A 50 GHz Divide-by-4 Injection Lock Frequency Divider Using Matching Method

A fully integrated divide-by-4 frequency divider has been designed, fabricated, and measured in the standard bulk 0.18-m complementary metal-oxide semiconductor (CMOS) technology. A newly proposed matching technique was used to eliminate the unwanted low frequency mixing terms at the common node of the circuit so as to achieve a high division ratio of 4. The frequency divider exhibits a measured operation range of 5 GHz from 45.9 to 50.9 GHz. It consumes a dc power of 7.56 mW at a 1.2 V supply in the steady state operation. The phase noise of the free running divider is 88.51 dBc/Hz at 1 MHz offset and the locked divider is 110.74 dBc/Hz at 1 MHz offset. The chip size is only 0.35 mm 0.5 mm including the pad frame. To our knowledge, this divider has the highest operation frequency to date among the high division ratio injection-lock type frequency dividers in commercial CMOS 0.18-m process.