Showing papers on "Patch antenna published in 2005"
TL;DR: In this article, a planar circular disc monopole has been demonstrated to provide an ultra wide 10 dB return loss bandwidth with satisfactory radiation properties, and the parameters which affect the performance of the antenna in terms of its frequency domain characteristics are investigated.
Abstract: This paper presents a study of a novel monopole antenna for ultrawide-band (UWB) applications. Printed on a dielectric substrate and fed by a 50 /spl Omega/ microstrip line, a planar circular disc monopole has been demonstrated to provide an ultra wide 10 dB return loss bandwidth with satisfactory radiation properties. The parameters which affect the performance of the antenna in terms of its frequency domain characteristics are investigated. A good agreement is achieved between the simulation and the experiment. In addition, the time domain performance of the proposed antenna is also evaluated in simulations.
948 citations
TL;DR: In this article, a ray analysis is employed in order to give physical insight into the performance of AMCs and derive design guidelines, and the bandwidth and center frequency of AMC surfaces are investigated using full-wave analysis and the qualitative predictions of the ray model are validated.
Abstract: Planar periodic metallic arrays behave as artificial magnetic conductor (AMC) surfaces when placed on a grounded dielectric substrate and they introduce a zero degrees reflection phase shift to incident waves. In this paper the AMC operation of single-layer arrays without vias is studied using a resonant cavity model and a new application to high-gain printed antennas is presented. A ray analysis is employed in order to give physical insight into the performance of AMCs and derive design guidelines. The bandwidth and center frequency of AMC surfaces are investigated using full-wave analysis and the qualitative predictions of the ray model are validated. Planar AMC surfaces are used for the first time as the ground plane in a high-gain microstrip patch antenna with a partially reflective surface as superstrate. A significant reduction of the antenna profile is achieved. A ray theory approach is employed in order to describe the functioning of the antenna and to predict the existence of quarter wavelength resonant cavities.
907 citations
TL;DR: In this article, a single-fed resonant slot loaded with a series of PIN diode switches constitutes the fundamental structure of the antenna and the antenna tuning is realized by changing its effective electrical length, which is controlled by the bias voltages of the solid state shunt switches along the slot antenna.
Abstract: In this paper the design of a compact, efficient and electronically tunable antenna is presented. A single-fed resonant slot loaded with a series of PIN diode switches constitute the fundamental structure of the antenna. The antenna tuning is realized by changing its effective electrical length, which is controlled by the bias voltages of the solid state shunt switches along the slot antenna. Although the design is based on a resonant configuration, an effective bandwidth of 1.7:1 is obtained through this tuning without requiring a reconfigurable matching network. Four resonant frequencies from 540-890 MHz are selected in this bandwidth and very good matching is achieved for all resonant frequencies. Theoretical and experimental behavior of the antenna parameters is presented and it is demonstrated that the radiation pattern, efficiency and polarization state of the antenna remain essentially unaffected by the frequency tuning
397 citations
Book•
02 Sep 2005
TL;DR: In this article, the authors present the early history of antennas and their development in between the First World War and the Second World War, as well as the post-war development of antennas.
