RF oscillator implementation using integrated CMOS surface acoustic wave resonators

This work is a proof of concept that a monolithic CMOS surface acoustic wave (SAW) resonator can function as an RF oscillator. The design of the oscillator includes the measurement characteristics of the CMOS SAW resonator, its matching networks, and RF amplifier is described. The integrated SAW resonator, with its operating frequency controlled by the spacing of its transducers was fabricated using a combination of CMOS plus post-CMOS processes. Based on the operation and performance of the SAW resonators, an equivalent circuit model of the CMOS SAW resonator was developed. A series resonant oscillator design was simulated using Microwave Office^TM. The designed matching network improves both the insertion losses and the phase slope of the resonator, while the RF amplifier provides sufficient gain to ensure oscillation. Measurements conducted on the RF-CMOS SAW oscillator demonstrated oscillation at 600 MHz.     

基于SAW谐振器无源无线传感器编码方法研究

为简化声表面波(SAW)传感器的编码过程,提出了一种基于SAW谐振器的编码方法,通过多个不同中心谐振频率的SAW谐振器分别连接不同的负载阻抗进行传感器的编码。设计了传感器的具体结构,建立了传感器的等效电路模型,利用ADS仿真软件对中心谐振频率分别为868MHz和915MHz的2个SAW谐振器组成的传感器进行仿真,结果表明,SAW谐振器外接1pF与4pF的阻抗,其谐振频率差可达200³00kHz。根据仿真结果,设计制作了不同编码的2个传感器,一个不外接阻抗,一个外接10pF的阻抗,测试谐振频率差别可达39.75300kHz。根据仿真结果,设计制作了不同编码的2个传感器,一个不外接阻抗,一个外接10pF的阻抗,测试谐振频率差别可达39.75⁴0.2kHz,因此,SAW谐振器外接不同阻抗时谐振频率的差异明显,基于SAW谐振器与外接阻抗的传感器编码方法是可行的。     

Development of a GaAs monolithic surface acoustic wave integratedcircuit

An oscillator technology using surface acoustic wave (SAW) delay lines integrated with GaAs MESFET electronics has been developed for GaAs-based integrated microsensor applications. The oscillator consists of a two-port SAW delay line in a feedback loop with a four-stage GaAs MESFET amplifier. Oscillators with frequencies of 470, 350, and 200 MHz have been designed and fabricated. This oscillator technology is most suitable for sensor applications but can logically be extended to radio-frequency oscillator and filter applications by methods well known for other piezoelectric substrates     

Fully CMOS integrated low voltage 100 MHz MEMS resonator

The development of a novel fully integrated microelectromechanical system (MEMS) for RF purposes is presented. It is composed of a paddle polysilicon micro-resonator electrostatically excited and a capacitive CMOS read-out amplifier. The micro-resonator is fabricated directly on a commercial CMOS technology, only requiring a wet etching process for the release of the resonant structure after the full CMOS integration. Electrical characterisation of the on-chip resonant device has been performed showing a resonance frequency near 100 MHz.     

2 200 MHz圆环形介质谐振器的研制

讨论了TE011谐振模式的圆环形介质谐振器的研制过程。固定ZnO添加量为质量分数1.00%,考察了WO3改性剂对(Zr0.8Sn0.2)TiO4微波陶瓷介电性能的影响。当w(WO3)为0.25%时,可得到εr为38.0、Q值大于5800(7GHz)、τf小于2.0×10–6/℃的瓷料。以该瓷料为原料制作谐振器,研究了制作工艺和支撑物高度对谐振器性能的影响。发现采用冷等静压成型工艺所制谐振器的Q值比采用干压成型工艺提高了4%。获得了谐振频率为2200MHz的高Q值、高功率、高稳定性圆环形介质谐振器,完全满足设计要求。     

Gold-Plated Micromachined Millimeter-Wave Resonators Based on Rectangular Coaxial Transmission Lines

Resonators based on microfabricated rectangular coaxial (recta-coax) transmission lines are presented. The resonators were fabricated using a multilayered nickel electroplating process that enables the fabrication of three-dimensional structures. As a method to improve performance, gold was plated on the resonators using an electroless process. A model for predicting the effect of the plating on a resonator quality (Q) factor is presented and verified by measurements. Measured resonators show that the plating can increase the Q factor of nickel resonators by over 50% at frequencies above 44 GHz. Utilizing gold plating, 50-Omega resonators are demonstrated at 44 and 60 GHz with unloaded Q factors of 213.1 and 242.3, respectively     

