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Showing papers on "Dipole antenna published in 2003"


Journal ArticleDOI
TL;DR: In this paper, a dual-band double-T monopole antenna is proposed for WLAN operation in the 2.4 and 5.2 GHz bands, which consists of two stacked T-shaped monopoles of different sizes, which generate two separate resonant modes for the desired dualband operation.
Abstract: A novel and simple printed dual-band double-T monopole antenna is proposed. The antenna comprises two stacked T-shaped monopoles of different sizes, which generate two separate resonant modes for the desired dual-band operation. The proposed antenna has a low profile and can easily be fed by using a 50 /spl Omega/ microstrip line. Prototypes of the proposed antenna designed for WLAN operations in the 2.4 and 5.2 GHz bands have been constructed and tested. Good radiation characteristics of the proposed antenna have been obtained. Effects of varying the monopole dimensions and the ground-plane size on the antenna performance have also been studied.

596 citations


Journal ArticleDOI
TL;DR: An introduction to the topic of circular polarization is necessary to promote an understanding of the propagation aspects of modern communications system design and a simple laboratory-based project is described that requires the design, fabrication, and measurement of a crossed dipole antenna.
Abstract: Many modern satellite and terrestrial point-to-point communications systems use circular polarization (CP) wave propagation in order to maximize the polarization efficiency component of the link budget. Therefore, in an undergraduate electromagnetics syllabus, an introduction to the topic of circular polarization is necessary to promote an understanding of the propagation aspects of modern communications system design. Students new to the antennas and propagation discipline often have difficulty in grasping the concept of CP; therefore, in this paper, the essential aspects of this topic are reinforced by a tutorial description of CP in terms of wave propagation, antenna properties, and measurement techniques. A simple laboratory-based project is described that requires the design, fabrication, and measurement of a crossed dipole antenna. The measured input impedance and radiation patterns are correlated with theory to highlight the conditions necessary to support CP wave propagation. By combining basic electromagnetic concepts with a series of simple intuitive laboratory experiments, the students can more easily visualize, and hence understand, CP wave propagation and its use in communications systems design.

451 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of surrounding an electrically small dipole antenna with a shell of double negative (DNG) material has been investigated both analytically and numerically, and it is shown that a properly designed dipole-DNG shell combination increases the real power radiated by more than an order of magnitude over the corresponding free space case.
Abstract: The effect of surrounding an electrically small dipole antenna with a shell of double negative (DNG) material (/spl epsiv//sub r/<0 and /spl mu//sub r/<0) has been investigated both analytically and numerically. The problem of an infinitesimal electric dipole embedded in a homogeneous DNG medium is treated; its analytical solution shows that this electrically small antenna acts inductively rather than capacitively as it would in free space. It is then shown that a properly designed dipole-DNG shell combination increases the real power radiated by more than an order of magnitude over the corresponding free space case. The reactance of the antenna is shown to have a corresponding decrease. Analysis of the reactive power within this dipole-DNG shell system indicates that the DNG shell acts as a natural matching network for the dipole. An equivalent circuit model is introduced that confirms this explanation. Several cases are presented to illustrate these results. The difficult problem of interpreting the energy stored in this dipole-DNG shell system when the DNG medium is frequency independent and, hence, of calculating the radiation Q is discussed from several points of view.

431 citations


Journal ArticleDOI
TL;DR: In this paper, the authors developed principle design procedures for a single-layer coaxially fed rectangular microstrip patch antenna through examination of the structure's multiple resonant frequencies as well as the radiation and impedance properties of different antenna geometries.
Abstract: A wide operating bandwidth for a single-layer coaxially fed rectangular microstrip patch antenna can be obtained by cutting a U-shaped slot on the patch. This antenna structure has recently been found experimentally to provide impedance bandwidths of 10%-40%, even with nonair substrates. However, design rules for this antenna have not yet been presented. This paper develops principle design procedures through examination of the structure's multiple resonant frequencies as well as the radiation and impedance properties of different antenna geometries. The approximate design rules are derived by analysis of former experiments, method of moments (MoM) simulations, and measurement results. Simulations and measurements of several antennas designed using these new rules are presented and directions for further study are discussed.

