Ata Khalid | University of Glasgow (original) (raw)
Papers by Ata Khalid
Microwave and Optical Technology Letters, 2014
ABSTRACT In this article, the resonant frequency and quality factor of a novel coplanar waveguide... more ABSTRACT In this article, the resonant frequency and quality factor of a novel coplanar waveguide (cpw) diamond-shaped resonator were analyzed using advanced design system-2009 momentum model software. The diamond resonator was compared with the cpw radial stub resonator on gallium arsenide (GaAs); the work indicated that the diamond resonator had a smaller physical size and higher quality factor (Q) at millimetric wave frequencies. Experimentally measured diamond cpw resonators fabricated on GaAs were in good agreement with the simulated results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1691–1693, 2014
26th International Conference on Indium Phosphide and Related Materials (IPRM), 2014
ABSTRACT We present, for the first time, the fabrication process for a submicron planar Gunn diod... more ABSTRACT We present, for the first time, the fabrication process for a submicron planar Gunn diode in In0.53Ga0.47As on an InP substrate operating at 265 GHz. A novel two stage lift off method has been developed to achieve a submicron gaps between contacts down to 135 nm with widths up to 120 μm.
Conference on Lasers and Electro-Optics, 2016
Solid-State Electronics, 2016
Microelectronic Engineering, Apr 1, 2009
IEEE Transactions on Electron Devices, 2015
Millimetre Wave and Terahertz Sensors and Technology VIII, 2015
2015 11th Conference on Ph.D. Research in Microelectronics and Electronics (PRIME), 2015
2015 11th Conference on Ph.D. Research in Microelectronics and Electronics (PRIME), 2015
2015 11th Conference on Ph.D. Research in Microelectronics and Electronics (PRIME), 2015
35th International Conference on Infrared, Millimeter, and Terahertz Waves, 2010
ABSTRACT In this paper, we demonstrate the operation of a truly planar Gunn diode working as a se... more ABSTRACT In this paper, we demonstrate the operation of a truly planar Gunn diode working as a self-oscillating mixer at millimeter-wave frequency. The Gunn diode was fabricated in a GaAs/Al0.23Ga0.77As layer structure. An initial proof-of-concept prototype yielded a measured conversion loss of around 20±2.5 dB between 30 GHz and 40 GHz.
35th International Conference on Infrared, Millimeter, and Terahertz Waves, 2010
ABSTRACT An In0.23Ga0.77As-based planar Gunn diode operating in its fundamental transit-time mode... more ABSTRACT An In0.23Ga0.77As-based planar Gunn diode operating in its fundamental transit-time mode of oscillation at 116 GHz with output power of -24 dBm is demonstrated. The diode has a pseudomorhpic HEMT-like structure grown on a semi-insulating GaAs substrate. The layer design was carried out using a two-dimensional drift-diffusion model. The realized devices show considerable potential as a source of millimeter-wave and even terahertz radiation.
2015 11th Conference on Ph.D. Research in Microelectronics and Electronics (PRIME), 2015
2nd IET Annual Active and Passive RF Devices Seminar, 2014
IEEE MTT/ED/AP/LEO Societies Joint Chapter United Kingdom and Republic of Ireland Section. 1997 Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications. EDMO (Cat. No.97TH8305), 1997
IEEE MTT/ED/AP/LEO Societies Joint Chapter United Kingdom and Republic of Ireland Section. 1997 Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications. EDMO (Cat. No.97TH8305), 1997
The dc characteristics of a graded AlGaAs/GaAs single HBT (SHBT) and an abrupt InGaP/GaAs double ... more The dc characteristics of a graded AlGaAs/GaAs single HBT (SHBT) and an abrupt InGaP/GaAs double HBT (DHBT) are studied using a thermionic-field emission boundary condition model. The model incorporates tunnelling and thermionic emission into a one-dimensional drift-diffusion numerical scheme and accounts for carrier degeneracy and bandgap narrowing. To our best knowledge, this is the first ever reported numerical analysis of
CAS 2010 Proceedings (International Semiconductor Conference), 2010
Planar Gunn diodes have been scaled vertically through combining multiple active epilayer stacks ... more Planar Gunn diodes have been scaled vertically through combining multiple active epilayer stacks present in previously successful GaAs/AlGaAs devices. Comparison of results from fabricated devices with those simulated using a Monte Carlo approach suggest that while current and power output rises in such scaled designs, this is limited by significant heating which results in sub-linear scaling with the number of stacks. The presence of additional current-limiting mechanisms, such as inactive stacks, are implied if considering the higher currents produced by un-scaled designs or scaled devices at below peak temperatures.