Thermally excited silicon oxide beam and bridge resonators in CMOStechnology

The design, fabrication, and characterization of thermally excited silicon oxide beam and bridge resonators by a modern industrial CMOS process combined with one additional maskless etching step is reported. The resonant frequencies, vibration amplitudes, and mode shapes of the devices are measured using a laser heterodyne interferometer. The acoustic transmitting and receiving sensitivities of the resonant structures in air are investigated in order to test their possible application as ultrasound transducers for proximity sensing. The experimental results are compared with finite element simulations using ANSYS     

Uniaxially strained ZnO/SiO2/Si SAW resonators

Surface-acoustic-wave (SAW) resonators fabricated on a ZnO/SiO2/Si layered medium have been cantilever-mounted. By deflecting the free end of the substrate, uniaxial biasing strains are induced in the SAW resonator. The effect of these static strains on resonant frequency and SAW phase velocity is assessed.     

On the Deembedding Issue of CMOS Multigigahertz Measurements

The purpose of this paper is to address the issues of deembedding multigigahertz CMOS measurements by extensively comparing six popular methods and by proposing a new method based on two-port measurements. The comparison aims to evaluate the maximum applicable frequency of equivalent-circuit methods (open-short, three step, ...) and the effect of the source dangling leg of MOSFETs on the cascade methods (two line and thru). Fifty dummy structures and 12 MOSFETs were fabricated using standard 0.18-mum CMOS technology. It was found that, at low frequencies (<6 GHz), all method results were comparable. The open-short method performed well over the entire frequency range (0.1-40 GHz) studied. The newly developed method, called the thru-short method, uses only two dummy structures, a thru and a short, to completely deembed the parasitics from probe pads, interconnects, and the semiconducting substrate. The measurements validated the thru-short algorithm and showed its usefulness for multigigahertz on-wafer CMOS measurements.     

Microwave circuit theory-based models to predict the resonant frequencies of a wide range of ring resonators

The concept of the ring resonance of a symmetric two-port network is used to determine the resonant frequencies of a variety of ring resonators, on the basis of simple transmission-line or coupled-transmission-line equivalent circuits. Several illustrative structures, from the closed ring microstrip to the Pendry-type split-ring slotline resonators, have been analysed and measured. Full-wave simulations and measurements are in excellent agreement with the proposed models, and even with its short-line approximations, when suitable.     

Bandpass Sigma–Delta Modulator Employing SAW Resonator as Loop Filter

Continuous-time bandpass (BP) sigma-delta modulators (SigmaDeltaMs) employing surface acoustic wave (SAW) resonators as loop filters are presented. Compared with the loop filters realized with G_m-C and LC resonators, the SAW resonator has the advantage of high-Q factor, wide resonant frequency range and accurate resonant frequency without the need for automatic tuning. With the proposed anti-resonance cancellation and loop filter phase compensation techniques, a second- and a fourth-order BP SigmaDeltaMs are demonstrated in a 0.35-mum CMOS technology. Both modulators are tested with 47.3-MHz off-chip SAW resonators. The second-order modulator attains a dynamic range of 57 dB and peak signal-to-noise distortion ratio (SNDR) of 54 dB and the fourth-order one achieves a dynamic range of 69 dB and peak SNDR of 66 dB, both in a 200-kHz signal bandwidth. The fourth-order modulator is also measured in a 3.84-MHz signal bandwidth and achieves a dynamic range of 52.5 dB and peak SNDR of 50 dB, an effective 8-bit resolution     

Integrated Circuit Compatible Surface Acoustic Wave Devices On Gallium Arsenide

Improvements in gallium arsenide materials technology have led to the rapid development of GaAs MIC, CCD, and digital IC technologies in the last several years. In this paper we consider the additional capabilities afforded by the inherent piezoelectric properties of GaAs. The primary emphasis of the work is on surface acoustic wave (SAW) device configurations using MESFET and Schottky-barrier diode fabrication techniques which are compatible with the eventual monolithic integration of electronic devices on the same substrate. The GaAs SAW technology described here provides a means for achieving electronically variable delay, high-Q resonator structures for VHF/UHF oscillator frequency control, and real-time signal processing operations such as convolution and correlation. Prototype device designs and performance are described, includlng two-port GaAs SAW resonators with Q's as large as 13 000 at 118 MHz and a programmable GaAs SAW PSK correlator capable of signal correlation at 10-MHz chip rates. Further GaAs SAW device development required for increasing the operating frequency range to 500 MHz and processing bandwidth to 100 MHz is indicated.     

