Design of active phase shifters based on multichannelheterojunction field effect transistors (MCHFET's)

Design criteria of active phase shifters based on GaAs/AlGaAs multichannel (MC) HFET in the frequency range 4-60 GHz are presented. The phase characteristics of MCHFET devices were studied using the computer aided design program TOUCHSTONE. The dependence of transmission phase on various intrinsic elements in the equivalent circuit model as a function of control gate bias was also studied. There are limited gate bias ranges which correspond to the active regions of the two conducting wells for which a quasi-linear continuous phase shift for analog applications was achieved. Continuously varying the gate bias from V_gs=-1.9 V to V_gs=-0.6 V results in a quasilinear phase shift of 10°, 15°, 21°, and 29° at f=12, 20, 30, and 60 GHz, respectively. Similarly, varying the gate bias from V_gs =-0.4 V to V_gs=0.7 V a quasi-linear phase shift of 21°, 26°, 27°, and 23° at f=12, 20, 30, and 60 GHz, respectively, was achieved. The gain variation was less than 3 dB in these bias regions. With digital applications in mind, a maximum differential phase shift of around 50° was obtained by switching the gate bias discretely. The transmission phase of single gate MCHFET mostly depends on variation of gate source capacitance with gate bias rather than on other intrinsic elements. The dependence of phase shift on various geometrical and structural parameters is also presented. To test the practicality of the device, other scattering parameters (e.g., S₁₁, S₂₂, S₁₂) and the noise figure (NF) were finally studied     

Correction technique for on-chip modulation response measurementsof optoelectronic devices

A new and accurate error correction technique for on-chip intensity modulation response measurements of high-frequency optoelectronic devices is presented. Mathematical expressions for the different sources of errors that exist in the measurement system are derived. The new correction technique applied to the modulation response measurement of a strained quantum well laser diode shows excellent agreement with the theoretically expected result. Simulation results for a small-signal circuit model of the laser diode show excellent agreement with the measured input reflection coefficient S₁₁ and the modulation response S₂₁. With the corrected modulation response measurement, more accurate parameters for this model are extracted     

A microwave oscillation loop for dielectric constant measurement

We designed and analyzed a microwave oscillation loop formed by a dielectric loaded cavity, amplifiers and transmission lines for the dielectric constant measurement of samples at both room and very high temperature. An oscillation condition for an arbitrary loop is derived in S-parameter notation, by which the commonly used oscillation condition in loop phase and gain notation is proved to be valid only in the special case when either S₁₁=S₂₁=0 or S₂₂ =S₁₂=0. Based on the S-parameter oscillation condition, a theoretical model is established and verified with a discrepancy of less than 0.041% between the calculated and the measured oscillation frequencies. With this model, the loop characteristics are investigated. From the measured loop oscillation frequency, the cavity resonant frequency, and thereby the dielectric constant of the sample in the cavity, can be predicted. Based on this analysis, an active dielectrometer is constructed with resultant errors of less than 4% for ϵ'<20 and less than 11% for ϵ'<80. This dielectrometer requires no tuning and no external microwave power source. Moreover, a high power (>100 W) oscillation loop for the dielectric constant measurement of a microwave heated sample (1000°C) is developed     

