Manos Karaboikis | University of Patras (original) (raw)

Papers by Manos Karaboikis

A SISO (Single Input Single Output) and a SIMO (Single Input Multiple Output) wireless transmissi... more A SISO (Single Input Single Output) and a SIMO (Single Input Multiple Output) wireless transmission system operating in a Rayleigh distributed environment at the 434 MHz ISM band are investigated. The two systems are simulated using the Finite Difference Time Domain (FDTD) method, which enables the simultaneous characterization of the propagation channel and the immersed wire dipoles antennas. A novel procedure to evaluate the method's accuracy for this type of systems is introduced, through the convergence of the SISO system's Transfer Function (H). The results show that a numerical phase error of 1 o per wavelength is acceptable for accurate estimation of H for a propagation distance of about 12 wavelengths. Moreover, the instantaneous correlation coefficient and the received power ratio versus dipoles' separation distance are estimated and presented for the SIMO system.

In this paper the diversity performance of several multi element antenna configurations consistin... more In this paper the diversity performance of several multi element antenna configurations consisting of a novel fractal rectangular curve patch antenna is studied. The fractal rectangular curve microstrip antenna was chosen due to its very good size reduction ability without compromising significantly on the bandwidth and efficiency. The evaluation of the diversity performance was conducted by means of calculating the envelope correlation coefficient, the mean effective gain and the effective diversity gain of the proposed configurations.

A SISO (Single Input Single Output) and a SIMO (Single Input Multiple Output) wireless transmissi... more A SISO (Single Input Single Output) and a SIMO (Single Input Multiple Output) wireless transmission system operating in a Rayleigh distributed environment at the 434 MHz ISM band are investigated. The two systems are simulated using the Finite Difference Time Domain (FDTD) method, which enables the simultaneous characterization of the propagation channel and the immersed wire dipoles antennas. A novel procedure to evaluate the method's accuracy for this type of systems is introduced, through the convergence of the SISO system's Transfer Function (H). The results show that a numerical phase error of 1 o per wavelength is acceptable for accurate estimation of H for a propagation distance of about 12 wavelengths. Moreover, the instantaneous correlation coefficient and the received power ratio versus dipoles' separation distance are estimated and presented for the SIMO system.

Compact multi element antenna systems for diversity and MIMO terminal devices operating at the 5.... more Compact multi element antenna systems for diversity and MIMO terminal devices operating at the 5.2 GHz ISM band under combining schemes are presented. The diversity performance is evaluated by means of the calculated envelope correlation coefficient, the mean effective gain and the effective diversity gain of the antennas. It is shown that by increasing the number of antenna elements the diversity gain increases in an asymptotic manner, which is attributed to the reduction of the antennas' efficiency.

IEEE Antennas and Wireless Propagation Letters, 2000

Dual-printed inverted-F antenna diversity systems for terminal devices operating at 5.2 GHz under... more Dual-printed inverted-F antenna diversity systems for terminal devices operating at 5.2 GHz under both switched and combining schemes are presented. Diversity performance is evaluated by means of the calculated envelope correlation coefficient, the mean effective gain and the effective diversity gain of the two antennas. An investigation for the antennas' placement and the corrugated ground plane effect on the performance of the system has also been conducted. It is shown that many configurations can provide uncorrelated signals of the same power level, but with significantly different radiation pattern complementarity, antenna efficiency, and effective diversity gain.

IEEE Antennas and Propagation Magazine, 2002

IEEE Transactions on Antennas and Propagation, 2004

The traditional Sierpinski gasket monopole antenna is well known for its multiband behavior, but ... more The traditional Sierpinski gasket monopole antenna is well known for its multiband behavior, but it cannot be printed on the circuit board of a portable wireless device due to the limited space availability. In this paper a modified Sierpinski gasket monopole antenna is presented that possesses a small physical size, high efficiency and the ability to allocate both the 2.4 and 5.2 GHz Industrial Scientific and Medical bands without the need of a matching network. The modified element respects the multiband behavior of the gasket since the input impedance characteristics of the upper bands maintain their symmetry. Several modification techniques are proposed making the monopole very flexible in terms of band allocation and fine-tuning. The dimensions of the ground plane are also proven to play a significant role on the operational bandwidth of the antenna system.

Microwave and Optical Technology Letters, 2004

The experiment results show that in the 10-Gb/s transmission system through G.652 fiber with disp... more The experiment results show that in the 10-Gb/s transmission system through G.652 fiber with dispersion compensated completely by FBGs, the PMD dispersion compensation is not necessary. But the PMD compensation cannot be neglected in the 40-Gb/s transmission system. It has been demonstrated that PMD induced by FBG can be compensated by using a short length of PMF. This PMD compensator is tested in the 40-Gb/s 122-km transmission system, showing good results. The same technique of PMD compensation could be extended to other devices introducing PMD in a deterministic fashion.

