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Showing papers on "Slot antenna published in 2008"


Journal ArticleDOI
TL;DR: In this paper, the angular emission of a coupled system is determined by the dominant antenna mode, i.e., the antenna design, regardless of molecular orientation, and the role of the plasmon mode in the emission process.
Abstract: Antennas have been used for more than a century to control the emission and collection of radio and microwave radiation1. An optical analogue is of great interest as it will allow unique control of absorption and emission2, 3 at the nanometre scale4. Despite the intense recent research on optical antennas5, 6, 7, 8, one of the main functions of traditional antennas, the directing of radiation, remains a challenge at optical frequencies. Here we experimentally demonstrate control of the emission direction of individual molecules by reversible coupling to an optical monopole antenna. We show how the angular emission of the coupled system is determined by the dominant antenna mode—that is, the antenna design—regardless of molecular orientation. This result reveals the role of the plasmon mode in the emission process and provides a clear guideline how to exploit the large available library of radio antennas to direct emission in nano-optical microscopy9, 10, spectroscopy11, 12 and light-emitting devices, including single-photon sources

707 citations


Journal ArticleDOI
TL;DR: In this paper, a low profile cavity backed planar slot antenna has been described, which is completely constructed at a single substrate by using substrate integrated waveguide technique and grounded coplanar waveguide.
Abstract: A novel design method of low profile cavity backed planar slot antenna has been described in this paper. The whole antenna including backed cavity and feeding element is completely constructed at a single substrate by using substrate integrated waveguide technique and grounded coplanar waveguide. An example with 1.7% bandwidth has been presented, which has 5.4 dBi gain, 16.1 dB front-to-back ratio and -19 dB maximum cross polarized radiation level with its total thickness less than lambda0/50. The proposed antenna keeps good radiation performance of conventional cavity backed antenna and has advantages of conventional planar antenna including low profile, light weight, easy fabrication with low cost and convenient integration with planar circuit.