Abstract: Preface. References. Acknowledgments. Acronyms. 1 Radiation. 1.1 The Early History of Electricity and Magnetism. 1.2 James Clerk Maxwell, The Union of Electricity and Magnetism. 1.3 Radiation by Accelerated Charge. 1.4 Reactive and Radiating Electromagnetic Fields. 2 Antennas. 2.1 The Early History of Antennas. 2.2 Antenna Developments During the First World War. 2.3 Antenna Developments in Between the Wars. 2.4 Antenna Developments During the Second World War. 2.5 Post-War Antenna Developments. 3 Antenna Parameters. 3.1 Radiation Pattern. 3.2 Antenna Impedance and Bandwidth. 3.3 Polarisation. 3.4 Antenna Effective Area and Vector Effective Length. 3.5 Radio Equation. 3.6 Radar Equation. 4 The Linear Broadside Array Antenna. 4.1 A Linear Array of Non-Isotropic Point-Source Radiators. 4.2 Plane Waves. 4.3 Received Signal. 4.4 Array Factor. 4.5 Side Lobes and Grating Lobes. 4.6 Amplitude Taper. 5 Design of a 4-Element, Linear, Broadside, Microstrip Patch Array Antenna. 5.1 Introduction. 5.2 Rectangular Microstrip Patch Antenna. 5.3 Split-T Power Divider. 5.4 Transmission and Reflection Coefficients for a Corporate Fed Array Antenna. 5.5 Simulation, Realisation and Measurement. 6 The Linear Endfire Array Antenna. 6.1 Introduction. 6.2 Phase Differences. 6.3 Hansen-Woodyard Endfire Array Antenna. 6.4 Mutual Coupling. 6.5 Yagi-Uda Array Antenna. 7 The Linear Phased Array Antenna. 7.1 Linear Phase Taper. 7.2 Beam Broadening. 7.3 Grating Lobes and Visible Space. 7.4 Means of Phase Shifting. 8 A Frequency Scanned Slotted Waveguide Array Antenna. 8.1 Slotted Waveguide Array Antenna. 8.2 Antenna Design. 8.3 Validation. 9 The Planar Array and Phased Array Antenna. 9.1 Geometry. 9.2 Planar Array Antenna. 9.3 Planar Phased Array Antenna. 10 Special Array Antenna Configurations. 10.1 Conformal Array and Phased Array Antennas. 10.2 Volume Array and Phased Array Antennas. 10.3 Sequential Rotation and Phasing. 10.4 Reactive Loading. 11 Array and Phased Array Antenna Measurement. 11.1 Input Impedance, Self-Coupling and Mutual Coupling. 11.2 Radiation Pattern Measurement. 11.3 Scan Element Pattern. 11.4 Waveguide Simulator. Appendix A: Complex Analysis. A.1 Complex Numbers. A.2 Use of Complex Variables. Appendix B: Vector Analysis. B.1 Notation. B.2 Addition and Subtraction. B.3 Products. B.4 Derivatives. Appendix C: Effective Aperture and Directivity. Appendix D: Transmission Line Theory. D.1 Distributed Parameters. D.2 Guided Waves. D.3 Input Impedance of a Transmission Line. D.4 Terminated Lossless Transmission Lines. D.5 Quarter Wavelength Impedance Transformer. Appendix E: Scattering Matrix. E.1 Normalised Scattering Matrix. E.2 Unnormalised Scattering Matrix. Appendix F: Voltage Incident at a Transmission Line. Appendix :G Cascaded Scattering Matrices. Index.
308 citations
TL;DR: In this paper, a novel ultra-wideband antenna with band elimination characteristic is presented, which has omnidirectional patterns in the E-plane and impedance bandwidth of about 3-18 GHz with VSWR below 2.
Abstract: A novel ultra-wideband antenna with band elimination characteristic is presented, which has omnidirectional patterns in the E-plane and impedance bandwidth of about 3-18 GHz with VSWR below 2. The proposed antenna is fed by microstrip line, and consists of the monopole type with two parasitism-patches rejecting 5.15-5.825 GHz bandlimited by IEEE 802.11a and HIPERLAN/2.
307 citations
TL;DR: This paper presents a novel evolutionary optimization methodology for multiband and wide-band patch antenna designs that combines the particle swarm optimization and the finite-difference time-domain to achieve the optimum antenna satisfying a certain design criterion.
Abstract: This paper presents a novel evolutionary optimization methodology for multiband and wide-band patch antenna designs. The particle swarm optimization (PSO) and the finite-difference time-domain (FDTD) are combined to achieve the optimum antenna satisfying a certain design criterion. The antenna geometric parameters are extracted to be optimized by PSO, and a fitness function is evaluated by FDTD simulations to represent the performance of each candidate design. The optimization process is implemented on parallel clusters to reduce the computational time introduced by full-wave analysis. Two examples are investigated in the paper: first, the design of rectangular patch antennas is presented as a test of the parallel PSO/FDTD algorithm. The optimizer is then applied to design E-shaped patch antennas. It is observed that by using different fitness functions, both dual-frequency and wide-band antennas with desired performance are obtained by the optimization. The optimized E-shaped patch antennas are analyzed, fabricated, and measured to validate the robustness of the algorithm. The measured less than - 18 dB return loss (for dual-frequency antenna) and 30.5% bandwidth (for wide-band antenna) exhibit the prospect of the parallel PSO/FDTD algorithm in practical patch antenna designs.
