30~83GHz Wideband Double-Balanced Mixer Based on Schottky Diodes in GaAs MMIC Technology

This paper presents a 30 GHz to 45 GHz wideband passive double-balanced mixer MMIC based on GaAs pHEMT technology. The mixers utilize a compact wideband Marchand balun with a planar structure, offering a 20-GHz to 90-GHz bandwidth. To enhance the operating bandwidth of the Marchand Balun, the constraints at the center frequency can be moderately relaxed, allowing for a slight reduction in reflection coefficient (transmission gain) at this frequency, and employing a heterogeneous layer coupling structure in the design. The proposed MMICs operate within the 30 to 83 GHz frequency range, exhibiting a typical conversion loss of approximately -12 dB, and LO-to-RF isolation exceeding 33 dB. The total area of the proposed mixer is 0.8 × 0.7 mm².