35 GHz dielectric resonator stabilised gunn oscillator

A 35 GHz dielectric resonator oscillator(DRO) using GaAs Gunn diode in microstrip configuration has been designed and developed. The oscillator, with an integral waveguide-to-microstrip transition, delivered an output greater than 18 dBm. Phase noise of the oscillator is found to be better than ?80 dBc/Hz at 100 KHz away from the carrier. A frequency drift of about ±25 MHz has been observed over the temperature range from ?10 °C to 50 °C.     

Development of Broad Band VCO at Ka-Band

A broad band VCO has been developed at Ka-band for FMCW Radar applications. To achieve a wide range of frequency variation, VCO has been designed in series configuration. Design steps have been presented. VCO exhibits a tuning range of 600 MHz with the power output of 50 mw, when the controlled varactor voltage varies from 7.5 volts to 15 volts. Frequency drift with temperature has been contained within 30 MHz using a proportionally controlled DC heater module over the temperature range of 0°C to +55°C. Phase Noise of the oscillator measured at the mid and extreme frequencies is about -70 dBc/kHz at 10 kHz away from the carrier. The experimental circuit and measured performance is also presented.     

Technique for improving the frequency/temperature characteristics of 3cm-band Gunn oscillators

A Gunn oscillator was used to stabilise another by injection locking. Over an ambient temperature range of +50 to ?20°C, the frequency drift of ?0.46 MHz/degC was reduced to +1.4 kHz/degC. The practical limit to the stability is set by changes in the pulling of the control-source frequency, but some improvement is possible by increasing the isolation between the oscillators.     

A novel millimeter wave gunn oscillator

It is described that the design, configuration and the performance of a novel millimeter wave Gunn oscillator stabilized by external cavity and temperature compensation in this paper. The frequency stability is 3.6 × 10^?6 at 52 GHz over the teperature range from ?10 to 50 °C. An output power of more than 100mW has been obtained in the frequency range from 51.5 to 52.8 GHz.     

Gunn diodes with improved frequency-stability/temperature variations

Improved frequency-stability/temperature variations have been obtained for Gunn diodes by using n+ contacts. 20 mW diodes were operated in a low-Q factor invar coaxial cavity. On decoupling by 6 dB, a total frequency drift as little as 9 MHz over the temperature range ?75°C to +60°C has been observed, i.e. less than 70 kHz/degC. This is compared to results of silver?tin-contact devices showing the usual drift of about ?1 MHz/degC. The absence of contact resistance in the n+ contact devices is the primary reason for their improved stability.     

Composite substrate material for surface acoustic-wave oscillator

Surface acoustic-wave (SAW) oscillators have advantageous features compared with other technologies. The Y-128° LiNbO₃ is a well-known, high electromechanical-coupling SAW material, but its usefulness is limited because of its poor temperature-stability property. The AlN films have some excellent characteristics, such as high SAW velocity, stable chemical properties, and high-temperature stability. In this research, different thickness AlN films were sputtered on Y-128° LiNbO₃ to be a composite substrate for the SAW oscillator. As AlN film thickness increased, the temperature coefficient of frequency (TCF) value of the oscillator varied from −76.32 ppm/°C to −28.81 ppm/°C giving an improvement in the TCF of 62.25%. The oscillator frequency at 25°C also varied from 40.0909 MHz to 41.6221 MHz, giving an improvement in the oscillator frequency of 3.8%. The composite substrate (AlN/Y-128° LiNbO₃) can enhance the oscillator frequency and effectively improve the poor temperature stability for the SAW oscillator.     

A low-noise voltage-controlled ring oscillator in 28-nm FDSOI technology for UWB applications

In millimeter wave systems, performance degradation mainly occurs due to high phase noise of voltage-controlled oscillators (VCOs). This paper proposes a low power, low phase noise ring-VCO developed for ultra-wide band applications identified for possible 5G usage. For this purpose, a novel differential symmetrical load delay cell based 3-stage ring oscillator has been introduced to design the ring-VCO. The 28 nm CMOS Fully Depleted Silicon On Insulator (FDSOI) technology is adopted for designing this VCO circuit with 1 V power supply while a new voltage control through the transistor body bias is implemented. The simulated results show that the proposed oscillator works in the tuning range of 29–49 GHz and dissipates 3.75 mW of power. It exhibits a phase noise of −129.2 dBc/Hz at 1 MHz offset from 49 GHz oscillation frequency, and a remarkable Figure of Merit (FoM) of −217.26 dBc/Hz. With similar power supply, the phase noise rises to −93.16 dBc/Hz for a second oscillator involving more of active components exactly 9 delay cells. Further, the impact of the operation temperature variation on the VCO performance is investigated. Results show a drift in the oscillation frequency for a temperature step from 27 °C to 40 °C and a degradation of 3dBc in the phase noise performance.     