306 citations
TL;DR: In this article, a defected ground structure (DGS) pattern is proposed to reduce the cross-polarized (XP) radiation of a microstrip patch antenna, which is simple and easy to etch on a commercial microstrip substrate.
Abstract: A defected ground structure (DGS) is proposed to reduce the cross-polarized (XP) radiation of a microstrip patch antenna. The proposed DGS pattern is simple and easy to etch on a commercial microstrip substrate. This will only reduce the XP radiation field without affecting the dominant mode input impedance and co-polarized radiation patterns of a conventional antenna. The new concept has been examined and verified experimentally for a particular DGS pattern employing a circular patch as the radiator. Both simulation and experimental results are presented.
275 citations
TL;DR: In this article, a printed wide-slot antenna fed by a microstrip line with a rotated slot for bandwidth enhancement is proposed and experimentally studied, and the measured impedance bandwidth, defined by 10 dB return loss, can reach an operating bandwidth of 2.2 GHz at operating frequencies around 4.5 GHz.
Abstract: In this paper, a printed wide-slot antenna fed by a microstrip line with a rotated slot for bandwidth enhancement is proposed and experimentally studied. Impedance, radiation, and gain characteristics of this antenna are presented and discussed. From experimental results, the measured impedance bandwidth, defined by 10 dB return loss, can reach an operating bandwidth of 2.2 GHz at operating frequencies around 4.5 GHz, which is about four times that of a conventional microstrip-line-fed printed wide-slot antenna. Also, the antenna gain within the operating band is measured and studied, and a 2-dB gain bandwidth of at least 1 GHz is achieved.
274 citations
TL;DR: In this article, a small microstrip-fed monopole antenna, which consists of a rectangular patch and a truncated ground plane, is presented for ultra wideband application, designed to operate over 3.1 to 11GHz for S/sub 11/<-10dB.
Abstract: A small microstrip-fed monopole antenna, which consists of a rectangular patch and a truncated ground plane, is presented for ultra wideband application. The proposed antenna is designed to operate over 3.1 to 11GHz for S/sub 11/<-10dB. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest.
250 citations
TL;DR: In this paper, a printed planar elliptic patch juxtaposed with the ground pattern in a single substrate providing an ultra-wideband impedance bandwidth is presented, which is achieved by using a new impedance-matching technique of cutting a notch at a ground pattern opposite the microstrip line.
Abstract: A printed planar elliptic patch juxtaposed with the ground pattern in a single substrate providing an ultra-wideband impedance bandwidth is presented. The ultra-wideband property for the proposed antenna is achieved by using a new impedance-matching technique of cutting a notch at the ground pattern opposite the microstrip line. The concavity of the ground pattern serves as an effective means for adjusting the gap between the radiating element and the ground plane. With suitable size of notch chosen, the impedance bandwidth of the proposed antenna can be enhanced. Details of the proposed antenna design and measured results are presented and discussed.
226 citations
TL;DR: In this article, a low-profile metamaterial ring antenna using two MCU cells is proposed using negative-refractive-index (NRI) microstrip transmission lines (TL) designed to incur a zero insertion phase at the antenna design frequency.
Abstract: A compact (/spl lambda//sub 0//11 footprint) and low-profile (/spl lambda//sub 0//28 height) metamaterial ring antenna is proposed using two metamaterial unit cells. Each constituent unit cell consists of negative-refractive-index (NRI) microstrip transmission lines (TL) designed to incur a zero insertion phase at the antenna design frequency. This allows the inductive posts to ground, which act as the main radiating elements, to be fed in phase. Hence, the antenna operates as two closely spaced monopoles that are fed in phase through a compact feed network. An embedded matching network ensures good VSWR performance. The theoretical performance of the antenna is verified by full-wave simulations and experimental data obtained from a fabricated prototype at 1.77 GHz. The antenna offers a 120 MHz -10 dB bandwidth and a measured efficiency exceeding 50%.
