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We obtained frequency increase in resonant-tunneling-diode (RTD) terahertz (THz) oscillators by thick antenna electrode. The THz oscillator was composed of an RTD and slot antenna. Because an oscillation at resonance frequency of the RTD and slot antenna occurs when the negative differential conductance of the RTD compensates for the loss of the antenna, a reduction in the conduction loss and inductance...
We report an increase in oscillation frequency of room-temperature terahertz oscillators using AIAs/InGaAs resonant tunneling diodes (RTDs) with optimized collector spacer thickness. Because of the trade-off relation between the capacitance and electron transit time for the spacer thickness, an optimum thickness exists in terms of the oscillation frequency. The highest frequency in this experiment...
This paper presents a digitally controlled oscillator (DCO) in inductor-capacitor (LC) topology with dual -band and fine frequency tuning steps. Using special Fibonacci sequence method and additional capacitor in the capacitor bank, this DCO operates two differential frequency bands and achieves finer tuning range than that of a conventional binary sequence DCO. The proposed circuit is implemented...
We proposed a resonant tunneling diode (RTD) with InAlGaAs/InP composite collector for reduction in transit delay caused by the gamma to L valley transition at the collector depletion region. Terahertz oscillators fabricated with this RTD show room-temperature fundamental oscillations of 680–770 GHz with the RTD areas of 1–1.5 square microns. Higher frequency will be possible by reducing the RTD area.
Room-temperature fundamental oscillation of up to 1.31 THz was achieved in thin-well resonant tunneling diodes integrated with planar slot antennas. The output powers were ∼10 µW at 1.31 THz and around 30 nW in the 0.8–1.1 THz region. This high frequency oscillation with relatively high output power is attributed to a reduction in the intrinsic delay and an increase in the widths of current density...
A novel 14-bit digitally controlled ring oscillator is designed in 0.18 µm CMOS technology. Sub-feedback technique is used to increase the output frequency that produces stable oscillation with even number of stages. Frequency can be tuned from 674 MHz to 4 GHz. Phase noise at 4 GHz carrier frequency and 4 MHz offset is −119.4dBc/Hz. Figure of Merit (FoM) calculated is 156 dBc/Hz.
A novel low power 8-bit digitally controlled oscillator in 0.18 µm CMOS technology is designed and implemented. It consumes only 12.6 mW to oscillate at 3.44 GHz. Sub-feedback technique is used to produce stable quadrature output with even number of stages. Tuning frequency range is from 1.2 GHz to 3.44 GHz, i.e., it has tuning width of about 97%. Phase noise of −110.9 dBc/Hz is achieved at 3.44 GHz...
A 14-bit digitally controlled ring oscillator (DCO) with operating frequency up to 1 GHz in 0.18 µm CMOS technology is designed. The design used digital control to obtain higher output voltage swing and to get lower flicker noise compared to the analog counterpart. To make the oscillator oscillate and to get stable quadrature output in the even number of stages, feed-forward technique is used. Designed...
This paper presents a digitally controlled oscillator (DCO) in Inductor-Capacitor (LC) topology with an enhanced frequency-steps and power consumption. Using special Fibonacci sequence method for optimizing capacitor sizes, this digitally-controlled oscillator (DCO) realizes frequency-tuning steps superior than a conventional DCO using binary sequence without increasing the power consumption. The...
This paper presents the design and implementation of a quadrature voltage-controlled ring oscillator with the improved figure of merit (FOM) using the four single-ended inverter topology. A new topology to prevent the latch-up in single ended ring oscillators is proposed. The design is implemented in 0.18 μm CMOS technology and the measurement results show a FOM of -163.8 dBc/Hz with the phase noise...
A digital-controlled oscillator (DCO) employing on-chip coplanar waveguide (CPW) resonator is proposed for 5 GHz-band wireless communication applications. A 10 bit DCO using on-chip designed, fabricated and tested. By comparing the measured results on the fabricated chip in 0.18 mum CMOS technology, it has noted that the proposed DCO employing on-chip CPW resonator is smaller in size and frequency-tuning...
Digitally controlled LC oscillator (LC-DCO) design in 0.18 mum CMOS technology is presented with low phase noise and low power dissipation. Particular attention is given to achieve the wide tuning range. A varactor array is implemented using new logic, which made the significant reduction in the number of signal lines and the reduction in the size of local decoder, used to decode the input control...
This paper presents a simple architecture for 8-bit digital controlled oscillator (DCO) on 3-stages ring topology in TSMC 0.18 um CMOS technology. A new schematic of tristate inverter is also proposed. The proposed tristate inverter has higher switching speed and low power consumption as compared to conventional one. The control digit changes the driving current that provides large tuning range from...
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