Temperature compensated and gated CMOS ring oscillator for time-to-digital converter application

This paper presents a CMOS voltage controlled ring oscillator with temperature compensation for low power time-to-digital converters (TDCs). In order to maintain the oscillation frequency stable, a novel compensation circuit is proposed through adaptively sensing temperature variations. This design has been implemented in TSMC 0.35 μm CMOS standard process with an active area of under 0.039 mm². Experimental results show that the clock frequency is around 159.0 MHz only with a power consumption of 550 μA. As respective to the room temperature the maximum frequency variation is between ?3.46 and +3.08 % under temperature range of ?40 to 85 °C. The bit error time induced by clock jitter is limited within 4.8 % in the whole clock period, and the differential nonlinearity of the TDC is less than 0.408 LSB.     

A 16 MHz, 59.2 ppm/°C CMOS DLL-Assisted VCO with Improved Frequency Stability Towards Single Chip Wireless IOT

A 16 MHz, highly stable voltage controlled oscillator (VCO) is reported in this paper. The proposed VCO consists of three cross-coupled RC stages, and is fully compatible with standard CMOS process. A positively biased PN junction with negative temperature coefficient is incorporated in the design to compensate frequency drift. In addition, a delay locked loop (DLL) directly following the VCO is utilized to further improve the output stability caused by temperature variations. The designed circuit was implemented using CMOS 0.18 μm technology, and was validated through experiments. Measurement results show that the DLL-assisted VCO output variation across the 25~120 °C temperature range is less than 0.56 %, corresponding to 59.2 ppm/°C. It also shows that the output standard deviation of the DLL-assisted VCO is only 6.816 KHz, ~ 16.6 % better compared with the same VCO without DLL’s assistance.     

1.25厘米单调谐体效应振荡器

本文报导了一种单调谐体效应振荡器.该振荡器结构类似于Kurkoawa电路.但谐振腔采用H_(011)高Q圆柱腔.该振荡器电路负载变化对振荡频率影响较小,能够避免通常反射腔稳频振荡器受到负载变化可能出现跳频的缺点.而且噪声电平比其它振荡源要小.对电路参数经过适当选择后,振荡器的输出效率能达到40～60%,输出功率30～100mW.机械牵引带宽大于600MHz.该振荡器的主腔和调谐活塞采用线胀系数不同的材料进行温度补偿.当温度循环在-40℃至+70℃的范围内,频率温度系数一般优于0.08MHz/℃,功率稳定度优于0.022dB/℃.     

A high performance 1 GHz voltage controlled oscillator using neural system architecture

In this paper, an improved voltage controlled oscillator scheme with temperature compensated frequency, a wide linear range, low phase noise and low power dissipation is presented for application in transmitting signals of gas sensors from mines using RF communication. The basic unit of the oscillator is a ring based differential amplifier incorporating temperature compensated voltage dependent PMOS capacitors and standard PMOS triode connected load with temperature compensated biasing scheme. The increased nonlinearity in the presence of PMOS capaciors is reduced to 0.001% using a digitally programmable neural architecture which is simulated in the mixed signal domain of SYNOPSYS. Additionally, the temperature compensated PMOS capacitor improves the sensitivity of the VCO and the standard temperature compensated biasing scheme of the PMOS triode connected load reduces the drift in amplitude with temperature variation. The PMOS varactor lowers the phase noise of the VCO compared to parasitic capacitors without increasing the power dissipation. The entire VCO is designed using 0.18 μm typical technology of TSMC with 1.8 V power supply. The tuning range of the VCO is 0.3–1.7 V, maximum frequency is 1 GHz with a linear change of around 750 MHz, temperature sensitivity and power consumption are around 50 ppm/°C and 2 mW respectively. The phase noise is obtained to be around −123dBc/Hz at 1 MHz offset frequency.     

与工艺、电源电压和温度无关的低功耗振荡环设计

分析了传统片外时钟和片内时钟各自的特点和应用背景,在Chartered 0.35μm CMOS工艺下实现了一个低功耗PVT(工艺、电源电压、温度无关)振荡环,对片内时钟的稳定性和功耗进行改进。该振荡环无需精准的电压源,采用了误差补偿技术,通过偏置电压和延时单元的相互补偿,使得振荡频率对于工艺、温度和电源电压均有较大的容差能力。并且由于针对延时单元补偿的方式,令周期大小易于调整。蒙特卡罗仿真显示,工艺误差引起的偏差要比补偿前的偏差减小了60%。流片测试结果表明,在工作温度变化范围0~100°C时,振荡环输出的频率偏差为±3.22%;在电源电压变化范围为2.8~3.8 V时,振荡环输出的频率偏差为±3.36%;在电源电压3.3 V的情况下,整个芯片消耗的电流为950μA。     

The performance of X-band Gunn oscillators over the temperature range 30°C to 120°C

The output power of a cavity-controlled Gunn oscillator has been measured at a frequency of 10 GHz, as a function of bias voltage over the temperature range 30°C to 120°C. The measurements were made using 500-ns pulses to avoid significant changes in-device temperature during a pulse, and at a duty cycle of 20:1 to maintain a low mean input power. The device was operated in a coaxial cavity made of invar, and temperature control effected by operating the cavity in an oven. It has been found that ranges of bias voltages exist over which power output and efficiency is extremely sensitive to temperature changes, and that, depending on the particular conditions, power output can either increase or decrease. The effect of increasing temperature has also been found to reduce the bias voltage required to obtain maximum power output and efficiency.     

