Session: Session 4

3:40 PM Friday, May 28, 2010

Room: Pacific A
     
Session: Session 4
Other Areas of Microwave and Millimetre-wave Measurements
Chair:
Jean-Pierre Teyssier, University of Limoges
Abstract:
In this short session we have papers describing state-of-the art pulse measurement techniques, a novel technique for direct measurement of impedance using microwave signals, and a report of an inter-laboratory comparison of millimetre-wave standards measurements.
 
 
Session 4-1
Impact of the Pulse-amplifier Slew-rate on the Pulsed-IV measurement of GaN HEMTs
3:40 PM-4:00 PM
S. A. Albahrani, A. E. Parker, Macquarie University, Sydney, Australia
(19)
The influence of the non-ideal response of the pulse-amplifier on the trap and self-heating dynamics, and hence, on the drain-current transient in a GaN HEMT is studied with new trap and self-heating models. It is shown that the study of the trap and self-heating dynamics requires a proper correction technique that accounts for the change in trap-potential, trap time-constant and thermal response due to the non-ideal response of the pulse-amplifier. Several post-measurement data correction techniques are discussed and shown to be incapable of predicting the true drain-current transient. A pre-measurement terminal correction technique using a new version of the pulse measurement system is used to solve the problem.
 
 
Session 4-2
A Novel Method for Direct Impedance Measurement in Microwave and mm-Wave Bands
4:00 PM-4:20 PM
M. Randus, K. Hoffmann, Czech Technical University in Prague, Prague, Czech Republic
(23)
A novel method for direct impedance measurement using a common vector network analyzer (VNA) is introduced. In commonly used methods impedance or admitance of a device under test (DUT) is derived from measured value of its reflection coefficient causing serious accuracy problems for very high or very low impedances. The proposed method makes possible to measure quantity directly proportional to the value of the impedance or admittance of the DUT. This enables us to accurately measure even impedances that are extremely different from value of the 50ohm reference impedance. The method can also significantly reduce effect of uncertainties of the VNA. A suitable calibration technique is suggested and fully mathematically described. The concept of the new method was verified by software simulation.
 
 
Session 4-3
Inter-laboratory Comparison of Reflection and Transmission Measurements in WR-06 waveguide (110 GHz to 170 GHz)
4:20 PM-4:40 PM
N. Ridler1, M. Salter1, P. Goy2, S. Caroopen2, J. Watts3, R. Clarke4, Y. Lau5, D. Linton6, R. Dickie6, P. Huggard7, M. Henry7, J. Hesler8, S. Barker9, J. Stanec9, 1NPL, Teddington, United Kingdom, 2AB Millimetre, Paris, France, 3Flann Microwave Ltd, Bodmin, United Kingdom, 4University of Leeds, Leeds, United Kingdom, 5OML Inc, Morgan Hill, United States, 6Queens University Belfast, Belfast, United Kingdom, 7Rutherford Appleton Laboratory, Didcot, United Kingdom, 8Virginia Diodes Inc, Charlottesville, United States, 9University of Virginia, Charlottesville, United States
(27)
This paper describes an exercise that was undertaken recently to compare reflection and transmission measurements in rectangular metallic waveguide from 110 GHz to 170 GHz (i.e. in the WR-06 waveguide size). The comparison involved making measurements on four devices fitted with 'precision' MIL-DTL-3922-67D style flanges. These devices were circulated amongst the nine organizations that chose to participate in the exercise. The comparison took place between August 2008 and September 2009. Results from the exercise will be presented in the paper in graphical form along with a statistical summary showing average variability for the measurements. The authors believe this is the first time that such a comparison of measurements has been made at these frequencies. These results provide a benchmark for the current state-of-the-art for measurements made in waveguide at these frequencies.
 
 
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