The design of small antennas printed on short range radio devices plays a significant role in mod... more The design of small antennas printed on short range radio devices plays a significant role in modern wireless communications. This paper addresses the analysis and design of a modified Sierpinski gasket monopole antenna printed on a PCMCIA card. The antenna/PCMCIA card system was simulated using two commercial Method of Moment codes (IE3D and Momentum). The integrated antenna/PCMCIA card system exhibits three resonances with the first two occurring in the 2.4 and 5.15 GHz ISM bands, incorporating favorable characteristics such as good omni-directional radiation patterns and efficiency. The proposed antenna can thus be used on future PCMCIA cards operating in the 5.15 GHz ISM band and at the same time maintain a backward compatibility with the current 2.4 GHz band.

A novel fractal rectangular curve monopole antenna is introduced and its input impedance characte... more A novel fractal rectangular curve monopole antenna is introduced and its input impedance characteristics are examined based on simulation results. The investigated fractal rectangular curve resonates at 2.45 GHz ISM band occupying the smallest area as compared to previously published printed fractal monopole geometries. Moreover, this novel geometry exhibited a very wide bandwidth and a high input resistance notwithstanding its very compact size.

In this paper a printed fractal Minkowski monopole is presented for use in wireless terminal devi... more In this paper a printed fractal Minkowski monopole is presented for use in wireless terminal devices utilizing single and multi element antenna systems. In the case of a single element system the effect of the antenna's placement with respect to the ground plane is examined and a method to fine tune the system in its worst case situation is proposed. The influence of the ground plane dimensions on the system's impedance and radiation characteristics is also investigated and general conclusions are drawn. Subsequently, a four element antenna system for diversity applications is investigated. The diversity performance is evaluated by means of the envelope correlation coefficient, the mean effective gain and the effective diversity gain. The impact of the mutual coupling on the system's performance is also addressed.

2003 IEEE International Symposium on Electromagnetic Compatibility, 2003. EMC '03., 2003

A novel fractal rectangular curve microstrip antenna is investigated as an efficient scheme of mi... more A novel fractal rectangular curve microstrip antenna is investigated as an efficient scheme of miniaturization. Based on simulation results the element possesses good size reduction ability without compromising significantly on the antenna's bandwidth and efficiency. The radiation patterns between the conventional quarter wavelength patch and the shorted fractal element are similar, concluding that the latter can be used to replace the former. Moreover, the novel geometry has several degrees of freedom that can be used to either reduce further the size of the antenna or keep the bandwidth to a satisfactory level. The novel geometry was also considered for production of circular polarization and exhibited very good results.

Automatika, 2004

In this paper a printed fractal Minkowski monopole is presented for use in wireless terminal devi... more In this paper a printed fractal Minkowski monopole is presented for use in wireless terminal devices utilizing single and multi element antenna systems. In the case of a single element system the effect of the antenna's placement with respect to the ground plane is examined and a method to fine tune the system in its worst case situation is proposed. The influence of the ground plane dimensions on the system's impedance and radiation characteristics is also investigated and general conclusions are drawn. Subsequently, a four element antenna system for diversity applications is investigated. The diversity performance is evaluated by means of the envelope correlation coefficient, the mean effective gain and the effective diversity gain. The impact of the mutual coupling on the system's performance is also addressed.

2007 19th International Conference on Applied Electromagnetics and Communications, 2007

The diversity and Multiple Input Multiple Output (MIMO) performance provided by common phase cent... more The diversity and Multiple Input Multiple Output (MIMO) performance provided by common phase center multi element antenna (CPCMEA) systems is evaluated using two practical methods which make use of the realized active element antenna patterns. These patterns include both the impact of the mutual coupling and the mismatch power loss at antenna ports. As a case study, two and four printed Inverted F Antenna (IFA)

2003 IEEE International Symposium on Electromagnetic Compatibility, 2003. EMC '03., 2003

Three-branch antenna diversity systems using various monopoles printed on wireless devices are de... more Three-branch antenna diversity systems using various monopoles printed on wireless devices are demonstrated. The antenna elements used are the Inverted F, the Koch and the Minkowski monopole. Computed results for the return losses and the radiation patterns are presented. The calculated envelope cross correlation and mean effective gain of the antennas satisfy the criteria for achieving good diversity performance. The impact of the mutual coupling between the antenna elements on their radiation efficiency and mean effective gain is also addressed.

