Showing papers on "Metamaterial antenna published in 1999"
Journal Article•
TL;DR: In this article, it is shown that patch antennas on high dielectric constant substrates are highly inefficient radiators due to surface wave losses and have very narrow frequency bandwidth (approximately one to two percent).
Abstract: Printed antennas exemplified by the microstrip patch antenna offer an attractive solution to compact, conformal and low cost design of modem wireless communications equipment, RF sensors and radar systems. Recent applications have pushed the frequency well into the ram-wave region even in the commercial arena as evidenced by the worldwide race to develop advanced collision warning radar systems for automobiles at the 76 GHz band.[1] Microstrip-based planar antennas fabricated on a substrate with a high dielectric constant (Si, GaAs and InP) are strongly preferred for easy integration with the MMIC RF front-end circuitry. However, it is well known that patch antennas on high dielectric constant substrates are highly inefficient radiators due to surface wave losses and have very narrow frequency bandwidth (approximately one to two percent). This situation becomes extremely severe as applications move to higher frequencies, resulting in patch antennas with reduced gain and efficiency as well as an unacceptably high level of cross polarization and mutual coupling within an array environment. Therefore, much effort has been made recently to realize high efficiency patch antennas on high permittivity substrates, including using the latest micromachining technology.[2,3]
146 citations
TL;DR: In this paper, a method for miniaturization of microstrip patch antennas without degrading radiation characteristics is investigated, which involves perforating the patch to form a microstrip square-ring antenna, which is investigated numerically and experimentally.
Abstract: A method for miniaturization of microstrip patch antennas without degrading radiation characteristics is investigated. It involves perforating the patch to form a microstrip square-ring antenna, which is investigated numerically and experimentally. The ring geometry introduces additional parameters to the antenna that can be used to control its impedance, resonance frequency, and bandwidth. For a single square ring increasing the size of perforation increases its input impedance, but decreases the resonance frequency and bandwidth. It has a small effect on directivity of the antenna. To match the antenna to a transmission line and also enhance its bandwidth, the ring is stacked by a square patch or another square ring. The computed results are compared with experimental data and again good agreement is obtained.
121 citations
TL;DR: A simple and practical method for the design of broad-band microstrip antennas is presented and it is confirmed that the method proposed is applicable to the designs of other types of multilayered planar antennas.
Abstract: The narrow bandwidth of a microstrip antenna is one of the important features that restrict its wide usage. A simple and practical method for the design of broad-band microstrip antennas is presented in this paper. Utilizing this design technique, several two-layer microstrip antennas have been proposed. To confirm the applicability of the method for the designs of antennas at L-band, experiments have been carried out. The measured results show that the proposed antennas have a bandwidth of up to 25.7%. Also, the method proposed in this paper is applicable to the design of other types of multilayered planar antennas.
106 citations
TL;DR: In this paper, the authors presented calculated and measured results for the input impedance and radiation performance of probe-fed printed annular ring antennas, and found that annular rings have certain advantages over circular and rectangular microstrip antennas.
Abstract: This paper presents calculated and measured results for the input impedance and radiation performance of probe-fed printed annular ring antennas. Geometries featuring stacked rings as well as shorting posts are considered. A numerical model is presented that is based on a full-wave spectral-domain moment-method solution. In this solution, a specialized attachment mode-expansion function is used to model the connection between the probe feed and the printed ring. Measured results are presented and compare well with the theory. Annular rings are found to have certain advantages over circular and rectangular microstrip antennas.
78 citations
13 Jun 1999
TL;DR: In this article, a new type of metallic electromagnetic structure has been developed that is characterized by having high surface impedance, and this new surface does not support propagating surface currents, and it reflects electromagnetic waves with no phase reversal.
Abstract: A new type of metallic electromagnetic structure has been developed that is characterized by having high surface impedance. Unlike normal conductors, this new surface does not support propagating surface currents, and it reflects electromagnetic waves with no phase reversal. This unique material can serve as the ground plane for new kinds of low-profile antennas.
