Showing papers on "Coaxial antenna published in 2009"

Dual-Band Wearable Textile Antenna on an EBG Substrate

Abstract: Performance of a dual-band coplanar patch antenna integrated with an electromagnetic band gap substrate is described. The antenna structure is made from common clothing fabrics and operates at the 2.45 and 5 GHz wireless bands. The design of the coplanar antenna, band gap substrate, and their integration is presented. The band gap array consists of just 3 times 3 elements but reduces radiation into the body by over 10 dB and improves the antenna gain by 3 dB. The performance of the antenna under bending conditions and when placed on the human body are presented.

Optical antenna thermal emitters

Abstract: Optical antennas are a critical component in nanophotonics research1 and have been used to enhance nonlinear2,3 and Raman4 cross-sections and to make nanoscale optical probes5. In addition to their ‘receiving’ properties, optical antennas can operate in ‘broadcasting’ mode, and have been used to modify the emission rate6 and direction7 of individual molecules. In these applications the antenna must operate at frequencies given by existing light emitters. Using thermal excitation of optical antennas, we bypass this limitation and realize emitters at infrared frequencies where sources are less readily available. Specifically, we show that the thermal emission from a single SiC whisker antenna is attributable to well-defined, size-tunable Mie resonances8. Furthermore, we derive a fundamental limit on the antenna emittance and argue theoretically that these structures are nearly ideal black-body antennas. Combined with advancing progress in antenna design, these results could lead to optical antenna emitters operating throughout the infrared frequency range. Single SiC whiskers can be made into infrared emitters by thermal excitation. The broadband thermal emission is coupled to the electromagnetic resonances of the whisker, allowing relatively narrowband emission at infrared frequencies. The emission frequency can be tuned by adjusting the size of the whiskers.

UWB Antenna With Single or Dual Band-Notches for Lower WLAN Band and Upper WLAN Band

Abstract: To prevent interference problems due to existing nearby communication systems within an ultrawideband (UWB) operating frequency, the significance of an efficient band-notched design is increased. Here, the band-notches are realized by adding independent controllable strips in terms of the notch frequency and the width of the band-notches to the fork shape of the UWB antenna. The size of the flat type band-notched UWB antenna is etched on 24 times 36 mm2 substrate. Two novel antennas are presented. One antenna is designed for single band-notch with a separated strip to cover the 5.15-5.825 GHz band. The second antenna is designed for dual band-notches using two separated strips to cover the 5.15-5.35 GHz band and 5.725-5.825 GHz band. The simulation and measurement show that the proposed antenna achieves a wide bandwidth from 3 to 12 GHz with the dual band-notches successfully.

A Broadband Dual-Polarized Magneto-Electric Dipole Antenna With Simple Feeds

Abstract: A novel dual-polarized magneto-electric dipole antenna excited by two -shaped strips is presented. The antenna achieves a common impedance bandwidth of 65.9% (SWR < 2) at both input ports. The antenna has excellent performance in isolation, which is more than 36 dB between the two input ports, and the gain of the antenna is about 9.5 dBi. The radiation pattern and bandwidth over the operating frequency band are very stable.

A New Reconfigurable Antenna Design for Cognitive Radio

Abstract: This letter presents a new antenna design suitable for cognitive radio communication. It consists of two structures incorporated together into the same substrate. The first structure is an ultrawideband (UWB) antenna covering the spectrum from 3.1-11 GHz for channel sensing. The second structure is a frequency reconfigurable triangular-shaped patch for establishing communication with another RF device. The antenna reconfigurability is achieved via a rotational motion. A prototype antenna was fabricated and tested in order to validate the suggested method.