17th International Conference on Applied Electromagnetics and Communications, 2003. ICECom 2003., 2003

Four-element antenna diversity systems suitable for operation in diversity and MIMO wireless devi... more Four-element antenna diversity systems suitable for operation in diversity and MIMO wireless devices for single (2.4 or 5.2 GHz) and dual band operation are addressed. The antenna elements used are the Minkowski, the Inverted F and the Koch monopole. The calculated envelope cross correlation and mean effective gain of the antennas satisfy the criteria for achieving good diversity performance. The impact of the mutual coupling between the antenna elements on their radiation efficiency and mean effective gain is also addressed indicating that the type of the antennas, their placement and their electrical distance are key parameters in the design of an efficient multi element antenna system.

17th International Conference on Applied Electromagnetics and Communications, 2003. ICECom 2003., 2003

This paper concentrates on a printed Minkowski monopole antenna that uses the ground plane as an ... more This paper concentrates on a printed Minkowski monopole antenna that uses the ground plane as an active part of the radiating system. The effect of the antenna's placement on the input impedance characteristics of the antenna-ground system is initially investigated and a method to fine tune the system in its worst case is proposed. The influence of the ground plane dimensions on the resonant frequency, bandwidth and input resistance are also examined.

The integration of compact printed multielement antenna (MEA) systems on small diversity and mult... more The integration of compact printed multielement antenna (MEA) systems on small diversity and multiple input multiple output (MIMO) terminal devices operating in the 5.2 GHz Industrial, Scientific and Medical (ISM) band is presented. The investigated MEA systems comprise up to six printed elements (inverted F and Minkowski monopole antennas) and their performance is evaluated by means of the effective diversity gain (EDG) and the 1% outage MIMO capacity. The role of the propagation environment (both outdoor and indoor) on EDG is examined, proving that the uniform scenario is a good approximation to many real environments. The tradeoff study between system's performance and number of integrated antenna elements indicates that both diversity and MIMO performance saturate when placing more than five closely spaced elements. Even the least efficient 6-element system however, can be advantageously used as a reconfigurable 2-element array under the concept of receive antenna selection, since it provides significantly improved MIMO performance over a conventional 2-element fixed one. The paper concludes with a summary of useful guidelines for the MEA design optimization procedure that emanated from this study.

A SISO (Single Input Single Output) and a SIMO (Single Input Multiple Output) wireless transmissi... more A SISO (Single Input Single Output) and a SIMO (Single Input Multiple Output) wireless transmission system operating in a Rayleigh distributed environment at the 434 MHz ISM band are investigated. The two systems are simulated using the Finite Difference Time Domain (FDTD) method, which enables the simultaneous characterization of the propagation channel and the immersed wire dipoles antennas. A novel procedure to evaluate the method's accuracy for this type of systems is introduced, through the convergence of the SISO system's Transfer Function (H). The results show that a numerical phase error of 1 o per wavelength is acceptable for accurate estimation of H for a propagation distance of about 12 wavelengths. Moreover, the instantaneous correlation coefficient and the received power ratio versus dipoles' separation distance are estimated and presented for the SIMO system.

In this paper the diversity performance of several multi element antenna configurations consistin... more In this paper the diversity performance of several multi element antenna configurations consisting of a novel fractal rectangular curve patch antenna is studied. The fractal rectangular curve microstrip antenna was chosen due to its very good size reduction ability without compromising significantly on the bandwidth and efficiency. The evaluation of the diversity performance was conducted by means of calculating the envelope correlation coefficient, the mean effective gain and the effective diversity gain of the proposed configurations.

A SISO (Single Input Single Output) and a SIMO (Single Input Multiple Output) wireless transmissi... more A SISO (Single Input Single Output) and a SIMO (Single Input Multiple Output) wireless transmission system operating in a Rayleigh distributed environment at the 434 MHz ISM band are investigated. The two systems are simulated using the Finite Difference Time Domain (FDTD) method, which enables the simultaneous characterization of the propagation channel and the immersed wire dipoles antennas. A novel procedure to evaluate the method's accuracy for this type of systems is introduced, through the convergence of the SISO system's Transfer Function (H). The results show that a numerical phase error of 1 o per wavelength is acceptable for accurate estimation of H for a propagation distance of about 12 wavelengths. Moreover, the instantaneous correlation coefficient and the received power ratio versus dipoles' separation distance are estimated and presented for the SIMO system.

