Patent ID: 7962114

Claim:
A sub-harmonic mixer comprising, a first transistor having a source and a drain; a second transistor having a source connected to the source of the first transistor and a drain connected to the drain of the first transistor; a mixing transistor configured to be biased in a linear operating region, the mixing transistor having a drain coupled to the sources of the first transistor and the second transistor, the mixing transistor having its drain driven by a signal at twice a local oscillator (LO) frequency and its gate driven by a radio frequency (RF) signal while the mixing transistor is biased in the linear region such that a process of frequency doubling and mixing are performed simultaneously; and an impedance transforming network connected between the mixing transistor and the first and second transistors to increase doubling efficiency and permit larger voltage swings at the drain of the mixing transistor to improve performance.