Ka-band Frequency Synthesizer Ltcc Technology Research

Low-Temperature Co-fired Ceramic (LTCC) technology is one type of Co-fired ceramic Multi-Chip Module (MCM-C), which is a high-integration and multilayer- printed packaging technology. Its three-dimension (3D) structure brings a bran-new design conception and methods into the domain of traditional microwave and millimeter-wave circuits and systems. Using LTCC technology, the theory and design for the millimeter-wave circuits and systems are present in this thesis.Firstly, the millimeter wave and its characteristics, the millimeter wave planar integrated circuits and its development, and the trend of LTCC in synthesizer are introduced. For achieving the requirements of the project, the phase noise model of the phased locked loop and a mathematical analysis model of the degradation in phase noise-to-carrier ratio of various components in the system are analyzed. Based on these theories, the scheme of PLL with mixer + quadrupler was confirmed, then were the specifications distribution, scheme design and specifications verification. Then, the fabrication-flow and properties of LTCC technology are presented, especially the advantages and drawbacks.Using LTCC technology for the millimeter-wave circuits, the passive components (including microstrip to stripline connection structures, X-band embedded bandpass filters and millimeter SIW bandpass filters) are dissertated. The filters embedded in LTCC substrate with novel folded SIR and tadpole SIR are proposed, which realize miniaturization of microwave bandpass filter, and have good performance of stopband rejection. An improved SIFW structure is proposed for the first time in this thesis. Through the cross-coupling, the filters could provide TZs on lower and higher stopband which greatly enhance the side-band rejection. Moreover, the length of the filter is nearly half of the unfolded counterpart.To resolve technical difficulties of this project, the research and analysis about system design and LTCC multi-layers layout of Ka-band frequency synthesizer are done. Finally, the modules of this frequency synthesizer (including PLL, microwave frequency multiplier chain, millimeter wave frequency multiplier chain) are manufactured and tested. Measurement and analysis show that the Ka-band phase locked frequency synthesizer covers 34.8GHz~35.2GHz with a minimal step of 40MHz, low phase noise (better than -83dBc/Hz@1kHz,-81dBc/Hz@10kHz,-90dBc/Hz@100kHz in the whole output band), sufficient power (beyond 16.9dBm), and a LTCC substrate size of 33cm2. Moreover, its frequency-hopping time is less than 15us, and spur level is below -61dBc.