IEEE Transactions on Antennas and Propagation, 2003
The properties of the Koch island fractal boundary microstrip patch antenna are presented. The be... more The properties of the Koch island fractal boundary microstrip patch antenna are presented. The behavior at the fundamental mode and the existence of high-order modes that exhibit localized current density distributions is discussed. The main features are the size reduction of the patch resonating at the fundamental frequency when compared to Euclidean-shaped patches, and the application of localized modes in designing microstrip patch antennas with directive patterns.
The unique geometrical properties of fractals have been proven to be useful to design advanced an... more The unique geometrical properties of fractals have been proven to be useful to design advanced antennas. Enhanced performance in terms of size, gain or multiband behaviour is observed in fractal-shaped antennas. Here, a small and high directivity antenna based on the Sierpinski bowtie geometry is presented.
Miniature behaviour of microstrip antennas with Sierpinski bowtie geometry is investigated and th... more Miniature behaviour of microstrip antennas with Sierpinski bowtie geometry is investigated and the existence of fracton modes is studied. A fracton mode is a mode found at a higher frequency than the one obtained for the fundamental mode. The antenna presents as many fracton-modes as fractal iterations. These fracton modes are interesting because they provide a broadside radiation pattern with higher directivity than that obtained from the fundamental mode.
Progress in Electromagnetics Research Letters, 2009
A dual-band enhanced-bandwidth microstrip antenna is presented with a frequency separation of f 2... more A dual-band enhanced-bandwidth microstrip antenna is presented with a frequency separation of f 2 /f 1 = 1.33. In order to achieve the dual-frequency operation, a rectangular patch is loaded with a stub at one of its radiating edges. To improve bandwidth at each band, two parasitic patches are coupled to the driven element.
The paper introduces both a new internal FM antenna for mobile phones based on the fractal Hilber... more The paper introduces both a new internal FM antenna for mobile phones based on the fractal Hilbert curve, and a new evaluation criterion for quantifying the quality of the signal received by the FM antenna of mobile phones. The main attribute of the new internal FM antenna is its reduced size; which is only 30⋆10⋆1 mm3. The measurements demonstrate that the power received by the internal FM antenna is 20 dB lower than the power received by the external wire antenna under the same measurement conditions. Despite the reduction of the power level, the evaluation criterion reveals that, owing to the threshold effect in FM receivers, the signal quality indicator is similar for both antennas. Additionally, the value of the signal quality indicator achieved by both antennas guarantees to listen to the FM radio channels clearly without noise nuisance and without interferences.
IEEE Antennas and Wireless Propagation Letters, 2007
A dual-band enhanced-bandwidth microstrip antenna is presented with a frequency separation of f2/... more A dual-band enhanced-bandwidth microstrip antenna is presented with a frequency separation of f2/f1=1.37. In order to achieve the dual-frequency operation, a rectangular patch antenna is reactively loaded with a stub placed along one of the radiating edges. Then, the bandwidth is enhanced using a stacked parasitic technique, whereas the matching and radiation characteristics are kept constant along each band and
IEEE Transactions on Antennas and Propagation, 2006
Abstract A triple-frequency antenna combining a dual-band and a monoband antenna with broadside r... more Abstract A triple-frequency antenna combining a dual-band and a monoband antenna with broadside radiation patterns is presented. The dual-band antenna is inspired in the Sierpinski fractal. Such a dual-band antenna is stacked over a monoband antenna. The ...
The localization properties of mass fractal patches are described in this paper for the Sierpinsk... more The localization properties of mass fractal patches are described in this paper for the Sierpinski patch antenna. The localization of the electrical current results in a patch antenna that has two localized modes with a frequency ratio of two and a directivity of 12.2 dB and 14.7 dB respectively.
IEEE Microwave and Wireless Components Letters, 2003
A multifrequency microstrip patch antenna comprised of a driven patch and a plurality of parasiti... more A multifrequency microstrip patch antenna comprised of a driven patch and a plurality of parasitic elements placed underneath a driven patch is proposed. The antenna features a multifrequency behavior (five operating band) with similar gain.
IEEE Antennas and Wireless Propagation Letters, 2003
A microstrip antenna formed by two stacked patches is proposed for dual-frequency and broad-band ... more A microstrip antenna formed by two stacked patches is proposed for dual-frequency and broad-band performance. Different E-plane and H-plane arrangements are studied to achieve an isolation between bands better than 30 dB. A prototype operating at the 1.8 GHz and 3.5 GHz bands has been simulated and tested.
... Iterative network model : The iterative network model is a simple, fast, numerical model that... more ... Iterative network model : The iterative network model is a simple, fast, numerical model that predicts the input parameters (input reflection coefficient and input impedance) of an antenna or cir-cuit whose topology is that of the Sierpinski gasket fractal shape. ...
Abstract The main interest in the design of a miniature microstrip patch antenna (MPA) is its sma... more Abstract The main interest in the design of a miniature microstrip patch antenna (MPA) is its small size in conjunction with the well-known advantages of a MPA (cost, profile, weight). However there is a big constraint on the bandwidth limitation either in a miniature antenna ...
It is well known that microstrip patch antennas have a poor bandwidth due to the small spacing be... more It is well known that microstrip patch antennas have a poor bandwidth due to the small spacing between the patch and the ground plane. A stacked patch configuration has been demonstrated experimentally as a feasible solution, but little information on the design procedure is available. Here, a systematic design procedure based on a single network model is shown.
The article shows that a patch antenna with fractal boundary exhibits, at a frequencies above the... more The article shows that a patch antenna with fractal boundary exhibits, at a frequencies above the fundamental mode, localized modes. These modes can have broadside directive patterns. As an example of this phenomenon experimental data on the Koch island patch antenna is presented.
