Resonators embedded in LTCC

Microwave electronics was usually realized by PWB-based system, monolithic microwave integrated circuits, or hybrid microwave integrated circuits. Next integrating IC and package solution to unit advantage of complete solution gives low temperature co-fired ceramic (LTCC). Base of this technology is a multi-layer ceramic process, which combines the advantages of multilayer substrates with very good high frequency properties and high conductivity metallization. The extent of integration is widely increased by the possibility to realize high frequency passive components embedded in the multi-layer ceramics substrates. That could be used for new generation of 3D-packages with the cost and size reduction by replacing discrete components. High quality factor (Q factor) inductors are essential to achieve suitably low phase noise performance in oscillator circuits and in the design of low loss passive filters and matching circuits. In this paper the design and realization of embedded inductors for a voltage controlled oscillator (VCO) resonator made by LTCC is discussed. The main focus was concentrated on achieving a high quality factor of realized inductors with a given inductance. This approach, co-designing various elements in LTCC configuration to achieve optimized size and performance, demonstrates the use of co-integration for wireless applications requiring smaller package size and higher performance at the lowest possible cost.