A 22-to-36.8 GHz low phase noise Colpitts VCO array in 0.13-μm SiGe BiCMOS technology

28 GHz balanced pHEMT VCO with low phase noise and high output power performance for 5G mm-Wave systems

“…In the literature, many VCOs have a relatively good FoM, however, observing the covered frequency range, we notice that it is very low: 5.45% and 6.91% of the central frequency for the two VCOs proposed in [8], 5.44% and 3.3% respectively for the VCOs proposed in [9,10]. On the other side, structures with wide frequency ranges but low phase noise levels, less than -102 dBc/Hz, which do not fulfill the 5G [11][12][13]. In addition to all these considerations, there is also the problem of the large space occupied by these circuits, of which it is in the order of 1.5 mm 2 [9] or much more [12][13][14].…”

“…On the other side, structures with wide frequency ranges but low phase noise levels, less than -102 dBc/Hz, which do not fulfill the 5G [11][12][13]. In addition to all these considerations, there is also the problem of the large space occupied by these circuits, of which it is in the order of 1.5 mm 2 [9] or much more [12][13][14].…”

A 5G mm-wave compact voltage-controlled oscillator in 0.25 µm pHEMT technology

“…The chip includes the oscillator circuit, RF access pad and three bias pads. While the chip size of the circuits presented in [8,12,15] are 3.75 mm 2 , 0.515 mm 2 and 0.5 mm 2 respectively. It is therefore a compact and reduced structure, compared to the structures published, recently, in the literature.…”

“…Therefore, the design of a VCO for millimeter frequencies presents a great challenge for RF circuit designers [5]. For most VCOs published in the literature, the oscillation frequency tuning is obtained using varactors [6][7][8][9][10]. Due to the high level of varactor Amplitude-to-Phase [11], reference [12] presents a frequency tuning technique based on varactor-mounted GaAs pHEMT transistors in order to minimize the noise conversion and to reduce the size of the final circuit and its fabrication costs, too.…”