The application of flip-chip bonding interconnection technique on the module assembly of 10 Gbps laser diode

Flip chip bonding technique using Pb/In solder bumps was applied to packaging of a 10 Gbps laser diode (LD) submodule for high speed optical communication systems. The effect of the flip-chip bonding interconnection technique instead of conventional wire bonding was investigated for high speed broad band devices. The broad band performance of 10 Gbps LD submodule was simulated using SPICE S/W and compared with experimental results. In this simulation, the 10 Gbps LD was modeled in a parallel RC circuit. The values of R and C used for the equivalent circuit were 5ω and 1 pF, respectively. The LD was placed in series with a 18ω thin film resistor to prevent the impedance mismatch between the LD and a 25ω transmission line. The dependence of parasitic parameters on the small signal modulation bandwidth and the scattering parameters of the LD submodule was investigated and analyzed up to 20 GHz. A small signal modulation bandwidth of 14 GHz at 10 mA dc bias current and the clean modulation response up to 20 GHz were found for the flip-chip bonded submodule. The bandwidth of flip-chip bonded 10 Gbps LD submodule is wider than that of the wire-bonded LD submodule by a difference of 3.8 GHz.     

Compact Tunable Left Handed Ferrite Transformer

In this paper, a novel compact and tunable impedance transmission line transformer is presented for the first time. The transformer is designed using a left handed coplanar waveguide transmission line on a ferrite substrate. Based on the dispersive properties of the ferrite medium, the theoretical study of the transformer has been carried out using its equivalent circuit analysis and the composite right / left handed transmission line theory. The theoretical study was verified through full wave electromagnetic numerical simulations. The results show that the transformer matches a 25 Ω load to a 50 Ω line with tunability from 2.55 GHz to 3.2 GHz. The return loss at center frequency is better than 20 dB with insertion loss better than -1 dB. The transformer has a very compact size with dimensions of 4.25 × 21 mm², showing approximately 64% reduction in size in comparison with a conventional right-handed transformer within the same operating frequency band. Moreover, the proposed coplanar waveguide transformer configuration has smaller demagnetization factor and hence it requires smaller DC magnetic bias values compared to microstrip configuration.     

An Equivalent Circuit Model for Broadband Modified Rectangular Microstrip-Fed Monopole Antenna

A new, simple equivalent circuit model for designing a multi-mode/broadband modified rectangular microstrip-fed monopole antennas using stepped cut at four corners (SCFC) method has been presented in this paper. The SCFC method is a method in which the four corners at the edges of the patch are cut for the purpose of designing the microstrip-fed monopole antenna. The design procedure of a single mode to a broadband microstrip-fed monopole antenna is explained in order to help understand more about the proposed equivalent circuit model and SCFC method. The computer simulation technology (CST) microwave studio and advanced design system (ADS) software are used to design and simulate of the proposed microstrip-fed monopole antennas and their equivalent circuit model, respectively. The operating bandwidth of the broadband antenna with \(\hbox {S}_{11}< -10\) dB, covers the operating frequency range from 0.9 to 2.6 GHZ that it is suitable for GSM (0.9 GHz), WiFi (2.4 GHz) and LTE (2.6 GHz) applications. For the purpose of validating the simulated results, the antennas prototype has been fabricated and measured. The comparison of the measurement and simulation results shows that, there is a good agreement between them.     

A broadband and compact asymmetrical backward coupled-line coupler with high coupling level

A new wideband asymmetric microstrip coupled-line coupler with 3 dB coupling value and quadrature phase difference is presented. Compared with the conventional edge-coupled couplers, this structure, consisting of two different transmission lines (interdigital and conventional microstrip transmission lines) as coupled lines, achieves wider operating bandwidth and larger coupling level. The coupled-line length of the proposed structure is approximately λ_g/4. To characterize the structure, an equivalent circuit model has been established. A 3 dB designed and fabricated coupler with 0.2 mm spacing between coupled lines exhibits an amplitude balance of 2 dB from 2.2 GHz to 4.2 GHz. Good agreements between the full-wave simulation and equivalent circuit model results has been achieved and verified the effectiveness of the proposed circuit model. Also, measurement results have been presented.     