402 citations


Book
13 Oct 2008
TL;DR: In this article, the authors present a short history of antennas and their applications in wireless networks. But they do not discuss their application in the context of wireless communication networks, except for the following:
Abstract: Preface. List of Symbols. 1. Introduction. 1.1 A Short History of Antennas. 1.2 Radio Systems and Antennas. 1.3 Necessary Mathematics. 1.3.1 Complex Numbers. 1.3.2 Vectors and Vector Operation. 1.3.3 Coordinates. 1.4 Basics of Electromagnetics. 1.4.1 Electric Field. 1.4.2 Magnetic Field. 1.4.3 Maxwell's Equations. 1.4.4 Boundary Conditions. Summary. References. Problems. 2. Circuit Concepts and Transmission Lines. 2.1 Circuit Concepts. 2.1.1 Lumped and Distributed Element Systems. 2.2 Transmission Line Theory. 2.2.1 Transmission Line Model. 2.2.2 Solutions and Analysis. 2.2.3 Terminated Transmission Line. 2.3 The Smith Chart and Impedance Matching. 2.3.1 The Smith Chart. 2.3.2 Impedance Matching. 2.3.3 Quality Factor and Bandwidth. 2.4 Various Transmission Lines. 2.4.1 Two-wire Transmission Line. 2.4.2 Coaxial Cable. 2.4.3 Microstrip Line. 2.4.4 Stripline. 2.4.5 Co-planar Waveguide (CPW). 2.4.6 Waveguide. 2.5 Connectors. Summary. References. Problems. 3. Field Concepts and Radiowaves. 3.1 Wave Equation and Solutions. 3.1.1 Discussion on Wave Solutions. 3.2 Plane Wave, Intrinsic Impedance and Polarisation. 3.2.1 Plane Wave and Intrinsic Impedance. 3.2.2 Polarisation. 3.3 Radiowave Propagation Mechanisms. 3.3.1 Reflection and Transmission. 3.3.2 Diffraction and Huygens' Principle. 3.3.3 Scattering . 3.4 Radiowave Propagation Characteristics in Media. 3.4.1 Media Classification and Attenuation. 3.5 Radiowave Propagation Models. 3.5.1 Free Space Model. 3.5.2 Two-ray Model/Plane Earth Model. 3.5.3 Multipath Models. 3.6 Comparison of Circuit Concepts and Field Concepts. 3.6.1 Skin Depth. Summary. References. Problems. 4. Antenna Basics 125. 4.1 Antennas to Radiowaves. 4.1.1 Near Field and Far Field. 4.1.2 Antenna Parameters from the Field Point of View. 4.2 Antennas to Transmission Lines. 4.2.1 Antenna Parameters from the Circuit Point of View. Summary. References. Problems. 5. Popular Antennas. 5.1 Wire-Type Antennas. 5.1.1 Dipoles. 5.1.2 Monopoles and Image Theory. 5.1.3 Loops and Duality Principle. 5.1.4 Helical Antennas. 5.1.5 Yagi-Uda Antennas. 5.1.6 Log-periodic Antennas and Frequency Independent Antennas. 5.2 Aperture-Type Antennas. 5.2.1 Fourier Transform and Radiated Field. 5.2.2 Horn Antennas. 5.2.3 Reflector and Lens Antennas. 5.2.4 Slot Antennas and Babinet's Principle. 5.2.5 Microstrip Antennas. 5.3 Antenna arrays. 5.3.1 Basic Concept. 5.3.2 Isotropic Linear Arrays. 5.3.3 Pattern Multiplication Principle. 5.3.4 Element Mutual Coupling. 5.4 Some Practical Considerations. 5.4.1 Transmitting and Receiving Antennas: Reciprocity. 5.4.2 Balun and Impedance Matching. 5.4.3 Antenna Polarisation. 5.4.4 Radomes, Housings and Supporting Structures. Summary. References. Problems. 6. Computer Aided Antenna Design and Analysis. 6.1 Introduction. 6.2 Computational Electromagnetics for Antennas. 6.2.1 Method of Moments (MoM). 6.2.2 Finite Element Method (FEM). 6.2.3 Finite Difference Time Domain (FDTD) Method. 6.2.4 Transmission Line Modelling (TLM) Method. 6.2.5 Comparison of Numerical Methods. 6.2.6 High Frequency Methods. 6.3 Examples of Computer Aided Design and Analysis. 6.3.1 Wire-type Antenna Design and Analysis. 6.3.2 General Antenna Design and Analysis. Summary. References. Problems. 7. Antenna Manufacturing and Measurements. 7.1 Antenna Manufacturing. 7.1.1 Conducting Materials. 7.1.2 Dielectric Materials. 7.1.3 New Materials for Antennas. 7.2 Antenna Measurement Basics. 7.2.1 Scattering Parameters. 7.2.2 Network Analysers. 7.3 Impedance, S11, VSWR, and Return Loss. 7.4 Radiation Pattern Measurements. 7.4.1 Open Area Test Sites (OATS). 7.4.2 Anechoic Chambers. 7.4.3 Compact Antenna Test Ranges (CATR). 7.4.4 Planar and Cylindrical Near Field Chambers. 7.4.5 Spherical Near Field Chambers. 7.5 Gain Measurements. 7.5.1 Comparison with a Standard-gain Horn. 7.5.2 Two-antenna Measurement. 7.5.3 Three-antenna Measurement. 7.6 Miscellaneous Topics. 7.6.1 Efficiency Measurements. 7.6.2 Reverberation Chambers. 7.6.3 Impedance De-embedding Techniques. 7.6.4 Probe Array in Near Field Systems. Summary. References. Problems. 8. Special Topics. 8.1 Electrically Small Antennas. 8.1.1 The Basics and Impedance Bandwidth. Introduction. Slope Parameters. Impedance Bandwidth. Fundamental Limits of Antenna Size, Q and Efficiency. The Limits of Bandwidth Broadening. Discussions and Conclusions. 8.1.2 Antenna size reduction techniques. Top Loading. Matching. Reactive Loading. Dielectric Loading. 8.2 Mobile Antennas, Antenna Diversity and Human Body Effects. 8.2.1 Introduction. 8.2.2 Mobile Antennas. The Cellular Frequency Bands. The "Connectivity" Frequency Bands. Typical Antenna Types. a). Monopoles. b). Helical Antennas. c). Monopole-Like Antennas. d). Planar Inverted F Antennas. The Effect of the PCB. Specific Absorption Rate (SAR). Multipath and Mean Effective Gain. 8.2.3 Antenna Diversity. De-correlation Methods. a). Polarisation Diversity. b). Spatial Diversity. c). Radiation Pattern Diversity. Combining Methods. a). Switched Combining (SWC). b). Selection Combining (SC). c). Equal Gain (EGC). d). Maximal Ratio (MRC). The Effect of Branch Correlation. The Effect of Unequal Branch Powers. Examples of Diversity Antennas. MIMO Antennas. 8.2.4 User Interaction. Introduction. Body Materials. Typical Losses. 8.3 Multi-band and Ultra Wideband Antennas. 8.3.1 Introduction. 8.3.2 Multi-band Antennas. Techniques. a). Higher Order Resonances. b). Resonant Traps. c). Combined Resonant Structures. c). Parasitic Resonators. Examples. 8.3.3 Wideband Antennas. 8.4 RFID Antennas. 8.4.1 Introduction. 8.4.2 Near Field Systems. 8.4.3 Far Field Systems. 8.5 Reconfigurable Antennas. 8.5.1 Introduction. 8.5.2 Switch and Variable Component Technologies. 8.5.3 Resonant Mode Switching/Tuning. 8.5.4 Feed Network Switching/tuning. 8.5.5 Mechanical Reconfiguration. Summary. References. 9. Appendix. 9.1 Industry Standard Coaxial Cables. 9.2 Connectors. 9.3 Selection of Antenna Simulation Software on the Market.