A Compact Transmission-Line Metamaterial Antenna With Extended Bandwidth

Abstract: A wideband and compact planar antenna is proposed using a doubly resonant transmission-line metamaterial (TL-MTM) structure. The antenna consists of two TL-MTM arms that resonate at different frequencies. Each arm comprises a microstrip transmission-line loaded with five spiral inductors and is well matched to 50 Omega through an embedded series meandered line. Each arm is designed to work as a single antenna at its own resonant frequency, determined by the loading spiral inductance, where a zero insertion phase occurs. A wideband antenna matching is enabled when these two resonances suitably merge together. A fabricated prototype has dimensions of lambdao/4 times lambdao/7 times lambdao/29, yielding a vertical linear electric field polarization, and provides a 100-MHz bandwidth (-10 dB) with a measured radiation efficiency of 65.8% at 3.30 GHz.

Conformal Ingestible Capsule Antenna: A Novel Chandelier Meandered Design

Abstract: This paper investigates a conformal antenna for the ingestible bio-telemetric capsule system. This system has the potential to provide real-time biological information from within the human body via a radio frequency link. The balanced planar meandered dipole (concept used for antenna miniaturization through space-filling) is discussed along with the offset planar meandered dipole, which facilitates better matching. The conformal chandelier meandered dipole antenna (CCMDA), which is an extension of the offset planar meandered dipole and envelopes the capsule surface, is then investigated. The return loss, input impedance, and radiation pattern characteristics of the CCMDA are discussed in detail at the operating frequency of 1.4 GHz. Additionally, electrical components (specifically the batteries) are modeled inside the capsule to investigate their effects on the conformal antenna performance in free space. The capsule antenna is then inserted into a simple box model (a simplification of the human torso) and a 4-mm precision human-body model (Ansoft) where the detuning effects are observed and discussed. Finally, a circularly polarized receiver antenna design consisting of orthogonal dipoles is suggested which provides polarization diversity and is miniaturized to fit into a personal digital assistant (PDA) for portability of the data telemetric link.

Microstrip and printed antenna design

Abstract: The approach in this book is historical and practical. It covers basic designs in more detail than other microstrip antenna books that tend to skip important electrical properties and implementation aspects of these types of antennas. Examples include: quarter-wave patch, quarter by quarter patch, detailed design method for rectangular circularly polarized patch, the use of the TM11 (linear and broadside CP), TM21 (monopole CP pattern) and TM02 (monopole linear) circular patch modes in designs, dual-band antenna designs which allow for independent dual-band frequencies. Limits on broadband matching are discussed. The appendix contains useful simple matching approaches, design details (gain, matching, sidelobes) of the little-studied omnidirectional microstrip antenna (OMA), limits and properties of common single and dual band Planar Inverted F Antenna (PIFA) antenna designs. The second edition has numerous additions to the earlier text which will make the concepts presented clearer. New cavity model analysis equations of circular polarization bandwidth, axial ratio bandwidth and power fraction bandwidth have been included. The section on omnidirectional microstrip antennas is expanded with further design options and analysis. This is also true of the section on Planar Inverted F (PIFA) antennas. The discovery and description of the fictious resonance mode of a microstrip slot antenna has been added to that section. Appendix A, on microstrip antenna substrates has been expanded to provide more detail on the types of substrate and their composition. This is often neglected in other texts. An appendix on elementary impedance matching techniques has been added as these methods have proven useful in my industrial work.

F-inverted compact antenna for wireless sensor networks and manufacturing method

Abstract: An F-inverted compact antenna for ultra-low volume Wireless Sensor Networks is developed with a volume of 0.024λ×0.06λ×0.076λ, ground plane included, where λ is a resonating frequency of the antenna. The radiation efficiency attained is 48.53% and the peak gain is −1.38 dB. The antenna is easily scaled to higher operating frequencies up to 2500 MHz bands with comparable performance. The antenna successfully transmits and receives signals with tolerable errors. It includes a standard PCB board with dielectric block thereon and helically contoured antenna wound from a copper wire attached to the dielectric block and oriented with the helix axis parallel to the PCB. The antenna demonstrates omnidirectional radiation patterns and is highly integratable with WSN, specifically in Smart Dust sensors. The antenna balances the trade offs between performance and overall size and may be manufactured with the use of milling technique and laser cutters.