55 citations
01 Oct 1999
TL;DR: In this paper, a dual-frequency design of an inset-microstrip-line-fed circular microstrip antenna with an arc-shaped slot is proposed and experimentally studied.
Abstract: A new dual-frequency design of an inset-microstrip-line-fed circular microstrip antenna with an arc-shaped slot is proposed and experimentally studied. The two operating modes of the proposed antenna are associated with the perturbed TM11 and TM01 modes and have the same polarisation planes and similar broadside radiation characteristics. By varying the length of the arc-shaped slot, the proposed antenna can provide a tunable frequency ratio of about 1.29 to 1.43 for the two operating frequencies. The application of the proposed antenna to the design of a two-element dual-frequency microstrip array is also demonstrated. Details of the obtained dual-frequency performances of the proposed dual-frequency design are presented and discussed.
29 citations
25 citations
11 Jul 1999
TL;DR: In this paper, a novel design of the inset-microstripline-fed circularly-polarized microstrip antenna by using a corner-truncated patch with an inserted slit is first successfully implemented.
Abstract: A novel design of the inset-microstripline-fed circularly-polarized microstrip antenna by using a corner-truncated patch with an inserted slit is first successfully implemented. By further inserting slits at the corner-truncated patch boundary, the compact inset-microstripline-fed circularly-polarized microstrip antenna is also studied. Results have been obtained that, due to the inset-microstripline-fed reactive effect, this truncated corner perturbation can not be directly applied to the inset-microstripline fed circularly polarized microstrip antenna with good impedance matching condition.
24 citations
Patent•
23 Nov 1999
TL;DR: In this article, a microstrip feeder structure for supplying properly phased signals to each radiator element in a micro-strip antenna array that may be utilized for radiating circularly polarized electromagnetic waves is described.
Abstract: Method and apparatus are provided for a microstrip feeder structure for supplying properly phased signals to each radiator element in a microstrip antenna array that may be utilized for radiating circularly polarized electromagnetic waves. In one disclosed embodiment, the microstrip feeder structure includes a plurality of microstrip sections many or all of which preferably have an electrical length substantially equal to one-quarter wavelength at the antenna operating frequency. The feeder structure provides a low loss feed structure that may be duplicated multiple times through a set of rotations and translations to provide a radiating array of the desired size.
21 citations
11 Jul 1999
TL;DR: In this paper, the design of a high efficiency circularly polarized nearly square patch antenna at L-band is presented, where a low permittivity substrate with /spl epsi/sub r/=1.1028 was obtained by using a combination of Rogers RT/Duroid 5880 and Rohacell hard foam.
Abstract: The design of a high efficiency circularly polarized nearly square patch antenna at L-band is presented. One way to improve the efficiency of the inherently low efficiency microstrip antennas is to use substrates with a low permittivity. A low permittivity substrate with /spl epsi//sub r/=1.1028 was obtained by using a combination of Rogers RT/Duroid 5880 and Rohacell hard foam. The effect of a 5 mils thick Rogers RT/Duroid 5880 superstrate on the efficiency was also studied. Results of the antenna efficiency and bandwidth for both the low dielectric substrate and superstrate are presented. The results were obtained using the 1E3D software package and compared with measured results. Efficiencies of the order of 85% for a single patch element were obtained.
17 citations
TL;DR: In this article, an improved linear transmission line (LTL) model was developed after incorporating several modifications in the reported LTL model for analyzing arbitrarily shaped microstrip antennas (MSAs), which should be symmetrical with respect to the feed axis.