Microwave and Optical Technology Letters, 2014
ABSTRACT In this article, the resonant frequency and quality factor of a novel coplanar waveguide... more ABSTRACT In this article, the resonant frequency and quality factor of a novel coplanar waveguide (cpw) diamond-shaped resonator were analyzed using advanced design system-2009 momentum model software. The diamond resonator was compared with the cpw radial stub resonator on gallium arsenide (GaAs); the work indicated that the diamond resonator had a smaller physical size and higher quality factor (Q) at millimetric wave frequencies. Experimentally measured diamond cpw resonators fabricated on GaAs were in good agreement with the simulated results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1691–1693, 2014
26th International Conference on Indium Phosphide and Related Materials (IPRM), 2014
ABSTRACT We present, for the first time, the fabrication process for a submicron planar Gunn diod... more ABSTRACT We present, for the first time, the fabrication process for a submicron planar Gunn diode in In0.53Ga0.47As on an InP substrate operating at 265 GHz. A novel two stage lift off method has been developed to achieve a submicron gaps between contacts down to 135 nm with widths up to 120 μm.
Conference on Lasers and Electro-Optics, 2016
Solid-State Electronics, 2016
Microelectronic Engineering, Apr 1, 2009
IEEE Transactions on Electron Devices, 2015
Millimetre Wave and Terahertz Sensors and Technology VIII, 2015
2015 11th Conference on Ph.D. Research in Microelectronics and Electronics (PRIME), 2015
2015 11th Conference on Ph.D. Research in Microelectronics and Electronics (PRIME), 2015
2015 11th Conference on Ph.D. Research in Microelectronics and Electronics (PRIME), 2015
35th International Conference on Infrared, Millimeter, and Terahertz Waves, 2010
ABSTRACT In this paper, we demonstrate the operation of a truly planar Gunn diode working as a se... more ABSTRACT In this paper, we demonstrate the operation of a truly planar Gunn diode working as a self-oscillating mixer at millimeter-wave frequency. The Gunn diode was fabricated in a GaAs/Al0.23Ga0.77As layer structure. An initial proof-of-concept prototype yielded a measured conversion loss of around 20±2.5 dB between 30 GHz and 40 GHz.
35th International Conference on Infrared, Millimeter, and Terahertz Waves, 2010
ABSTRACT An In0.23Ga0.77As-based planar Gunn diode operating in its fundamental transit-time mode... more ABSTRACT An In0.23Ga0.77As-based planar Gunn diode operating in its fundamental transit-time mode of oscillation at 116 GHz with output power of -24 dBm is demonstrated. The diode has a pseudomorhpic HEMT-like structure grown on a semi-insulating GaAs substrate. The layer design was carried out using a two-dimensional drift-diffusion model. The realized devices show considerable potential as a source of millimeter-wave and even terahertz radiation.
2015 11th Conference on Ph.D. Research in Microelectronics and Electronics (PRIME), 2015
2nd IET Annual Active and Passive RF Devices Seminar, 2014
IEEE MTT/ED/AP/LEO Societies Joint Chapter United Kingdom and Republic of Ireland Section. 1997 Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications. EDMO (Cat. No.97TH8305), 1997
IEEE MTT/ED/AP/LEO Societies Joint Chapter United Kingdom and Republic of Ireland Section. 1997 Workshop on High Performance Electron Devices for Microwave and Optoelectronic Applications. EDMO (Cat. No.97TH8305), 1997
The dc characteristics of a graded AlGaAs/GaAs single HBT (SHBT) and an abrupt InGaP/GaAs double ... more The dc characteristics of a graded AlGaAs/GaAs single HBT (SHBT) and an abrupt InGaP/GaAs double HBT (DHBT) are studied using a thermionic-field emission boundary condition model. The model incorporates tunnelling and thermionic emission into a one-dimensional drift-diffusion numerical scheme and accounts for carrier degeneracy and bandgap narrowing. To our best knowledge, this is the first ever reported numerical analysis of
CAS 2010 Proceedings (International Semiconductor Conference), 2010
Planar Gunn diodes have been scaled vertically through combining multiple active epilayer stacks ... more Planar Gunn diodes have been scaled vertically through combining multiple active epilayer stacks present in previously successful GaAs/AlGaAs devices. Comparison of results from fabricated devices with those simulated using a Monte Carlo approach suggest that while current and power output rises in such scaled designs, this is limited by significant heating which results in sub-linear scaling with the number of stacks. The presence of additional current-limiting mechanisms, such as inactive stacks, are implied if considering the higher currents produced by un-scaled designs or scaled devices at below peak temperatures.