Showing papers on "Monopole 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
04 Apr 2005
TL;DR: In this article, a six-monopole circular antenna array for use in a MIMO system is considered and the authors show how to calculate the embedded element patterns, both by classical analytical modeling and by the method of moments.
Abstract: A six-monopole circular antenna array for use in a MIMO system is considered. The authors show how to calculate the embedded element patterns, both by classical analytical modeling and by the method of moments. Thereafter, these are used to calculate the radiation efficiency of each embedded element, correlation and diversity gain, as well as the maximum average capacity of the MIMO system when the array is located in a rich scattering environment. The theoretical value for the capacity is obtained by numerically distributing many plane wave sources statistically uniformly over 4/spl pi/, letting them illuminate the calculated embedded element pattern and using Shannon's capacity formula on the received wave amplitudes. The calculated results are compared with measurement in a reverberation chamber, representing a similar scattering environment. The agreement is good.
353 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: In this paper, a reduced size microstrip monopole slot antennas with different slot shapes-straight, L and inverted T, and placed on a small ground plane, are investigated.
Abstract: Reduced size microstrip monopole slot antennas with different slot shapes-straight, L and inverted T, and placed on a small ground plane, are investigated. The ground plane size is 50 mm/spl times/80 mm, which is about the size of a typical PC Wireless card. Detailed simulation and experimental investigations are conducted to understand their behavior and optimize for broadband operation. It is shown that, the variation in the slot shape, from straight to L and T shapes, helps in generating additional resonances, which when coupled to the original resonances of the slot, further increases impedance bandwidths. The bent shapes of the L and T slots reduce their height and provide more space on the ground plane for electronics. A mirror image dual L-slot antenna, placed at two adjacent corners of the ground plane, is also investigated and optimized for the polarization diversity. They provide an impedance bandwidth of 87%, with near orthogonal radiation characteristics. The measured impedance bandwidths (S/sub 11/=-10 dB) of up to 60%, 84%, and 80% are achieved for these straight, L and inverted T slots respectively, by suitably selecting their design parameters. The simulation results are in good agreement with the experimental data considering several practical issues.
293 citations
19 Dec 2005
TL;DR: In this article, a coplanar waveguide (CPW) fed circular disc monopole antenna for ultra wideband (UWB) applications is presented, and the performance and characteristics of the antenna are investigated in order to understand its operation.
Abstract: The paper presents a study of coplanar waveguide (CPW) fed circular disc monopole antenna for ultra-wideband (UWB) applications. A circular disc monopole printed on a dielectric substrate and fed by a 50 /spl Omega/ CPW on the same layer can yield an ultra-wide -10 dB return loss bandwidth with satisfactory radiation patterns. The performance and characteristics of the antenna are investigated in order to understand its operation. Good agreement has been obtained between the simulation and experiment.
279 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 article, a trident-shaped feeding strip was used to feed a square planar metal-plate monopole antenna with a very wide impedance bandwidth of about 10 GHz (about 1.4-11.4 GHz, bandwidth ratio about 1:8.3).
Abstract: A square planar metal-plate monopole antenna fed by using a novel trident-shaped feeding strip is presented. With the use of the proposed feeding strip, the square planar monopole antenna studied shows a very wide impedance bandwidth of about 10 GHz (about 1.4-11.4 GHz, bandwidth ratio about 1:8.3), which is larger than three times the bandwidth obtained using a simple feeding strip (about 1.5-3.3 GHz, bandwidth ratio about 1:2.3). In addition, the proposed feeding strip can be integrated with the square planar monopole, that is, the feeding strip and the square planar monopole together can be easily fabricated using a single metal plate, making the proposed antenna easy to construct at a low cost. Details of the experimental and simulation results for the proposed planar monopole antenna are presented and analyzed.
236 citations
Abstract: A novel planar tapered-slot-fed annular slot antenna is proposed in this paper. The antenna utilizes a unique tapered-slot feeding structure and simultaneously possesses ultrawide bandwidth, almost uniform radiation patterns, and low profile. It is, hence, adequate for ultrawide-band (UWB) applications. By means of a normalized antenna transfer function, both frequency domain and time domain characteristics of the antenna are carefully investigated. Two measures, the uniformity related to the radiation patterns and the fidelity associated with the transient behaviors, are used to quantitatively describe the performance of an antenna over such an ultrawide bandwidth. Effects of varying the antenna's geometric parameters on the performance are then investigated. Finally, the influence of minimizing the antenna dimension is discussed at the end of the paper.