TL;DR: In this paper, a half U-slot patch antenna with shorting wall was proposed to reduce the size of the E-shaped patch and showed that the impedance bandwidth, radiation patterns, radiation efficiencies and gains of the half-structures are comparable to the corresponding full structures.
Abstract: The U-slot patch antenna, a single-layer single-patch antenna on a relatively thick substrate (/spl sim/0.08/spl lambda//sub 0/), is a wide-band antenna with an impedance bandwidth in a range of 20%-30%, which is about an order of magnitude larger than that of the regular patch antenna. Recently, it was shown that a half U-slot patch antenna, with half of one of the dimensions of the U-slot patch, maintains similar wide-band behavior. The half-structure was also successfully applied to the U-slot with shorting wall. In this paper, new results on half structures, not previously published, are presented. First, the shorting pin technique is used to reduce the size of the half U-slot patch antenna. By both simulation and experimental studies, it is concluded that the impedance bandwidths, radiation patterns, radiation efficiencies and gains of the half-structures are comparable to the corresponding full structures. Bandwidth of 28.6% and radiation efficiencies exceeding 90% are obtained for the half U-slot patch with shorting pin. Radiation patterns are stable across the matching band. Second, it is shown that a structure obtained from halving the E-shaped patch, which is a derivative of the U-slot patch, also maintains its wide-band behavior.
TL;DR: In this article, a resonator antenna made from a complex artificial surface and a metallic ground plane is described, which is realized using a woodpile electromagnetic bandgap (EBG) material, and the antenna has a frequency dependent reflection plane location.
Abstract: A resonator antenna made from a complex artificial surface and a metallic ground plane is described. The complex surface is realized using a woodpile electromagnetic bandgap (EBG) material, which is shown to have a frequency dependent reflection plane location. A highly directive radiation pattern is created due to the angle-dependent attenuation of the resonator antenna coupling to free space. The antenna has the advantages of low height, low loss, and low sidelobes. It is shown that the directivity can be varied over a fixed range by changing the aperture size of the device, with the maximum directivity determined by both the feed element and EBG material properties. The complete bandgap for the woodpile EBG material is confirmed from a band diagram, and its properties as a complex surface are investigated through transmission calculation and measurement. The design of the antenna is described, and two means of exciting the resonator, a microstrip patch and a double slot, are investigated. Theoretical results for these two antennas are calculated the using finite-difference time-domain and are shown to be in good agreement with measured results.
TL;DR: In this article, a novel and compact ultra-wideband (UWB) microstrip-fed monopole antenna having frequency band notch function is presented, where a narrow slit is used to increase the impedance bandwidth of an antenna.
Abstract: A novel and compact ultra-wideband (UWB) microstrip-fed monopole antenna having frequency band notch function is presented. To increase the impedance bandwidth of an antenna, a narrow slit is used. By inserting a modified inverted U-slot on the proposed antenna, the frequency band notch characteristic is obtained. The designed antenna satisfies the voltage standing wave ratio requirement of less than 2.0 in the frequency band between 3 and 11 GHz while showing the band rejection performance in the frequency band of 5.0 to 5.9 GHz.
TL;DR: In this paper, a dual-band circularly polarized patch antenna dedicated to satellite communications is presented, which is obtained by inserting a small X-band microstrip patch antenna into a large L-band one.
Abstract: This letter presents a dual-band circularly polarized patch antenna dedicated to satellite communications. The dual-band behavior is obtained by inserting a small X-band microstrip patch antenna into a large L-band one. Both patches are printed on the same substrate and fed by electromagnetic coupling through two perpendicular slots etched in their ground planes. These slots are fed by two different 90/spl deg/ microstrip branch-line couplers printed on a stacked lower substrate. A prototype of the antenna was realized with a 1.5-mm-thick upper layer substrate and a 0.758-mm-thick feed layer substrate, both of the same dielectric material with a relative permittivity of /spl epsiv//sub r/=2.22. Simulation and measurement results are presented, showing this compact dual-band antenna achieves the required Meteosat specifications in terms of frequency bandwidth, circular polarization bandwidth, and isolation between the two communication bands.
TL;DR: In this paper, the authors proposed the total active reflection coefficient (TARC) as the square root of the sum of all incident powers at the ports minus radiated power, which is a real number between zero and one.