Abstract: An improved linear transmission line (LTL) model has been developed after incorporating several modifications in the reported linear transmission line model for analyzing arbitrarily shaped microstrip antennas (MSAs), which should be symmetrical with respect to the feed axis. Simulations have been carried out for rectangular, circular, and equilateral triangular MSAs and the results are in good agreement with reported results. A parametric study for these MSAs has also been performed. A study of the temperature sensitivity for rectangular MSAs for different types of substrates has been carried out. An MSA utilizing a substrate with a lower dielectric constant and thermal coefficient is less sensitive to temperature variations.
11 Jul 1999
TL;DR: In this article, the effect of using a superstrate PBG material on a microstrip line fed slot antenna is investigated, where the PBG layer is composed of periodic metallic blocks inside a host dielectric material with high material permittivity and exhibits a complete bandgap at the design frequency of the slot antenna.
Abstract: The effect of using a superstrate PBG material on a microstrip line fed slot antenna is investigated. The PBG material is composed of periodic metallic blocks inside a host dielectric material with high material permittivity, and exhibits a complete bandgap at the design frequency of the slot antenna. Simulation results show that by adding the PBG layer as a superstrate, radiation in the E-plane near the endfire direction is suppressed, while radiation in the H-plane is enhanced.
11 Jul 1999
TL;DR: In this article, the authors presented a new structure of using an inset-microstrip line to simplify the matching network, which makes the present proposed design simpler and easier to be constructed.
Abstract: A variety of dual-frequency microstrip antennas have been previously reported. However, it is noted that these dual-frequency designs usually support limited tunable frequency ratios for the two operating frequencies. To provide a very flexible frequency ratio for a single-feed dual-frequency microstrip antenna, the design with two circular patches has also been shown. Such a design, however, uses a relatively complicated matching network between the two patches. We present a new structure of using an inset-microstrip line to simplify the matching network, which makes the present proposed design simpler and easier to be constructed. The proposed design method applied to two rectangular patches has been successfully implemented. The obtained frequency ratio of the two operating frequencies can be flexible, and good dual-frequency performances are also observed. Details of the antenna design and experimental results are presented and discussed.
01 Oct 1999
TL;DR: In this article, a locally nonhomogeneous substrate configuration is proposed for optimizing both the dimensions and the radiation efficiency of microstrip patch antennas, which is achieved through an optimal combination of a high permittivity substrate, for size criteria, with a foam matrix for radiation pattern improvement.
Abstract: A locally non-homogeneous substrate configuration is proposed for optimizing both the dimensions and the radiation efficiency of microstrip patch antennas. This is achieved through an optimal combination of a high permittivity substrate, for size criteria, with a foam matrix for radiation pattern improvement Comparisons between simulations, based upon the TLM method, and measurements are provided.
11 Jul 1999
TL;DR: In this paper, the authors investigated the impedance behavior and scanning potential of microstrip patch antenna arrays consisting of the broadband elements presented in Waterhouse and Targonski et al. (1998).
Abstract: We thoroughly investigate the impedance behaviour and scanning potential of microstrip patch antenna arrays consisting of the broadband elements presented in Waterhouse (1998) and Targonski et al. (1998). In particular, a design strategy is developed for these broadband printed antenna arrays. Arrays of probe-fed stacked microstrip patches utilizing high-low dielectric constant material combinations (Waterhouse and Kokotoff 1998) are also investigated. All the arrays presented are analyzed using full-wave spectral domain infinite array analysis.
30 Nov 1999
TL;DR: In this article, the integrated reactive loading is designed to be resonant at the fundamental resonant mode of the microstrip antenna, which makes it possible for the fundamental mode to be split into two near-degenerate modes, resulting in a much wider operating bandwidth.
Abstract: Broadband operation of microstrip antennas using the integrated reactive loading technique is studied. Such reactive loading can be integrated with the microstrip patch, retaining the advantages of low profile and easy fabrication. The integrated reactive loading is designed to be resonant at the fundamental resonant mode of the microstrip antenna, which makes it possible for the fundamental mode to be split into two near-degenerate modes, resulting in a much wider operating bandwidth. A number of design examples have been implemented. Details of the antenna designs and experimental results are presented.
