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Electromagnetics and Transmission Lines for Wearable Communication Systems
Published in Albert Sabban, Wearable Systems and Antennas Technologies for 5G, IOT and Medical Systems, 2020
Smith chart guidelines: The Smith chart contains almost all possible complex impedances within one circle.Smith chart horizontal center line represents resistance/conductance.Zero resistance is located on the left end of the horizontal center line.Infinite resistance is located on the right end of the horizontal center line.Horizontal centerline – resistive/conductive horizontal scale of the chart.Impedances in the Smith chart are normalized to the characteristic impedance of the transmission line and are independent of the characteristic impedance of the transmission.The center of the line and of the chart is 1.0 point, where R = Z0 or G = Y0.At point r = 1.0, Z = Z0 and no reflection will occur.
Impedance Matching Networks
Published in Abdullah Eroglu, Introduction to RF Power Amplifier Design and Simulation, 2018
The Smith chart is a conformal mapping between the normalized complex impedance plane and the complex reflection coefficient plane. It is a graphical method of displaying impedances and all related parameters using the reflection coefficient. It was invented by Phillip Hagar Smith while he was working at Radio Corporation of America (RCA). The process of establishing the Smith chart begins with normalizing the impedance, as shown by () zL=ZLZ0=RL+jXLZ0
Monolithic Microwave IC Technology
Published in Mike Golio, RF and Microwave Semiconductor Device Handbook, 2017
Impedance matching: One of the main design activities in microwave circuit design. An impedance matching network is made up of a combination of lumped elements (resistors, capacitors, and inductors), or distributed elements (transmission lines of varying characteristic impedance and length). Impedance matching networks transform network impedance from one value to another. For example, on the input to a low noise transistor, the impedance of an incoming 75 ohm transmission line would be transformed by the input matching network to the impedance Zopt, required to achieve the minimum noise figure of the transistor. The Smith Chart is a tool commonly used by microwave engineers to aid with impedance matching.
Design of an Improved Differentially Fed Antenna Array for RF Energy Harvesting
Published in IETE Journal of Research, 2020
Deepak Kumar, Kalpana Chaudhary
Over the last decade, satellite solar power station (SSPS) and wireless power transfer have become an interesting topic for the energy transmission in the future [1–3]. In wireless power transmission (WPT), the rectenna (antenna and rectifier) is an elementary part for receiving RF energy and converting RF energy into DC power [4,5]. For higher frequency operation, i.e. 5.8 GHz application Schottky diode is used for rectifying AC to DC [5]. The value of rectifier’s input impedance needs to match with antenna output for maximum power transfer. For impedance matching, Smith chart tool is utilized in ADS design guide toolbox [6]. Microstrip open stub or quarter wavelength matching technique is used for the purpose, as it is easy in fabrication and design in microstrip environment [7,8].
A brief introduction to nomography: graphical representation of mathematical relationships
Published in International Journal of Mathematical Education in Science and Technology, 2019
One significant nomographic application is the elaborate (and, indeed, beautiful) Smith chart [28–30], which continues to be used by electrical engineers for calculations relating to transmission lines and impedance matching. An ancient application of nomography (even if not generally recognized as such) is on sundials [31], where the upright gnomon (note the presence of ‘nomo’) casts a moving shadow, which thus acts as the isopleth, on the face of the sundial. A set of nomographs for predicting fire behaviour in vegetation [32] demonstrates an application which would likely prove helpful in emergency situations.