An Ultrawideband Diversity Antenna

Abstract: A compact diversity antenna operating at an ultrawideband (UWB) frequency range of 3.1-5 GHz is proposed for use in portable devices. The antenna printed on a printed circuit board (PCB) slab consists of two notched triangular radiating elements with two feeding ports. A ground plane is etched on the reverse side of the PCB. The shape of the ground plane is optimized to improve the isolation between the ports as well as impedance matching. The simulated and measured results show that across the operating bandwidth, the antenna can achieve a broad impedance bandwidth with good performance in terms of isolation of -2 dBi, and efficiency of > 70%. The correlation between the radiation patterns shows consistent diversity performance across the UWB bandwidth. A method to derive thetransfer function of the antenna has been proposed, which can be used to obtain the radiated pulses in the time domain. Furthermore, a parametric study is conducted to provide antenna engineers with useful information for designing and optimizing the antenna.

Novel Planar UWB Monopole Antenna With Triple Band-Notched Characteristics

Abstract: A novel spade-shaped ultrawideband (UWB) printed planar monopole antenna with triple band-notched characteristics is proposed. By employing a hook-shaped defected ground structure (DGS) in each side of the ground plane, embedding an Omega-shaped slot on the radiating patch as well as adding a semi-octagon-shaped resonant ring on the back side of the antenna, triple notched frequency bands are achieved. The proposed antenna has been successfully simulated, fabricated, and measured. Effects of the key parameters on the frequency ranges of the notched bands are also investigated. The measured impedance bandwidth defined by VS WR < 2 of 10.1 GHz (2.9-13 GHz), with the triple notched bands of 3.3-3.9, 5.2-5.35, and 5.8-6.0 GHz, is obtained. Measured group delay and transmission characteristics indicate that the antenna has good transient response. Furthermore, the proposed antenna shows the merit of insensitivity to both finite ground size and fabrication tolerances.

The Analysis of a Reconfigurable Antenna With a Rotating Feed Using Graph Models

Abstract: This letter investigates a new reconfigurable antenna technique based on the rotation of a slot. The surface currents are redistributed for each slot position. The antenna is simulated, fabricated, and tested. The return loss frequency tuning matches the simulated data. The antenna radiation pattern remains unchanged for different slot positions. Finally, the process for automatic rotation and control of the slot is investigated using graph models.

Aperture antenna with shaped dielectric loading

Abstract: An antenna structure and a method of propagating an electromagnetic (EM) wave with the antenna structure. The antenna structure comprises a first aperture antenna element and a second element inside the first element adapted to strengthen the directivity of the wave.

Antenna array with metamaterial lens

Abstract: An antenna array comprises two or more antenna elements. Each of the two or more antenna elements is configured to scan within a field of view. Each of the two or more antenna elements is further configured to transmit or receive a signal. The antenna array also comprises a metamaterial lens coupled to the two or more antenna elements. The metamaterial lens is configured to distribute the signal according to a sinc-like distribution over an aperture of the antenna array.

A Dual-Polarized Magneto-Electric Dipole With Dielectric Loading

Abstract: A plusmn45degdual-polarized magneto-electric dipole loaded with dielectric substrate is presented. This antenna is composed of shorted-circuited patches and planar dipoles and is fed by four Gamma-shaped probes. The height of a prototype antenna operated at 1.9 GHz is only 24 mm (0.15lambdao). A wide impedance bandwidth of 24.9% is achieved. The average gain is about 8.2 dBi and the isolation between the two ports is higher than 29 dB over the operating bandwidth. It is demonstrated that the antenna performance can be improved by adding metallic side walls.