227 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%.
219 citations
TL;DR: In this paper, a self-resonant, electrically small electric dipole antenna is presented that exhibits an impedance near 50 Ohms, an efficiency in excess of 95% and a quality factor that is within 1.5 times the fundamental lower bound at a value of less than 0.27.
Abstract: Electrically small antennas are generally presumed to exhibit high impedance mismatch (high VSWR), low efficiency, high quality factor (Q); and, therefore, narrow operating bandwidth. For an electric or magnetic dipole antenna, there is a fundamental lower bound for the quality factor that is determined as a function of the antenna's occupied physical volume. In this paper, the quality factor of a resonant, electrically small electric dipole is minimized by allowing the antenna geometry to utilize the occupied spherical volume to the greatest extent possible. A self-resonant, electrically small electric dipole antenna is presented that exhibits an impedance near 50 Ohms, an efficiency in excess of 95% and a quality factor that is within 1.5 times the fundamental lower bound at a value of ka less than 0.27. Through an arrangement of the antenna's wire geometry, the electrically small dipole's polarization is converted from linear to elliptical (with an axial ratio of 3 dB), resulting in a further reduction in the quality factor. The elliptically polarized, electrically small antenna exhibits an impedance near 50 Ohms, an efficiency in excess of 95% and it has an omnidirectional, figure-eight radiation pattern.
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.
Patent•
12 Apr 2005
TL;DR: An antenna assembly includes a common reflector and multiple monopole type antenna elements positioned on a ground plane and fed with a switch assembly as discussed by the authors, which is capable of feeding individual antennas as well as combining multiple antennas for improved radiation pattern coverage.
Abstract: An antenna assembly includes a common reflector and multiple monopole type antenna elements positioned on a ground plane and fed with a switch assembly The switch assembly is capable of feeding individual antennas as well as combining multiple antennas for improved radiation pattern coverage Multiple antenna elements are placed around the common reflector to cover sectors of space around the antenna assembly to provide transmission and reception of radio frequency (RF) signals for mobile communication devices in a wireless network The ground plane can be grounded or capacitively coupled to an existing circuit board or metal surface, allowing for reduced ground plane dimensions
TL;DR: In this article, a novel ground plane shape was proposed to improve the horizontal gain of ESPAR antennas. But the ground plane is not suitable for ground-based communication, as the peak directivity of a monopole antenna is at a higher angle from the horizon than that of a dipole antenna.
Abstract: A novel ground-plane shape to improve the horizontal gain for electrically steerable passive array radiator (ESPAR) antennas is investigated. The peak directivity of a monopole antenna with a finite ground plane, such as a circular or rectangular ground plane is at a higher angle from the horizon. Thus, the horizontal gain is lower than that of a dipole antenna. Using a circular ground plane of a half-wavelength radius with a skirt of a quarter wavelength wound around it, the angle of the peak directivity and the horizontal gain for the ground-based communication system were improved. For an ESPAR antenna - one of the monopole arrays - the horizontal gain was also improved. It was confirmed that it was possible to form the main-beam radiation and a beam null in the horizontal plane, each in an arbitrary direction, by changing the control voltage to the passive element. This was shown by an experiment with an ESPAR antenna with a finite reflector, a feed element, and seven passive elements.
TL;DR: In this paper, a planar triangular monopole antenna (PTMA) is presented for high-frequency structure simulator ultra-wideband (UWB) communication, and the Kirchhoff's surface integral representation is adopted in the developed finite-difference time-domain code to compute the far field distributions from the near filed ones in time-dimensional space.
Abstract: A planar triangular monopole antenna (PTMA) is presented for high-frequency structure simulator ultra-wideband (UWB) communication. The high-frequency structure simulator three-dimensional electromagnetic solver is employed for design simulation. A printed PTMA has been realized by using the FR-4 printed circuit board substrate. The measured voltage standing wave ratio is less than 3 from 4 to 10 GHz. In the UWB communication frequency range, the measured phase distribution of the input impedance is quite linear and the H-plane patterns are almost omni-directional. The Kirchhoff's surface integral representation was adopted in the developed finite-difference time-domain code to compute the far field distributions from the near filed ones in time-domain. This is to investigate the radiated power density spectrum (PDS) shaping to comply with FCC emission limit mask. The effect of various source pulses (first-order Rayleigh pulses with /spl sigma/ of 20, 30, and 50 ps) on the radiated PDS shaping is also studied.