328 citations


Patent
03 Feb 2003
TL;DR: An antenna array that uses at least two passive antennas and one active antenna disposed above a ground plane but electrically isolated from the ground plane, and a respective resonant strip positioned beneath each passive antenna.
Abstract: An antenna array that uses at least two passive antennas and one active antenna disposed above a ground plane, but electrically isolated from the ground plane, and a respective resonant strip positioned beneath each passive antenna. The passive antenna elements are positioned about the active element, and each of the at least two passive antenna elements is individually set to a reflective or a transmissive mode to change the characteristics of an input/output beam pattern of the antenna apparatus.

306 citations


Journal ArticleDOI
TL;DR: New meander line antennas with improved gain are proposed as low-profile self-resonant tags for application in passive radio frequency identification.
Abstract: New meander line antennas with improved gain are proposed as low-profile self-resonant tags for application in passive radio frequency identification. Antenna shape and size is optimized by genetic algorithm, taking conductor losses into account. Examples are presented for application at 869 MHz with antennas of different materials and sizes.

279 citations


Patent
18 Apr 2003
TL;DR: In this paper, a closed loop wireless communication of signals using an adaptive transmit antenna array is considered, in which multiple copies of signals to be transmitted by the transmitter are produced with delays and weights that are functions of the multi-path transmission channel characteristics from the transmitter to the receiver.
Abstract: Closed loop wireless communication of signals using an adaptive transmit antenna array, in which multiple copies of signals to be transmitted by the transmit antenna array are produced with delays and weights that are functions of the multi-path transmission channel characteristics from the transmit antenna array to a receive antenna array of a receiver and are combined before transmission by the transmit antenna array. The delays and weights of the transmit copies for each transmit antenna element are functions of the respective multi-path transmission channel characteristics from that transmit antenna element to the receive antenna array such that the multi-path signal components propagated to each receiver element are received with distinguishable delays according to the propagation path. The receiver combines the received signal components from each receive antenna element with delays and weights that are respective functions of the multi-path transmission channels.

265 citations


Journal ArticleDOI
Abstract: A novel planar monopole antenna is proposed. It has a very low profile (antenna height less than 0.04 times the operating wavelength in free space) and is capable of multiband operation. The proposed antenna has a planar rectangular radiating patch in which a folded slit is inserted at the patch's bottom edge. The folded slit separates the rectangular patch into two subpatches, one smaller inner subpatch encircled by the larger outer one. The proposed antenna is then operated with the inner subpatch resonating as a quarter-wavelength structure and the outer one resonating as both a quarter-wavelength and a half-wavelength structure. The proposed antenna, 12 mm high and 30 mm wide, has been constructed, and the obtained bandwidths cover the global system for mobile communication (890-960 MHz), digital communication system (1710-1880 MHz), personal communication system (1850-1990 MHz), and universal mobile telecommunication system (1920-2170 MHz) bands. Details of the proposed design and obtained experimental results are presented and discussed.

251 citations


Journal ArticleDOI
TL;DR: In this paper, a square planar monopole antenna with two feed points and a bevelled variant is designed to improve pattern and impedance bandwidth, and these antennas exhibit an excellent performance compared to existing planar mono-mono antennas.
Abstract: Planar monopole antennas with multiple feed points are proposed to improve pattern and impedance bandwidth. A square planar monopole antenna including two feed points and a bevelled variant are designed. These antennas exhibit an excellent performance compared to existing planar monopoles.

246 citations


Journal ArticleDOI
Wen Geyi1
TL;DR: In this article, a method is presented to calculate the quality factor (Q) of small antennas, which is based on the understanding that for a small antenna the total energy in Poynting theorem can be easily separated into the stored energy and radiated energy by using the low frequency expansions.
Abstract: A method is presented to calculate the quality factor (Q) of small antennas, which is based on the understanding that for a small antenna the total energy in Poynting theorem can be easily separated into the stored energy and radiated energy by using the low frequency expansions. The Poynting theorem in frequency domain provides an equation on the stored electric and magnetic energy while the Poynting theorem in time domain can be used as another independent equation for the stored electric and magnetic energy. By solving these equations the stored electric and magnetic energy can be obtained, thus, making the Q calculation possible.

240 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a novel pattern and frequency reconfigurable microstrip antenna that uses switched connections, which provides a re-directed radiation pattern while maintaining a common operating impedance bandwidth with the baseline configuration.
Abstract: This paper presents a novel pattern and frequency reconfigurable microstrip antenna that uses switched connections. The basic antenna operates with linear polarization around 3.7 GHz. One set of connections provides a re-directed radiation pattern while maintaining a common operating impedance bandwidth with the baseline configuration. The second set of connections results in operation at a higher frequency band at 6 GHz with broadside patterns. Measured results of the three antenna configurations are provided. Potential applications of this reconfigurability and directions for future work are discussed.