基于新型蝶形单元结构人工表面等离子体激元低通陷波滤波器的设计

为降低滤波器的插入损耗以及实现滤波器的小型化,该文提出一种新型具有陷波功能的人工表面等离子体激元(SSPPs)低通滤波器,该滤波器主要由新型蝶形单元结构、过渡结构以及用于实现陷波功能的叉指电容环路谐振器(IDCLLR)结构组成。新型蝶形单元结构是由一个椭圆形贴片向左右方向旋转30°构成,经过镂空处理后可以显著降低插入损耗,相比传统的矩形和椭圆形结构具有更好的色散特性,大大提高了滤波器的带内的平坦度和带外抑制能力。该文对矩形、椭圆形、梯形以及新型蝶形等不同单元结构的色散曲线进行了分析,并仿真分析了滤波器的S₂₁和S₁₁曲线,验证了新型蝶形单元结构在色散特性、插入损耗、低截止频率和带外抑制方面所具有的优势。最后,对该滤波器进行了加工和测试,测试结果表明,该滤波器仿真结果和测试结果吻合较好,表现出较好的带外抑制和带内平坦度,可以实现对特定干扰频段陷波抑制。滤波器尺寸为0.98λ₀×0.17λ₀。该人工表面等离子体激元滤波器从设计新型单元结构的角度出发,实现了良好性能的同时,实现了滤波器的小型化。     

A Ka-Band CMOS Wilkinson Power Divider Using Synthetic Quasi-TEM Transmission Lines

This work presents a Ka-band two-way 3 dB Wilkinson power divider using synthetic quasi-transverse electromagnetic (TEM) transmission lines (TLs). The synthetic quasi-TEM TL, also called complementary-conducting-strip TL (CCS TL), is theoretically analyzed. The equivalent TL model, whose production is based on the extracted results, is applied to the power divider design. The prototype is fabricated by the standard 0.18 mum 1P6M CMOS technology, showing the circuit size of 210.0 mumtimes390.0 mum without contact pads. The measurement results, which match the 50 Omega system, reveal perfect agreements with those of the simulations. The comparison reveals the following characteristics. The divider exhibits an equal power-split with the insertion losses (S₂₁ and S₃₁) of 3.65 dB. The return losses (S₁₁, S₂₂ and S₃₃) of the prototype are higher than 10.0 dB from 30.0 to 40.0 GHz.     

A Compact, ESD-Protected, SiGe BiCMOS LNA for Ultra-Wideband Applications

Two 3.65-mW, ESD-protected, BiCMOS ultra-wideband low-noise amplifiers (LNAs) for operation up to 10 GHz are presented. These common-base LNAs achieve significant savings in die area over more widely used cascoded common-emitter LNAs because they do not use an LC input matching network. A design with a shunt peaked load achieves a high S₂₁ (17-19 dB) and low noise figure (NF) (4-5 dB) across the band. A resistively loaded design exhibits a lower S₂₁ (15-16 dB) and higher NF (4.5-6 dB), but also utilizes 20% less silicon area. Both LNAs achieve a 1.5 kV ESD protection level and an acceptable S₁₁ (<-10 dB) across the band. Current source noise reduction is critical in common base topologies. Therefore, detailed noise analyses of MOS- and HBT-based current sources are provided     

微波双工器电路综合

近年微波滤波器多项式综合技被广泛用于微波滤波器的设计,将此技术由双端口网络推广至三端口网络可以实现微波双工器的综合。根据微波网络技术,可以推导得到微波双工器电路等效y参数与S参数的关系,进而得到微波双工器散射参数s11,s21,s31与两个通道单通带微波滤波器散射参数s11,s21的关系。应用推广后的微波双工器电路综合技术可以实现微波双工器的精确、快速综合。经过对比发现,微波双工器多项式综合结果与微波双工器电路建模仿真响应吻合度很好。     

Comments on “A deterministic approach for designingconditionally stable amplifiers”

For original paper see M.L. Edwards et al., ibid., vol.43, no.7, pp.1567-75 (July 1995). In the above paper, the authors presented a careful analysis of single-sided matched conditionally stable amplifiers. In particular, they determined a maximum single-sided matched gain G_msm which is reached for passive jointly stable source (load) terminations G_msm=2 kG_ms where k is the Rollett's stability factor and G_ms=|S₂₁/S₁₂| is the maximum stable gain of device. However, at least some of the results presented in the above paper can be found in other literature. In this paper, I would like to outline the formerly published papers treating conditionally stable amplifiers in terms of the scattering parameters. A reply by the original authors is included     

Temperature analysis and characteristics of highly strainedInGaAs-GaAsP-GaAs (λ > 1.17 μm) quantum-well lasers

