A Decade Bandwidth Mixers Based on Planar Transformers and Quasi-vertical Schottky Diodes Implemented in GaAs MMIC Technology

This paper presents a decade bandwidth passive double balanced mixers implemented in GaAs MMIC technology. The mixers employ ultra-broadband coupled balun transformers with planar structure of 3 to 30 GHz and 5 to 50 GHz bandwidth. To overcome the high level of amplitude and phase imbalance at the edge of the frequency range the classical balun was modified to novel topology structure by adding phase shifting components. The circuits are based on quasi-vertical GaAs Schottky diodes with low parasitics. The fabricated MMICs operate in 3 to 30 GHz and 5 to 50 frequency range and demonstrate -10 dB conversion loss, +12 dBm input 1 dB gain compression, 30 dB of LO-IF isolation and up to +30 dBm of input IP3 at +15 dBm input LO power.