Patent
18 Aug 2003
TL;DR: In this article, an aircraft phased array antenna system has transmit and receive antenna structures externally mounted on the aircraft fuselage, each antenna comprises a plurality of phased array elements and antenna power and support equipment.
Abstract: An aircraft phased array antenna system has transmit and receive antenna structures externally mounted on the aircraft fuselage. Each antenna comprises a plurality of phased array elements and antenna power and support equipment. Aerodynamically shaping antenna structure to enclose an antenna element grid provides additional antenna structure volume, which is efficiently utilized by locating antenna support equipment within the antenna structure. To control signal attenuation a receive antenna internal converter converts receive frequency signals to L-band frequency signals for aircraft use, and a similar transmit antenna converter converts L-band frequency signals to transmit frequency signals, thus unconstraining antenna to internal aircraft equipment spacing. To reduce power loss and cabling weight, antenna operating power is first generated in the 28 to 270 volts DC range within the aircraft, and locally converted in each antenna to the 3 to 6 volt DC power to operate each antenna's phased array elements.

Journal ArticleDOI
TL;DR: In this paper, a coplanar waveguide fed square slot antenna loaded with conducting strips is proposed and experimentally studied, and the obtained results show that the impedance bandwidth, determined by 10-dB return loss, of the proposed slot antenna can be greater than 60%.
Abstract: A novel broadband design of a coplanar waveguide fed square slot antenna loaded with conducting strips is proposed and experimentally studied. The obtained results show that the impedance bandwidth, determined by 10-dB return loss, of the proposed slot antenna can be greater than 60%. The design considerations for achieving broad-band operation of the proposed slot antenna are described, and experimental results are presented.

Journal ArticleDOI
Wen Geyi1
TL;DR: In this paper, a discussion of minimum possible antenna quality factor (Q) is presented based on the spherical wave function theory and the maximum possible ratios of gain to Q for both directional antenna and omnidirectional antenna are examined and new upper limits for both cases have been obtained.
Abstract: A discussion of minimum possible antenna quality factor (Q) is first presented . Based on the spherical wave function theory, the maximum possible ratios of gain to Q for both directional antenna and omnidirectional antenna are examined and new upper limits for both cases have been obtained. Universally applicable numerical results and some related discussions are also included.

Journal ArticleDOI
TL;DR: In this paper, the numerical analysis and experimental characterization of an ultrawideband (UWB) antenna designed for radiating short microwave pulses is presented, which consists of a pyramidal horn, a ridge, and a curved launching plane terminated with resistors.
Abstract: We report the numerical analysis and experimental characterization of an ultrawideband (UWB) antenna designed for radiating short microwave pulses. The antenna consists of a pyramidal horn, a ridge, and a curved launching plane terminated with resistors. The pyramidal horn is connected to the outer conductor of the coaxial feed and serves as the ground plane. The curved launching plane is connected to the central conductor of the coaxial feed. Detailed three-dimensional finite-difference time-domain (FDTD) simulations have been conducted to assist with the characterization of the antenna. FDTD results are compared with experimental data and are shown to be in good agreement. We demonstrate that the antenna exhibits a very low voltage standing wave ratio (/spl les/1.5) over a wide frequency range from 1 to 11 GHz and a very high fidelity (/spl ges/0.92). The spatial distribution of radiated energy is characterized both in the time domain, using transient field observations at various angles, as well as in the frequency domain, using single-frequency far-field radiation patterns. We conclude that this antenna offers high-fidelity transmission and reception of ultrashort microwave pulses with minimal distortion.

