UHF Applications for Radar and Pico-Satellite Communication Systems

Abstract

This thesis first discusses the design, fabrication, and test results of UHF preamplifier designed to operate from 400 to 500 MHz. The preamplifier integrates a single-pole double-throw (SPDT) switch, tapped-line interdigital filter, balanced low-noise amplifier, and gain stage in a compact, multilayer package. The switch and amplification stages are realized on one layer, and the stripline filter is realized on a second layer. The circuit board dimensions measure 4 inches x 1.25 inches x 0.12 inches. One hundred eight units were manufactured. The preamplifier has a 3-dB bandwidth of 100 MHz, 31 dB gain, 3 dB noise figure, and 30.6 dBm output third-order intercept. The second part of the thesis discusses the CubeSat project at the University of Hawaiʻi and presents an analysis on the radiation pattern of the active antenna on the cube satellite. The analysis for the active antenna compares two antenna models to the measured results of a 4x4 grid oscillator. The first approximation model is a rectangular aperture spaced away from a mirror, and the second model is a dipole array spaced from a mirror. Two simulation experiments are presented to show how the spacing between the grid and mirror compares to the measured data and which antenna model more accurately predicts the radiation pattern.