IEEE Transactions on Antennas and Propagation, 2003
The properties of the Koch island fractal boundary microstrip patch antenna are presented. The be... more The properties of the Koch island fractal boundary microstrip patch antenna are presented. The behavior at the fundamental mode and the existence of high-order modes that exhibit localized current density distributions is discussed. The main features are the size reduction of the patch resonating at the fundamental frequency when compared to Euclidean-shaped patches, and the application of localized modes in designing microstrip patch antennas with directive patterns.
The unique geometrical properties of fractals have been proven to be useful to design advanced an... more The unique geometrical properties of fractals have been proven to be useful to design advanced antennas. Enhanced performance in terms of size, gain or multiband behaviour is observed in fractal-shaped antennas. Here, a small and high directivity antenna based on the Sierpinski bowtie geometry is presented.
Miniature behaviour of microstrip antennas with Sierpinski bowtie geometry is investigated and th... more Miniature behaviour of microstrip antennas with Sierpinski bowtie geometry is investigated and the existence of fracton modes is studied. A fracton mode is a mode found at a higher frequency than the one obtained for the fundamental mode. The antenna presents as many fracton-modes as fractal iterations. These fracton modes are interesting because they provide a broadside radiation pattern with higher directivity than that obtained from the fundamental mode.
Progress in Electromagnetics Research Letters, 2009
A dual-band enhanced-bandwidth microstrip antenna is presented with a frequency separation of f 2... more A dual-band enhanced-bandwidth microstrip antenna is presented with a frequency separation of f 2 /f 1 = 1.33. In order to achieve the dual-frequency operation, a rectangular patch is loaded with a stub at one of its radiating edges. To improve bandwidth at each band, two parasitic patches are coupled to the driven element.
The paper introduces both a new internal FM antenna for mobile phones based on the fractal Hilber... more The paper introduces both a new internal FM antenna for mobile phones based on the fractal Hilbert curve, and a new evaluation criterion for quantifying the quality of the signal received by the FM antenna of mobile phones. The main attribute of the new internal FM antenna is its reduced size; which is only 30⋆10⋆1 mm3. The measurements demonstrate that the power received by the internal FM antenna is 20 dB lower than the power received by the external wire antenna under the same measurement conditions. Despite the reduction of the power level, the evaluation criterion reveals that, owing to the threshold effect in FM receivers, the signal quality indicator is similar for both antennas. Additionally, the value of the signal quality indicator achieved by both antennas guarantees to listen to the FM radio channels clearly without noise nuisance and without interferences.
IEEE Antennas and Wireless Propagation Letters, 2007
A dual-band enhanced-bandwidth microstrip antenna is presented with a frequency separation of f2/... more A dual-band enhanced-bandwidth microstrip antenna is presented with a frequency separation of f2/f1=1.37. In order to achieve the dual-frequency operation, a rectangular patch antenna is reactively loaded with a stub placed along one of the radiating edges. Then, the bandwidth is enhanced using a stacked parasitic technique, whereas the matching and radiation characteristics are kept constant along each band and
IEEE Transactions on Antennas and Propagation, 2006
Abstract A triple-frequency antenna combining a dual-band and a monoband antenna with broadside r... more Abstract A triple-frequency antenna combining a dual-band and a monoband antenna with broadside radiation patterns is presented. The dual-band antenna is inspired in the Sierpinski fractal. Such a dual-band antenna is stacked over a monoband antenna. The ...
The localization properties of mass fractal patches are described in this paper for the Sierpinsk... more The localization properties of mass fractal patches are described in this paper for the Sierpinski patch antenna. The localization of the electrical current results in a patch antenna that has two localized modes with a frequency ratio of two and a directivity of 12.2 dB and 14.7 dB respectively.
IEEE Microwave and Wireless Components Letters, 2003
A multifrequency microstrip patch antenna comprised of a driven patch and a plurality of parasiti... more A multifrequency microstrip patch antenna comprised of a driven patch and a plurality of parasitic elements placed underneath a driven patch is proposed. The antenna features a multifrequency behavior (five operating band) with similar gain.
IEEE Antennas and Wireless Propagation Letters, 2003
A microstrip antenna formed by two stacked patches is proposed for dual-frequency and broad-band ... more A microstrip antenna formed by two stacked patches is proposed for dual-frequency and broad-band performance. Different E-plane and H-plane arrangements are studied to achieve an isolation between bands better than 30 dB. A prototype operating at the 1.8 GHz and 3.5 GHz bands has been simulated and tested.
... Iterative network model : The iterative network model is a simple, fast, numerical model that... more ... Iterative network model : The iterative network model is a simple, fast, numerical model that predicts the input parameters (input reflection coefficient and input impedance) of an antenna or cir-cuit whose topology is that of the Sierpinski gasket fractal shape. ...
Abstract The main interest in the design of a miniature microstrip patch antenna (MPA) is its sma... more Abstract The main interest in the design of a miniature microstrip patch antenna (MPA) is its small size in conjunction with the well-known advantages of a MPA (cost, profile, weight). However there is a big constraint on the bandwidth limitation either in a miniature antenna ...
It is well known that microstrip patch antennas have a poor bandwidth due to the small spacing be... more It is well known that microstrip patch antennas have a poor bandwidth due to the small spacing between the patch and the ground plane. A stacked patch configuration has been demonstrated experimentally as a feasible solution, but little information on the design procedure is available. Here, a systematic design procedure based on a single network model is shown.
The article shows that a patch antenna with fractal boundary exhibits, at a frequencies above the... more The article shows that a patch antenna with fractal boundary exhibits, at a frequencies above the fundamental mode, localized modes. These modes can have broadside directive patterns. As an example of this phenomenon experimental data on the Koch island patch antenna is presented.
Uploads
Papers by Carmen Borja