Parametric Simulation and Optimization of Cold-test Properties for a 220 GHz Broadband Folded Waveguide Traveling-wave Tube

Characterized with full-metal structure, high output power and broad bandwidth, microfabricated folded waveguide is considered as a robust slow-wave structure for millimeter wave traveling-wave tubes. In this paper, cold-test (without considering the real electron beam) properties were studied and optimized by 3D simulation on slow-wave structure, for designing a 220 GHz folded waveguide traveling-wave tube. The parametric analysis on cold-test properties, i.e., phase velocity, beam-wave interaction impedance and cold circuit attenuation, were conducted in half-period circuit with high frequency structure simulator, assisted by analytical model and equivalent circuit model. Through detailed parametric analyses, interference between specified structural parameters is found on determining beam-wave interaction impedance. A discretized matrix optimization for interaction impedance was effectively carried out to overcome the interference. A range of structural parameters with optimized interaction impedance distributions were obtained. Based on the optimized results, a broadband folded waveguide with cold pass-band of about 80 GHz, flat phase velocity dispersion and fairly high interaction impedance was designed for a 220 GHz central frequency traveling-wave tube. A three-dB bandwidth of 20.5 GHz and a maximum gain of 21.2 dB were predicted by small signal analysis for a 28 mm-long lossy circuit.     

Design of a Compact Ka-band Balanced Mixer Based on a Novel Wide-band Equivalent Circuit of the Schottky Diode

A compact Ka-band balanced mixer based on a novel Schottky diode model is presented in this paper. According to its physical structure, a novel 3D electromagnetic model of the Schottky diode is proposed. Meanwhile, a wide-band equivalent circuit is built, which takes all high frequency effects existing in the diode into account. All the parasitic reactances are extracted from the electromagnetic model-based S-parameters up to 110 GHz. Based on the proposed equivalent circuit, a Ka-band balanced mixer is designed and optimized, where bandpass filters with open stubs and a lowpass filter based on defected ground structure cells are used. The measured results show that the conversion loss is below 9 dB from 30 GHz to 40 GHz with the minimum of 6.7 dB at 35 GHz. The normalized size of the mixer is only 3.3λ _g  × 3.3λ _g , whereλ _g is the wavelength at 35 GHz.     

砷化镓0.25μm PHEMT开关模型研究

借助于传统的FET等效电路模型,给出了0.25μm GaAs PHEMT的开关模型,并在ICCAP和ADS软件中,完成等效电路参数的提取与优化。通过对单刀单掷(SPST)开关的仿真和测试,表明,在0.1～20 GHz的频域内,其"开"态插入损耗误差、端口1和端口2的电压驻波比误差分别小于0.3 dB、0.24和0.19;其"关"态隔离度误差、端口1和端口2的电压驻波比误差分别小于1.9 dB、0.12和0.08。文中得到的PHEMT开关模型将有助于控制类单片集成电路的研究与开发。     

High efficiency microwave rectenna circuit: modelling and design

An equivalent circuit approach used for the modelling of a system consisting of an antenna and an RF/DC rectifying circuit (rectenna) is presented. It is shown that using this approach, no electromagnetic simulation tool is required for the simulation and optimisation of the overall circuit. The realised rectenna operates at 2.45 GHz, and shows very good agreement between the predicted efficiency using the presented model (about 75%) and the measured one.     

六边形环复合吸波超材料性能的等效电路分析方法

该文提出一种针对六边形环复合吸波超材料吸波性能的等效电路分析方法。基于六边形环谐振特性建立了等效电路模型,通过对六边形点阵分布的傅里叶分析,提出了等效分布周期参数,给出了基于模型尺寸的RLC参数提取方法。与全波仿真结果比较,所提出的等效电路模型对分析多种尺寸的六边形环复合吸波材料具有较好的适用性和准确性。通过样品制作和测量,进一步验证了该模型的有效性,最后实现了一款工作于1.7～5.7 GHz的宽带雷达吸波材料。     

Analysis of diodes with a relatively low barrier in the microwave planar mixer

Diodes with a relatively low barrier are investigated in 1D mixer at frequencies of about 94 GHz at a low power of heterodyne. A planar antenna that contains diodes whose differential resistance ranges from 2 to 9 kΩ at zero bias is used for the frequency conversion. The optimal signal output at an intermediate frequency of 700 MHz is reached using transforming circuits that close the diode with respect to direct current and provide the matching of the signal source with an internal resistance of 1 or 2.2 kΩ and a transmission line with an impedance of 50 Ω. The minimum conversion loss (12.5–16 dB) corresponds to the heterodyne power 10–40 μW.     