Substrate lens antenna device

Abstract: A device with a substrate lens antenna uses a lens shaped dielectric body (14) located on top of a planar feed antenna. A leaky wave antenna structure is used as feed antenna. The leaky wave antenna structure has a feed input (22) and a first and second wave propagation branch (20) extending from the feed input. The lens shaped dielectric body (14) has a plane surface containing a focal point of the lens shaped dielectric body, the plane surface located adjacent the first plane, with the focal point adjacent the position of the feed input. Preferably the lens shaped dielectric body (14) is spaced from the leaky wave structure at a sufficient distance (42) to remove most of the propagation speed reduction effect of the dielectric on wave propagation along the leaky wave antenna. This helps to suppress undesirable side-lobes.

High-Efficient and High-Gain Superstrate Antenna for 60-GHz Indoor Communication

Abstract: A high-efficient and high-gain aperture coupled patch antenna with superstrate at 60 GHz is studied and presented. It is noted that adding superstrate will result in a significant effect on the antenna performances, and the size of the superstrate is critical for the optimum performance. The maximum measured gain of a single antenna with superstrate is 14.6 dBi, which is higher than that of a classical 2 x 2 array. It is found that the gain measured of a single antenna with superstrate increases nearly 9 dB at 60 GHz over its basic patch antenna. This superstrate antenna gives a very high estimated efficiency of 76%. The 2:1 measured VSWR bandwidth with superstrate is 6.8%. The radiation patterns are found to be broadside all over the frequency band. Also, this letter explains a comparison to another source of parasitic patch superstrate antenna with normal microstrip coupling. It is found that aperture coupling is better for high-gain antenna applications.

Foldable and Stretchable Liquid Metal Planar Inverted Cone Antenna

Abstract: A mechanically flexible planar inverted cone antenna (PICA) for ultrawideband (UWB) applications is presented. It can be both folded and stretched significantly without permanent damage or loss of electrical functionality. The antenna is manufactured with a process in which conductors are realized by injecting room temperature liquid metal alloy into micro-structured channels in an elastic dielectric material. The elastic dielectric material together with the liquid metal enables bending with a very small radius, twisting, and stretching along any direction. Port impedance and radiation characteristics of the non-stretched and stretched antenna are studied in simulations and experiments. The presented antenna has a return loss better than 10 dB within 3-11 GHz and a radiation efficiency of > 70% over 3-10 GHz, also when stretched. Tests verify that stretching up to 40% is possible with maintained electrical performance. The presented antenna is useful for example for body-worn antennas and in applications in harsh environments where mechanical flexibility helps improve durability.

A Dual-Band Circularly Polarized Stub Loaded Microstrip Patch Antenna for GPS Applications

Abstract: A single-feed low-profile and easy to fabricate circularly polarized microstrip patch antenna has been developed for GPS applications. For dual frequency operation, four slots are etched near edges of the patch and a crossed slot etched in the center for generating circular polarization. In order to reducing the frequency ratio of two frequency bands of the antenna, the patch is loaded by four short circuit microstrip stubs. The paper reports several simulation results that confirm the desired characteristics of the antenna. Using stub loading, the frequency ratio of two bands of the antenna can be, even, reduced to 1.1.

A Novel Compact Ultra-Wideband (UWB) Wide Slot Antenna with via Holes

Abstract: A novel compact ultra-wideband (UWB) wide slot antenna with via holes is presented for UWB applications. The antenna is composed of a trapezoidal slot on the ground plane, a rectangular patch in the center of the slot and three via holes connecting the rectangular patch and the microstrip feed-line. The antenna is successfully designed, implemented, and measured. The measured results show that the proposed antenna with compact size of 27:0mm£29:0mm£1:0mm achieves good performance, such as an impedance matching bandwidth of 111.7% (jS11j • i10dB), constant gain and stable radiation patterns over its whole frequency range.