389 citations


Journal ArticleDOI
TL;DR: In this article, two different types of Vivaldi antenna arrays have been designed for UWB see through wall applications, one is a 16 × 1 antipodal antenna covering 8-12 GHz, and the second is an 8× 1 tapered slot antenna for 2-4 GHz frequency range.
Abstract: Two different types of Vivaldi antenna arrays have been designed for UWB see through wall applications. The first is a 16 × 1 antipodal Vivaldi antenna covering 8-12 GHz, and the second is an 8×1 tapered slot antenna for 2-4 GHz frequency range. The array elements are optimized to have a compact size and almost constant gain with frequency. Wilkinson power dividers were designed and fabricated to compose the feed network for the Vivaldi antenna arrays. Measured results of the manufactured antipodal and tapered slot Vivaldi antenna arrays are in excellent agreement with the simulated ones, with a gain of more than 13dBi and 12 dBi respectively within their respective operating band. The first array is geared towards see through dry wall with high resolution, while the second is designed at lower frequencies to allow see through concrete wall applications. Full arrays were manufactured and connected to multi-throw switches and have been utilized as part of synthetic aperture radar.

219 citations


Patent
05 Mar 2008
TL;DR: In this paper, a handheld electronic device may have a housing and a display, and the display may be attached to the housing by a conductive bezel, which is used to modify the perimeter of the slot so as to tune the communications bands.
Abstract: A handheld electronic device may be provided that contains wireless communications circuitry. The handheld electronic device may have a housing and a display. The display may be attached to the housing a conductive bezel. The handheld electronic device may have one or more antennas for supporting wireless communications. A ground plane in the handheld electronic device may serve as ground for one or more of the antennas. The ground plane and bezel may define a opening. A rectangular slot antenna or other suitable slot antenna may be formed from or within the opening. One or more antenna resonating elements may be formed above the slot. An electrical switch that bridges the slot may be used to modify the perimeter of the slot so as to tune the communications bands of the handheld electronic device.

199 citations


Journal ArticleDOI
TL;DR: Fallahi, Kalteh, and Golparvar Roozbahani as discussed by the authors presented a novel band-notched elliptical slot antenna for UWB communication, which is printed on a dielectric substrate of RT/duroid 6006 with relative permittivity (er) of 6.0, thickness of 1.27 mm, and fed by an elliptical open ended microstrip line connected to the 50 Ω main line.
Abstract: This paper presents a novel band-notched elliptical slot antenna for Ultra Wide-Band (UWB) communication, which is printed on a dielectric substrate of RT/duroid 6006 with relative permittivity (er) of 6.0, thickness of 1.27 mm, and fed by an elliptical open ended microstrip line connected to the 50 Ω main line. This antenna is designed to be used in frequency band of 3.1–10.6 GHz. Bandnotched characteristics of antenna to reject the frequency band of 5.15–5.825GHz, which is limited by IEEE 802.11a, is realized by parasitic inverted-U strip attached to the elliptical slot plane. Effects of varying the parameters of parasitic inverted-U strip on performance of proposed antenna have been investigated. The antenna with optimal parameters obtained from parametric study is fabricated and measured. It is observed that the simulation and experimental results have good agreements with each other. 128 Fallahi, Kalteh, and Golparvar Roozbahani