Characteristic temperature coefficients of the threshold current (T₀) and the external differential quantum efficiency (T₁) are studied as simple functions of the temperature dependence of the physical parameters of the semiconductor lasers. Simple expressions of characteristic temperature coefficients of the threshold current (T₀) and the external differential quantum efficiency (T₁) are expressed as functions as physical parameters and their temperature dependencies. The parameters studied here include the threshold (J_th) and transparency (J_tr ) current density, the carrier injection efficiency (η_inj ) and external (η_d) differential quantum efficiency, the internal loss (α_i), and the material gain parameter (g_o). The temperature analysis is performed on low-threshold current density (λ = 1.17-1.19 μm) InGaAs-GaAsP-GaAs quantum-well lasers, although it is applicable to lasers with other active-layer materials. Analytical expressions for T ₀ and T₁ are shown to accurately predict the cavity length dependence of these parameters for the InGaAs active lasers     

First demonstration of monolithic InP-based HBT amplifier with PNPactive load

An InP-based integrated HBT amplifier with PNP active load was demonstrated for the first time using complementary HBT technology (CRBT). Selective molecular beam epitaxy (MBE) regrowth was employed and a merged processing technology was developed for the monolithic integration of InP-based NPN and PNP HBTs on the same chip. The availability of PNP devices allowed design of high gain amplifiers with low power supply voltage. The measured amplifier with PNP HBT active load achieved a voltage gain of 100 with a power supply (V_CC) of 1.5 V. The corresponding voltage swing was 0.9 V to 0.2 V. The amplifier also demonstrated S₂₁ of 7.8 dB with an associated S₁₁ and S₂₂ of -9.5 dB and -8.1 dB, respectively, at 10 GHz     

Efficient detection of resonances in anechoic chambers using thematrix pencil method

In a previous paper we have presented a method for evaluating the performance of anechoic chambers by analyzing the S-parameters of a system comprising two antennas facing each other in an anechoic chamber using the matrix pencil method. In this work, we present an improvement of this resonance detection technique using only the transmission parameter S₂₁. The propagating components of the transmission parameter S₂₁ are derived over small frequency intervals using the matrix pencil method and then removed from S₂₁ in a two-level decomposition procedure. The resonances are clearly identified from the residual signal. Two examples of resonance detection in two different anechoic chambers illustrate the proposed method     

0.18 μm 21-27 GHz CMOS UWB LNA with 9.3 ± 1.3 dB gain and 103.9 ± 8.1 ps group delay

A 21-27 GHz CMOS ultra-wideband low-noise amplifier (UWB LNA) with state-of-the-art phase linearity property (group delay variation is only ± 8.1 ps across the whole band) is reported for the first time. To achieve high and flat gain (S₂₁) and small group delay variation at the same time, the inductive series peaking technique was adopted in the output of each stage for bandwidth enhancement. The LNA dissipated 27 mW power and achieved input return loss (S₁₁) of 213 to 220.1 dB, output return loss (S₂₂) of 28.2 to 230.2 dB, flat S21 of 9.3 ± 1.3 dB, reverse isolation (S₁₂) of 252.7 to 273.3 dB, and noise figure of 4.9?6.1 dB over the 21-27 GHz band of interest. The measured 1 dB compression point (P_1dB) and input third-order intermodulation point (IIP3) were 214 and 24 dBm, respectively, at 24 GHz.     

