Sub-harmonic self-oscillating mixer design using dual-mode substrate integrated waveguide cavity

This paper presents a novel sub-harmonic self-oscillating mixer (SOM) topology that makes use of the orthogonality of two operating modes in a substrate integrated waveguide (SIW) cavity. The SOM circuit consists of a dual-mode SIW band-pass filter (BPF), a common source hetero-junction FET (HJFET) and a low-pass filter. The fundamental mode (H₁₀₁) of the SIW cavity is used for RF mode operation while the H₂₀₂ mode is used for local oscillation. A K_a-band experimental prototype has been designed to demonstrate and validate our circuit concept. Measurement results show good performances of our proposed circuitry.