Mr James Glover

Job: PhD Student

Faculty: Technology

School/department: School of Engineering and Sustainable Development

Address: De Montfort University, The Gateway, Leicester, LE1 9BH UK

T: +44 (0) 116 2577090

E: james.glover@email.dmu.ac.uk

W: http://www.dmu.ac.uk

 

Personal profile

James Glover received his BEng (Hons) in 2009 from De Montfort University (DMU), Leicester.  He is currently studying for a PhD (also at DMU) in thermal properties and measurements of electronic devices, as part of the Electrical Engineering Group within the Faculty of Technology at De Montfort University.  His PhD is part of an EPSRC funded project to research the integration of on-wafer micro-coolers for III-V planar Gunn diodes.  Supervisor Dr Chris Oxley.

Publications and outputs 

  • The design and thermal measurement of III-V integrated micro-coolers for thermal management of microwave devices
    The design and thermal measurement of III-V integrated micro-coolers for thermal management of microwave devices Glover, James Modern high frequency electronic devices are continually becoming smaller in area but capable of generating higher RF power, thereby increasing the dissipated power density. For many microwave devices, for example the planar Gunn diode, standard thermal management may no longer be sufficient to effectively remove the increasing dissipated power. The work has looked at the design and development of an active micro-cooler, which could be fully integrated with the planar Gunn diode at wafer level as a monolithic microwave integrated circuit (MMIC). The work also resulted in the further development of novel thermal measurement techniques, using micro-particle sensors with infra-red (IR) thermal microscopy and for the first time to measure thermal profiles along the channel of the planar Gunn diode. To integrate the gallium arsenide (GaAs) based planar Gunn diode and micro-cooler, it was first necessary to design and fabricate individual GaAs based planar Gunn diodes and micro-coolers for thermal and electrical characterisation. To obtain very small area micro-coolers, superlattice structures were investigated to improve the ratio between the electrical and thermal conductivities of the micro-cooler. To measure the specific contact resistivity of the superlattice based micro-cooler contacts, the Reeves & Harrison TLM (transmission line method) was used as it included both horizontal and vertical components of the contact resistance. It was found, for the GaAs based micro-cooler, only small amounts of cooling (<0.4 ºC) could be obtained, therefore the novel temperature measurement method using micro-particle sensors placed on both the anode and cathode contacts was utilised. The bias probes used to supply DC power to the micro-coolers were found to thermally load these very small structures, which led to anomalously high measured cooling temperatures of >1 ºC. A novel approach of determining if the measured cooling temperature was due to cooling or probe loading was developed. A 1D model for the integrated micro-cooler was developed and the results indicated that when the micro-cooler was used as a cooling element in a monolithic microwave integrated circuit, the supporting substrate thickness was very important. Simulation showed to obtain cooling the substrate thickness had to be very thin (<50 μm), which may preclude the use of GaAs micro-coolers as part of a monolithic microwave integrated circuit.
  • Micro-coolers fabricated as a component in an integrated circuit
    Micro-coolers fabricated as a component in an integrated circuit Glover, James; Khalid, A.; Stephen, A.; Dunn, G.; Cumming, D.; Oxley, C. H.
  • An AlGaAs/GaAs-Based Planar Gunn Diode Oscillator with a Fundamental Frequency Operation of 120 GHZ
    An AlGaAs/GaAs-Based Planar Gunn Diode Oscillator with a Fundamental Frequency Operation of 120 GHZ Maricar, M.; Glover, James; Khalid, A.; Li, Chong; Evans, Gwynne; Cumming, D.; Oxley, C. H.
  • Design and Characterisation of a Novel Diamond Resonator
    Design and Characterisation of a Novel Diamond Resonator Maricar, M.; Glover, James; Evans, G.; Khalid, A.; Cumming, D.; Oxley, C. H.
  • Extraction of second harmonic from the In0.57Ga0.47As planar Gunn diode using radial stub resonators
    Extraction of second harmonic from the In0.57Ga0.47As planar Gunn diode using radial stub resonators Maricar, M.; Khalid, A.; Glover, James; Evans, Gwynne; Vasileious, P.; Li, Chong; Cumming, D.; Oxley, C. H.
  • Terahertz oscillations in an In0.53Ga0.47As submicron planar Gunn diode
    Terahertz oscillations in an In0.53Ga0.47As submicron planar Gunn diode Khalid, A.; Dunn, G. M.; Macpherson, R. F.; Thoms, S.; Macintyre, D.; Li, C.; Steer, M. J.; Papageorgiou, V.; Thayne, I. G,; Kuball, M.; Oxley, C. H.; Montes Bajo, M.; Stephen, A.; Glover, James; Cumming, D. R. S.
  • Micro-cooler enhancements by barrier interface analysis
    Micro-cooler enhancements by barrier interface analysis Stephen, A.; Dunn, G. M.; Glover, James; Oxley, C. H.; Bajo, M. M.; Cumming, D. R. S.; Khalid, A.; Kuball, M.
  • DSP Control of Smart Antennas
