New Impedance Matching Scheme for 60 GHz Band Electro‐Absorption Modulator Modules

This letter proposes a new impedance matching scheme of a traveling wave electro‐absorption modulator (TWEAM) module for a 60 GHz band radio‐over‐fiber (ROF) link. A microstrip bandpass filter (BPF) was used to achieve impedance matching at the 60 GHz band, and termination resistance was carefully designed to obtain an input impedance close to 50 Ω. Also, a bias circuit for the device was designed in the module. The measured return loss and frequency response show that the modulator module observes the characteristics of a filter without the need of a further tuning process.     

A Novel Quasi-Optical Frequency Multiplier Design for Millimeter and Submillimeter Wavelengths

This paper describes a novel design for millimeter and sub-millimeter wavelength varactor frequency triplers and quadruplers. The varactor diode is coupled to the pump source via waveguide and stripline impedance matching and filtering structures. Output power at the various harmonics of the pump frequency is fed to quasi-optical filtering and tuning elements. The low-loss quasi-optical structures enable near-optimum control of the impedances seen by the varactor diode at the idler and output frequencies, resulting in efficient high-order harmonic conversion. A minimum efficiency of 4 percent with 30-mW input power has been obtained for a tripler operating between 200 and 280 GHz, with a peak efficiency of 8 percent between 250 and 280 GHz. Another tripler, designed for the 260-350-GHz band, gave a minimum conversion efficiency of 3 percent with 30-mW input power, with a peak efficiency of 5 percent at 340 GHz.     

T／R组件中滤波低噪声放大器一体化设计

常规低噪声放大器的设计中,输入输出匹配网络一般不考虑带外抑制的要求,主要考虑的是实现最佳噪声和输出功率匹配,因而带外抑制性能较差。本文研制了一种相控阵雷达T/R组件用滤波低噪声放大器,该放大器通过改进输入输出匹配电路的设计,实现了滤波器和低噪声放大器的一体化,在低噪声放大的同时具有较好的带外抑制作用。采用这种设计将会多个方面改善T/R组件的性能。     

A dual-mode complex filter for GNSS receivers with frequency tuning

A fifth/seventh order dual-mode OTA-C complex filter for global navigation satellite system receivers is implemented in a 0.18 fxm CMOS process. This filter can be configured as the narrow mode of a 4.4 MHz bandwidth center at 4.1 MHz or the wide mode of a 22 MHz bandwidth center at 15.42 MHz. A fully differential OTA with source degeneration is used to provide sufficient linearity. Furthermore, a ring CCO based frequency tuning scheme is proposed to reduce frequency variation. The measured results show that in narrow-band mode the image rejection ratio (IMRR) is 35 dB, the filter dissipates 0.8 mA from the 1.8 V power supply, and the out-of-band rejection is 50 dB at 6 MHz offset. In wide-band mode, IMRR is 28 dB and the filter dissipates 3.2 mA. The frequency tuning error is less than ±2%.     

A 2.4-GHz ring-oscillator-based CMOS frequency synthesizer with a fractional divider dual-PLL architecture

A 2.4-GHz frequency synthesizer was designed that uses a fractional divider to drive a dual-phase-locked-loop (PLL) structure, with both PLLs using only on-chip ring oscillators. The first-stage narrow-band PLL acts as a spur filter while the second-stage wide-band PLL suppresses VCO phase noise so that simultaneous suppression of phase noise and spur is achieved. A new low-power, low-noise, low-frequency ring oscillator is designed for this narrow-band PLL. The chip was designed in 0.35-/spl mu/m CMOS technology and achieves a phase noise of -97 dBc/Hz at 1-MHz offset and spurs of -55 dBc. The chip's output frequency varies from 2.4 to 2.5 GHz; the chip consumes 15 mA from a 3.3-V supply and occupies 3.7 mm/spl deg/.     

Insensitive current-mode universal filter using dual output current conveyors

A new current-mode universal filter with single input and three outputs employing only three dual output current conveyors and five grounded passive elements is presented. The proposed filter realizes three filter functions simultaneously, all at high impedance outputs. No component matching is required and all the passive and active sensitivities are low. Furthermore, the filter can also realize the notch and all-pass responses. Orthogonal control of the natural angular frequency and the quality factor is achieved.     