Journal ArticleDOI
TL;DR: In this article, multiple resonant frequencies of fractal element antennas using Koch curves are related to their fractal dimension, and a curve-fit expression can also be obtained for the performance of antennas at their primary resonance.
Abstract: This paper relates for the first time, multiple resonant frequencies of fractal element antennas using Koch curves to their fractal dimension. Dipole and monopole antennas based fractal Koch curves studied so far have generally been limited to certain standard configurations of the geometry. It is possible to generalize the geometry by changing its indentation angle, to vary its fractal similarity dimension. This variation results in self-similar geometry which can be generated by a recursive algorithm. Such a variation is found to have a direct influence on the input characteristics of dipole antennas. The primary resonant frequency, the input resistance at this resonance, and the ratio of first two resonant frequencies, have all been directly related to the fractal dimension. Curve-fit expressions can also be obtained for the performance of antennas at their primary resonance, in terms of fractal iteration and fractal dimension. The antenna characteristics have been studied using extensive numerical simulations and are experimentally verified. These findings underscore the significance of fractal dimension as an important mathematical property of fractals that can be used as a design parameter for antennas. The use of these ideas would not only reduce the computational intensity of optimization approaches for design of fractal shaped antennas, but also help antenna designers approach the problem systematically. Design formulation for antennas based on other fractal geometries can be similarly obtained after identifying suitable parameters of variation. This would therefore help analytical design of multiband and multifunctional antennas using fractal geometries.

Journal ArticleDOI
TL;DR: In this paper, a 2.4 GHz printed dipole antenna with a microstrip via-hole balun feeding structure and a p-i-n diode circuit is used to switch and select the desired antenna polarization.
Abstract: Detailed numerical simulation, fabrication, and experimental measurements of a 2.4-GHz polarization-diversity printed dipole antenna are presented for wireless communication applications. Two orthogonal printed dipole antennas, each with a microstrip via-hole balun feeding structure, are combined and fabricated on an FR-4 printed-circuit-board substrate. A p-i-n diode circuit is used to switch and select the desired antenna polarization. In the antenna design simulation, a full-wave method of a three-dimensional finite-difference time-domain (FDTD) method is employed to analyze the entire structure of the printed antenna including the lumped elements of the polarization-selected p-i-n diode switching circuit. The Berenger perfectly matched layer absorbing-boundary condition is used for the FDTD computation. Numerical and measured results of antenna radiation characteristics, including input standing-wave ratio, radiation patterns, and polarization diversity are presented.

Journal ArticleDOI
TL;DR: In this article, a genetic algorithm using a finite element based cost function was used to optimize the antenna's structure and loading conditions for maximal main lobe gain in a single azimuth direction.
Abstract: The design of an optimized electronically steerable passive array radiator (ESPAR) antenna is presented. A genetic algorithm using a finite element based cost function optimized the antenna's structure and loading conditions for maximal main lobe gain in a single azimuth direction. Simulated gain results of 7.3 dBi at 2.4 GHz were attained along the antenna's elemental axis. The optimized antenna was fabricated and tested with the corresponding experimental gain better than 8 dBi. The 0.7 dB error between simulated and measured gain was constant for numerous structures and therefore did not affect the optimization. The optimized antenna reduced average main lobe elevation by 15.3/spl deg/ to just 9.7/spl deg/ above the horizontal.

Patent
16 Dec 2003
TL;DR: In this article, a dual-polarized variable beam tilt antenna with offset element trays and pairs of dipole elements to orient the dipole element pattern boresight at a downtilt is presented.
Abstract: A dual polarized variable beam tilt antenna (10) having a plurality of offset element trays (12) each supporting pairs of dipole elements (14) to orient the dipole element pattern boresight at a downtilt. The maximum squint level of the antenna is a consistent downtilt off of boresight and which is at the midpoint of the antenna tilt range. The antenna provides a high roll-off radiation pattern through the use of Yagi dipole elements configured in this arrangement, having a beam front-to-side ratio exceeding 20 dB, a horizontal beam front-to-back ratio exceeding 40 dB, and is operable over an expanded frequency range.

Patent
02 Jan 2003
TL;DR: In this article, the authors describe an antenna arrangement in which a pair of at least generally planar opposing antenna arms each support a first high frequency antenna current responsive to an input Each arm includes a peripheral outline for confining the first high-frequency current to the pair of first and second dominant paths.
Abstract: An antenna arrangement is described in which a pair of at least generally planar opposing antenna arms each support a first high frequency antenna current responsive to an input Each arm includes a peripheral outline for confining the first high frequency current to a pair of first and second dominant paths, that are defined by the peripheral outline, in a spaced apart relationship across each of the opposing antenna arms so as to define an isolated area between the first and second paths A configuration is located in this area of at least one of the antenna arms for producing an additional high frequency current responsive to the input The additional high frequency current cooperates with the first high frequency antenna current to produce an overall antenna response In one feature, the opposing antenna arms are bow arms which cooperate to define an overall bow-tie configuration as the peripheral outline

Patent
07 Oct 2003
TL;DR: In this paper, a magnetically coupled antenna range extender is designed to be interposed between an RF antenna and an electronic device, for extending the operating range over which information may be communicated and exchanged between the RF antennas and the electronic devices.
Abstract: A magnetically coupled antenna range extender structured to be interposed between an RF antenna and an electronic device. The antenna range extender is positioned between and proximate to one of the RF antenna and the electronic device, for extending the operating range over which information may be communicated and exchanged between the RF antenna and the electronic device.