Compact Antenna Array With Port Decoupling for LTE-Standardized Mobile Phones

Abstract: A compact dual-element antenna has been designed at 710 MHz for newly emerging long-term evolution (LTE) personal wireless communication standard applications. The proposed antenna consists of two printed meander-line monopoles with edge-to-edge separation of nearly ?/45. The antenna elements are printed on FR-4 substrate and are located at the top edge of the ground plane measuring 50 × 87 mm2. An LC-components-based branchline hybrid coupler is used to decouple the antenna elements. The prototype antenna has been evaluated through the scattering parameters, radiation patterns, envelope cross correlation, and the channel capacity measurements. Isolation between the ports is better than 35 dB with matched ports at 710 MHz. The antenna offers reasonable multiple-input-multiple-output (MIMO) performances that make it suitable for LTE-standardized mobile phones.

Broadband Microstrip Antenna With Left-Handed Metamaterials

Abstract: A novel type of microstrip antenna is proposed for compact wideband wireless applications. The antenna is composed of six unit cells of left-handed metamaterial (LHM) and a dipole element. The dipole is directly connected to three of six LHM unit cells, which are arranged in a 2 times 3 antenna array form. In this aspect, the proposed antenna is regarded as LHM loaded dipole antenna. The antenna is matched with a stepped impedance transformer and rectangular slot in the truncated ground plane. The coupled LH resonances and simultaneous excitation of different sections of unit cells and dipole result into broad bandwidth. The proposed antenna has a maximum gain of -1 dBi at 2.5 GHz. The measured return loss indicates 63% bandwidth for |S11| < -10 dB over the band of 1.3-2.5 GHz. The overall size of LHM loaded antenna is lambda0/2.87 times lambda0/11.27 times lambda0/315.80 at the center frequency. The radiation of the electrically small LHM unit cells is also demonstrated by the simulated radiation pattern, which is an important concept for the antenna miniaturization.

Compact triple band antenna for WLAN/ WiMAX applications

Abstract: A low profile printed antenna with triple band operation is presented for simultaneous use in wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The antenna consists of a rectangular radiating element fed asymmetrically by a 50 Ω microstrip line and a shaped trapezoidal ground plane. Rectangular horizontal strips are attached to the radiation element to form different current paths which make the antenna resonate in WLAN and WiMAX frequency bands. The antenna operates in dipole configuration outlining overall dimensions of 38×30×0.8 mm3.

Traveling-wave antenna

Abstract: Embodiments of endfire aperture-based traveling-wave antennas are described. For example, an embodiment, including a Vivaldi antenna, may have a director incorporated into the aperture region of the antenna to provide enhanced radiation directivity. The director may be a shaped dielectric that interacts with an electromagnetic field to reduce the divergence of the resultant beam as it exits the antenna. Additional dielectric substrate layers may be stacked on both sides of the antenna in order to balance the dielectric loading between the different conductors. The dielectric substrates may also eliminate contact between the antenna metallization and the lossy environment. Certain disclosed Vivaldi antennas may be used in tissue screening applications.

Integrated Bluetooth and UWB Antenna

Abstract: A small-sized, low-profile, and planar integrated Bluetooth and ultrawideband (UWB) antenna is presented. The antenna exhibits a dual-band operation covering 2400-2484 MHz (Bluetooth) and 3100-10600 MHz (UWB) frequency bands. It is fed by a microstrip line and built on a FR-4 substrate with 42times46 mm2 surface area. The impedance, radiation, phase linearity, and impulse response properties of the antenna are studied both theoretically and experimentally. The calculated and measured results agree well. The antenna shows acceptable gain flatness with stable omnidirectional radiation patterns across the integrated Bluetooth and UWB bands. The average group delay is approximately 0.2 ns across UWB frequencies. The impulse response is very good, with some level of ringing observed.