Abstract: This paper focuses on the multiport characterization of antennas. In particular, special attention is given to the cavity backed annular patch antenna (CABAPA) for multipolarization operations. We will show that the reflection coefficient is not the best representative parameter to determine the frequency response of the multiport antenna and its radiation performance. Therefore, we seek a new generalized parameter that conveys the frequency response of multiport antennas. The total active reflection coefficient (TARC) is introduced as the square root of the sum of all incident powers at the ports minus radiated power, divided by the sum of all incident powers at the ports. The TARC is a function of frequency and is a real number between zero and one. With this definition we can characterize the multiport antenna's frequency bandwidth and radiation performance. A method for calculating the TARC is detailed for different port excitations directly from the scattering matrix of the antenna and independent of the feeding network. First, the CABAPA is analyzed by the method of moments. Next, the corresponding scattering matrix is employed to calculate the TARC for different polarizations. The calculated results, when compared to the measured results, show good agreement. The measured -10 dB TARC bandwidth of the CABAPA is 30% compared with 68% as measured using only the s/sub 11/.
TL;DR: In this paper, a frequency notched ultra wideband (UWB) microstrip slot antenna with a fractal tuning stub is proposed, which achieves good radiation performance over the entire frequency range.
Abstract: A frequency notched ultra-wideband (UWB) microstrip slot antenna with a fractal tuning stub is proposed. The antenna is similar to a conventional microstrip slot antenna, and by introducing a fractal tuning stub, frequency notched function is achieved. The antenna was studied experimentally regarding impedance bandwidth, radiation patterns and gain. The operation bandwidth of the antenna is from 2.66 to 10.76 GHz, in which a frequency notched band from 4.95 to 5.85 GHz was achieved, along with good radiation performance over the entire frequency range.
TL;DR: In this article, a microstrip patch antenna integrated with two-dimensional photonic bandgap (PBG) and one-dimensional defected ground structure (DGS) jointly in ground plane is presented.
Abstract: This letter presents a microstrip patch antenna integrated with two-dimensional photonic bandgap (PBG) and one-dimensional defected ground structure (DGS) jointly in ground plane. It is demonstrated that application of both PBG and DGS eliminates the second and third harmonics and improves the return loss level. Moreover, the combination use of PBG and DGS decreases the occupied area by 70% compared to the conventional PBG patch antenna.
TL;DR: In this paper, a low profile single dipole antenna that can generate circularly polarized (CP) radiation patterns was proposed, which was achieved using a specially designed artificial ground plane: a thin grounded slab loaded with periodic rectangular patches.
Abstract: A low profile single dipole antenna that can generate circularly polarized (CP) radiation patterns is proposed in this paper. The CP patterns and low profile configuration are achieved using a specially designed artificial ground plane: a thin grounded slab loaded with periodic rectangular patches. The artificial ground plane exhibits in-phase reflection coefficients with polarization-dependent feature. The radiation mechanism of the antenna is described, and experimental results verify the antenna concept.
TL;DR: In this article, a wide-band slot antenna element is proposed as a building block for designing single or multi-element wideband or dual-band antenna elements, which shows dual resonant behavior with similar radiation characteristics at both resonant frequencies and therefore can be used as a wide band or dual band element.
Abstract: A wide-band slot antenna element is proposed as a building block for designing single- or multi-element wide-band or dual-band slot antennas. It is shown that a properly designed, off-centered, microstrip-fed, moderately wide slot antenna shows dual resonant behavior with similar radiation characteristics at both resonant frequencies and therefore can be used as a wide-band or dual-band element. This element shows bandwidth values up to 37%, if used in the wide-band mode. When used in the dual-band mode, frequency ratios up to 1.6 with bandwidths larger than 10% at both frequency bands can be achieved without putting any constraints on the impedance matching, cross polarization levels, or radiation patterns of the antenna. The proposed wide-band slot element can also be incorporated in a multi-element antenna topology resulting in a very wide-band antenna with a minimum number of elements. It is also shown that, by using only two of these elements in a parallel feed topology, an antenna with good radiation parameters over a 2.5:1 bandwidth ratio can be obtained.