191 citations


Journal ArticleDOI
TL;DR: In this article, a new wideband circularly polarized square slot antenna (CPSSA) with a coplanar waveguide (CPW) feed was proposed, which features two inverted-L grounded strips around two opposite corners of the slot and a widened tuning stub protruded into the slot from the signal strip of the CPW.
Abstract: This paper presents a new wideband circularly polarized square slot antenna (CPSSA) with a coplanar waveguide (CPW) feed. The proposed antenna features two inverted-L grounded strips around two opposite corners of the slot and a widened tuning stub protruded into the slot from the signal strip of the CPW. Broadside circular-polarization (CP) radiation can be easily obtained using a simple design procedure. For the optimized antenna prototype, the measured bandwidth with an axial ratio (AR) of less than 3 dB is larger than 25% and the measured VSWR les 2 impedance bandwidth is as large as 52%.

185 citations


Journal ArticleDOI
TL;DR: In this article, a wideband circularly polarized (CP) L-slot antenna single fed by L-shaped feed line is designed, which truncates one of the corners of the antenna element.
Abstract: A wideband circularly polarized (CP) L-slot antenna single fed by L-shaped feed line is designed. Wideband CP is obtained by truncating one of the corners of the antenna element. This arrangement introduces orthogonal components with quadrature phase difference to excite circularly polarized wave. A bandwidth of 46.5% (2.18-3.5 GHz) is achieved with an dB and dB. Good agreement between measured and computed results is achieved. Moreover, parametric study results are presented.

167 citations


Journal ArticleDOI
TL;DR: In this paper, a dual wideband CPW-fed modified Koch fractal printed slot antenna is proposed for WLAN and WiMAX operations, which exhibits omnidirectional radiation coverage with a gain better than 2.0 dBi.
Abstract: A dual wide-band CPW-fed modified Koch fractal printed slot antenna, suitable for WLAN and WiMAX operations, is proposed in this paper. Here, the operating frequency of a triangular slot antenna is lowered by the Koch iteration technique resulting in a compact antenna. Studies on the impedance and radiation characteristics of the proposed antenna indicate that a modified Koch fractal slot antenna has an impedance bandwidth from 2.38 to 3.95 GHz and 4.95-6.05 GHz covering 2.4/5.2/5.8 GHz WLAN bands and the 2.5/3.5/5.5 GHz WiMAX bands. The antenna exhibits omnidirectional radiation coverage with a gain better than 2.0 dBi in the entire operating band. Empirical relations are deduced and compared with the results.

152 citations


Journal ArticleDOI
TL;DR: In this article, a printed monopole antenna with two steps and a circular slot for ultrawide band (UWB) applications is presented, which has a wide frequency bandwidth of 8.4 GHz.
Abstract: This letter presents a printed monopole antenna with two steps and a circular slot for ultrawide band (UWB) applications. The proposed antenna is fabricated and tested. The proposed antenna has a wide frequency bandwidth of 8.4 GHz starting from 3 GHz up to 11.4 GHz for a return loss (S_11) of less than - 10dB and gain flatness over the frequency range. Measured results show also that the proposed antenna features satisfactory radiation characteristics within the achieved impedance bandwidth. By introducing a simple and proper narrow slot in the radiating element, frequency-notched characteristics can be obtained and a good band-notched performance in the 56 GHz band can be achieved.

149 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the application of EBG radar absorbing material (RAM) to asymmetric ridged waveguide slot antenna array to reduce its backward RCS and measured results show that performance of the antenna array is preserved when EBG RAM is used.
Abstract: This letter investigates the application of EBG radar absorbing material (RAM) to asymmetric ridged waveguide slot antenna array to reduce its backward RCS. The EBG RAM is based on the mushroom-like EBG structure loaded with lumped resistances. A ridged waveguide slot antenna array with 4 times 10 slot elements was designed and built, part of the metal ground plane of the array is replaced with this EBG RAM. The measured results show that performance of the antenna array is preserved when EBG RAM is used. At working frequency the backward RCS of antenna array with EBG RAM has dramatically reduced than that of the common antenna array.

