Cryogenic Millimeter-Wave Receiver Using Molecular Beam Epitaxy Diodes

A millimeter-wave cryogenic receiver has been built for the 60-90-GHz frequency band using GaAs mixer diodes prepared by molecuIar beam epitaxy (MBE). The diodes are mounted in a reduced-height image rejecting waveguide mixer which is followed by a cooled parametric amplifier at 4.5-5.0 GHz. At a temperature of 18 K the receiver has a total single-sideband (SSB) system temperature of 312 K at a frequency of 81 GHz. This is the lowest system temperature ever reported for a resistive mixer receiver. The low-noise operation of the mixer is seen to be a result of 1) the short-circuiting of the noise entering the image port and 2) an MBE mixer diode with a noise temperature which is consistent with the theoretical shot noise from the junction and the thermal noise from the series resistance.     

混频二极管及混频器的噪声分析

本文讨论了混频二极管在直流偏置和交流信号激励时的噪声温度比,提出了以“有效噪声温度比(tD)_(eff)”来表征二极管在交流激励下的噪声性能.文中还讨论了在信号及镜像频率的变频损耗不同时混频器输出噪声温度比和二极管噪声温度比的关系.根据分析结果对倒极性并联二极管对的噪声性能作了分析,表明这种复合管的(tD)_(eff)为一常数(0.5).这对降低混频器的系统噪声系数是十分有利的.可以相信:利用倒极性并联二极管对于研制优良性能的毫米波段混频器是一种很有希望的办法.     

Effect of Magnetic Field on Performance of SIS Mixers Measured at 385–500 GHz

We have investigated the effect of a moderately strong magnetic field (up to 1200 Gauss, 13 quantum fluxes within a single junction) on the heterodyne mixing performance of a 385-500GHz superconductor-insulator-superconductor mixer. Both experimental and numerical results indicate that the mixer conversion gain can be significantly reduced by a magnetic field. Surprisingly, the mixer noise shows very weak dependence. The overall receiver noise increase is merely caused by the intermediate frequency noise contribution amplified by a factor of gain reduction. At the expense of little system noise degradation, a relatively strong magnet field can make the mixer more stable at the bias point corresponding to its noise minimum     

Generalized Linear Periodic Time-Varying Analysis for Noise Reduction in an Active Mixer

A simple linear periodic time-varying circuit model is proposed to rigorously analyze the noise behavior in an active mixer. This analysis can be shown to be a generalization of existing LPTV mixer models, which assume that the mixer is a memoryless device and, as a result, is valid for low frequency only. Based on the proposed LPTV circuit model, explicit formulas for noise figure that accounts for the effect of the thermal noise folding and the flicker noise leakage are derived. Our analysis shows that the mixer operating at OFF overlap mode yields a better noise performance. The analysis is validated against simulations and measurements.     

Noise in RF-CMOS mixers: a simple physical model

Flicker noise in the mixer of a zero- or low-intermediate frequency (IF) wireless receiver can compromise overall receiver sensitivity. A qualitative physical model has been developed to explain the mechanisms responsible for flicker noise in mixers. The model simply explains how frequency translations take place within a mixer. Although developed to explain flicker noise, the model predicts white noise as well. Simple equations are derived to estimate the flicker and white noise at the output of a switching active mixer. Measurements and simulations validate the accuracy of the predictions, and the dependence of mixer noise on local oscillator (LO) amplitude and other circuit parameters     

A High IIP2 Mixer Enhanced by a New Calibration Technique for Zero-IF Receivers

The second-order intercept point (IP2) performance of direct conversion receivers is limited by the second-order nonlinearity of the mixer. A new technique which is based on calibrating mixer by injecting a programmable nonlinear current into the mixer output is introduced in this paper. The proposed calibration technique can be used in multistandard mixers. A CMOS mixer demonstrating the performance for Universal Mobile Telecommunication System application and working with supplies as low as 1 V is designed in a 65-nm technology. The simulation results show that the mixer IIP2 is improved more than 25 dB while the mixer current consumption is increased less than 1 mA. The calibration circuit is low noise not to affect the mixer noise figure.     

A CMOS switched transconductor mixer

A new CMOS active mixer topology can operate at low supply voltages by the use of switches exclusively connected to the supply voltages. Such switches require less voltage headroom and avoid gate-oxide reliability problems. Mixing is achieved by exploiting two transconductors with cross-coupled outputs, which are alternatingly activated by the switches. For ideal switching, the operation is equivalent to a conventional active mixer. This paper analyzes the performance of the switched transconductor mixer, in comparison with the conventional mixer, demonstrating competitive performance at a lower supply voltage. Moreover, the new mixer has a fundamental noise benefit, as noise produced by the switch-transistors and LO-port is common mode noise, which is rejected at the differential output. An experimental prototype with 12-dB conversion gain was designed and realized in standard 0.18-/spl mu/m CMOS to operate at only a 1-V supply. Experimental results show satisfactory mixer performance up to 4 GHz and confirm the fundamental noise benefit.     

