Principles and limitations of ultra-wideband FM communications systems
EURASIP Journal on Applied Signal Processing
Design issues of a low power wideband frequency doubler implementation in 0.18 μm CMOS
Analog Integrated Circuits and Signal Processing
Design of Analog CMOS Integrated Circuits
Design of Analog CMOS Integrated Circuits
A low-voltage high-linearity ultra-wideband down-conversion mixer in 0.18-µm CMOS technology
Microelectronics Journal
A 1-V 4-GHz wide tuning range voltage-controlled ring oscillator in 0.18µm CMOS
Microelectronics Journal
A 10GHz wideband VCO with low KVCO variation
Microelectronics Journal
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In this paper, a low-power inductorless ultra wideband (UWB) CMOS voltage-controlled oscillator is designed in TSMC 0.18@mm CMOS technology as a part of a ultra wideband FM (UWBFM) transmitter. The VCO includes a current-controlled oscillator (CCO) which generates output frequencies between 1.5 and 2.8GHz and a voltage-to-current (V-to-I) converter. A low-power frequency doubler based on a Gilbert cell, which operates in weak inversion, doubles the VCO tuning range achieving oscillation frequencies between 3 and 5.6GHz. Thus, the well-known proportionality between the oscillation frequency and the bias tuning current in CCOs is avoided for the entire achieved tuning range, resulting in a lower power design. The employed architecture provides high suppression, over 45dB, of the 1st and 3rd harmonics, while enabling high-frequency operation and conversion gain due to the unbalanced structure and the single-ended output. The current consumption is 5mA at a supply voltage of 1.8V. The VCO exhibits a phase noise of -80.56dBc/Hz at 1MHz frequency offset from the carrier and a very high ratio of tuning range (60.4%) over power consumption equal to 8.26dB which is essential for a UWBFM transmitter.