Patent
Robert J. Hill1, Scott A. Myers1, Robert W. Schlub1, Dean F. Darnell1, Zhijun Zhang1 
13 May 2008
TL;DR: In this article, a hybrid antenna is used to provide antenna coverage in a first communications band and the inverted-F antenna portion of the hybrid antenna may be used to cover a second communications band.
Abstract: A portable electronic device is provided that has a hybrid antenna. The hybrid antenna may include a slot antenna structure and an inverted-F antenna structure. The slot antenna portion of the hybrid antenna may be used to provide antenna coverage in a first communications band and the inverted-F antenna portion of the hybrid antenna may be used to provide antenna coverage in a second communications band. The second communications band need not be harmonically related to the first communications band. The electronic device may be formed from two portions. One portion may contain conductive structures that define the shape of the antenna slot. One or more dielectric-filled gaps in the slot may be bridged using conductive structures on another portion of the electronic device. A conductive trim member may be inserted into an antenna slot to trim the resonant frequency of the slot antenna portion of the hybrid antenna.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a compact dual-band slot antenna for 2.4/5 GHz WLAN applications, which is composed of a square ring slot and a circular ring slot.
Abstract: This paper presents a compact dual-band slot antenna for 2.4/5 GHz WLAN applications. The radiating elements of the proposed antenna are composed of a square ring slot and a circular ring slot, operating at 2.4 GHz and 5 GHz bands respectively. The antenna size is very compact (40 mm × 40 mm × 1 mm), and can be integrated easily with other RF front-end circuits. It is demonstrated that the proposed antenna can completely cover the required bandwidths of IEEE 802.11b/g (2.4–2.485 GHz) and IEEE 802.11a (5.15–5.825 GHz) with satisfactory radiation characteristics. Good agreement is achieved between the simulated and measured results.

Journal ArticleDOI
TL;DR: A comprehensive parametric study has been carried out to understand the effects of various dimensional parameters and to optimize the performance of the designed antenna, which exhibits stable far-field radiation characteristics in the entire operating bandwidth, relatively high gain, and low cross polarization.
Abstract: The design and analysis of a novel printed wide-slot antenna, fed by a microstrip line, for wideband communication systems is presented. Detailed simulation and experimental investigations are conducted to understand its behavior and optimize for broadband operation. The designed antenna has a wide operating bandwidth of over 120% (2.8-11.4 GHz) for S11 <-10 dB. In addition to being small in size, the antenna exhibits stable far-field radiation characteristics in the entire operating bandwidth, relatively high gain, and low cross polarization. By properly choosing the suitable slot shape, selecting similar feed shape and tuning their dimensions, the design with very wide operating bandwidth, relatively small size and improved radiation pattern is obtained. A comprehensive parametric study has been carried out to understand the effects of various dimensional parameters and to optimize the performance of the designed antenna. Results show that the impedance matching of this kind of antenna is greatly affected by the feed-slot combination and feed gap width, with the slot shape being a main contributor of the radiation characteristics. The simulated and measured Results for return loss, far-field E and H-plane radiation patterns, and gain of designed antenna are presented and discussed.

Journal ArticleDOI
TL;DR: In this article, a dual-frequency dual circularly-polarized slot antenna is proposed, which is achieved using a single-layer microstrip-fed configuration coupled to a modified annular-slot antenna.
Abstract: A new design of a dual-frequency dual circularly-polarized slot antenna is presented. The dual-frequency is achieved using a single-layer microstrip-fed configuration coupled to a modified annular-slot antenna. The dual sense circular-polarization is obtained by four unequal linear slots which augment the annular slot. Experimental results show the proposed antenna has good circular polarization characteristics for both right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP). The 10 dB return loss impedance bandwidths for the lower (RHCP) and higher (LHCP) bands are 26.7% and 11.3%, respectively. The 3 dB axial-ratio bandwidths are 6.1% and 6.0% with respect to 1.5 GHz (RHCP) and 2.6 GHz (LHCP), respectively.

Patent
05 Sep 2008
TL;DR: In this paper, a substrate integrated waveguide (SIW) slot full-array antenna is fabricated employing printed circuit board technology, which greatly reduces the overall height and physical steering requirements of a mobile antenna when compared to a conventional metallic waveguide slot array antenna.
Abstract: A substrate integrated waveguide (SIW) slot full-array antenna fabricated employing printed circuit board technology. The SIW slot full-array antenna using either single or multi-layer structures greatly reduces the overall height and physical steering requirements of a mobile antenna when compared to a conventional metallic waveguide slot array antenna. The SIW slot full-array antenna is fabricated using a low-loss dielectric substrate with top and bottom metal plating. An array of radiating cross-slots is etched in to the top plating to produce circular polarization at a selected tilt-angle. Lines of spaced-apart, metal-lined vias form the sidewalls of the waveguides and feeding network. In multi-layer structures, the adjoining layers are coupled by transverse slots at the interface of the two layers.