基于CMOS工艺的改进型电流注入混频器

设计了一种改进型电流注入混频器.通过在吉尔伯特混频器电路的本振开关管源极引入电感形成谐振电路,消除了开关管源极寄生电容的影响,降低了混频器电路的闪烁噪声,增大了混频器电路的增益.混频器电路的设计采用SMIC 0.35 μm CMOS 工艺库,本振功率为-3 dBm.仿真结果表明,与改进前的混频器电路相比,当本振功率为-3 dBm时,改进型电流注入混频器电路的增益提高了1.76 dB,IIP3提高2.1 dBm,噪声系数降低了0.5 dB.     

2cm低噪声波导腔混频器

本文研究了影响混频噪声系数的诸因素,提出采用砷化镓肖特基势垒二极管、交叉场混频器和和频回收来实现低噪声混频器。实测的最小噪声系数为5.8dB(包括前中噪声系数1.5dB),最大为7dB。实验结果与理论计算相一致。     

Noise in Current-Commutating Passive FET Mixers

Noise in the mixer of zero-IF receivers can compromise the overall receiver sensitivity. The evolution of a passive CMOS mixer based on the knowledge of the physical mechanisms of noise in an active mixer is explained. Qualitative physical models that simply explain the frequency translation of both the flicker and white noise of different FETs in the mixer have been developed. Derived equations have been verified by simulations, and mixer optimization has been explained.      

Low-noise 320?360 GHz cryogenically cooled waveguide Schottky diode mixer

Construction details and results of noise measurements on a cryogenically cooled Schottky diode mixer for the 320?360 GHz range are given. Critical mixer parts are electro-formed or machined on a precision lathe. The system double-sideband noise temperature is close to 400 K over a 30 GHz range with a lowest temperature of 385 K at 335 GHz. The mixer uses a tunable contacting backshort and has a total RF/IF double-sideband conversion loss of about 6dB, including input lens and diplexer losses. Corrected for input losses and second-stage contribution, a mixer double-sideband noise temperature of 271 K has been calculated at 335 GHz. This mixer has shown reliable and reproducible performance during five cooldowns to 15 K.     

A 1.2-V RF front-end with on-chip VCO for PCS 1900 direct conversion receiver in 0.13-/spl mu/m CMOS

In this paper, a 1.2-V RF front-end realized for the personal communications services (PCS) direct conversion receiver is presented. The RF front-end comprises a low-noise amplifier (LNA), quadrature mixers, and active RC low-pass filters with gain control. Quadrature local oscillator (LO) signals are generated on chip by a double-frequency voltage-controlled oscillator (VCO) and frequency divider. A current-mode interface between the downconversion mixer output and analog baseband input together with a dynamic matching technique simultaneously improves the mixer linearity, allows the reduction of flicker noise due to the mixer switches, and minimizes the noise contribution of the analog baseband. The dynamic matching technique is employed to suppress the flicker noise of the common-mode feedback (CMFB) circuit utilized at the mixer output, which otherwise would dominate the low-frequency noise of the mixer. Various low-voltage circuit techniques are employed to enhance both the mixer second- and third-order linearity, and to lower the flicker noise. The RF front-end is fabricated in a 0.13-/spl mu/m CMOS process utilizing only standard process options. The RF front-end achieves a voltage gain of 50 dB, noise figure of 3.9 dB when integrated from 100 Hz to 135 kHz, IIP3 of -9 dBm, and at least IIP2 of +30dBm without calibration. The 4-GHz VCO meets the PCS 1900 phase noise specifications and has a phase noise of -132dBc/Hz at 3-MHz offset.     

Design of wide-band optical heterodyne balanced mixer receivers

The optical heterodyne balanced mixer, or dual-detector receiver, offers significant advantages over a single detector receiver. Balanced mixer receivers are particularly attractive for use in optical heterodyne communication systems because they conserve local oscillator power and cancel excess intensity noise present in the local oscillator. Simple circuit models that illustrate the noise performance, small signal gain, and bandwidth of a balanced mixer receiver are developed. A figure-of-merit for receiver noise performance is also derived. An example design of a gigahertz bandwidth optical heterodyne balanced mixer receiver and the techniques used to characterize near-quantum-limited receiver performance are discussed.     

