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A Neto - One of the best experts on this subject based on the ideXlab platform.

  • norton equivalent circuit for pulsed photoconductive Antennas part i theoretical model
    IEEE Transactions on Antennas and Propagation, 2018
    Co-Authors: Alessandro Garufo, Giorgio Carluccio, Nuria Llombart, A Neto
    Abstract:

    A novel equivalent circuit for pulsed photoconductive sources is introduced for describing the coupling between the photoconductive gap and the Antenna. The proposed circuit effectively describes the mechanism of feeding the Antenna by the semiconductor when this latter is illuminated by a laser operating in a pulsed mode. Starting from the classical continuity equation, which models the free carriers’ density with respect to the laser power pump and the semiconductor features, a Norton equivalent circuit in the frequency domain is derived. According to the Norton theorem, the equivalent source representation is decoupled from the Antenna. In particular, for photoconductive Antennas (PCAs), the Norton circuit takes into account of the electrical and optical properties of the semiconductor material, the features of the laser excitation, as well as the geometrical dimensions of the gap. The presence of the electrodes around the gap is part of the Antenna and, therefore, it is taken into account in the Antenna Impedance. The proposed circuit allows the analysis of the coupling between the photoconductive source and the Antenna, providing a tool to analyze and design PCAs.

  • effect of internal reflections on the radiation properties and input Impedance of integrated lens Antennas comparison between theory and measurements
    IEEE Transactions on Microwave Theory and Techniques, 2001
    Co-Authors: M J M Van Der Vorst, A Neto, P De Maagt, A L Reynolds, R M Heeres, W Luinge, M H A J Herben
    Abstract:

    This paper presents the effect of internal reflections on the beam pattern and input Impedance of integrated lens Antennas. A silicon lens was designed and manufactured, and measurements were conducted at a frequency of 100 (Impedance) and 500 GHz (beam pattern). A frequency-dependence characterization of the beam pattern clearly showed the existence and impact of internal reflections. The measurements confirmed that most of the frequency variations of the beam pattern could be attributed to internal reflections, as predicted by the model. An on-wafer measurement strategy for determining the Antenna Impedance at millimeter-wave frequencies is presented. The validity of the model was also proven by an excellent match of the input Impedance measurements and predictions. Not only the level, but also the oscillation on the Impedance curve was predicted accurately. Initial space qualification was performed in the form of thermal cycling.

M Ali - One of the best experts on this subject based on the ideXlab platform.

  • Effects of EBG Reflection Phase Profiles on the Input Impedance and Bandwidth of Ultrathin Directional
    2016
    Co-Authors: M Ali, Faisal M. Abedin, Student Member, Senior Member
    Abstract:

    Abstract—A comprehensive study of the effects of the reflection phase profiles on dipole Antennas is presented with the ultimate objective of designing ultrathin printed dipoles (as thin as one hundredth of the wavelength). Dipole driving-point Impedance and bandwidth are studied as function of various electromagnetic bandgap (EBG) reflection phase profiles. It is demonstrated that although many different reflection phase profiles can be generated for a certain Antenna height, it is the profile that satisfies a specific range of reflection phase angles that is required to achieve good Antenna performance. Such optimum EBG phase profiles are generated for a number of Antenna heights and their influence on a dipole Antenna Impedance and bandwidth are also studied. Finally, an actual EBG structure and a printed dipole Antenna are designed, fabricated and tested. The overall Antenna height for this case was 0 03. The computed and measured results show that efficient printed dipoles on ultrathin grounded dielectric substrates can be developed that will substantially reduce the sizes and weight of large arrays. Index Terms—electromagnetic bandgap (EBG), input Impedance, low-profile, reflection phase

  • effects of ebg reflection phase profiles on the input Impedance and bandwidth of ultrathin directional dipoles
    IEEE Transactions on Antennas and Propagation, 2005
    Co-Authors: M F Abedin, M Ali
    Abstract:

    A comprehensive study of the effects of the reflection phase profiles on dipole Antennas is presented with the ultimate objective of designing ultrathin printed dipoles (as thin as one hundredth of the wavelength). Dipole driving-point Impedance and bandwidth are studied as function of various electromagnetic bandgap (EBG) reflection phase profiles. It is demonstrated that although many different reflection phase profiles can be generated for a certain Antenna height, it is the profile that satisfies a specific range of reflection phase angles that is required to achieve good Antenna performance. Such optimum EBG phase profiles are generated for a number of Antenna heights and their influence on a dipole Antenna Impedance and bandwidth are also studied. Finally, an actual EBG structure and a printed dipole Antenna are designed, fabricated and tested. The overall Antenna height for this case was 0.03/spl lambda/. The computed and measured results show that efficient printed dipoles on ultrathin grounded dielectric substrates can be developed that will substantially reduce the sizes and weight of large arrays.