Enhanced-Gain Microstrip Antenna Using Engineered Magnetic Superstrates

Abstract: This letter presents a novel engineered magnetic superstrate designed to enhance the gain and efficiency of a microstrip patch antenna without any substantial increase in the profile of the whole structure (the antenna with the superstrate). The modified split ring resonator (MSRR) inclusions are used in the design of the engineered magnetic superstrate. Numerical full-wave simulations as well as analytical models are used to analyze the entire radiating system. Considering as an example a microstrip antenna operating within the UMTS band, the broadside gain of the antenna was improved by 3.4 dB and the efficiency was improved by 17% when using the engineered superstrate. The total height of the proposed structure, antenna with superstrate, is lambda0/7, where lambda0 is the free-space wavelength at the resonance frequency of the antenna.

Microstrip Antenna's Gain Enhancement Using Left-Handed Metamaterial Structure

Abstract: The design, simulation and fabrication of a left-handed metamaterial (LHM) structure is presented. The combination of the modifled square rectangular Split Ring Resonator (SRR) and the Capacitance Loaded Strip (CLS) were used to obtain the negative value of permeability, " and the negative permittivity, ". Nicolson- Ross-Wier approach was used to identify the double negative region. A good agreement between simulated and measured results has been achieved. Upon incorporation with a single patch microstrip antenna, the performance of the antenna was improved where the gain of the microstrip antenna was increased up to 4dB, and its bandwidth widens from 2.9% to 4.98%. These improvements are due to the negative refraction characteristics of the LHM structure that acts as a lens when placed in front of the antenna.

Broadband E-h Shaped Microstrip Patch Antenna for Wireless Systems

Abstract: A broadband inverted E-H shaped microstrip patch antenna is proposed and experimentally investigated. The antenna employs novel E-H shaped patch with L-probe feed technique. Prototype of the proposed antenna has been fabricated and measured for electromagnetic analysis including the impedance bandwidth, radiation pattern, and antenna gain. The designed antenna has a dimension of 80mm by 50mm, leading to broad bandwidths covering 1.76GHz to 2.38GHz. Stable radiation patterns across the operating bandwidth are observed. In addition, a parametric study is conducted to facilitate the design and optimization process.

Development of a Novel UWB Vivaldi Antenna Array Using SIW Technology

Abstract: A compact Vivaldi antenna array printed on thick substrate and fed by a Substrate Integrated Waveguides (SIW) structure has been developed. The antenna array utilizes a compact SIW binary divider to significantly minimize the feed structure insertion losses. The low-loss SIW binary divider has a common novel Grounded Coplanar Waveguide (GCPW) feed to provide a wideband transition to the SIW and to sustain a good input match while preventing higher order modes excitation. The antenna array was designed, fabricated, and thoroughly investigated. Detailed simulations of the antenna and its feed, in addition to its relevant measurements, will be presented in this paper.

Design and Development of a Novel 3-D Cubic Antenna for Wireless Sensor Networks (WSNs) and RFID Applications

Abstract: A novel miniaturized 3-D cubic antenna for use in a wireless sensor network (WSN) and RFIDs for environmental sensing is introduced. The antenna produces a truly omnidirectional pattern in both E-plane and H-plane, which allows for non-intermittent communication that is orientation independent. The frequency of operation lies in the UHF RFID band, 902 MHz-928 MHz (centered at 915 MHz). The ultra-compact cubic antenna has dimensions of 3 cm times 3 cm times 3 cm (27 cm3), which features a length dimension of lambda/11 . The cubic shape of the antenna allows for ldquosmartrdquo packaging, as sensor equipment may be easily integrated inside the cube's hollow (or Styrofoam-filled) interior. The prototype fabrication was performed on six (planar) sides on liquid crystal polymer (LCP) substrate, and then folded into the cubic structure. The geometry of the design is inspired by the RFID inductively coupled meander line structures, which are folded around the sides of the cube. Due to the large number of freedom degrees, this antenna concept may be easily reconfigured for many values of impedances and design parameters. Experimental data verify the simulation results.