A 350GHz Radial-Probe SIS Mixer for Astronomical Imaging Arrays

We have developed a 330-370GHz SIS mixer for small-format, heterodyne, astronomical imaging arrays. Fixed-tuned broadband operation is achieved by means of a superconducting radial waveguide probe. A horn-reflector antenna provides high-efficiency optical coupling. Using a variable-temperature cryogenic noise source, we measured a DSB system noise temperature of 32±1K. The mixer contributes 3±3K, supporting the theoretically-predicted result that the noise temperature of a DSB mixer can be less than hω/2κ (8.6K)     

A 0.18μm CMOS Gilbert low noise mixer with noise cancellation

正This paper presents a broadband Gilbert low noise mixer implemented with noise cancellation technique operating between 10 MHz and 0.9 GHz.The Gilbert mixer is known for its perfect port isolation and bad noise performance.The noise cancellation technique of LNA can be applied here to have a better NF.The chip is implemented in SMIC 0.18μm CMOS technology.Measurement shows that the proposed low noise mixer has a 13.7-19.5 dB voltage gain from 10 MHz to 0.9 GHz,an average noise figure of 5 dB and a minimum value of 4.3 dB.The core area is 0.6 x 0.45 mm~2.     

A low-noise mixer with an image-reject notch filter for 2.4 GHz applications

This paper presents a low noise first down-conversion mixer with a notch filter for the heterodyne receiver. The notch filter connected to the output node of the mixer driver stage plays a role of image rejection at an image frequency, thereby suppressing the sideband image noise and improving the mixer noise performance. Targeted for 2.4 GHz industrial-scientific-medical band applications, a simple source-degenerated down-conversion single balanced mixer with the filter is implemented. The measurement results of the proposed down-conversion mixer shows about 3.0 dB improvement of single-side band noise figure, about 2.9 dB power conversion gain improvement, and 25 dB image suppression compared to those without the filter dissipating 4 mA from a 2.5 V supply voltage.     

一种低闪烁噪声高线性度WLAN混频器的设计

提出一种适用于零中频接收的WLAN混频器,采用折叠结构降低开关对的偏置电流,以得到良好的闪烁噪声性能;通过在混频器的驱动级引入辅助管,并优化其衬底电压和尺寸来抵消跨导管的非线性,进而提升电路的线性度.利用Volterra级数辅助分析制约线性度特性的限制因素.基于Chartered O.18 μm CMOS工艺的Spectre-RF仿真表明,电路在WLAN的2.4 GHz频段具有良好的电学性能,噪声系数为8.6 dB,闪烁噪声角为105 kHz,IIP3为5.8 dBm,芯片整体功耗为10 mW,核心电路占用面积为0.09 mm2.     

A New RF CMOS Gilbert Mixer With Improved Noise Figure and Linearity

The noise figure of an RF CMOS mixer is strongly affected by flicker noise. The noise figure can be improved using pMOS switch circuits, which insert current at the on/off crossing instants of the local oscillator switch stage because the circuits reduce the flicker noise injection. When it is applied to a conventional Gilbert mixer, the injection efficiency and linearity are degraded by the nonlinear parasitic capacitances of the pMOS switch circuits and the leakage through the parasitic path. We propose the pMOS switch circuits with an inductor, which tunes out the parasitic components at 2f_o and closes out the leakage path. The mixer fabricated in 0.13-mum CMOS at 2.4-GHz center frequency has provided improved characteristics for linearity and noise figure.     

Noise reduction in sputtered W/GaAs Schottky junctions

The noise characteristics of sputtered W/GaAs Schottky diodes, annealed at temperatures up to 700°C, have been investigated. A useful figure of merit for such millimeter and submillimeter mixer diodes is the noise performance at an RF where accurate measurements are available. Noise temperatures measured at a typical mixer intermediate frequency of 4GHz under DC biased conditions have been reduced significantly by rapid thermal annealing. The best noise data have been obtained with an annealing time of 2 minutes at 600°C and are consistent with good mixer performance.     

A 2.4 GHz CMOS sub-sampling mixer with integrated filtering

A sub-sampling mixer that incorporates sampling switches and hold capacitors into the parallel resonant LC load of an LNA is proposed. The noise figure of the proposed sub-sampling mixer is lower than that of a standard sampling circuit because the proposed mixer has narrow-band gain and input noise filtering properties. A novel level-shifting clock buffer with fast rise and fall times to drive the mixer sampling switches is presented. The mixer was fabricated in a 0.18 /spl mu/m CMOS process and measured results are presented for an RF input frequency of 2.42 GHz and a sampling frequency of 100 MHz. With a measured noise figure of 21.8 dB, the proposed circuit shows improved performance compared to other published sub-sampling mixers.