11 Jul 1999
TL;DR: A new technique is introduced to increase the bandwidth of a microstrip antenna drastically using a leaky-wave concept, and experimental results are shown.
Abstract: One of the most detrimental aspects of microstrip antennas despite their many advantages is narrow bandwidth. Even though numerous successful results have been reported, a bandwidth more than 20% is difficult to achieve. In this paper a new technique is introduced to increase the bandwidth of a microstrip antenna drastically using a leaky-wave concept. Experimental results are shown.
13 Jun 1999
TL;DR: In this article, a TLM (SCN) algorithm was developed for the simulation of microstrip antenna on magnetized ferrite substrate, where the anisotropic permeability tensor of ferrite is modelled by state equations derived from the Polder tensor.
Abstract: A new TLM(SCN) algorithm has been developed for the simulation of microstrip antenna on magnetized ferrite substrate. The anisotropic permeability tensor of ferrite is modelled by state equations derived from the Polder tensor. Simulation results agree with measurement.
11 Jul 1999
TL;DR: In this paper, the performance of printed bowtie antennas fed by electromagnetic coupling from an embedded microstrip line is investigated, an impedance transformer circuit is optimized and the obtained performances are compared to those given by a simple 50 /spl Omega/microstrip line.
Abstract: Printed planar antennas are widely used in many current applications. One of the main limitations is their narrow bandwidth. To improve this last parameter, several shapes have been studied, namely: bowtie, spiral, logarithmic antennas, ... The investigated results indicate that the radiating performances are influenced, as expected, by the dielectric substrate, the radiating element shape and the feeding circuits. In the present research, printed bowtie antennas fed by electromagnetic coupling from an embedded microstrip line are investigated, An impedance transformer circuit is optimized and the obtained performances are compared to those given by a simple 50 /spl Omega/ microstrip line. Measurements of return loss and radiation patterns are also presented and compared to the calculated ones.
11 Jul 1999
TL;DR: In this article, the microstrip line and the probe were combined to form a microstrip-probe feed for the two-element array of U-slot rectangular patches, which improved the matching and the front to back ratio (F/B) characteristic over a wide bandwidth.
Abstract: We propose a new type of feeding method for the two-element array of U-slot rectangular patches. We combine the microstrip line and the probe to form a microstrip-probe feed. As confirmed by our experimental measurements, by placing the feeder between the patch and the ground plane, we improved the matching and the front to back ratio (F/B) characteristic over a wide bandwidth, compared to the conventional coaxial-probe feeding method used by Lee (Electron. Lett., vol.31, no.5, p.819-420, 1996).
01 Oct 1999
TL;DR: To this aim, various original topologies of radiators derivable by uniform microstrip lines are proposed and tested based on rigorous spectral-domain approaches to achieve advanced leaky-wave antenna configurations.
Abstract: In this work we analyze some perspectives for improving the performances of printed leaky-wave antennas for MIC applications. To this aim, based on rigorous spectral-domain approaches, we have in particular proposed and tested various original topologies of radiators derivable by uniform microstrip lines. The relevant properties have been discussed to achieve advanced leaky-wave antenna configurations.
05 Sep 1999
TL;DR: Simulation indicates that this stacked square ring microstrip patch antenna with slot coupling has a 10-dB return loss bandwidth, good front-to-back ratio and cross-polarization over the band 4.65-5.45 GHz.
Abstract: A stacked square ring microstrip patch antenna with slot coupling is studied. Simulation indicates that this radiation structure has a 10-dB return loss bandwidth of 15.8%, good front-to-back ratio and cross-polarization over the band 4.65-5.45 GHz.
11 Jul 1999
TL;DR: In this article, a theoretical analysis of the mutual coupling between SAR-RSW antennas is presented, along with experimental results, which demonstrates how mutual coupling varies with patch separation, and a theoretical investigation of both lateral and surface-wave contributions to the coupling is performed to investigate the importance of these two contributions.
