26 GHz MMIC linear vector modulator

This paper reports on the design and measurement results of a monolilhic linear vector modulator for the 25.5-27.5 GHz frequency band. This is a parallel type of 1,Q modulator. The design is based on the use of cold PHemts to realise the linear modulation. Two versions have been made. In the first case the I and Q modulators are single balanced , while in the second case double balanced modulators are used. The 90 and 180 degree couplers as well as an output buffer are included on the chip. Chip size is 3mm x 4mm.