Patent
12 Sep 2003
TL;DR: In this paper, a RFID tag or label comprises a tag module (comprising an electronic identification circuit and a coupling means) and an antenna structure coupled to the coupling means, which is separate from, separable or arranged to be severable from, the antenna structure.
Abstract: A RFID tag or label comprises a RFID tag module (comprising an electronic identification circuit and a coupling means) and an antenna structure coupled to the coupling means. The RFID tag module is separate from, separable or arranged to be severable from, the antenna structure. The tag module can be placed in or on an object and the antenna structure in or on packaging material for use with the object. A patch antenna type RFID tag antenna structure has a ground plane spaced from the patch antenna so as to increase the range of the tag. The ground plane is not substantially larger than, and electrically insulated from, the patch antenna. The ground plane is flexible, so the RFID tag structure can be worn by a human, and can be incorporated into a piece of clothing. A RFID antenna structure for use with a tag reader is made flat and robust so that it can be mounted on the ground to be walked upon or driven over. A bi-directional YAGI type RFID tag antenna structure has director elements on two opposite sides so that the YAGI antenna radiates in two opposite directions. An object includes a gain increasing metallic structure for increasing the gain of a RFID tag when placed near the object so as to form a RFID tag antenna structure.

Journal ArticleDOI
TL;DR: A low profile egg-crate array with wideband printed flared dipole ("bunny-ear") elements was developed for dual-pol applications as discussed by the authors, and a small test array of 9/spl times/9 elements was built and tested in a 1-5 GHz experiment.
Abstract: A low profile egg-crate array with wide-band printed flared dipole ("bunny-ear") elements was developed for dual-pol applications A small test array of 9/spl times/9 elements was built and tested in a 1-5 GHz experiment Gain and scan element patterns in E-, H-, and diagonal cuts were measured Excellent results including low cross-pol were observed

Journal ArticleDOI
TL;DR: This paper presents the results achieved with a dual-polarized multiple-input multiple-output (MIMO) measurement system in the 2 GHz range, and suggests that the capacity limit seems to be higher in an indoor picocell than in an outdoor microcell environment.
Abstract: This paper presents the results achieved with a dual-polarized multiple-input multiple-output (MIMO) measurement system in the 2 GHz range. Results from continuous measurement routes were used in evaluating and comparing different MIMO antenna configurations. Different pattern and polarization diversity possibilities were studied using two methods: elements were selected from the antenna arrays used in measurements, and as another option, in the mobile station the incident waves were estimated and used in different dipole antenna arrays. The capacity limit seems to be higher in an indoor picocell than in an outdoor microcell environment. At the mobile station, directive elements result in 35% higher average capacities than those of the omnidirectional elements; however, the capacity of the directive elements also depends on the azimuth direction of arrival of the incident field. Dual-polarized antenna configurations have approximately 14% higher capacities than copolarized configurations. Increasing the number of mobile antenna elements increases the capacity in those environments where the angular spread of the incident field is large. Increasing the distance between elements at the fixed station increases the capacity - especially in microcells where signals arrive from specific directions.

Proceedings ArticleDOI
22 Jun 2003
TL;DR: In this article, the design of planar monopole antennas for use with UWB and having band-notched characteristics is demonstrated, where a GA code is used to develop a reduced size planar antenna which exhibits good impedance matching and stable radiation towards the horizon.
Abstract: The design of planar monopole antennas for use with UWB and having band-notched characteristics is demonstrated. A GA code is used to develop a reduced size planar monopole which exhibits good impedance matching and stable radiation towards the horizon across the entire UWB band. Part of the metal is then removed from this design to create a band-notched characteristic. While this feature offers significant attenuation in the notched band, it has little effect on the antenna operation outside of the band. An analysis demonstrates the resemblance of this feature to a quarter-wave, open-ended transmission line, and that the notched band can be varied by changing the size of the feature.