Journal ArticleDOI
TL;DR: In this paper, a dual-broadband design of the open slot antenna with small size is obtained for WLAN applications in the 2.4 GHz (2400-2484 MHz) and 5 GHz (5150-5825 MHz) bands.
Abstract: The band-rejected designs of the printed open slot antenna for wireless local area network (WLAN)/worldwide interoperability for microwave access (WiMAX) applications are investigated. First, the broadband characteristic (2.3 ~ 6uarr GHz) of open slot antenna design with small size is implemented and measured. Then, inserted a single strip on the broadband antenna is studied and investigated. By inserting a strip on the printed open slot of the broadband antenna, to reject frequency from 3.56 to 4.58 GHz, a dual-broadband design of the open slot antenna with small size is obtained for WLAN applications in the 2.4 GHz (2400-2484 MHz) and 5 GHz (5150-5825 MHz) bands. Furthermore, by inserting two strips of different length on the open slot antenna, a three-band antenna is achieved. By adjusting the dimension of two strips on open slot antenna, a three operating modal frequencies at 2.37 ~ 2.72,3.31 ~ 3.78, and 4.5 ~ 5.97 GHz for WiMAX application have been obtained. Detailed design steps and experimental results for the designs are studied and investigated in this paper.

Journal ArticleDOI
TL;DR: In this paper, two kinds of band-notched ultra wide-band slot antennas are proposed and the parameters which affect the performance of the antennas in terms of its frequency domain characteristics are investigated.
Abstract: Two kinds of band-notched ultra wide-band slot antennas are proposed. Printed on a dielectric substrate of FR4with relative permittivity of 4.4 and fed by a 50 Ω microstrip line, the proposed antennas introduce semicircular annular strips to reject the frequency band (5.15-5.85 GHz) limited by IEEE802.11a. The parameters which affect the performance of the antennas in terms of its frequency domain characteristics are investigated in this paper.

Book ChapterDOI
01 Oct 2008
TL;DR: In this article, a low profile surface wave antenna (SWA) is proposed to achieve a monopole-like radiation pattern with a null in the broadside direction, which is more attractive than a traditional monopole antenna that is a quarterwavelength high.
Abstract: The concept of surface wave antennas (SWA) was initiated in the 1950s [1–2] and numerous theoretical and experimental investigations have been reported in the literature [3–10]. To support the propagation of surface waves, a commonly used structure in SWA designs is a corrugated metal surface. However, the corrugated structure is thick, heavy, and costly, which may limit the applications of surface wave antennas in wireless communication systems. In this chapter, novel surface wave antennas are presented. Compared to traditional SWA designs, surface waves are now guided along a thin grounded slab loaded with periodic patches, resulting in a low profile conformal geometry. In contrast to the previous wire-EBG antennas or patch antennas that radiate to the broadside direction, the proposed SWA achieve a monopole-like radiation pattern with a null in the broadside direction. The low profile SWA is more attractive than a traditional monopole antenna that is a quarter-wavelength high. A grounded slab loaded with periodic patches Comparison of two artificial ground planes We start with analyzing a complex artificial ground plane, which will be subsequently used in surface wave antenna designs. Figure 7.1 shows two artificial surfaces: a mushroom-like EBG surface and a grounded dielectric slab loaded with periodic patches. In the latter structure vertical vias are removed, which results in different surface wave properties in the two ground planes. To compare the electromagnetic properties of these two structures, the finite difference time domain (FDTD) method is used to simulate their performance [11–12].

Journal ArticleDOI
TL;DR: In this article, a planar inverted cone antenna (PICA) based wide-slot antenna is proposed for ultrawideband (UWB) with a double-layer substrate.
Abstract: A novel ultrawideband (UWB) printed wide-slot antenna is presented. The design is based on the planar inverted cone antenna (PICA), introduced by Suh. The presented design comprises PICA-like structures, etched from a double-layer substrate. Compared to the original PICA, it is lower in profile, more compact and maintains comparable performance. A prototype integrated in a printed circuit board and fed by a microstrip line is fabricated and measured. The results show that the proposed antenna provides at least 13:1 impedance bandwidth at 10-dB return loss.

