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ECE 453 Lab 1 High-Frequency Component Models. Serge Minin. Pre-lab quiz. How many winds are needed to make a 2.2uH inductor with a T-44-6 core What is the parasitic capacitance that causes a resonance of 200 MHz for the above inductor. Learning objectives.
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ECE 453 Lab 1High-Frequency Component Models Serge Minin
Pre-lab quiz How many winds are needed to make a 2.2uH inductor with a T-44-6 core What is the parasitic capacitance that causes a resonance of 200 MHz for the above inductor.
Learning objectives • After this lab session students should be able to articulate what they will be doing in lab throughout the semester and how they will be graded. They should also be able to use basic functionalities of the simulation program (ADS) and an instrument for measurement of RF components (Network Analyzer). More specifically, they should know how to simulate an RLC circuit in ADS to obtain its impedance as a function of frequency, and to convert that impedance into the frequency-dependent reflection coefficient (assuming a 50Ω reference). With regards to measurement, they should learn how to calibrate a Network Analyzer up to 500 MHz for one-port reflection coefficient measurements, how to conduct such measurements at different frequency scales, and how to convert them to display in ADS as complex impedances. The students should also learn how to model as ideal RLCs two reactive components, a Quartz crystal (later used in an oscillator) and a toroid inductor (later used in a filter matching network), and to characterize their resonant behaviors. The students should learn how to construct the above inductor.
Lab tasks • Next time • Model several components based on provided data • Start on spectrum exploration with VSA • Today • Wind 2.2 uH inductor • Go through ADS tutorial/Xtal model • Calibrate NA, measure inductor • Calibrate NA, measure Xtal
Construction of inductors • Background • core confines field • fewer turns • Look up the cores • Calculate N of turns • Wind the inductors • see Appendix A • Sand the leads
Network analyzer S22 - measures voltage reflection from 2nd port – terminating impedance Port 1 Port 2 component fixture
Calibration standards • Uncalibrated – measures all after the port • Calibration – brings reference to fixture port • Standards – open, short, 50Ω • After calibration – check Smith chart component fixture
Standards on Smith chart • Polar graph of Γ (S22) • Γ= 1, -1, 0 for O, S, L • Should look like dots after calibration (hardly visible)
Inductor • Toroidal inductors exhibit parallel resonance • L from low frequency, C from resonance • R relates to Q – peak width
Quartz crystal • Quartz between two plates – capacitor • Motion arm due to piezo effect • Example values: • At resonance – like high Q inductor • Rapid phase change – stable oscillations
Quartz crystal • Co – from low f
Quartz crystal • Shift in fp due to parallel cap
Important points • Slow down the sweep to a few sec • Change trigger to single • Change IF BW to 500 Hz • Calibrate NA on 8 to 11 MHz • Number of points should be large • Reduce the range, remeasure