Low-power broadband quadrature signal generator based on phase-tunable dividers

This paper presents the design and experimental results of a low-power 300–960 MHz I/Q signal generator for low-IF receivers. The circuit is based on phase-tunable dividers and uses delay-locked loops, which provide phase accuracy for the quadrature signals as well as low-sensitivity of the phase error against temperature and power supply variations. Thanks to the adopted technique, the phase error can be further reduced by trimming the reference voltage of the delay-locked loops through a calibration digital word, which can be stored in a non-volatile memory during manufacturing. The I/Q generator exhibits an absolute phase error before calibration that is lower than 1.5°. The I/Q phase drift due to temperature variations from ?40 to 85 °C and power supply variations from 1.1 to 1.3 V is 0.3° and 0.2°, respectively. By dividing the overall frequency range into four 165-MHz wide sub-bands and using only four 5-bit calibration words, the I/Q phase variation with respect to frequency, temperature, and power supply is lower than 1° in the 300–960 MHz operating band. The I/Q generator is implemented in a 90-nm CMOS technology and exhibits a current consumption as low as 0.5 mA.     

Design Consideration for Frequency-Stabilized MIC IMPATT Oscillators in the 26-GHz Band

A 26-GHz frequency-stalbilized MIC IMPATT oscillator using a dielectric resonator has been developed. In designing such an oscillator in the high-frequency range, many parameters affecting frequency stability should be considered. This paper discusses oscillation frequency variations caused by deviations in the resonant frequency of dielectric resonators, in diode reactance, and in the electrical length between the diode and resonator, all of which are due to temperature variation. Design criteria for a highly frequency-stabilized oscillator are also presented. With these techniques, we have obtained an MIC IMPATT oscillator with frequency stability of less than +-5.0x10/sup -5/, output power deviation of less thau +-2.0 dB, and output power of more than 23 dBm over the temperature range of 0°C to 50°C.     

A Temperature Compensated CMOS Ring Oscillator for Wireless Sensing Applications

This paper presents a CMOS voltage controlled ring oscillator (VCO) with temperature compensation circuit suitable for low-cost and low-power MEMS gas sensor. This compensated ring oscillator is dedicated to Chopper Stabilized CMOS Amplifier (CHS-A). To operate at low frequency, a control voltage generated by a CMOS bandgap reference (BGR) is described and the measurement results of the fabricated chips are presented. The output voltage of the reference is set by resistive subdivision. In order to achieve small area and low power consumption, n-well resistors are used. This design features a reference voltage of 1 V. The chip is fabricated in AMS 0.35 μm CMOS process with an area of 0.032 mm². Operating at 1.25 V, the output frequency is within 200?±?l0 kHz over the temperature range of ?25 °C to 80 °C with power consumption of 810 μW.     

Novel technique for improving the frequency stability of Gunn oscillators

The frequency stability of a Gunn oscillator employing waveguide below cutoff as a resonator is investigated over the temperature range 20?100°C. A novel technique is described for improving the frequency stability of the oscillator. Experimental results using the negative temperature coefficient of the permittivity of titania are presented in support of this method.     

Silicon Resonator Based 3.2 $mu$W Real Time Clock With $pm$10 ppm Frequency Accuracy

This paper presents an ultra-low power generic compensation scheme that is used to implement a real time clock based on an AlN-driven 1 MHz uncompensated silicon resonator achieving 3.2 ?W power dissipation at 1 V and ±10 ppm frequency accuracy over a 0-50°C temperature range. It relies on the combination of fractional division and frequency interpolation for coarse and fine tuning respectively. By proper calibration and application of temperature dependent corrections, any frequency below that of the uncompensated resonator can be generated yielding programmability, resonator fabrication tolerances and temperature drift compensation without requiring a PLL. To minimize the IC area, a dual oscillator temperature measurement concept based on a ring oscillator/resistor thermal sensor was implemented yielding a resolution of 0.04°C. The IC was fabricated on a 0.18 ?m 1P6M CMOS technology.     

A Highly Stabilized MIC Gunn Oscillator Using a Dielectric Resonator

An X-band frequency-stabilized MIC Gunn oscillator of a very simple structure using a dielectric resonator is developed. It is studied how the oscillating characteristics can be controlled by circuit parameters, with special attention to the factors affecting the frequency stability with temperature. By optimizing these factors and by selecting the proper temperature coefficient of a newly developed dielectric resonator, the high frequency stability of less than /spl plusmn/100 MHz over the temperature range from -20 to 60/spl deg/C (2x10 /sup -7/ / /spl deg/C) was obtained.