TL;DR: In this paper, a hybrid antenna consisting of an annular dielectric resonator antenna combined with a quarter-wave monopole to simultaneously act as a radiator and a loading element is presented.
Abstract: A hybrid antenna is presented, consisting of an annular dielectric resonator antenna combined with a quarter-wave monopole to simultaneously act as a radiator and a loading element, producing an ultra wideband response. A prototype antenna is designed and a 3:1 bandwidth is demonstrated.
TL;DR: In this paper, a theoretical, computational, and experimental study for a two-element superdirective array of resonant monopoles was conducted, and it was shown that the measured gain of the monopole array does indeed continually increase with decreasing spacing, provided the relative magnitudes and phases are maintained.
Abstract: In principle, the end-fire directivity of a linear periodic array of N isotropic radiators can approach N/sup 2/ as the spacing between elements decreases, provided the magnitude and phase of the input excitations are properly chosen. Thus, the directivity of a two-element array of isotropic radiators would approach a value of four, that is, 6 dB higher than that of a single isotropic radiator. We have conducted a theoretical, computational, and experimental study for a two-element superdirective array of resonant monopoles. In agreement with the theoretical and computational curves, the measured gain of the monopole array does indeed continually increase with decreasing spacing of the monopoles, provided the relative magnitudes and phases are maintained. However, for very small separation, maximum achievable gain is not reached due to the presence of ohmic loss.
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.
Patent•
15 Apr 2005
TL;DR: In this paper, a circular-polarization dipole helical antenna is used for electronic device and satellite terminal and includes a base, and an antenna conductor arranged on surface of the base.
Abstract: A circular-polarization dipole helical antenna is used for electronic device and satellite terminal and includes a base, and an antenna conductor arranged on surface of the base. The antenna conductor includes a plurality of metal conductors with high Q value and anti-oxidation property and continuously and helically coated on surface of the base. The base is made of low loss and high dielectric constant material. An unbalance-to-balance circuit module connects two signal-feeding ends to the base with phase difference of 180 degree. The problems of narrow bandwidth, low efficiency, complicated structure and precise manufacture can be solved.
Patent•
22 Jul 2005
TL;DR: In this paper, the shape of the antenna is described as a space-filling curve, including a Hilbert, box-counting or grid dimension curve, and the antennas are spaced away from the antenna to prevent interference with the antenna.
Abstract: A IC package for a wireless device includes an antenna that is attached to the chip. The electrically conductive elements of the antenna are spaced away from the antenna and particularly the endpoint of the antenna to prevent interference with the antenna. An element on the IC package may be shielded antenna. The antenna may have the shape of a space-filling curve, including a Hilbert, box-counting or grid dimension curve.
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.
TL;DR: In this paper, a passive RFID tag antenna in the UHF band using two bent dipoles and a modified double T-matching network is proposed, which provided a quasi-isotropic radiation pattern and a fairly broad bandwidth S11 <−10 dB, 8.5 dB.
Abstract: A passive RFID tag antenna in the UHF band using two bent dipoles and a modified double T-matching network is proposed. The antenna was fabricated with a thin copper layer printed on a 50 µm-thick PET substrate for low-cost production. The proposed antenna provided a quasi-isotropic radiation pattern and a fairly broad bandwidth S11<−10 dB, 8.5%) for conjugate-matching with a commercial tag chip. The efficiency of the antenna was about 90% in the operating frequency band. The measured readable range was between 170 –240 cm for an arbitrary rotation angle of the tag.
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.
TL;DR: In this article, a dielectric embedded electronically steerable passive array radiator (ESPAR) antenna array for mobile wireless communication terminal is developed by finite element method-based numerical modeling technique.