TL;DR: In this paper, the design and measurements of a wide-band patch antenna with circular polarization were presented. And the proposed antenna possessed a 14dB return loss bandwidth of 35% (from 1.49 to 2.12 GHz), and a 3-dB axial ratio bandwidth of 20.4% with an L-probe and an aperture to feed the patch orthogonally.
Abstract: The design and measurements of a wide-band patch antenna with circular polarization are presented. For the proposed antenna, an L-probe and an aperture are utilized to feed the patch orthogonally. The distance between the patch and the ground plane is 0.1 free-space wavelength at 1.8 GHz. Air is used as the dielectric substrate. A Wilkinson power combiner is connected to the feeds to generate circular polarization. The antenna possessed a 14-dB return loss bandwidth of 35% (from 1.49 to 2.12 GHz), and has a 3-dB axial ratio bandwidth of 20.4% (from 1.67 to 2.05 GHz). The 3-dB axial ratio beamwidth and the boresight axial ratio are 84/spl deg/ and 1.94 dB at 1.8 GHz, respectively.
Patent•
20 Jun 2005
TL;DR: In this paper, a compact antenna for use in a device for controlling the power delivered to an electric load and operable to transmit or receive radio frequency signals at a specified frequency is presented.
Abstract: A compact antenna for use in a device for controlling the power delivered to an electric load and operable to transmit or receive radio frequency signals at a specified frequency is presented. The antenna comprises a first loop of conductive material having a capacitance and an inductance forming a circuit being resonant at the specified frequency, and a second loop of conductive material having two ends adapted to be electrically coupled to an electronic circuit. The second loop is substantially only magnetically coupled to the first loop and is electrically isolated from the first loop. In a first embodiment of the antenna, the first and second loops are formed on respective first and second printed circuit boards, which allow for a small, low-cost antenna that is easy to manufacture and maximizes efficiency. When the antenna is installed in a load control device, such as a dimmer, the first loop of the antenna is mounted on an outer surface of the device. The second loop of the antenna may be at a high-voltage potential such as line voltage.
TL;DR: In this paper, a rectifying antenna (rectenna) designed in a finite ground coplanar waveguide (FG-CPW) circuit is presented, which is based on a new patch antenna and a new band-stop filter, in the form of compact CPW resonant cell (CCRC), located between the antenna and the rectifying diode.
Abstract: This paper presents a rectifying antenna (rectenna) designed in a finite ground coplanar waveguide (FG-CPW) circuit. The new rectenna element is based on a new patch antenna and a new band-stop filter, in the form of compact CPW resonant cell (CCRC), located between the antenna and the rectifying diode. The novel coplanar patch antenna with about 9-dBi gain is proposed for the rectenna. The CCRC is adopted to suppress the second harmonic from radiation. With the use of this band-stop filter, a radio-frequency-to-direct-current (RF-to-dc) conversion efficiency of 68.5% using a 270-/spl Omega/ load resistor is obtained.
TL;DR: In this article, two photonic bandgap (PBG) structures, namely, the defected ground structure (DGS) and the compact microstrip resonant cell (CMRC), are applied to the feed line of microstrip antennas.
Abstract: Microstrip antennas inherently have a high input impedance at resonant frequency. This may not be convenient for some applications. For active integrated antennas, moreover, the radiated power of microstrip antennas needs to be very low at harmonic frequencies. The main goals of this study are impedance matching and harmonic suppression of microstrip antennas. In order to meet these requirements, two one-dimensional (1-D) photonic bandgap (PBG) structures, namely, the defected ground structure (DGS) and the compact microstrip resonant cell (CMRC), are applied to the feed line of microstrip antennas. The characteristic impedance of the microstrip line is controlled by the additional effective inductance of the PBG structure. Without any matching circuits, microstrip antennas can be easily fed by a simple 50 /spl Omega/ microstrip line with a PBG structure at the operating frequency. Additionally, the second harmonic of the proposed antennas is properly suppressed compared to a conventional antenna. Measured results indicate that the two PBG structures are quite effective for harmonic suppression. Therefore, the proposed antennas are suitable for active integrated antennas.
TL;DR: In this article, a broad-band dual-polarized microstrip patch antenna with proximity coupling is presented. But the performance of the proposed antenna is limited by the fact that the antenna can only use one patch.
