Microwave Oscillatorand Mixer Design

Abstract

Our final year project is the design of a microwave oscillator and mixer. Oscillators and mixers serve as the foundation of many RF front-end systems, and have applications in many areas such as in sensing and communication. The mixer designed is a singly balanced mixer, based off a quadrature 90-degree hybrid coupler. The oscillator is designed using the negative resistance topology. We have also characterized a dielectric resonator to find its resonant frequency. The oscillator was designed to generate a 5.15 GHz signal. The function of the mixer was efficient down-conversion of the RF signal with a low conversion loss of 4.524 dB. The simulation and characterization of the dielectric resulted in a resonant frequency of 4.9 GHz. After the design and fabrication of our circuits, testing of the hardware showed that the oscillator was producing an oscillation at 4.835 GHz with 7.89 dBm of power. The mixer was properly performing down-conversion with a conversion loss of 6.12 dB. Finally, the test setup for the dielectric resonator showed that it had a resonant frequency of 5.59-GHz. All simulations were done using Keysight Advanced Design System (ADS) and Ansys High frequency Structure Simulation (HFSS) software.