“…The most common approaches using SiGe for designing a VM are variable gain amplifiers (VGAs) in combination with multiple coupler paths or switching elements [32], [33], [34], [35], [36], [37], Gilbert Cells (GCs) with analog tuning voltages [38], [39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], and reflection type phase-shifters [51], [52], [53], [54]. Besides that, GCs with on-chip digital-analog converters (DACs) [55], [56], switchable delay lines [57], modified Doherty amplifier [58], modified GCs [59], and tunable attenuators [60] have been presented. Moreover, there are many published BPSK modulator circuits [61], [62], [63], [64].…”