A Study of the Optimum Design of Wide-Band Parametric Amplifiers and Up-Converters

Single-diode parametric amplifiers or up-converters using multiple-resonator filters as coupling networks can be made to have considerably larger bandwidths than corresponding amplifiers having single-resonator coupling circuits. Data are presented from which the coupling-filter bandwidths required for given coupling network complexity, diode parameters, and required gain can be determined for both parametric amplifiers and up-converters. In the cases of nondegenerate parametric amplifiers and up-converters, the fact that the diode must be brought to resonance at more than one frequency has an added limiting effect on bandwidth. Some trial amplifier designs are shown, and important considerations in the synthesis of the coupling filters are noted. It is seen that for the case upper-sideband up-converters, if a filter having n resonators is used in both the input and upper-sideband circuits, then the over-all response can be made to correspond to that of a filter with 2n resonators. The gain characteristics of the trial amplifier designs as determined with a digital computer are included. Computed responses ranging in bandwidth from 9 to 27 per cent are obtained for multi-resonator designs having C/sub 1// C/sub 0/ = 0.25.     

Some Aspects of the Design of Wide-Band Up-Converters and Nondegenerate Parametric Amplifiers

Proper design of the diode-resonating circuit is seen to be extremely important if large bandwidth is desired in a varactor-diode parametric amplifier. Cases where there is one resonance of the diode-resonating circuit at a frequency between the frequencies of the signal-input and the sideband resonances are examined in some detail. It is shown that the frequency of this intermediate resonance can greatly influence the bandwidth capabilities of an amplifier design, and the optimum frequency for such a resonance is given for upper-sideband up-converters. The optimum frequency of such a resonance is greatly different if the diode is resonated in series than it is if the diode is resonated in shunt. It is believed that the same results would also apply for lower-sideband up-converters and nondegenerate parametric amplifiers. Some upper-sideband up-converter designs were worked out and their computed responses are given including the effects of all of the parasitic elements of the diode. Bandwidths of the order of an octave are obtained. A systematic sign procedure is given for wide-band nondegenerate parametric amplifiers which use the diode parasitic resistance as the idler termination. Some designs of this type were also worked out and their computed responses (includlng effects of all diode parasitic parameters) are presented. Bandwidths as large as 33 per cent are obtained depending on the peak gain and operating frequency range.     

A Waveguide Band-Stop Filter as an Image Rejection Filter for Measurement of Stratospheric Ozone

In this report we present the performance and test observation results of a waveguide band-stop filter (BSF) as an image rejection filter for the measurement of stratospheric ozone. By using the waveguide BSF, we are able to adopt a very simple optical system and achieve a good image rejection ratio. Additionally, we are able to observe in both single sideband (SSB) mode and double sideband (DSB) mode by only changing the local oscillator (LO) frequency. We have installed the waveguide BSF into an atmospheric ozone-measuring system using a superconductive (SIS) receiver and have successfully observed an ozone spectrum at 110 GHz in SSB and DSB mode. The receiver noise temperature (SSB) and the image rejection ratio at 110 GHz are about 60 K and more than 30 dB, respectively. Because of the IF power ripple, the waveguide BSF cannot be used with a wide-band spectrometer. However, it is quite practical for narrow-band observation.     

5～10 GHz MMIC低噪声放大器

采用稳懋公司150 nm GaAs赝配高电子迁移率晶体管(PHEMT)工艺,设计了一款5 ～ 10 GHz单片微波集成电路(MMIC)低噪声放大器(LNA).该LNA采用三级级联结构,且每一级采用相同的偏压条件,电路的低频工作端依靠电容反馈,高频工作端依靠电阻反馈调节阻抗匹配,从而实现宽带匹配,芯片面积为2.5 mm×1 mm.测试结果表明,工作频率为5～10 GHz,漏极电压为2.3V,工作电流为70 mA时,LNA的功率增益达到35 dB,平均噪声温度为82 K,在90％工作频段内输入输出回波损耗优于-15 dB,1 dB压缩点输出功率为10.3 dBm,仿真结果与实验结果具有很好的一致性.     

