for low frequencies are the main advantages of this antenna. Simulations and measurements are presented for the proposed antenna. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Hybrid triangular dielectric resonator antenna (DRA) for WLAN/ISM application

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (551 KB)  

    A triangular DRA is analyzed theoretically. Resonant frequency and internal field components both for even and odd modes are given. In addition, a hybrid triangular DRA using a CPW loop feed is designed for WLAN/ISM application. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Coplanar Waveg uide fed Semielliptical ring UWB antenna

    Publication Year: 2011 , Page(s): 1 - 3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    A novel compact coplanar waveguide fed UWB antenna for short range applications is presented in this paper. The antenna consists of outer semi circular ring, middle semi elliptical ring and inner semi ellipse. The center position of the middle semi ellipse is shifted to form tapering in structure to achieve wide impedance bandwidth. In addition the proposed CPW fed antenna has a small size of 31×15.5 mm2, which makes it an excellent candidate for UWB systems and portable applications. The experimental results shows that the proposed antenna can achieve a return loss 10dB over an ultra wide band. Detailed design and experiments are shown and discussed in this paper. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A CPW fed H-shaped reconfigurable patch antenna

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1137 KB)  

    In this paper a novel frequency reconfigurable CPW fed H-shaped patch antenna is designed. The basic antenna consists of CPW fed two H-shaped patches which operates at 2.48GHz. The basic antenna is suitable for IEEE 802.11 b WLAN (2.4GHz - 2,484GHz) application. The reconfigurability in frequency is obtained by connecting two switches in basic antenna by use of MEMS. By controlling the switches the antenna can be operated at three different frequencies namely 4.39GHz, 12.84GHz and 12.58GHz. The effect of antenna length, size, substrate, thickness, shape has been evaluated and obtained good and acceptable 2D Radiation Pattern in elevation plane, gain, and efficiency. The proposed antenna is described and simulated results are illustrated using Method of Moments based IE3D commercial software. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Metamaterial inspired planar broadband antenna

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB)  

    An electrically small metamaterial-inspired antenna is presented and discussed. The antenna requires a small foot print of λ/5 × λ/10 where λ is the wavelength corresponding to the resonant frequency, when printed on a substrate of dielectric constant 4.4 and thickness 1.6mm. The antenna offers a 2:1 VSWR from 750MHz-1.4GHz which covers CDMA, GSM and ISM bands. A top loaded monopole with a meandered element ground plane constitutes the antenna structure. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A circularly polarized patch antenna and DRA hybrid

    Publication Year: 2011 , Page(s): 1 - 3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (818 KB)  

    This paper investigates the effect of a metamaterial superstrate on a single-feed circularly polarized microstrip patch antenna (SFCP-MPA) using CAD simulations. Simultaneous enhancement on antenna gain (up to 3dB), impedance bandwidth (BWZ) and axial ratio bandwidth (BWAR) are observed as well as multi-frequency operations at 5.125 GHz, 11.34 GHz 12.43GHz. Also it is observed that the invisible first harmonic becomes prominent and visible. Besides, the result also suggest that the Superstrate acts as a DRA (at 12.43GHz). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Quad-ridge horn antenna analysis and design for Radio Astronomy applications

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (652 KB)  

    This paper presents the simulation and analysis of a 1-3GHz dual polarization Quad-ridge Horn Antenna (QRHA) to be used for Radio Astronomy applications. The coaxial to waveguide transition is a crucial design aspect of such an antenna. Using the CST Microwave Studio an air cavity coaxial connector to quad-ridge waveguide transition is designed with S11 better than -10 dB for the entire band. The QRHA is characterized for gain, co & cross polarization and edge taper. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Inscribed gasket fractal circular monopole antenna for UWB application

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1049 KB)  

    This article presents the new ultra-wideband fractal antenna with CPW-fed. The band-rejection operation achieved at the WLAN (5.15-5.85GHz) band by adding defected ground structure (DGS) or slit in the ground plane. Size reduction of the antenna is done by Sierpinski gasket fractal concept which offers 24% thinning and provides excellent bandwidth better than a equivalent circular monopole which is around 12GHz (span from 2.44 to 14.31 GHz) corresponding to 142% impedance bandwidth. The simulated radiation patterns of the antenna are nearly omnidirectional. The proposed antenna is useful for UWB communication. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Synthesis of broadside uniform circular antenna array with low on-surface scanning

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB)  

