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Fernandez-Barciela M.,University of Vigo | Pelaez-Perez A.M.,TELEVES S.A. | Woodington S.,MESURO Ltd | Alonso J.I.,Technical University of Madrid | Tasker P.J.,University of Cardiff
IEEE Microwave Magazine | Year: 2014

In the design of most electronic circuits and systems, designers use computer-aided design (CAD) tools to guide the design flow. They exploit the ability of CAD tools to perform algebraic operations to compute/predict circuit and system performance. This is possible because, in most electronic circuits and systems, linear operation can be assumed. The behavior of microwave components, circuits, and systems can, for example, be described in terms of behavioral parameters, such as Z-parameters, Y-parameters, and S-parameters. Transformation from one parameter to another is achieved by simple linear algebraic operations [1]. The performance of more complex circuits can be computed via linear matrix operations using the relevant parameters, i.e., Y-parameters for parallel connections and Z-parameters for series connections. More significantly, performance predictions can also be obtained via linear algebra transformations, i.e., the maximum gain, minimum noise figure, potential instability, etc., along with design insight, i.e., gain circles, noise circles, optimum input/output match requirements, and so on [1], [2]. © 2014 IEEE.


Aldoumani A.,University of Cardiff | Williams T.,Mesuro Ltd | Lees J.,University of Cardiff | Tasker P.J.,University of Cardiff
83rd ARFTG Microwave Measurement Conference: Microwave Measurements for Emerging Technologies, ARFTG 2014 | Year: 2014

This paper presents an alternative approach to improving the vector measurement accuracy, especially near the edge of the Smith Chart, of load-pull measurement systems. Improved measurement accuracy, after vector calibration, is achieved by exploiting the load-pull capability during calibration to minimize the impact of measurement errors on the raw data of the calibration standards before it is utilized in the traditionally implemented LRL/TRL calibration algorithm. This approach eliminates the need to utilize complex optimization algorithms post calibration. The proposed method has been tested and applied to actual measurement data. © 2014 IEEE.


Pelaez-Perez A.M.,Technical University of Madrid | Pelaez-Perez A.M.,Mesuro Ltd | Woodington S.,Alcatel - Lucent | Fernandez-Barciela M.,University of Vigo | And 2 more authors.
IEEE Transactions on Microwave Theory and Techniques | Year: 2013

Recently, X -parameters have been introduced to model active device nonlinear behavior. In addition to providing a measurement-based tool to numerically predict nonlinear device behavior in computer-aided design, they can also provide the designer of nonlinear circuits an analytical design tool. Exploiting this design tool aspect, this work presents an application that combines the nonlinear vector network analyzer PNA-X and a passive tuner to extract a transistor load-independent X -parameter model, focused around targeted circuit impedances for optimal performance. Furthermore, an experimental search algorithm, based on X-parameters analytical computations and developed by Peláez-Pérez , has been used and experimentally validated in this paper, aimed to speed up the characterization and design process, minimizing the number of load-pull measurements necessary to provide an accurate transistor X-parameter model for use in analytical and/or numerical circuit design. © 1963-2012 IEEE.


The present invention relates to a measurement system and method for analysing, and characterising, the behaviour of a high frequency device, commonly referred to in the art as a device under test (or DUT) at relatively high power levels. Such devices may for example need to be analysed when designing devices or designing circuits utilising such devices, for use in high power (large signal) high frequency amplifiers, such as an amplifier for use in a mobile telephone network or other telecommunications-related base-station. The measurement apparatus for measuring the response of an electronic device to a high frequency input signal includes an active load-pull circuit connectable in use to an electronic device to be measured. The active load-pull circuit includes a passive load-pull device.


Patent
Mesuro Ltd | Date: 2011-07-13

An analyser for measuring the response of an electric device (DUT 206) to an RF input signal from a signal generator (240a) is described. An active load pull circuit (201) is connected to the DUT 206, which receives an output signal from the DUT 206 and then feeds a modified signal back to the DUT 206. The signal is modified by a signal processing circuit (237) in view of input signals x, y to control the magnitude gain and phase change effected by the feedback circuit (237). Thus, positive feedback loops are avoided and better control of the analyser is permitted. A network analyser, or other signal measuring device (242), logs the waveforms (from which s-parameters derived) observed at ports of the DUT 206, thereby allowing the behaviour of the DUT 206 under various load conditions to be analysed.


