Millimeter wave micromachined cavity resonators on MCM-D: Oscillator-resonator co-design and packaging considerations

This paper reports on the integration of millimeter wave micromachined cavity resonators on MCM-D and their optimization for use in ultra low phase noise oscillator modules at 60 GHz and 77 GHz. We will discuss some important oscillator/resonator co-design and packaging considerations in order to optimally take advantage of the high inherent quality factor of these cavity resonators. In addition we will present modeling and measurement results for CPW slot coupled cavities around 60 GHz and 74.3 GHz mounted onto an MCM-D carrier realized in IMEC´s 3D-IPD technology. The measured cavity resonators showed resonant frequencies of 58.89 GHz and 75.26 GHz with unloaded quality factors of 755 and 300, respectively. These agree extremely well to the simulated values of 58.92 GHz and 75.27 GHz for the resonant frequency and 879 and 323 for the quality factor. These values include the effects of a long CPW line and of coupling losses which are largely due to parasitic substrate modes.