Compact multi element antenna systems for diversity and MIMO terminal devices operating at the 5.... more Compact multi element antenna systems for diversity and MIMO terminal devices operating at the 5.2 GHz ISM band under combining schemes are presented. The diversity performance is evaluated by means of the calculated envelope correlation coefficient, the mean effective gain and the effective diversity gain of the antennas. It is shown that by increasing the number of antenna elements the diversity gain increases in an asymptotic manner, which is attributed to the reduction of the antennas' efficiency.

IEEE Antennas and Wireless Propagation Letters, 2000

Dual-printed inverted-F antenna diversity systems for terminal devices operating at 5.2 GHz under... more Dual-printed inverted-F antenna diversity systems for terminal devices operating at 5.2 GHz under both switched and combining schemes are presented. Diversity performance is evaluated by means of the calculated envelope correlation coefficient, the mean effective gain and the effective diversity gain of the two antennas. An investigation for the antennas' placement and the corrugated ground plane effect on the performance of the system has also been conducted. It is shown that many configurations can provide uncorrelated signals of the same power level, but with significantly different radiation pattern complementarity, antenna efficiency, and effective diversity gain.

IEEE Antennas and Propagation Magazine, 2002

IEEE Transactions on Antennas and Propagation, 2004

The traditional Sierpinski gasket monopole antenna is well known for its multiband behavior, but ... more The traditional Sierpinski gasket monopole antenna is well known for its multiband behavior, but it cannot be printed on the circuit board of a portable wireless device due to the limited space availability. In this paper a modified Sierpinski gasket monopole antenna is presented that possesses a small physical size, high efficiency and the ability to allocate both the 2.4 and 5.2 GHz Industrial Scientific and Medical bands without the need of a matching network. The modified element respects the multiband behavior of the gasket since the input impedance characteristics of the upper bands maintain their symmetry. Several modification techniques are proposed making the monopole very flexible in terms of band allocation and fine-tuning. The dimensions of the ground plane are also proven to play a significant role on the operational bandwidth of the antenna system.

Microwave and Optical Technology Letters, 2004

The experiment results show that in the 10-Gb/s transmission system through G.652 fiber with disp... more The experiment results show that in the 10-Gb/s transmission system through G.652 fiber with dispersion compensated completely by FBGs, the PMD dispersion compensation is not necessary. But the PMD compensation cannot be neglected in the 40-Gb/s transmission system. It has been demonstrated that PMD induced by FBG can be compensated by using a short length of PMF. This PMD compensator is tested in the 40-Gb/s 122-km transmission system, showing good results. The same technique of PMD compensation could be extended to other devices introducing PMD in a deterministic fashion.

The design of small antennas printed on short range radio devices plays a significant role in mod... more The design of small antennas printed on short range radio devices plays a significant role in modern wireless communications. This paper addresses the analysis and design of a modified Sierpinski gasket monopole antenna printed on a PCMCIA card. The antenna/PCMCIA card system was simulated using two commercial Method of Moment codes (IE3D and Momentum). The integrated antenna/PCMCIA card system exhibits three resonances with the first two occurring in the 2.4 and 5.15 GHz ISM bands, incorporating favorable characteristics such as good omni-directional radiation patterns and efficiency. The proposed antenna can thus be used on future PCMCIA cards operating in the 5.15 GHz ISM band and at the same time maintain a backward compatibility with the current 2.4 GHz band.

A novel fractal rectangular curve monopole antenna is introduced and its input impedance characte... more A novel fractal rectangular curve monopole antenna is introduced and its input impedance characteristics are examined based on simulation results. The investigated fractal rectangular curve resonates at 2.45 GHz ISM band occupying the smallest area as compared to previously published printed fractal monopole geometries. Moreover, this novel geometry exhibited a very wide bandwidth and a high input resistance notwithstanding its very compact size.

In this paper a printed fractal Minkowski monopole is presented for use in wireless terminal devi... more In this paper a printed fractal Minkowski monopole is presented for use in wireless terminal devices utilizing single and multi element antenna systems. In the case of a single element system the effect of the antenna's placement with respect to the ground plane is examined and a method to fine tune the system in its worst case situation is proposed. The influence of the ground plane dimensions on the system's impedance and radiation characteristics is also investigated and general conclusions are drawn. Subsequently, a four element antenna system for diversity applications is investigated. The diversity performance is evaluated by means of the envelope correlation coefficient, the mean effective gain and the effective diversity gain. The impact of the mutual coupling on the system's performance is also addressed.

