GaAs MMIC I/Q downconverter optimised for microwave radio applications

Analog Devices HMC908A GaAs MMIC I/Q Downconverter is a Gallium Arsenide Monolithic Microwave Integrated Circuit In-phase/Quadrature Downconverter housed in a small RoHS-compliant package. The device is optimised for point to point and point to multipoint microwave radio applications running in the 9GHz to 12GHz input RF frequency range. The device supports LO input frequencies of 8.5GHz to 15.5GHz and IF output frequencies of DC to 3.5GHz.

The device gives a small signal conversion gain of 11dB with a noise figure of 2dB and 25dB of image rejection at 100MHz. It uses an LNA followed by an image rejection mixer driven by a LO buffer amplifier. The image rejection mixer removes the requirement for a filter following the LNA, and removes thermal noise at the image frequency. I/Q mixer outputs are supplied and an external 90-degree hybrid is required to choose the necessary sideband. The device is a much smaller alternative to hybrid style image rejection mixer downconverter assemblies, and it removes the requirement for wire bonding by enabling the use of surface-mount manufacturing techniques.

The downconverter is provided in a compact, 4.9mm x 4.9mm, 32-terminal ceramic LCC.