M F Abedin - One of the best experts on this subject based on the ideXlab platform.

  • effects of ebg reflection phase profiles on the input Impedance and bandwidth of ultrathin directional dipoles
    IEEE Transactions on Antennas and Propagation, 2005
    Co-Authors: M F Abedin, M Ali
    Abstract:

    A comprehensive study of the effects of the reflection phase profiles on dipole Antennas is presented with the ultimate objective of designing ultrathin printed dipoles (as thin as one hundredth of the wavelength). Dipole driving-point Impedance and bandwidth are studied as function of various electromagnetic bandgap (EBG) reflection phase profiles. It is demonstrated that although many different reflection phase profiles can be generated for a certain Antenna height, it is the profile that satisfies a specific range of reflection phase angles that is required to achieve good Antenna performance. Such optimum EBG phase profiles are generated for a number of Antenna heights and their influence on a dipole Antenna Impedance and bandwidth are also studied. Finally, an actual EBG structure and a printed dipole Antenna are designed, fabricated and tested. The overall Antenna height for this case was 0.03/spl lambda/. The computed and measured results show that efficient printed dipoles on ultrathin grounded dielectric substrates can be developed that will substantially reduce the sizes and weight of large arrays.

Alessandro Garufo - One of the best experts on this subject based on the ideXlab platform.

  • norton equivalent circuit for pulsed photoconductive Antennas part i theoretical model
    IEEE Transactions on Antennas and Propagation, 2018
    Co-Authors: Alessandro Garufo, Giorgio Carluccio, Nuria Llombart, A Neto
    Abstract:

    A novel equivalent circuit for pulsed photoconductive sources is introduced for describing the coupling between the photoconductive gap and the Antenna. The proposed circuit effectively describes the mechanism of feeding the Antenna by the semiconductor when this latter is illuminated by a laser operating in a pulsed mode. Starting from the classical continuity equation, which models the free carriers’ density with respect to the laser power pump and the semiconductor features, a Norton equivalent circuit in the frequency domain is derived. According to the Norton theorem, the equivalent source representation is decoupled from the Antenna. In particular, for photoconductive Antennas (PCAs), the Norton circuit takes into account of the electrical and optical properties of the semiconductor material, the features of the laser excitation, as well as the geometrical dimensions of the gap. The presence of the electrodes around the gap is part of the Antenna and, therefore, it is taken into account in the Antenna Impedance. The proposed circuit allows the analysis of the coupling between the photoconductive source and the Antenna, providing a tool to analyze and design PCAs.

Chean Khan Goh - One of the best experts on this subject based on the ideXlab platform.

  • Impedance characterization of rfid tag Antennas and application in tag co design
    IEEE Transactions on Microwave Theory and Techniques, 2009
    Co-Authors: Xianming Qing, Chean Khan Goh
    Abstract:

    In this paper, an experimental methodology for the characterization of the Impedance of balanced RF identification (RFID) tag Antennas is presented, and the application of the proposed method in RFID tag co-design is demonstrated. The balanced tag Antenna is considered as a two-port network and the Impedance of the Antenna is characterized using network parameters. In the measurement, the Antenna is connected to the two ports of a vector network analyzer through a test fixture. The influence of the test fixture is deembedded by using a port-extension technique and the Antenna Impedance can be extracted directly from the measured S -parameters. The proposed method is useful in practical RFID applications for co-designing the RFID tag with the attached platforms for enhancing the tag performance. An example of co-designing an ultra-high-frequency RFID tag with a plastic Sushi plate is demonstrated. The co-designed tag Antenna achieves conjugate matching with the application-specific integrated circuit so that the reading range of the RFID tag is greatly enhanced.