ps4_2011_match - ECE 145A and 218A Transmission-line properties impedance-matching exercises Problem#1 This is a circuit file to study a transmission

# ps4_2011_match - ECE 145A and 218A Transmission-line...

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1 ECE 145A and 218A. Transmission-line properties, impedance-matching exercises Problem #1 This is a circuit file to study a transmission line. The 2 resistors are included to allow easy disconnection of port 2 without causing numerical problems in the simulator. MSUB defines the microstrip substrate; H is the dielectric thickness, Er its constant, and T the metal thickness. I've cheated and made the metal conductivity very high, so as to minimize skin loss. Please simulate S11, plot on a Smith chart, and from the frequencies at which the line is multiples of a quarter-wavelength, determine the line Zo. Make R1 zero, and R2 1GOhm (open ckt line), simulate S11, and plot Z11 vs frequency. From the frequenies of the poles (singularities) and zeros, determine the wave velocity.
2 Problem 2 We want to design a bypass capacitor, either to AC ground a power supply or an internal node in a transistor amplifier. We wish this impedance to be small over a wide range of frequencies. A large capacitor gives a low impedance Cj/1, but its large dimesions will give standing-wave resonances at a low frequency. While our WiFi circuit is designed to work at only 60 GHz, the transistor bandwidth is almost 300 GHz, so we must ensure that the capacitor impedance remains small from few GHz to 300 GHz We will use substrate parameters as below: a