Intelligence driven load-pull measurement strategies

The objective of this thesis is to provide improved load-pull measurement strategies based on an open-loop active load pull measurement system. A review of the evolution of non-linear measurement systems as well as behavioural model generation approaches has been presented. An intelligence driven active load-pull system has been presented in this thesis, based on deriving local PHD models to aid the prediction of the desired active signal in order to achieve a target reflection coefficient. The algorithm proved to be effective in reducing the number of iterations in an open-loop active load-pull system and thus improving the utilisation efficiency. A non-linear measurement approach suitable for wafer mapping and technology screening applications has also been presented as an application of this new algorithm. In this thesis, it has also been shown how the Cardiff Behavioural model is effective in its ability to interpolate or extrapolate non-linear measurement data and thereby improve the quality of measurement data and speed of measurement systems. This investigation was carried out in two stages; fundamental interpolation testing and harmonic interpolation and extrapolation testing

A waveform engineering approach to the design of improved efficiency wideband MMIC amplifiers

This paper describes a design methodology based on waveform engineering within a harmonic active load-pull system and utilizing the Cardiff Direct Look-Up Table (DLUT) model. The process seeks to address some of the key issues facing designers when using nonlinear simulation of high power microwave amplifiers: model validity, boundary conditions and yield. The application of this process to the design of a 0.5 W, 5-10 GHz GaAs pHEMT with good PAE is detailed

Interpolation and extrapolation capabilities of non-linear behavioural models

This paper demonstrates how the Poly Harmonic Distortion (PHD) modelling framework is effective in its ability to interpolate or extrapolate non-linear measured data and thereby improve the quality and speed of measurement systems. Fundamental interpolation was verified and demonstrated using a 7-coefficient model extracted from a sparse set of fundamental impedances (19 points). It was shown that a relatively low order polynomial was required to capture the second harmonic space. Interpolation accuracy was however increased by including more coefficients. Second harmonic extrapolation was carried out on measured data and shown to be accurate to an average confidence of 99% when 6 model coefficients were extracted on a 0.7 reflection coefficient circle and then used to predict data on a 1.0 reflection coefficient circle. Measurements were carried out using an open loop active load-pull system operating at a fundamental frequency of 9GHz, on a 0.5W 10×75μm GaAs PHEMT device

Behavioral model analysis of active harmonic load-pull measurements

This paper outlines the formulation of a mixing based behavioral model, capable of capturing the nonlinear response of microwave transistors to fundamental and harmonic load pull effects for use in Computer Aided Design tools. The key to the model formulation was the experimental identification of the dominating mixing terms. The model is able to accurately compute the voltage and current waveforms present at a Transistors Terminals. The formulation lends itself to economical use of measured data, reducing data storage required within the CAD environment. In this paper the modeling approach has been demonstrated on a 10 × 75 μm GaAs HEMT operating at 9 GHz

Understanding Sustenance of Small Farm Holders: A Study of Income Inequality among Farm Households in Indian Punjab

The sustenance of marginal and small farm households is a pertinent question given that their number is on the rise in South-Asia. The study aims to assess their present socio-economic profile and the challenges faced in order to draw a roadmap of development for these underprivileged households. The study pertains to Indian Punjab and data from the Situation Assessment Survey of the 70th Round of NSSO are used. The concepts of economic surplus, occupational diversity, farm productivity and vertical and horizontal inequalities are used to achieve the objectives. This study reveals that marginal farm households faced food insecurity as they failed to meet consumption expenditure from the income earned. In fact, small farm households are left with an annual economic surplus of Rs 8890 per capita only, after meeting consumption needs. Income is unevenly distributed among farm households with a Gini coefficient of 0.48. The majority of the marginal and small farm households fall in lower-income quintiles and are occupationally more diversified than their larger counterparts. Horizontal inequalities are lower between the farm-size categories (0.14) than within farm-size categories (0.27). The Gini coefficient within each farm-size category is the highest among marginal farm households (0.50), followed by small farm households (0.45), highlighting their economic stress and tug-of-war survival. Further, the farm households belonging to socially lower castes falls only in the marginal farm-size category and represent the lowest income. Development must be sustainable and inclusive, hence, policies to develop marginal farmers’ centric farming systems and high value crops such as potato, cotton, sugarcane and oilseeds, providing high yielding livestock breeds, value addition through farmer-producer organizations, non-farm employment through MGNREGA, provision of institutional credit at subsidised rate of interest and quality health and education facilities in the public sector are recommended to uplift the affected households

Understanding Sustenance of Small Farm Holders: A Study of Income Inequality among Farm Households in Indian Punjab

The sustenance of marginal and small farm households is a pertinent question given that their number is on the rise in South-Asia. The study aims to assess their present socio-economic profile and the challenges faced in order to draw a roadmap of development for these underprivileged households. The study pertains to Indian Punjab and data from the Situation Assessment Survey of the 70th Round of NSSO are used. The concepts of economic surplus, occupational diversity, farm productivity and vertical and horizontal inequalities are used to achieve the objectives. This study reveals that marginal farm households faced food insecurity as they failed to meet consumption expenditure from the income earned. In fact, small farm households are left with an annual economic surplus of Rs 8890 per capita only, after meeting consumption needs. Income is unevenly distributed among farm households with a Gini coefficient of 0.48. The majority of the marginal and small farm households fall in lower-income quintiles and are occupationally more diversified than their larger counterparts. Horizontal inequalities are lower between the farm-size categories (0.14) than within farm-size categories (0.27). The Gini coefficient within each farm-size category is the highest among marginal farm households (0.50), followed by small farm households (0.45), highlighting their economic stress and tug-of-war survival. Further, the farm households belonging to socially lower castes falls only in the marginal farm-size category and represent the lowest income. Development must be sustainable and inclusive, hence, policies to develop marginal farmers’ centric farming systems and high value crops such as potato, cotton, sugarcane and oilseeds, providing high yielding livestock breeds, value addition through farmer-producer organizations, non-farm employment through MGNREGA, provision of institutional credit at subsidised rate of interest and quality health and education facilities in the public sector are recommended to uplift the affected households

Behavioral model analysis using simultaneous active fundamental load-pull and harmonic source-pull measurements at X-band

Recently there has been a renewed interest in improving power amplifier performance via input waveform engineering. In order to support this development it is important that non-linear behavioral device models can accurately describe and fully account for the high levels of input harmonic signal injection necessary. The work presented in this paper introduces an adapted mixing model formulation, which was used to extract input second harmonic model coefficients from a set of simultaneous active fundamental load-pull and harmonic source-pull measurements at 9 GHz. It was observed that a fourth order model was sufficient to capture the response of the scattered travelling b2,1 and b2,2 waves to a confidence of 99.46% and 97.62% respectively of the measured data. Hereafter the behavioral model was used to accurately generate the full fundamental output impedance space and the respective port current and voltage waveforms within a CAD environment