Low Cost Ka Band IQ Vector Modulator with Flip Chip Diodes

This paper presents the design and the measured results of an IQ vector modulator using flip chip mounted diodes. This circuit has been developed for the 29.5 - 30GHz band and is based on discrete subharmonic mixers on low cost substrate. The performance achieved demonstrates the feasibility of such a modulator as a key component in consumer premises equipment for future interactive multimedia satellite services. This discrete component concept achieved approximately 2° phase and 0.5dB amplitude accuracy over the whole bandwith and the ¿20°C to +60°C temperature range. These static residual quadrature errors can be easily compensated by adjusting the amplitude and phase of the modulating input signals.