lec.7 microwave network analysis
TRANSCRIPT
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RF & Microwave EngineeringBETE-Spring 2009
Department of Electrical EngineeringAir University
Microwave Network Analysis
N-port Microwave devices
Lecture No. 7
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
Introduction
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
Basic Port Definitions
Z Parameters
Y Parameters ABCD Parameters Scattering Parameters
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
Impedance and Admittance Matrix
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
Z-Matrices
As an example of Z-matrix, consider this 2-port network. The Z-matrix can be written as:
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
Z-Parameters
where
Z-matrix helps to relate the terminal port voltages and currents to each other, which is helpful to determine the behavior of an unknown device connected between the two ports.
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
T- Network Example
This matrix is symmetric
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
T- Network Example
The Z- matrix representation is also useful when two or more networks are connected in Series
We can simply add the Z-matrices to form the final Z-matrix that incorporates the electrical characteristics of both networks and their mutual interaction
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
Y-Matrix
A closely related characterization of a 2-port network is Y-matrix description:
where
Useful when connecting networks in parallel.
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
Matrices for Microwave Networks
We can generalize these Z and Y parameter descriptions for microwave networks and multi-port networks.
Consider an N-port Network connected to N number of transmission lines.
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
N-Ports Microwave Networks
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
Voltages and Currents Vn , In
At these terminal planes (also called phase planes), we defined our reference position as zn=0. The voltage on nthTL becomes:
This means that at these terminal phase planes i.e., our reference position at zn=0, the voltage on TL is the sum of the incident waves and outgoing waves.
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
N-port Matrix Descriptions
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
Global Characteristics of Z and Y Matrices
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
Reciprocity Theorem
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
Global Characteristics of Z and Y Matrices
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
N-port Matrix Descriptions
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RF & Microwave EngineeringBETE-Fall 2009
Basit Ali ZebDepartment of Electrical Engineering, AU
Study
Articles 4.1, 4.2 from the text book
Next topic Scattering Matrix and Parameters