A 16-21 GHz Double-Balanced Gilbert Upconversion Mixer with Low in-Band Spurious Using 0.25μm GaAs pHEMT Technology

This paper presents a 16-21 GHz double-balanced Gilbert upconversion mixer with low RF in-band spurious implemented in 0.25μm GaAs pHEMT technology. To achieve good balance performance, a Marchand balun with spiral structure is set at the LO port, CS-CG baluns with low unbalanced and good matching performances are designed and optimized to set at IF and RF ports. Gilbert mixer is improved by adding charge injection part and LR load to realize high in-band spurious target as well as moderate gain and linearity. The full mixer with baluns is integrated on MMIC chip with an area of 2.7mm×1.76mm. RF in-band suppression of the mixer is more than 40dB over the frequency of 16-21GHz. The mixer has a conversion gain of more than 7dB and OP1dB of -8dBm, OIIP3 of 4dBm when LO power is 5dBm.