Enhanced performance in traveling-wave electroabsorption Modulators based on undercut-etching the active-region

A novel traveling-wave electroabsorption modulator (TWEAM) based on undercut-etching-active-region waveguide (UEAW) is proposed and demonstrated. By selectively wet-etching the InGaAsP from InP to reduce InGaAsP active region, the waveguide can reduce parasitic capacitance with high conductivity in n-InP and p-InP cladding layers. In comparison with conventional ridge-waveguide (RW) TWEAM, 3 dB lower optical-insertion-loss, at least 6 dB higher in radio-frequency-link gain (dc to 40 GHz), and faster electrooptical response (3-dB bandwidth of 25 GHz at 50 /spl Omega/-termination for UEAW and 15 GHz for RW) are obtained in UEAW-TWEAM. A 10-Gbs/s operation with low swing voltage of 0.6 V has been achieved in UEAW-TWEAM, a 3.2-dB enhancement over RW-TWEAM. It indicates the tradeoff in designing electroabsorption modulators can be greatly released.     

5 THz混频二极管等效电路模型研究

采用电磁场和电路联合仿真,基于直流测试和三维电磁建模仿真技术,建立了截止频率5 THz的混频肖特基二极管的等效电路模型。重点研究了二极管的非线性结模型和外围结构三维电磁全波仿真模型,构建了考虑实际电路形式的四端口三维电磁全波仿真模型。该等效电路模型可用于太赫兹低频段混频模块设计,该模型的建立方法也为更高频段模型的建立提供了一种参考。基于该模型设计了一款220 GHz分谐波混频器,在192~230 GHz宽带范围内,双边带变频损耗小于10 dB,测试结果与仿真结果较为一致。     

A design-oriented methodology for accurate modeling of on-chip interconnects

An accurate modeling methodology for typical on-chip interconnects used in the design of high frequency digital, analog, and mixed signal systems is presented. The methodology includes the parameter extraction procedure, the equivalent circuit model selection, and mainly the determination of the minimum number of sections required in the equivalent circuit for accurate representing interconnects of certain lengths within specific frequency ranges while considering the frequency-dependent nature of the associated parameters. The modeling procedure is applied to interconnection lines up to 35 GHz obtaining good simulation-experiment correlations. In order to verify the accuracy of the obtained models in the design of integrated circuits (IC), several ring oscillators using interconnection lines with different lengths are designed and fabricated in Austriamicrosystems 0.35 μm CMOS process. The average error between the experimental and simulated operating frequency of the ring oscillators is reduced up to 2% when the interconnections are represented by the equivalent circuit model obtained by applying the proposed methodology.     

垂直腔面发射激光器的小信号电路模型和调制特性

给出了垂直腔面发射激光器的小信号电路模型和调制特性,调制特性用解析计算和电路模型模拟两种方法得到,解析计算和电路模型模拟的结果一致,实验证实了电路模型的正确性.     

Unified SPICE compatible model for large and small-signal envelope simulation of linear circuits excited by modulated signals

The envelope-simulation method, developed earlier for large-signal simulation [time domain (TRAN)] is extended to include small-signal envelope simulation (ac) and dc sweep simulation (steady state for a range of carrier frequencies). The model is derived for amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM) modulation schemes and is demonstrated on a piezoelectric transformer circuit. The model is based on the equivalent circuit approach and can be run on any modern electronic circuit simulator. An excellent agreement was found between the simulation results according to the new unified envelope model, full simulation, and experimental results.     