Abstract: A novel dielectric embedded electronically steerable passive array radiator (ESPAR) (DE-ESPAR) antenna array for mobile wireless communication terminal is developed by finite element method based numerical modeling technique. The size reduction of the seven-element monopole antenna was accomplished by embedding the array in a cylindrical rod of FIK ceramic complex with a relative permittivity around /spl epsiv//sub r/=4.5. Dielectric embedded prototypes of a seven-element ESPAR antenna array were modeled and experimentally characterized. Experimental and numerical results are in good agreement. The optimized antenna produced a horizontal directivity of 5.1 dBi and return loss of 19 dB at 2.48 GHz. An overall volume reduction of 80% and footprint reduction of 50% were achieved.
TL;DR: In this paper, a coplanar waveguide fed planar monopole antenna for multiband operation is presented, which embeds appropriate slits into the 50 /spl Omega/ feeding line, and good impedance matching for multiresonant mode is obtained.
Abstract: A novel coplanar waveguide fed planar monopole antenna for multiband operation is presented in this paper. By embedding appropriate slits into the 50 /spl Omega/ feeding line, good impedance matching for multiresonant mode is obtained. The evolutionary design process of using a particle swarm optimization (PSO) algorithm in conjunction with the method of moments is employed to effectively obtain the geometry parameters of the antenna for optimum multiband performance. Prototypes of the obtained optimized design have been constructed and experimentally studied. The measured results explore good multiband operation with 10 dB impedance bandwidths of 55%, 8.5%, and 4.4% at bands of 2.51, 3.98, and 5.24 GHz, respectively, which cover the personal communication system and 2.4/5.2 GHz wireless local-area network operating bands, and show good agreement with the numerical prediction. Good monopole-like radiation patterns and antenna gains over the operating bands have also been observed. Effects of the patch size on the antenna performance and implementation of the physical PSO for the optimized configuration are all examined and discussed in detail.
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 paper, a compact CPW-fed monopole antenna is proposed for dual-band wireless local area network (WLAN) operations, which consists of two strips, and has compact size of 20/spl times/155/pl times/16 mm/sup 3/ including the ground.
Abstract: A compact CPW-fed monopole antenna is proposed for dual-band wireless local area network (WLAN) operations The proposed antenna, which consists of two strips, has compact size of 20/spl times/155/spl times/16 mm/sup 3/ including the ground The proposed antenna effectively covers both 24 GHz (24-2484 GHz) and 5 GHz (515-5825 GHz) bands The measured peak gains are 13 dBi at 244 GHz and 28 dBi at 532 GHz
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, an antenna theory approach in the frequency domain is presented to compute electromagnetic fields radiated by a lightning return stroke, where the lightning channel is modeled as a lossy-wire monopole antenna (a wire antenna with distributed resistance) energized by a current source at its base.
Abstract: An antenna theory (AT) approach in the frequency domain is presented to compute electromagnetic fields radiated by a lightning return stroke. The lightning channel is modeled as a lossy-wire monopole antenna (a wire antenna with distributed resistance) energized by a current source at its base, and the ground is modeled as a lossy half-space. The method of moments is used for solving the governing electric field integral equation (EFIE) in the frequency domain. The resultant current distribution along the channel is used to calculate electromagnetic fields at different distances from the channel. All field components are evaluated using a rapid but accurate procedure based on a new approximation of Sommerfeld integrals. In contrast with the previous models, the approach proposed here is characterized by a self-consistent treatment of different field components in air or on the surface of a lossy half-space. It is shown that the omission of surface wave terms in the general field equations, as done in the perfect-ground approximation, can strongly affect model-predicted field components.
TL;DR: In this paper, a dual-band antenna with double L-slits for wireless local area network (WLAN) applications in IEEE 802.11a/b/g is presented.
Abstract: This letter presents a compact dual-band antenna with double L-slits for wireless local area network (WLAN) applications in IEEE 802.11a/b/g. The proposed antenna effectively covers both 2.4/5-GHz bands with three resonances that are caused by the double L-slits. The proposed antenna has compact size of 15 mm/spl times/9 mm/spl times/7 mm, which is only half size of the antenna using double U-slots. The parametric study is performed to understand the characteristics of the proposed antenna. The measured return loss and radiation patterns indicate the suitability of this antenna for the WLAN applications. The peak antenna gains of 1.3 dBi at 2.4-GHz band and 5.1 dBi at 5-GHz band are measured.