MMIC Frequency Doublers

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  • Author: John E. Penn
Several frequency doublers were designed using a 0.13 um GaAs Pseudomorphic High Electron Mobility Transistor (PHEMT) process from TriQuint Semiconductor. The design and fabrication of these circuits was performed as part of the Fall 2011 Johns Hopkins University Monolithic Microwave Integrated Circuit (MMIC) Design Course, taught by the author. The design approach is applicable to frequency multiplier MMICs that could be used for a variety of RF and Microwave systems. Frequency multipliers can be useful for generating higher frequency sources from an existing lower frequency source. It can be simpler to take an existing Microwave communications system operating at one band and use multipliers to quickly up-convert the system for higher frequency operation. Whether mixing for up or down conversion, or directly up converting, a multiplier is one option for increasing the transmission or reception frequency. Harmonics will be of concern with multipliers, so two of the three designs use a quarter wave stub to “short” out the fundamental input frequency, while optimizing the output load for the second harmonic. This approach could also be used for a harmonic tripler. Following is a discussion of the design and measured performance of these frequency doublers, a 10 GHz doubler, and an 8 GHz and 16 GHz doubler with harmonic stubs.