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 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