Ka-band oscillator integrating a high-Q low-temperature co-fired ceramic circular resonator using zigzagged via posts and a λ/4 short stub

A Ka-band oscillator with a high-Q low-temperature co-fired ceramic circular resonator is presented. The resonator, including zigzagged dual-row via posts for tightly confined electromagnetic power as a metallic boundary wall, is presented. The unloaded-Q of the proposed resonator is improved by 22.1% compared to that of a conventional one with vertical via posts. Another resonator is fed with a lambda/4 short stub on a feeding via post in the circular resonator for effectively power transmission in the resonator to the output load without radiation loss. The measured unloaded-Q of the proposed resonator with zigzagged dual-row via posts and a lambda/4 short stub is improved by 45.1% compared with that of a conventional one. Approaches for enhancing Q-factors using two techniques are demonstrated. The Ka-band oscillator integrating a negative resistance generator monolithic microwave integrated circuit and the resonator with zigzagged dual-row via posts and the lambda/4 short stub shows an output power of 19.34 dBm at 26.98 GHz and phase noise of -102.17 dBc/Hz at 1 MHz offset. The figure-of-merit is -164.1 dBc/Hz, and the DC-to-RF conversion efficiency is 18.28%. It can be easily implemented without any additional processes to achieve the high resonator Q-factor. At the same time, it is also very suitable to implement in high-integrated systems for millimeter-wave applications.