Diplexing dual-gate FET distributed mixer

It has been shown that single-gate FET distributed mixers with composite right/left-handed transmission lines can exhibit new frequency responses such as diplexing performance. The main limitations of these circuits are the lack of intrinsic isolation between the local oscillator and radiofrequency signals and thus the need for an external coupler to inject both signals into the mixer. Dual-gate FETs are commonly used in conventional distributed mixers to overcome these limitations. A similar approach is proposed for dual-gate FET diplexing distributed mixers. The resulting novel configuration is validated by means of the design and measurement of a lumped-element-based prototype.