Modeling and characterization of a 5.2 GHz VCO for UWB applications in 0.13 μm CMOS process

This paper describes a 5.2 GHz voltage-controlled oscillator (VCO) as a key component in RF transceivers. The circuit includes a complementary cross-coupled MOSFET as a negative conductance, beside a tank circuit which consists of an optimal on-chip spiral inductor (L), and an accumulation mode MOS varactor (C(V)). A model for phase noise and figure merit is introduced and verified through simulation in a standard 0.13 μm CMOS process. The VCO core drew a 4.2 mA of current from a 1.2 V power supply and a phase noise of −98.5 dBc/Hz at 1 MHz offset from the 5.2 GHz carrier was calculated. The whole performance of the circuit specifically the tuning range was found to be 26%.     

A monolithic GaAs IC for heterodyne generation of RF signals

An integrated heterodyne signal-generating GaAs chip is reported. This circuit contains: an on-chip local oscillator with external inductors tunable by means of on-chip variable capacitors from 2.1 to 2.5 GHz; a doubly balanced mixer with associated drive circuitry; and an IF preamplifier. The circuit delivers +6 dBm (equivalent 50 Ω) into the designed load impedance of 200 Ω with -30-dBc harmonic distortion over a 1.4-GHz 3-dB bandwidth. Circuit elements presented include: a unique variable-threshold limiter, a self-biasing push-pull oscillator, doubly balanced mixer, and a self-biasing unity-gain phase splitting amplifier.     

A 4 Gsample/s 2 bits flash ADC with 2–4 GHz input bandwidth for radio astronomy applications

This paper presents the design and the measurement results of a high speed A/D converter (ADC or digitizer) developed for radio-astronomy applications and especially for the ALMA (Atacama Large Millimeter Array) project. This monolithic digitizer is implemented in a BiCMOS 0.35 μm SiGe process for high frequency mixed-signal applications. The main characteristics of this circuit are a 2 bits resolution with 3 quantization levels (equivalent to 1.5 bits) with 4 Gsample/s rate, a wide input bandwidth from 2 GHz up to 4 GHz under full Nyquist condition. The adopted digitizer architecture is that of a conventional flash analog to digital converter structure. The overall chip dissipates 652 mW under ± 1.25 V supply and the die area is 5.4 mm².     

Cascaded single-stage distributed amplifier using DPHEMT devices for multioctave performance

This paper describes a multioctave (2–18 GHz) distributed amplifier design using the concept of cascaded reactively terminated single-stage distributed amplifier (CRTSSDA) configuration for EW applications. The concept of CRTSSDA is demonstrated to provide broadband performance with high gain, reduced power consumption, circuit stability and superior power-added efficiency compared to conventional distributed amplifiers using the same number of active devices. The broadband amplifier employing three-CRTSSDA is designed and fabricated using three different DPHEMT devices in the three respective stages of the design to further enhance the amplifier’s efficiency performance. The amplifier achieved an associated gain level above 26 dB with flatness of <± 0.5 dB, an average power-added efficiency in access of 27% at an output power of 25 dBm across 2–18 GHz with an efficiency peak of 30% at 12 GHz. The input and output VSWR of better than 2:1 was achieved. Furthermore, the CRTSSDA provides a cost-effective solution when compared to the conventional travelling wave amplifier as only half the number of active devices is used. Fabrication of the amplifier was carried out by using the conventional thin-film microwave integrated circuit technology. The CRTSSDA is also disposed to realization by monolithic circuit technology.     

An Approach for Extracting Small-Signal Equivalent Circuit of Double Heterojunction δ-Doped PHEMTs for Millimeter Wave Applications

Pseudomorphic high electron mobility transistors (PHEMTs) are very important in millimeterwave application. A simple and accurate method for extracting small-signal equivalent curcuit for Double Heterojunction δ-doped PHEMT valid up to 40GHz is presented. First, the parasitic parameters of the equivalent circuit are determined using pinch off PHEMT except for PAD capacitances. The initial intrinsic elements are then determined by conventional analytical method. Advanced Design System is then used to optimize the whole model parameters with very small dispersion of initial values. Good agreement is obtained between simulation results and measured results for a 0.25um DH PHEMT.