Design and characterization of low phase noise microwave circuits

This thesis addresses the short term stability, expressed as phase noise, of a variety of microwave circuits relevant to communication and radar systems. In specific, the following types of circuits are discussed in detail: (1) low-phase noise fundamental frequency oscillators for carrier signal generation; (2) high-efficiency amplifiers with low additive phase noise for carrier amplification; and (3) harmonic generators with ultra-low phase noise using varactor nonlinear transmission lines (NLTLs).; A low phase noise 4.6-GHz local oscillator design is applied to a Cesium miniature atomic clock. The design is based on a micro-coaxial resonator and silicon bipolar transistor. The goal of this work is to determine the tradeoff between low DC power consumption, size (volume{rcub} and low phase noise at small deviations from the carrier. To that end, a smaller than 0.2 cubic centimeter varactor-tuned oscillator that consumes 16mW of DC power with a phase noise of -102dBc/Hz at 10kHz from the carrier is developed.; When amplifying a clean oscillator in a transmitter, the noise added by the amplifier close to the carrier frequency is relevant. This thesis analyzes additive phase noise in several high-efficiency X-band power amplifiers based on different device technologies and compares it to the equivalent linear power amplifier. It is shown that highly-efficient PAs have on the order of 10-20dB higher phase noise between 100Hz and 10kHz as compared to the linear PA.; Often it is more desirable to multiply a clean lower frequency oscillator in order to achieve higher frequency generation. Step recovery diodes exhibit additive noise greater than the oscillator reference, degrading overall performance. The main contribution of this thesis is design and characterization of NLTLs as low-phase noise frequency converters. Additive phase noise measurements at the fundamental and 10th harmonics demonstrate true 20logN multiplication with an input referred phase noise of -182dBc/Hz. The work has demonstrated, both theoretically and in measurement, that NLTLs exhibit ultra-low phase noise as high-order frequency multipliers.