Design of GaAs MMIC passive WaveProbes

Abstract

GaAs MMIC are taking big space in the wireless communication in today s world. The devices are to be characterized for higher frequencies. External passive waveprobes are used to characterize the devices. As the use and technology is increasing there will be more development on MMICs. It would be nice to have a passive waveprobe on the chip itself so as to minimize the losses created due to junctions.In this master s thesis several wave probes designing techniques are described. The wave probes are designed and simulated. Wave probes are loop couplers with a sufficient directivity and very small insertion loss. The proposed wave probes or coupler are realized using TriQuint GaAS pHEMT MMIC process. Simulated data for different wave probes are compared and it is found that a loop coupler at the edge of the transmission line radiating electromagnetic is best suited. The electromagnetic radiation causes coupling or cross talk. Radiation at the discontinuities or edge is high and this advantage is used to design a coupler with a high directivity. In the design process size of the device is tried to be kept as small as possible so as to make the cost low. EM-simulation of passive MMIC have been carried out and compared with the experimental result to validate the use of foundry models with real life measurements.