Fully integrated double balanced MMIC mixer using a star arrangement of diodes for extended IF performance

Abstract

A double balanced diode mixer with all circuitry contained on a single MMIC (monolithic microwave integrated circuit) die has been designed and fabricated. The mixer consists of four diodes arranged in a star configuration connected to several balun-type structures. The configuration allows extracting the IF (intermediate frequency) signal at a node which is a virtual ground to both LO (local oscillator) and RF signals. Thus, compared to conventional MMIC mixers, a significant improvement in extracting the IF signal to achieve a broad bandwidth performance is possible. On-chip matching circuitry is included between diodes and baluns to enhance performance across a 6-GHz IF bandwidth.<>