2003 IEEE International Symposium on Electromagnetic Compatibility, 2003. EMC '03., 2003

A novel fractal rectangular curve microstrip antenna is investigated as an efficient scheme of mi... more A novel fractal rectangular curve microstrip antenna is investigated as an efficient scheme of miniaturization. Based on simulation results the element possesses good size reduction ability without compromising significantly on the antenna's bandwidth and efficiency. The radiation patterns between the conventional quarter wavelength patch and the shorted fractal element are similar, concluding that the latter can be used to replace the former. Moreover, the novel geometry has several degrees of freedom that can be used to either reduce further the size of the antenna or keep the bandwidth to a satisfactory level. The novel geometry was also considered for production of circular polarization and exhibited very good results.

Automatika, 2004

In this paper a printed fractal Minkowski monopole is presented for use in wireless terminal devi... more In this paper a printed fractal Minkowski monopole is presented for use in wireless terminal devices utilizing single and multi element antenna systems. In the case of a single element system the effect of the antenna's placement with respect to the ground plane is examined and a method to fine tune the system in its worst case situation is proposed. The influence of the ground plane dimensions on the system's impedance and radiation characteristics is also investigated and general conclusions are drawn. Subsequently, a four element antenna system for diversity applications is investigated. The diversity performance is evaluated by means of the envelope correlation coefficient, the mean effective gain and the effective diversity gain. The impact of the mutual coupling on the system's performance is also addressed.

2007 19th International Conference on Applied Electromagnetics and Communications, 2007

The diversity and Multiple Input Multiple Output (MIMO) performance provided by common phase cent... more The diversity and Multiple Input Multiple Output (MIMO) performance provided by common phase center multi element antenna (CPCMEA) systems is evaluated using two practical methods which make use of the realized active element antenna patterns. These patterns include both the impact of the mutual coupling and the mismatch power loss at antenna ports. As a case study, two and four printed Inverted F Antenna (IFA)

2003 IEEE International Symposium on Electromagnetic Compatibility, 2003. EMC '03., 2003

Three-branch antenna diversity systems using various monopoles printed on wireless devices are de... more Three-branch antenna diversity systems using various monopoles printed on wireless devices are demonstrated. The antenna elements used are the Inverted F, the Koch and the Minkowski monopole. Computed results for the return losses and the radiation patterns are presented. The calculated envelope cross correlation and mean effective gain of the antennas satisfy the criteria for achieving good diversity performance. The impact of the mutual coupling between the antenna elements on their radiation efficiency and mean effective gain is also addressed.

17th International Conference on Applied Electromagnetics and Communications, 2003. ICECom 2003., 2003

Four-element antenna diversity systems suitable for operation in diversity and MIMO wireless devi... more Four-element antenna diversity systems suitable for operation in diversity and MIMO wireless devices for single (2.4 or 5.2 GHz) and dual band operation are addressed. The antenna elements used are the Minkowski, the Inverted F and the Koch monopole. The calculated envelope cross correlation and mean effective gain of the antennas satisfy the criteria for achieving good diversity performance. The impact of the mutual coupling between the antenna elements on their radiation efficiency and mean effective gain is also addressed indicating that the type of the antennas, their placement and their electrical distance are key parameters in the design of an efficient multi element antenna system.

17th International Conference on Applied Electromagnetics and Communications, 2003. ICECom 2003., 2003

This paper concentrates on a printed Minkowski monopole antenna that uses the ground plane as an ... more This paper concentrates on a printed Minkowski monopole antenna that uses the ground plane as an active part of the radiating system. The effect of the antenna's placement on the input impedance characteristics of the antenna-ground system is initially investigated and a method to fine tune the system in its worst case is proposed. The influence of the ground plane dimensions on the resonant frequency, bandwidth and input resistance are also examined.

The integration of compact printed multielement antenna (MEA) systems on small diversity and mult... more The integration of compact printed multielement antenna (MEA) systems on small diversity and multiple input multiple output (MIMO) terminal devices operating in the 5.2 GHz Industrial, Scientific and Medical (ISM) band is presented. The investigated MEA systems comprise up to six printed elements (inverted F and Minkowski monopole antennas) and their performance is evaluated by means of the effective diversity gain (EDG) and the 1% outage MIMO capacity. The role of the propagation environment (both outdoor and indoor) on EDG is examined, proving that the uniform scenario is a good approximation to many real environments. The tradeoff study between system's performance and number of integrated antenna elements indicates that both diversity and MIMO performance saturate when placing more than five closely spaced elements. Even the least efficient 6-element system however, can be advantageously used as a reconfigurable 2-element array under the concept of receive antenna selection, since it provides significantly improved MIMO performance over a conventional 2-element fixed one. The paper concludes with a summary of useful guidelines for the MEA design optimization procedure that emanated from this study.