Grant
Agency: GTR | Branch: Innovate UK | Program: | Phase: Smart - Proof of Concept | Award Amount: 52.16K | Year: 2012

Recent advances in microwave test equipment through the use of microwave sources employing Direct Digital Synthesis (DDS) techniques enable frequencies up to 67GHz to be achieved. When these are combined with state-of-the-art Vector Network Analyser (VNA) receivers, new opportunities are opened up to develop current and voltage waveform measurement systems, including active load-pull systems, that operate at very high frequencies. The major technical hurdle that prevents this from being possible is the provision of an accurate, wide-band phase reference which is required to convert a frequency domain VNA into a time domain receiver capable of handling current and voltage waveforms. Attempts have been made to solve this issue through the development of new types of phase reference standards, however all of the approaches tried to date have been severely limited in their frequency of operation. This research project would therefore look into the feasibility of developing a new type of phase reference that is not frequency limited, but could in principle be used to frequencies up to 67GHz and beyond.


Williams T.,Mesuro Ltd. | Wee B.,National Instruments | Saini R.,Mesuro Ltd. | Mathias S.,Mesuro Ltd. | Bossche M.V.,National Instruments
83rd ARFTG Microwave Measurement Conference: Microwave Measurements for Emerging Technologies, ARFTG 2014 | Year: 2014

This paper presents a cost effective, digital, PXI-based active load-pull tuner architecture. This allows for significant reduction in test time, without compromising measurement quality or control. We will demonstrate for the first time, ability to compensate for the non-linear behavior of the loop amplifier within the active loop, thus moving from a proof of concept architecture to one that is applicable to real-world applications. The calibration process required for accurate reflection coefficient setting is presented, as well as analysis of the long-term reflection coefficient stability. It is shown how the RF bandwidth of the architecture can be increased through the use of up/down convertors directly in the feedback loop, with testing completed at 17GHz. A direct comparison in measurement time between passive, active open-loop and the digital architecture is also presented, showing the digital tuner as much as 14 times faster than a passive tuner for a fixed power impedance grid, using the same measurement receiver and setup. © 2014 IEEE.


Patent
Mesuro Ltd | Date: 2011-12-20

A method of fabricating a bone substitute material comprises the steps of providing a foam material (3) having an open cell structure, distorting the shape of the foam material (3) and holding the material in a distorted shape, coating the walls of the cells of the foam material with a ceramic slip (5), removing the foam material, and sintering the ceramic slip to form a bone substitute material that is approximately a positive image of the distorted foam material (3). In another method, a granular bone material is formed from a multiplicity of pieces of foam that are not distorted.


Patent
MESURO Ltd | Date: 2013-10-24

A method of calibrating a high frequency signal measurement system is described. The measurement system is in the form of a network analyser (6) and has first and second phase-locked signal sources (SS1 & SS2) and at least two measurement receivers (18a, 18b). A phase meter (26) is provided. A reference signal (F0) is outputted at a first frequency from the first signal source (SS1). The second signal source (SS2) steps through a multiplicity of different test frequencies (nF0), being phase-locked with the reference signal (F0), which are applied in turn to a part of the measurement system. Measurements are taken, via the two measurement receivers (18a, 18b), of characteristics of the resulting signal at a measurement plane. The absolute phase of the signal at the measurement plane is also measured with the phase meter (26). Calibration data is generated which relates the characteristics of the signals as measured by the measurement system (6) and the absolute phase as measured with the phase meter (26).


Patent
MESURO Ltd | Date: 2010-10-18

An analyser for measuring the response of an electronic device (DUT 206) to an RF input signal from a signal generator 240a is described. An active load pull circuit 201 is connected to the DUT 206, which receives an output signal from the DUT 206 and then feeds a modified signal back to the DUT 206. The signal is modified by a signal processing circuit 237 in view of input signals x, y to control the magnitude gain and phase change effected by the feedback circuit 237. Thus, positive feedback loops are avoided and better control of the analyser is permitted. A network analyser, or other signal measuring device 242, logs the waveforms (from which s-parameters derived) observed at ports of the DUT 206, thereby allowing the behaviour of the DUT 206 under various load conditions to be analysed.

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