Realization of mm-Wave MMIC Frequency Doubler for Astronomical Applications

This letter presents the design and characterization of a 52–60-GHz monolithic microwave integrated circuit (MMIC) based frequency doubler using Schottky barrier diodes (SBDs) on a 25- $\mu$ m thick GaAs substrate. An improved MMIC configuration with eight diodes provides continuous high output power with high efficiency. The design is fabricated and housed in an $E$ -plane split block waveguide structure. The fabricated prototype evinces a peak efficiency of 37.2% and output power of 186.2 mW with an input power of 500 mW at 57 GHz. The design provides measured 3-dB output power bandwidth of $\sim$ 22% (50–62 GHz). To the best of the authors’ knowledge, the proposed design with a comparatively smaller circuit size, provides highest continuous output power and conversion efficiency at this frequency band. Moreover, design is less sensitive to the dimensional tolerances which has been demonstrated through sensitivity analysis and repeated measurements over several blocks.