    DSP Control of Smart Antennas Maricar, M.; Bahar, A.; Raju, Y.; Glover, James; Nama, K.; Cross, R. B. M. Modern beam steered antennas where pattern is shaped according to optimum criteria. Smart antennas are the practical realization of adaptive array signal processing. Smart antennas can be applied to mobile wireless communication, WLAN, Wi-Max, MANET, MIMO systems; satellite communication etc. In mobile wireless communication smart antenna can provide higher system capacity by directing narrow beams towards users of interest. Smart antennas mitigate the effects multi-path fading. Smart antennas pattern are controlled via adaptive algorithms based upon maximizing signal to interference ratio, minimizing mean square Error (MSE), steering towards signal of interest, nulling interference. A smart antenna consists of an array of antenna elements (Dipole, Microstrip etc) and uses Digital Signal Processing (DSP) for phase shifting of the signal feed to individual elements of the array. In this paper, we are going to design a DSP control smart antennas array with digital beam forming techniques. Multiple Resonant is achieved by changing the structure of normal patch antenna. These antennas will be suitable for mobile and wireless LAN communication Centre for Electronic and Communications Engineering
  • Improvements in thermionic cooling through engineering of the heterostructure interface using Monte Carlo simulations
    Improvements in thermionic cooling through engineering of the heterostructure interface using Monte Carlo simulations Stephen, A.; Dunn, G. M.; Oxley, C. H.; Glover, James; Montes, Miguel; Cumming, D. R. S.; Khalid, A.; Kuball, M. A self-consistent Ensemble Monte Carlo (EMC) model was developed to simulate the thermionic effect in heterostructure barrier coolers. The model was validated on an InGaAs-InGaAsP heterostructure device of variable barrier height and width, producing good quantitative agreement with previous literature results. The operation of the cooler was found to be a complex and intricate process depending on the field, conduction band and details of barrier structure. When applied to a GaAs-AlGaAs micro-cooler there was good agreement with the experimental results. Importantly, very small alterations in the barrier structure were found to lead to considerable changes in device performance
  • Impact ionisation electroluminescence in planar GaAs-based heterostructure gunn diodes: spatial distribution and impact of doping non-uniformities
    Impact ionisation electroluminescence in planar GaAs-based heterostructure gunn diodes: spatial distribution and impact of doping non-uniformities Stephen, A.; Khalid, A.; Cumming, D. R. S.; Oxley, C. H.; Glover, James; Kuball, M.; Montes, Miguel; Dunn, G. When biased on the negative differential resistance regime, electroluminescence (EL) is emitted from planar GaAs heterostructure Gunn diodes due to the recombination of electrons in the device channel with holes that are generated by impact ionisation when the Gunn domains reach the anode edge. This EL forms non-uniform patterns whose intensity shows short-range intensity variations in the direction parallel to the contacts and decreases along the device channel towards the cathode. This paper employs Monte Carlo models, in conjunction with the experimental data, to analyse these non-uniform EL patterns and to study the carrier dynamics responsible for them. It is found that the short-range lateral (i.e. parallel to the device contacts) EL patterns are probably due to non-uniformities in the doping of the anode contact, hence demonstrating the usefulness of EL analysis on the detection of such inhomogeneities. The overall decreasing EL intensity towards the anode is also discussed in terms of the interaction of holes with the time-dependent electric field due to the transit of the Gunn domains. Due to their lower relative mobility and to the low electric field outside of the Gunn domain, freshly generated holes remain close to the anode until the arrival of a new domain accelerates them towards the cathode. This results, when averaged over several Gunn domain transits, on a higher hole density, and hence a higher EL intensity, next to the anode.

Click here to view a full listing of James Glover's publications and outputs.

Research interests/expertise

Infra-red Thermal Microscopy, Micro-particle Manipulation, Thermoelectric Cooler Design & Characterisation.

Areas of teaching

Analogue Electronics (ENGD1002), High Frequency Technology (ENGD3002), Digital Electronics (ENGD1003), Audio and Media Systems (TECH3009).

Qualifications

First class honours degree in Electronic Engineering from De Montfort University

Conference attendance

ARMMS RF and Microwave society, 19th-20th Nov 2012, Wyboston, Bedfordshire, UK, “Novel infra-red (IR) Thermal Measurement on GaAs Micro-coolers”, J. Glover, R.H. Hopper, M. Maricar, A. Khalid, D.R.S. Cumming, M. Montes, M. Kuball, G. Dunn, A. Stephen, and C.H. Oxley, paper and presentation.

Externally funded research grants information

EPSRC funding (EP/H012966/1) on “Novel Thermal Management of Power Electronic Devices: High Power High Frequency Planar Gunn Diodes”, from 1st April 2010 to 30th Sept 2013 (£184K).

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