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Session: Session 18:00 AM Friday, June 20, 2008 Room: Omni Hotel |
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Session: Session 1 | 50 Years of VNAs |
Chair: | Nick Ridler, National Phyical Laboratory |
| | Session 1-1 | ARFTG 50 Year Network Analyzer History | - | D. Rytting, Rytting Conslting, Santa Rosa, United States |
(15) | Network analyzers are a key measurement technology for the RF and microwave industry. About fifty years ago the first network analyzer products started to be introduced and have had a significant influence on the design and testing of passive and active components. This paper traces the development of these network analyzers during the past fifty years discussing the technology used in their design and measurement contributions. The first network analyzers were focused on transmission and reflection measurements and then became the mainstay of s-parameter characterization. Error correction techniques were developed for improved accuracy. As time passed additional capabilities and measurements have been added. Features such as error corrected power, noise, converter, and nonlinear measurements have been added to address the growing market needs. Multiport configurations along with balanced and differential characterization have addressed the more integrated solutions of today. | | |
Session 1-2 | Network Analyzer Calibrations - Yesterday, Today and Tomorrow | - | K. Wong, Agilent Technologies, Inc., Santa Rosa, United States |
(25) | From the very beginning, network analyzers were calibrated manually. Grease pencils were used to mark the reference level on a CRT display or meter display. Such calibration methods were able to remove some of the measurement scalar errors. Full real time vector error correction wasn’t possible until the introduction of the hp8540A automatic vector network analyzer. It also allowed imperfect standards, i.e. an open, to be defined by a device model. The short-open-load-through calibration method was fully enabled. Since then, a surge in research on vna calibration methods brought us the through-reflect-line family of calibrations. Electronic calibration was invented to simplify calibration. Multi-port, differential and non-linear calibration methods and standards are the current and future challenges. | | |
Session 1-3 | Using Uncertain Complex Numbers with VNA measurements | - | B. D. Hall, Industrial Research Ltd , Lower Hutt, New Zealand |
(20) | The 'uncertain complex number' is a simple construct that can be used to achieve full uncertainty propagation in multi-step processing of measurement data. The entity encapsulates information about a measured complex quantity and propagates it through equations by using a few simple algorithms. Software can easily automate the operations involved. The paper shows how uncertain complex numbers can be used to implement calibration and data-processing routines for VNA measurements. An example is presented in which the uncertainties associated with a pair of reflection measurements are evaluated, as well as the uncertainties associated with the ratio and difference of these measurements. It is shown that, by using uncertain complex numbers, the variances associated with the ratio and difference results can be reduced by an order of magnitude, by correctly accounting for correlated errors associated with the VNA calibration. | | |
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