    Circular Array is one of the most widely used antenna array designs. Its applications include radio direction finding, air and space navigation, underground propagation, radar, sonar, and many other applications. A broadside uniform circular array radiates (receives) not only in the broadside direction, but, in the other directions as well. Such an array has a significant power loss due to along resting plane scanning property. The power radiation or reception pattern of a circular array is dependent on the linear distance between two consecutive elements, the radius, and the number of elements. This paper aims to reduce the along resting plane scanning by adjusting the uniform inter-element distance and the radius of the array. It has been shown analytically that, with proper choice of number of elements, and radius, the on-resting plane scanning of the array can be minimized significantly. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Design and development of W-band pencil beam antenna

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1171 KB)  

    The paper describes the design, development and realization of W-band pencil beam antenna. The proposed antenna is in prime focus reflector configuration consisting of parabolic reflector, conical feed and circular to standard rectangular waveguide (WR-10) transition. The antenna is simulated on GRAPS 9.0 and HFSS EM Simulator using proper boundary conditions. The antenna has narrow beam width (1.4 degree) in both the planes for better angular resolution and low side lobe level (-21 dB) to minimize reception from undesired directions. Measured results are very close to simulated ones. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Modified high frequency omnidirectional antenna for wireless communication

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1069 KB)  

    The need for multi band antenna are to provide simultaneous communication with multiple remote sites. This paper deals the modified Continuous Transverse Stub antenna structures for high frequency wireless Communication. Continuous Transverse Stub antenna Technology Multiband antennas are attractive for many military and commercial applications where it is required to have a single antenna that can be dynamically reconfigured on multiple frequency bands. Such antennas result in considerable savings in size and weight, as well as cost. The proposed antenna design on different Stub radius and lengths. This single antenna can radiate for three different bands. The simulation frequency range can be chosen to the range of 0.1 GHz to 13 GHz. This single antenna not only offers the multiband if provides Omni-directional radiation pattern in the horizontal plane. In this proposed structure offers 99% of total radiation efficiency in the frequency range of nearly 6.4 GHz. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Low current tapered non-uniform linear array synthesis with decreasing sidelobe using NPSO

    Publication Year: 2011 , Page(s): 10 - 14
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (423 KB)  

    Linear Antenna Arrays are the simplest and most popular type of antenna arrays. In this paper, symmetric linear array structures, with and without centre element are assumed. Simulated results reveal, non-uniform location profile and non-uniform excitation distribution can provide low and decreasing sidelobe and narrow first null beamwidth. Low tapering of excitation moreover restricts the directivity to that of a uniform linear broadside array with inter-element spacing as λ/2. Optimal radiation pattern is compared to initial radiation pattern and with that of the uniform array of same length. Improvement has been found for both cases. Optimal non-uniform location and excitation profile is worked out by using Novel Particle Swarm Optimization (NPSO). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Design considerations for a wide scan cavity backed patch antenna for active phased array radar

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1042 KB)  

    This paper presents design & development process of a wide band, wide beam, foam-filled cavity backed patch antenna in C-Band for an active phased array radar. The measured results have shown a return loss <; -10dB, 3-dB beamwidth >; ±60°/ ± 50° in H-/ E-planes, gain between 4.0-4.8 dB and efficiency >; 85% over 18% bandwidth in C-Band. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Influence on side band radiation of uniformly excited TMAA during reduction of SLL of the main beam

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    In addition to the desired frequency, theoretically the Time Modulated Antenna Array (TMAA) radiates signals at the infinite number of different harmonics of the modulation frequency. But the radiation energy at the first few harmonics (called sidebands) is most significant. In this paper, the maximum radiation at first two harmonics of TMAA has been studied for the different values of the side lobe levels (SLLs) of the main beam. The SLLs of the main beam of TMAA are varied from - 15dB to - 50dB with almost - 5dB interval. Global search and optimization algorithm GA is used to get the desired different SLLs. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A novel measurement technique for the alignment of satellite reflectors and feeds: From subsystem to spacecraft and up to final RF testing

    Publication Year: 2011 , Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1206 KB)  

    Balancing spacecraft performance and design against manufacturing capability and configuration control requirements is a fundamental process for any s/c. The balancing process defines the degree of success of a spacecraft program and the mission as a whole. The effort and energy expended defining and refining these issues consumes significant resources from virtually every component of the organization. A key product of this organization is to realize a successful mission wherein the process starts with 3D CAD definition of Mechanical/Optical/RF axes of various components, subassemblies, and major assemblies (Fig 1). After finalization of the 3D CAD definition the same is sent for the fabrication. Once the fabrication is over the critical geometries and parameters of each component are measured using the different contact and non-contact methods before the same is assembled to the spacecraft main assembly. The measurement of the geometries of the subsystem and their relative orientation with respect to the spacecraft main assembly is a challenging task. The alignment of the subsystems with respect to the spacecraft main assembly includes the measurement of six transformation parameters and correcting the deviations between the theoretical CAD model and the measured assembly. The evolving technology of intelligent cameras with automated photogrammetric measurements & use of computational metrology has recently begun to play a prominent role in enhancing the productivity and meet the accuracy requirements. An attempt is made to use the Close range Photogrammetry system with digital intelligent camera and various optical metrology techniques for spacecraft applications right from the fabrication stages of components to the final spacecraft main assembly. This paper provides the details of a case study carried out by performing measurements on the antenna system right from fabrication level to the final integration to the spacecraft. The paper further encompasses - arious error sources during the whole process and provides a brief on recent advancements in the optical and digital metrology techniques as well as their advantages/limitations over the existing conventional metrology techniques used for any typical s/c. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Challenges in multibeam onboard Tracking Antenna charecterization: An ISRO experience