Abstract: Jackson et al. (1993) developed a new microstrip patch, the shorted annular ring-reduced surface wave (SAR-RSW) antenna. This microstrip antenna produces only a small amount of surface-wave excitation. In addition, if printed on an electrically thin substrate (so that /spl beta/(TM/sub 0/)/spl ap/k/sub 0/), this antenna only weakly excites lateral waves (the space-wave fields that propagate along the air-dielectric interface). In this presentation we summarize our study of the mutual coupling between SAR-RSW antennas. The mutual coupling between conventional circular patches is used as a comparative reference, since these results are representative of the coupling between typical microstrip antennas. The same analysis is used for both antennas, since the SAR-RSW antenna becomes a conventional circular patch in the limiting case when the inner radius goes to zero. We present numerical results from a theoretical analysis of the mutual coupling, along with experimental results. The mutual coupling behavior is then explained using an asymptotic analysis, which demonstrates how the mutual coupling varies with patch separation. Finally, a theoretical investigation of both lateral- and surface-wave contributions to the coupling is performed to investigate the importance of these two contributions to the mutual coupling.
TL;DR: In this article, a microstrip circuit operating in the G band is presented, which allows an emitting printed antenna to self-tune its resonance frequency when it is disturbed, in order to stay resonant and matched at the desired transmit frequency.
Abstract: A microstrip circuit operating in the G band is presented. It allows an emitting printed antenna to self-tune its resonance frequency when it is disturbed, in order to stay resonant and matched at the desired transmit frequency. The principle, design and experimental results of the circuit are presented.
11 Jul 1999
TL;DR: In this article, a pair of properlybent slots close to the nonradiating edges of a rectangular microstrip patch are used to embed two resonant modes with the same polarization planes and similar radiation characteristics for single-feed dual-frequency operation.
Abstract: By embedding a pair of properly-bent slots close to the nonradiating edges of a rectangular microstrip patch, two resonant modes [TM/sub 10/ and TM/sub /spl delta/0/ (1
09 Aug 1999
TL;DR: In this article, the transverse transmission line (TTL) method along with the transmission line model was used to analyze the antenna arrays of a rectangular microstrip patch antenna and its array factor.
Abstract: In this work, the rectangular microstrip patch antenna and its arrays are analyzed using the Transverse Transmission Line (TTL) method along with the Transmission Line Model. Since the TTL is a full wave method and very much suitable for microwave components study, it gives accurate effective dielectric constant which contributes definitively to obtaining higher precision antenna parameters. For each type of array is calculated the array factor, considering the excitation, phase and the distance between the individual elements as well as the dimensions. Results for the radiation pattern in E and H-plane in 2 and 3D are presented.
11 Jul 1999
TL;DR: New broadband designs of an equilateral-triangular microstrip antenna with a pair of bent slots are proposed and experimentally studied for the case of the thin-substrate condition.
Abstract: Applications of microstrip antennas are limited mainly because of their narrow inherent bandwidth. There are many reports on solving this problem, such as using electrically thick substrates or stacked multipatch structures. All these designs, however, require a large antenna volume for broadband operation. In this article, new broadband designs of an equilateral-triangular microstrip antenna with a pair of bent slots are proposed and experimentally studied for the case of the thin-substrate condition.
01 Dec 1999
TL;DR: In this paper, an optically controllable microstrip adaptive array using the semiconductor plasma and the genetic algorithm was proposed, which consists of the slot-coupled microstrip patch antennas whose weights are controlled by optically induced semiconductor plasmas.
Abstract: This paper proposes an optically controllable microstrip adaptive array using the semiconductor plasma and the genetic algorithm. The array antenna consists of the slot-coupled microstrip patch antennas whose weights are controlled by optically induced semiconductor plasma. The plasma densities an determined by the GA, and the validity for the null steering and beam forming technique was shown.