Analysis, design, and optimization of InGaP-GaAs HBTmatched-impedance wide-band amplifiers with multiple feedback loops

The realization of matched impedance wide-band amplifiers fabricated by InGaP-GaAs heterojunction bipolar transistor (HBT) process is reported. The technique of multiple feedback loops was used to achieve terminal impedance matching and wide bandwidth simultaneously. The experimental results showed that a small signal gain of 16 dB and a 3-dB bandwidth of 11.6 GHz with in-band input/output return loss less than -10 dB were obtained. These values agreed well with those predicted from the analytic expressions that we derived for voltage gain, transimpedance gain, bandwidth, and input and output impedances. A general method for the determination of frequency responses of input/output return losses (or S₁₁, S₂₂) from the poles of voltage gain was proposed. The intrinsic overdamped characteristic of this amplifier was proved and emitter capacitive peaking was used to remedy this problem. The tradeoff between the input impedance matching and bandwidth was also found     

Multimode $G_{m}$– $C$ Channel Selection Filter for Mobile Applications in 1-V Supply Voltage

A CMOS transconductor for multimode channel selection filter is presented. The transconductor includes a voltage-to-current converter and a current multiplier. Voltage-to-current conversion employs linear region MOS transistors, and the conversion features high linearity over a wide input swing range. The current multiplier which operates in the weak inversion region provides a wide transconductance tuning range without degrading the linearity. A third-order Butterworth low-pass filter implemented with the transconductors was designed by TSMC 0.18 mum CMOS process. The measurement results show that the filter can operate with the cutoff frequency of 135 kHz to 2.2 MHz. The tuning range and the linearity performance would be suitable for the wireless specifications of GSM, Bluetooth, cdma2000, and wide-band CDMA. In the design, the maximum power consumption at the highest cutoff frequency is 2 mW under a 1-V supply voltage.     

Wide-band amplifiers for television

The maximum uniform amplification that can be secured over a wide frequency band by means of a single vacuum tube is much greater than that of the usual simple circuits. It can be secured by either of two arrangements, one using an individual filter coupling each tube to the next, and the other using degenerative feedback in each stage to make the stage behave as a section of a confluent filter. In either case, the shunt capacitance on each side of each tube is included in an individual full-shunt arm of a band-pass or low-pass filter. One end of each interstage filter, or of each filter including one or more feedback stages, is extended to a dead-end termination with resistance approximately matching the image impedance. The other end is terminated at one of the tubes in a full-shunt arm, where the filter presents the maximum uniform impedance that can be built up across the tube capacitance. These concepts in terms of wave filters lead to practical wide-band circuits adapted to meet any given requirements. The following general formula is shown to express the maximum uniform amplification that can be secured in one tube: A = gm/πfw√CgCpin which A is the voltage ratio between input and output circuits of equal impedance, gmis the transconductance of the tube, Cgand Cpare the grid and plate capacitance of the tube, and fwis the width of the frequency band.     

一种采用有源电感的可调增益小面积超宽带低噪声放大器

设计了一款采用可调谐有源电感（TAI）的可调增益的小面积超宽带低噪声放大器(LNA),输入级采用共基极结构,输出级采用射随器结构,分别实现了宽带输入和输出匹配;放大级采用带有反馈电阻的共射共基结构以取得宽的带宽,并采用TAI作负载,通过调节TAI的多个外部偏压使LNA的增益可调。结果表明,该LNA在2~9GHz的频带内,通过组合调节有源电感调节端口的偏压可实现S21在16.5~21.1dB的连续可调;S11小于-14.7dB;S22小于-19.3dB;NF小于4.9dB;芯片面积仅为0.049mm2。     

基于悬置线双模谐振器谐波控制型滤波功放

为了实现高效率的射频滤波功率放大器（filtering power amplifier）,将基于悬置线的截线加载谐振器（stub-loaded resonator）带通滤波器的输入阻抗直接匹配到射频功放管CGH40010F的最佳基波阻抗和谐波阻抗,实现射频功率放大器与滤波器的联合设计,使滤波器同时实现了滤波、阻抗匹配和谐波控制的功能,避免了额外的输出匹配结构,实现了结构紧凑、具有滤波功能的高效率谐波控制型射频功放.实测结果表明在中心频率2.45GHz处,其输出功率约为40dBm,最大电源附加效率（power added efficiency）为76.9%,同时具有良好的滤波特性.     