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1465 KB)  

    This paper describes the various challenges experienced and their resolving techniques during RF characterization of multi beam onboard Tracking Antenna in Compact Antenna Test Facility (CATF) of ISRO Satellite centre (ISAC), Bangalore. ISAC-CATF has rich experience of successfully testing 12 spacecrafts covering wide frequency range from L-band to Ka-band with Linear and circular polarization having single and multiple beams. Challenges experienced in RF characterization of onboard Ka-band Tracking antenna and special requirement of zero-g are also discussed. ISRO's experience in transponder characterization of multiple spot beam antenna is shared. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Wideband two-layer rectangular dielectric resonator antenna with (Zr0.8Sn0.2)TiO4-epoxy composite system

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (720 KB)  

    In this study, (Zr0.8Sn0.2)TiO4-Epoxy composite have been synthesized and characterized at X-band frequencies. (Zr0.8Sn0.2)TiO4 and Epoxy are mixed in five different ratios, i.e. 50:50, 60:40, 70:30, 80:20 and 90:10 with small amount of hardner (HY 951). The complex permittivity of the composite is measured at different microwave frequencies in X-band (8.2-12.4 GHz). It is found that the permittivity is reduced by increasing the percentage of epoxy in the composite. The optimized ratio of (Zr0.8Sn0.2)TiO4 and Epoxy composite material have been used in two layer rectangular dielectric resonator antenna using coaxial excitation. The proposed design provides the measured impedance bandwidth of 58.7% (at resonance frequency 8.40 GHz) from 6.45 to 11.38 GHz for reflection coefficient (S11) less than -10dB with absolute gain of 6.7 dB. The radiation patterns are consistent throughout the operational bandwidth. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The input impedance of triangular shape dielectric resonator antenna

    Publication Year: 2011 , Page(s): 1 - 3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (458 KB)  

    The input impedance of an equilateral triangular shape DRA is theoretically investigated. To the best of our knowledge neither any experimental result nor any design guide line is available in open literature to estimate the input impedance of a triangular shape DRA. So, a very simple CAD model based on cavity model analysis is proposed to compute the input impedance of an equilateral triangular shape DRA. The computed values for wide range of DRA parameters are presented in this paper. This structure is validated by employing electromagnetic software. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A monopole type Sierpinski carpet fractal patterned rectangular dielectric resonator antenna for UWB application

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1016 KB)  

    A Sierpinski carpet fractal patterned rectangular dielectric resonator antenna (SCFRDRA) with microstrip line feed arrangement is presented in this paper. A solid rectangular dielectric resonator mounted on a vertical ground plane edge with a micro strip line feed monopole arrangement reduces the total antenna volume as compared with horizontal ground plane. In addition, the antenna weight is also reduced significantly by the removal of materials in Sierpinski carpet fractal pattern. An impedance bandwidth of 87.86 % is obtained with similar radiation pattern throughout the band. The average peak gain within the band is about 4.6 dBi. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dual band metal loaded double-segment cylindrical DRA

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (716 KB)  

    The paper discusses the simulated analysis on two cylindrical dielectric resonator antenna (DRA) with a conducting sheet, loaded with the 50Ω CPW feed. The antenna offers almost 54% miniaturization with dual band at 2.45 GHz and 3.44 GHz applicable at the ISM (WiFi, 802.11b/g) and 3.5GHz band (WiMAX) respectively. The return loss, impedance matching and radiation characteristics of the antenna are studied. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Ultrawideband pawn DRA: Time domain studies

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (503 KB)  

    Pawn DRA, investigated and reported very recently by this group as UWB antenna is reinvestigated in time domain. About 122% impedance bandwidth of operation predicted by frequency domain characteristics has been verified through the time domain figures of merit like transmit-receive response, ringing and group delay. Commercially available mathematical and EM computational tools are used. Computed transmission and reception characteristics corroborate the UWB operation as indicated earlier in frequency domain investigations. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.