Patent
09 Jun 2008
TL;DR: A log-periodic antenna is a type of antenna having a layer of dielectric media interposed between a microstrip and a slot log periodic portion as mentioned in this paper, where an array of two or more logperiodic antennas that may be placed about vehicles, such as air vehicles, or mounted on stationary structures such as communication towers.
Abstract: A log-periodic antenna having a layer of dielectric media interposed between a microstrip log-periodic portion and a slot log-periodic portion where an array of two or more log-periodic antennas that may be placed about vehicles, such as air vehicles, or mounted on stationary structures, such as communication towers.

Journal ArticleDOI
TL;DR: The dual V-type linearly tapered slot antenna (DVLTSA) as mentioned in this paper is a modified version of the Vivaldi radiator and is first introduced here. But it is not suitable for a monopulse antenna owing to its special configuration.
Abstract: The dual V-type linearly tapered slot antenna (DVLTSA) is a modified version of the Vivaldi radiator and is first introduced here. It is much more compact and keeps the advantages of the conventional tapered slot antenna (TSA). Furthermore, this antenna is suitable for a monopulse antenna owing to its special configuration. Both the sum and difference beams can be generated only employing a single DVLTSA respectively through the multimode substrate integrated waveguide (SIW) feeding technology. With detailed theoretical analysis, a prototype of the monopulse antenna proposed at the center frequency of 36 GHz was integrated on a single substrate using the normal PCB process. Measured gain of the sum beam is 10.6 dBi, while the zero depth of the difference beam is lower than -35 dB. It also has good cross-polar characteristics and can be applied over a broad bandwidth as well.

Journal ArticleDOI
TL;DR: In this article, a broadband circularly-polarized (CP) square slot antenna fed by an asymmetric coplanar waveguide (CPW) from a corner of the slot is proposed.
Abstract: A novel broadband circularly-polarised (CP) square slot antenna fed by an asymmetric coplanar waveguide (CPW) from a corner of the slot is proposed. A CP bandwidth larger than 10% can be attained simply by using an inverted-L tuning stub protruded from the signal line of the CPW. With an additional pair of grounded strips implanted in the slot, the 3 dB axial-ratio bandwidth and the VSWR les 2 impedance bandwidth can be greatly raised to be as high as 30 and 35%, respectively.

Patent
03 Jan 2008
TL;DR: In this article, the authors considered a hybrid antenna that contains both a slot antenna structure formed from the slot and a planar inverted-F antenna structure constructed from the planar resonating element and the ground element.
Abstract: Handheld electronic devices are provided that contain wireless communications circuitry having at least one antenna. The antenna may have a planar ground element and a planar resonating element. The planar ground element may have a rectangular shape that matches a rectangular housing shape for a handheld electronic device. A dielectric-filled slot may be formed in one end of the planar ground element. The planar resonating element may be located above the slot. The antenna may be a hybrid antenna that contains both a slot antenna structure formed from the slot and a planar inverted-F structure formed from the planar resonating element and the planar ground element. The antenna may be fed using a single transmission line or two transmission lines. With two transmission lines, one transmission line may be associated with the slot antenna structure and one transmission line may be associated with the planar inverted-F antenna structure.

Journal ArticleDOI
TL;DR: A compact switched-beam antenna with eight directional patterns and many nearly omnidirectional patterns in the azimuth plane can be a promising solution for digital home applications to overcome multipath problems and increase the transmission data rate.
Abstract: In this paper a compact switched-beam antenna is proposed. The antenna is composed of a four-element antenna array based on L-shaped quarter-wavelength slot antenna elements. Such an antenna element is a planar structure and presents a directional radiation pattern in the azimuth plane. Its maximum radiation direction is toward near the direction of the open end of the slot. As a result, the open ends of the four slot antennas are arranged toward 0, pi/2, pi, and 3pi/2 , respectively. The statuses of these antennas are controlled by some diodes. Consequently, by carefully controlling the diodes, an antenna with several switchable patterns can be achieved. To prove the concept, a 2.4-2.5 GHz switched-beam antenna for WLAN applications is designed and implemented. Its size is 52 mm in square. The antenna possesses eight directional patterns and many nearly omnidirectional patterns in the azimuth plane. The experiment results fully demonstrate the performance of the proposed design. The envelope correlations and the characteristics of the designed antenna are also discussed. Due to the compact size and low manufacture cost, such a design can be a promising solution for digital home applications to overcome multipath problems and increase the transmission data rate.