Abstract: This work presents a novel broad-band dual-polarized microstrip patch antenna, which is fed by proximity coupling. The microstrip line with slotted ground plane is used at two ports to feed the patch antenna. By using only one patch, the prototype antenna yields a bandwidth of 22% and 21.3% at the input port 1 and 2, respectively. The isolation between two input ports is below -34 dB across the bandwidth. Good broadside radiation patterns are observed, and the cross-polar levels are below -21 dB at both E and H planes. Due to its simple structure, it is easy to form arrays by using this antenna as an element.
Patent•
01 Jun 2005
TL;DR: A micro-helix antenna as mentioned in this paper consists of a helically-shaped conductive element disposed on a dielectric core, which can be further compressed into two-and three-dimensional shapes such as spirals, helices and meandering or stochastic patterns.
Abstract: A micro-helix antenna. The antenna comprises a helically-shaped conductive element disposed on a dielectric core. The diameter of the helix formed by the conductive element is very small relative to the wavelength of the antenna, preferably no more than about 1/100th of the wavelength. Having such a small diameter, this micro-helix antenna can be further compressed into two- and three-dimensional shapes, such as spirals, helices and meandering or stochastic patterns. The micro-helix antenna can be created by pressing a fine wire into a helical shape. Alternately, the helical conductor can be formed by a laser ablation process or laying down the helical shape using a direct-write process.
Patent•
29 Aug 2005
TL;DR: In this paper, a co-planar waveguide-based antenna with at least two slot radiators and a transmission line is proposed. But the circuit is also configured to match the impedance of the antenna.
Abstract: Embodiments generally relate to an antenna. The antenna includes at least two slot radiators, where each slot radiator has an input port and a profile that has been defined to optimize the return loss bandwidth of the antenna. The antenna also includes a transmission line and a circuit configured to connect the transmission line and the at least two slot radiators at the respective input ports. The circuit is also configured to match the impedance of the at least two slot radiators and the co-planar waveguide.
TL;DR: In this article, the effect of varying the plate width, feed gap height, and feedline width on the impedance bandwidth was examined, and it was shown that for a fixed groundplane size, that optimization of these parameters can yield an impedance bandwidth ratio of 43:1 without using any broadbanding techniques.
Abstract: This paper describes a printed rectangular-plate monopole fed by microstrip line The effect of varying the plate width, feed-gap height, and feedline width on the impedance bandwidth is examined It is shown that for a fixed ground-plane size, that optimization of these parameters can yield an impedance bandwidth ratio of 43:1, without using any broadbanding techniques © 2005 Wiley Periodicals, Inc Microwave Opt Technol Lett 47: 153–154, 2005; Published online in Wiley InterScience (wwwintersciencewileycom) DOI 101002/mop21109
TL;DR: In this paper, a hybrid-resonator antenna consisting of a microstrip patch resonator coupled to a dielectric resonator is presented. But the performance of the hybrid-reonator is limited.
Abstract: Experimental results are presented for a hybrid-resonator antenna, consisting of a microstrip patch resonator coupled to a dielectric resonator. They demonstrate a 10 dB return-loss bandwidth of 5.14-6.51 GHz (23.5%) and a radiation pattern similar to that of a conventional microstrip patch or dielectric-resonator antenna. The peak cross-polarization level in the upper hemisphere is at least 18 dB below the peak co-polarization level.
03 Jul 2005
TL;DR: In this article, a quasi-static analysis is used to show that a sub-wavelength spherical negative permittivity resonator will have a Q that is a factor of 3/2 above the Chu limit.
Abstract: We consider the use of materials with negative electric permittivity as a building block for constructing effective small antenna elements. In this paper, we show that negative permittivity alone is sufficient for constructing an effective small antenna element. Further, we clarify, here the issue of the radiation Q: a quasi-static analysis is used to show that a sub-wavelength spherical negative permittivity resonator will have a Q that is a factor of 3/2 above the Chu limit. We demonstrate through finite element simulation a practical antenna geometry composed of a coaxial transmission line coupled to a half-sphere of negative permittivity adjacent to a ground plane. The resonator is impedance-matched to the transmission line, resulting in an antenna Q matching that predicted by the quasi-static analysis.