Journal ArticleDOI
TL;DR: In this article, the performance properties of the Koch fractal monopole are examined and compared with the performance of other bent wire geometry monopoles having the same total wire length and overall height, and it is shown that the fractal limit in lowering of resonant frequency is related to the limit in the increase in the antenna's effective volume.
Abstract: Koch fractal monopole antennas are known to exhibit lower resonant frequencies than Euclidean monopoles of the same height. It has been concluded that there exists a unique relationship between the antenna's fractal geometry and its electromagnetic behavior. Here, the performance properties of the Koch fractal monopole are examined and compared with the performance properties of other bent wire geometry monopoles having the same total wire length and overall height. It is demonstrated that monopoles with less complex shapes exhibit lower resonant frequencies because they are more effective at increasing the electrical volume of the antenna. When these antennas are made to be resonant at the same frequency, they exhibit virtually identical performance properties independent of differences in their geometric shape and total wire length. It is also demonstrated that the effective height of these monopoles converge to that of an electrically small Euclidean monopole near the small antenna limit and they exhibit virtually identical radiation resistance properties at low frequencies. Finally, it is shown that the fractal limit in lowering of resonant frequency is related to the limit in the increase in the antenna's effective volume.

Proceedings ArticleDOI
11 May 2003
TL;DR: This paper calculates interference based capacity bounds for a generic antenna model as well as a real-world antenna model and analyzes how these bounds are affected by important antenna parameters like gain and beamwidth.
Abstract: Directional antennas can be useful in significantly increasing the capacity of wireless ad hoc networks. With directional antennas, independent communications between nodes can occur in parallel, even if the nodes are within range of each other. However, mutual interference by simultaneous transmissions limits the maximum number of such concurrent communications. Furthermore, it poses bounds on the amount of capacity gain one can achieve by using directional antennas instead of omni-directional ones. These bounds depend on the specific antenna type and its parameters, as well as higher layer protocol requirements. In this paper, we calculate interference based capacity bounds for a generic antenna model as well as a real-world antenna model and analyze how these bounds are affected by important antenna parameters like gain and beamwidth.

Proceedings ArticleDOI
22 Jun 2003
TL;DR: In this paper, a folded dipole antenna is used and placed symmetrically above a metal plate to simulate the dependency of antenna parameters on the size of the plate, and the distance between the plate and the antenna.
Abstract: The paper presents the effects on antenna parameters when an antenna is placed horizontally near a metal plate. The plate has finite size and rectangular shape. A folded dipole antenna is used and it is placed symmetrically above the plate. The FEM (finite element method) is used to simulate the dependency of antenna parameters on the size of the plate and the distance between the plate and the antenna. The presence of the metal plate, even a small one if it is at the right distance, causes very big changes in the behaviour of the antenna. The bigger the plate, especially in width, the sharper and narrower are the lobes of the radiation pattern. The antenna height defines how many lobes the radiation pattern has. A number of the antenna parameters, including impedance, directivity and front-to-back ratio, change periodically as the antenna height is increased. The resonant frequency of the antenna also changes under the influence of the metal plate.

Proceedings ArticleDOI
16 Nov 2003
TL;DR: In this article, the authors describe the bottom-fed planar elliptical dipoles, which are electrically small ultra-wideband (UWB) dipoles with bandwidths on the order of 3:1 or better.
Abstract: This paper describes the "bottom fed" planar elliptical dipoles These antennas are electrically small ultra-wideband (UWB) dipoles with bandwidths on the order of 3:1 or better Return loss is typically -14 dB, and boresight gain is nominally 3 Bi Bottom fed planar elliptical dipole antennas are well suited for commercial applications

Journal ArticleDOI
TL;DR: In this article, the authors proposed two novel designs of a multiband antenna using multiple rings, one consisting of a set of self-similar circular rings and the other by varying the shape of the circular structure to an elliptical one.
Abstract: This paper proposes two novel designs of a multiband antenna using multiple rings. The first design consists of a set of self-similar circular rings. This is an alternative to the recently reported triangular fractal Sierpinski gasket monopole antenna, and comparison is made to this and the circular disk monopole antenna. The second design is realized by varying the shape of the circular structure to an elliptical one. Larger bandwidth and improved patterns are achieved. In comparison to the circular disk, improved radiation pattern control at higher operating bands, due to the discrete structure of the multiple rings, is shown by numerical and experimental results. The bandwidth is significantly larger than the Fractal Sierpinski gasket and Parany monopole.