Journal ArticleDOI
Yuandan Dong1, Wei Hong1, Zhen Qi Kuai1, Chen Yu1, Yan Zhang1, Jian Yi Zhou1, Jixin Chen1 
TL;DR: In this article, a planar ultrawideband (UWB) antenna with multiple band-notched characteristics based on half mode substrate integrated waveguide technology is presented, which can generate multiple stopbands by proper arrangement.
Abstract: Investigations on planar ultrawideband (UWB) antenna with multiple band-notched characteristics based on half mode substrate integrated waveguide technology are presented. The proposed antenna consists of a planar UWB monopole antenna and a half mode substrate integrated waveguide cavity which can generate multiple stopbands by proper arrangement. Planar antennas with dual, triple and quadruple notched bands are designed and implemented. The notched frequencies and their bandwidths can be adjusted according to specification by altering the cavity and feed line independently. These antennas are fabricated with two-layer printed circuit board (PCB) process. Sharp and high band rejection, narrow frequency notches are achieved, which are in good agreement with the simulated results. This technique is suitable for designing wideband antenna with multiple frequency notches or for creating multiband antennas.

Journal ArticleDOI
TL;DR: In this article, a broadband circularly-polarized (CP) slot antenna is described and its key parameters are investigated to show how to couple the two CP modes and achieve impedance matching, and the effects of the distance between the parasitic patch and wide slot on the CP bandwidth and antenna gain are also discussed.
Abstract: A design is described of a broadband circularly-polarized (CP) slot antenna. A conventional annular-ring slot antenna is first analyzed, and it is found that two adjacent CP modes can be simultaneously excited through the proximity coupling of an L-shaped feed line. By tuning the dimensions of this L-shaped feed line, the two CP modes can be coupled together and a broad CP bandwidth is thus formed. The design method is also valid when the inner circular patch of the annular-ring slot antenna is vertically raised from the ground plane. In this case, the original band-limited ring slot antenna is converted into a wide-band structure that is composed of a circular wide slot and a parasitic patch, and consequently the CP bandwidth is further enhanced. For the patch-loaded wide slot antenna, its key parameters are investigated to show how to couple the two CP modes and achieve impedance matching. The effects of the distance between the parasitic patch and wide slot on the CP bandwidth and antenna gain are also presented and discussed in details.

Journal ArticleDOI
TL;DR: Anovel ultra-wideband bow-tie slot antenna fed by CPW is proposed in this paper, which has been demonstrated to provide an UWB with return loss less than −10 dB from 9.5 GHz to 22.4 GHz.
Abstract: Anovel ultra-wideband bow-tie slot antenna fed by CPW is proposed in this paper. This antenna has been demonstrated to provide an UWB with return loss less than −10 dB from 9.5 GHz to 22.4 GHz. The bandwidth is up to 80%, which is quite better than the traditional bow-tie slot antenna. Simulated and measured results are presented.

Journal ArticleDOI
TL;DR: In this paper, an ultra wideband (UWB) monopole antenna with a band-notch characteristic is presented, which needs only two parameters to tune the notch frequency.
Abstract: An ultra-wideband (UWB) monopole antenna with a band-notch characteristic is presented which needs only two parameters to tune the notch frequency. The proposed monopole antenna is embedded with a crescent slot, whose length is determined by parametric study. By adjusting the slot length, the notched frequency band within the antenna's operating bandwidth can be easily controlled. Also, the time-domain behaviours are discussed and the fidelity factor is calculated.

Journal ArticleDOI
TL;DR: In this paper, a printed slot antenna using the printed structure in order to improve its dual-band and compact size performances is presented. But the performance of the antenna is limited to the 2.4 GHz WLAN band.
Abstract: This paper presents a printed slot antenna using the printed structure in order to improve its dual-band and compact size performances. The printed slot structure is used as additional resonators to produce dual-band operation for covering the worldwide interoperability for microwave access (WiMAX) and the 5.2-GHz wireless local area network (WLAN) bands. In order to achieve wideband and multi-band operation, the slot antennas with a slotted structure and an inverted-L slot structure for covering the wireless communication operations are developed. Finally, we propose a novel and compact printed slot antenna with mixing slot structures to obtain and cover for the 2.4-GHz WLAN (2.4–2.484 GHz), the WiMAX (IEEE 802.16e in the Taiwan: 2.5–2.69/3.5–3.65 GHz), and the 5GHz WLAN (5.15–5.35/5.725–5.825 GHz). Several properties of the proposed antennas for dualand multi-band characterize radiation performances such as impedance bandwidth and radiation pattern. Measured gain has been confirmed experimentally for the multi-band wireless communication systems.