CMOS active-LC bandpass filters with coupled-inductor Q-enhancement and center frequency tuning

A novel CMOS circuit for obtaining a bandpass response from a triple-coupled-inductor arrangement is presented, featuring Q-enhancement and center frequency tuning by means of vector-modulating a current flowing through one of the coupled inductors. A 0.35-/spl mu/m CMOS LC filter prototype employing the technique has been fabricated and exhibits a center frequency tuning range of 11% around 1 GHz and Q values up to 180. The input 1-dB compression point is -13 dBm with Q set to 20 and a power consumption of 12.2 mW. Additionally, an input impedance matching scheme around a spiral transformer is presented, which tracks the center frequency of the filter. The active-LC approach can be applied to higher order filter responses and find applications in tunable building blocks for agile RF front ends and multistandard radios.     

On Bounds of Shift Variance in Two-Channel Multirate Filter Banks

Critically sampled multirate FIR filter banks exhibit periodically shift variant behavior caused by nonideal antialiasing filtering in the decimation stage. We assess their shift variance quantitatively by analysing changes in the output signal when the filter bank operator and shift operator are interchanged. We express these changes by a so-called commutator. We then derive a sharp upper bound for shift variance via the operator norm of the commutator, which is independent of the input signal. Its core is an eigensystem analysis carried out within a frequency domain formulation of the commutator, leading to a matrix norm which depends on frequency. This bound can be regarded as a worst case instance holding for all input signals. For two channel FIR filter banks with perfect reconstruction (PR), we show that the bound is predominantly determined by the structure of the filter bank rather than by the type of filters used. Moreover, the framework allows to identify the signals for which the upper bound is almost reached as so-called near maximizers of the frequency-dependent matrix norm. For unitary PR filter banks, these near maximizers are shown to be narrow-band signals. To complement this worst-case bound, we derive an additional bound on shift variance for input signals with given amplitude spectra, where we use wide-band model spectra instead of narrow-band signals. Like the operator norm, this additional bound is based on the above frequency-dependent matrix norm. We provide results for various critically sampled two-channel filter banks, such as quadrature mirror filters, PR conjugated quadrature filters, wavelets, and biorthogonal filters banks.     

S波段大功率、高效率GaN HEMT器件研究

基于国产的SiC衬底GaN外延材料,研制出大栅宽GaN HEMT单胞管芯。通过使用源牵引和负载牵引技术仿真出所设计模型器件的输入输出阻抗,推导出本器件所用管芯的输入输出阻抗。使用多节λ/4阻抗变换线设计了宽带Wilkinson功率分配/合成器,对原理图进行仿真,优化匹配网络的S参数,对生成版图进行电磁场仿真,通过LC T型网络提升管芯输入输出阻抗。采用内匹配技术,成功研制出铜-钼-铜结构热沉封装的四胞内匹配GaN HEMT。在频率为2.7～3.5 GHz、脉宽为3 ms、占空比为50%、栅源电压Vgs为-3 V和漏源电压Vds为28 V下测试器件,得到最大输出功率Pout大于100 W(50 dBm),PAE大于47%,功率增益大于13 dB。     

声表面波器件输入及输出负载阻抗匹配研究

针对声表面波器件测量中网络分析仪的负载阻抗与射频传输线特性阻抗不匹配,导致传输线上反射波幅值较大的问题,提出一种减少传输线上反射波的负载阻抗匹配系统与方案。负载阻抗匹配方案针对声表面波器件测量中输入与输出端分别设计不同的无源负载阻抗匹配网络,使输入输出端同时达到匹配状态。负载阻抗匹配系统集成了未匹配通道与匹配通道,根据负载阻抗不同调整匹配参数。对一个中心频率为101.764MHz,带宽为30MHz的声表面波器件使用该匹配方案前后中心频率处的衰减进行测量对比,实验结果表明采用该匹配方案后在中心频率点处输入及输出反射损耗分别为-49.36dB和-38.13dB,比未采用匹配方案时分别减少了44.99dB和29.44dB。     

Approximate band-pass limiter envelope distributions

An approximate distribution is computed for the envelope of sine wave plus noise after passage through a wide-band filter, limiter, and narrow-band filter. It is shown that as the input bandwidth to the limiter increases, the output envelope distribution converges to the usual sine wave in noise envelope distribution, without limiting, but with a definite1.04db loss. First-order correction terms are supplied which make it possible to compute first-order statistics for the output envelope when the output signal-to-noise ratio is on the order of one.