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This letter describes a single-transistor oscillator implemented on a paper substrate at the operating frequency of 24 GHz, based on a design procedure that makes it possible to overcome the limitations caused by thin high-loss substrates and package parasitics of commercial components. The commercial transistor adopted in the oscillator is led to instability by exploiting its parasitic gate inductance. The drain network compensates for the parasitic inductance of the transistor package and connects the oscillator circuit to a 50- $\Omega $ load resistance. Finally, an external inductor at the source terminal is used to resonate out the capacitive contribution of the circuit at the oscillation frequency. Overall, the active device appears in a quasi-common-drain stage. Experimental results on prototype show that the oscillator exhibits an output power of +6.2 dBm at 24 GHz, with a dc power consumption of 72.5 mW. [ABSTRACT FROM AUTHOR]

River discharge is an important variable to measure in order to predict droughts and flood occurrences. Once the cross-sectional geometry of the river is known, discharge can be inferred from water level and surface flow velocity measurements. Since river discharges are of particular interest during extreme weather events, when river sites cannot be safely accessed, noncontact sensing technologies are particularly appealing. To this purpose, this work proposes a prototype of a low-cost continuous wave (CW) Doppler radar sensor, which is able to monitor the surface flow velocity of rivers. The prototype is tested at two gauged sites in central Italy, along the Tiber River. The surface flow velocity distribution across the river is monitored by means of the analysis of received Doppler signal. The surface velocity statistics are then extracted using a novel algorithm that is optimized to run on a microprocessor platform with minimal computing power (ArduinoUNO). In particular, the radar measurements are used to initialize a 2-D entropy-based velocity model (EVM) that is able to estimate river discharges in any flow condition. Finally, the results concerning the observed discharge provided by the EVM prove to be comparable with those obtained with more expensive commercial solutions. The results are important since the described methodology can be extended to small-size Doppler radar sensors onboard unmanned aerial vehicles (UAVs), the latter providing a method for mapping surface velocity of rivers. [ABSTRACT FROM AUTHOR]

This paper presents two 4-bit (16-phase) mm-wave vector modulator phase shifters exploiting a novel in-phase and quadrature signal generator that consists of a single-input double-output cascode amplifier incorporating a lumped-element coupled-line quadrature coupler. The two circuit implementations have been designed and fabricated in a 28 nm fully depleted silicon-on-insulator CMOS. The first (PS1) achieves a higher gain and the second (PS2) has a more compact area (reduced to about 50%). Each consumes 18 mA from a 1.2 V supply. PS1 exhibits an average gain of 2.3 dB at 87.4 GHz and B3\text {dB} from 78.8 to 92.8 GHz; rms gain error of 1.68 dB at 87.4 GHz and <2 dB in the B3\text {dB} ; rms phase error of 9.4° at 87.4 GHz and <11.9° in B3\text {dB} ; S11 <-10.5 dB in B3\text {dB} ; average P1\text {dB} of −7 dBm; and average noise figure (NF) equal to 10.8 dB at 87 GHz. PS2 exhibits an average gain of 0.83 dB at 89.2 GHz and B3\text {dB} from 80.2 to 96.8 GHz; rms gain error of 1.46 dB at 89.2 GHz and <2 dB in B3\text {dB} ; rms phase error of 11.2° at 89.2 GHz and <11.9° in B3\text {dB} ; S11 <-11.5 dB in B3\text {dB} ; average P1\text {dB} of −6 dBm; and average NF of 11.9 dB at 89 GHz. [ABSTRACT FROM AUTHOR]

This paper addresses the extension of the on-chip cold-source noise figure (NF) measurement methodology to millimeter-wave (mm-wave) integrated circuits by using the PNA-X. The proposed methodology has been successfully applied to the on-chip NF measurements of mm-wave building blocks on silicon such as a 4-b programmable 16-phase active phase shifter. The results show how the cold-source method can be extended up to the mm-wave frequency range by using the PNA-X with frequency extenders and an active frequency down-converter, so allowing satisfactory NF measurements of mm-wave integrated circuits. [ABSTRACT FROM AUTHOR]