用于声光移频的声表面波谐振器

针对一种喇曼型声表面波声光器件的设计需求,设计制作出一种能够满足喇曼-奈斯衍射要求的、低损耗、高Q值声表面波谐振器。利用耦合模(COM)理论仿真谐振器的性能,建立谐振器的COM模型,求解COM方程,提取出COM参数。利用COM软件仿真设计谐振器的结构参数,设计的谐振器中心频率为78.028MHz,Q值为10 428,插入损耗为-6.153dB。利用微加工技术加工制作出声表面波谐振器,用矢量网络分析仪对其性能进行测试,得到谐振器实际中心频率为78.34MHz,插入损耗为-11.273dB,Q值为6 465.7,该谐振器能够满足喇曼型声表面波声光器件的应用需求。     

基于谐振原理的RF MEMS滤波器的研制

采用与IC工艺兼容的硅表面MEMS加工技术,以碳化硅材料作为结构材料,研制出一种新型的基于谐振原理工作的RF MEMS滤波器。详细介绍了器件的工作原理、制备方法、测试技术和结果,并对测试结果做出分析。该RF MEMS滤波器由弹性耦合梁连接两个结构尺寸和谐振频率完全相同的MEMS双端固支梁谐振器构成,MEMS谐振器的结构决定了滤波器的中心频率,弹性耦合梁的刚度决定了滤波器的带宽。在大气环境下测试器件的频响特性,得到中心工作频率为41.5MHz,带宽为3.5MHz,品质因数Q为11.8。     

低损耗贴片式独块状介质滤波器的设计与制作

设计制作了一种低损耗、贴片式(SMD)独块状的八级介质滤波器。该滤波器采用切比雪夫响应的方法设计,利用εr为45的高Q值独块状微波陶瓷制作,谐振器之间使用电容和电容加载耦合。制备出了中心频率为897.5MHz、插入损耗小于2.5 dB的介质滤波器。测试结果表明,该滤波器满足800~1 500 MHz频率范围通讯基站要求。     

Electrically small resonator using thick-film high-Tcsuperconducting wire helix

A method for optimizing the geometry of half wave shielded helical resonators is presented, Copper and superconducting helical resonators, the latter made of YBCO thick film coated on zirconia wire, were designed and fabricated for tests. The resonant frequency could be predicted in relation to the helix and shield parameters. The surface resistance of YBCO was found at different frequencies and temperatures by the two-fluid model approximations and used to calculate the total loss resistance of the helix. The key parameters of the resonators were predicted, measured and compared. Good agreement was found for copper, but the unloaded Q of the superconducting resonator was lower than predicted, although this was expected, due to the polycrystalline nature of the superconductor     

LGS声表面波双模温度传感器研究

该文研究了基于硅酸镓镧（La3Ga5SiO14,LGS）压电衬底的声表面波(SAW)谐振器的瑞利波模式谐振频率和体声波模式谐振频率的温度特性,并利用这两种模式构建了一种宽温度范围的具有线性输出特性的温度传感器。研究结果表明,基于LGS衬底的谐振器的瑞利波模式和体波模式的谐振频率均与温度成二次函数关系,且二阶频率温度系数接近,利用此特性构建的双模温度传感器测试结果和热电偶测试结果基本一致。该文提出的这种双模温度传感器可获得全温度范围的线性输出特性,可应用于LGS高温SAW温度传感器。     

可编程SAW滤波器CMOS集成电路的研究

本文介绍了一种采用1 μm CMOS工艺实现的可编程声表面波滤波器的八位取样、加权、控制、叠加集成电路,并对电路的性能进行了模拟和测试,同时与延迟线型、多组IDT型的声表面波滤波器以多芯片模式进行在线功能测试.该电路由两个三明治电容和两个高宽长比的高跨导NMOS晶体管组成.该电路结构简单,制造工艺与传统的CMOS工艺兼容.该集成电路的工作频率范围为15MHz~250MHz时,插入损耗为-8dB~-20dB,加权电路开关比(on/off ratio)为7dB~18dB左右.