A 1.4-2.7-GHZ ANALOG MMIC VECTOR MODULATOR FOR A CROSSBAR BEAMFORMINGNETWORK

The design and performance of a monolithic 1.4-2.7-GHz vector modulato r with analog amplitude and phase control are presented in this paper, A full 360 degrees coverage range and a dynamic range greater than 13 dB is achieved by combining two out of three vectors 120 degrees apar t with variable amplitude, Amplitude control is performed by three set s of quasi-dual-gate MESFET's (two single-gate MESFET's in cascade) wh ile the 120 degrees shift among the vectors is achieved through LC fil ters covering the 1.4-2.7-GHz band, Since the active devices throughou t the circuit are not working in saturation, large-signal models must be used in the simulations. The circuit is used as the matrix node ele ment in an analog crossbar beamforming network (CBFN) and as the gener al-purpose wide-band vector modulator device.