Analytical design of 3-D wavelet filter banks using themultivariate Bernstein polynomial

The design of 3-D multirate filter banks where the downsampling/upsampling is on the FCO (face centred orthorhombic) lattice is addressed. With such a sampling lattice, the ideal 3-D sub-band of the low-pass filter is of the TRO (truncated octahedron) shape. The transformation of variables has been shown previously to be an effective technique for designing M-D (multidimensional) filter banks. A design technique is presented for the transformation function using the multivariate Bernstein polynomial which provides a good approximation to the TRO sub-band shape. The method is analytically based and does not require any optimisation procedure. Closed form expressions are obtained for the filters of any order. Another advantage of this technique is that it yields filters with a flat frequency response at the aliasing frequency (ω₁, ω₂ , ω₃)=(π, π, π). This flatness is important for giving regular discrete wavelet transform systems     

Polarized light scattering: a biophysical method for studyingbacterial cells

The authors outline a method which uses differentially polarized light scattering to study the properties of bacterial cell suspensions, i.e., spores of Bacillus Subtilis. The identification of bacterial cells of different strains, with and without plasmid insertion, was performed by means of differential polarization light scattering (DPLS). The samples displayed distinct angular behaviors for the S₁₄ and S₃₄ normalized scattering parameters of the Mueller matrix depending on the strain and on a plasmid insertion in the chromosomal unit. These experiments, performed blindly, point out the possibility of achieving real time identification of micro-organisms by DPLS spectrometry     

A 60-dB gain, 55-dB dynamic range, 10-Gb/s broad-band SiGe HBTlimiting amplifier

A limiting amplifier IC implemented in a silicon-germanium (SiGe) heterojunction bipolar transistor technology for low-cost 10-Gb/s applications is described. The IC employs 20 dB gain limiting cells, input overload protection, split analog-digital grounds, and on-chip isolation interface with transmission lines. A gain enhancement technique has been developed for a parallel-feedback limiting cell. The limiting amplifier sensitivity is less than 3.5 mV_pp at BER=10^-9 with 2-V_pp maximum input (55-dB dynamic range). The total gain is over 60 dB, and S₂₁ bandwidth exceeds 15 GHz at 10-mV_pp input. Parameters S₁₁ and S₂₂ are better than -10 dB in the 10-GHz frequency range. The AM to PM conversion is less than 5 ps across input dynamic range. The output differential voltage can be set from 0.2 to 2 V_pp with IC power dissipation from 250 mW to 1.1 W. The chip area is 1.2×2.6 mm². A 10-Gb/s optical receiver, built with the packaged limiting amplifier, demonstrated -19.6-dBm sensitivity. The IC can be used in 10-Gb/s fiber-optic receivers requiring high sensitivity and wide input dynamic range     

Fabrication and Characteristics of 40-Gb/s Traveling-Wave Electroabsorption Modulator-Integrated DFB Laser Modules

We have developed 40-Gb/s traveling-wave electroabsorption-modulator-integrated distributed feedback laser (TW-EML) modules using several advanced technologies. First, we have adopted a selective area growth (SAG) method in the fabrication of the 40-Gb/s EML device to provide active layers for the laser and the electroabsorption modulators (EAMs) simultaneously. The fabricated device shows that the measured 3-dB bandwidth of electrical-to-optical (E/O) response reaches about 45 GHz and the return loss (S₁₁) is kept below -10 dB up to 50 GHz. For the module design of the device, we mainly considered electrical and optical factors. The measured S₁₁ of the fabricated 40 Gb/s TW-EML module is below -10 dB up to about 30 GHz and the 3-dB bandwidth of the E/O response reaches over 35 GHz. We also have developed two types of coplanar waveguide (CPW) for the application of the driver amplifier integrated 40 Gb/s TW-EML module, which is a system-on-package (SoP) composed of an EML device and a driver amplifier device in a module. The measured S₁₁ of the two-step-bent CPW is below -10 dB up to 35 GHz and the measured S₁₁ of the parallel type CPW is below -10 dB up to 39 GHz.     

Beam-cavity interaction circuit at W-band

In this paper, we describe the design, fabrication, and bench study of a millimeter-wave cavity employed as a relativistic klystron output structure. The oxygen-free electronic-grade copper cavity was prepared by electro-discharge machining and diffusion bonding, and cleaned and tuned to 91.4 GHz. Measured cavity characteristics are presented and compared with theory, including quality factor Q, coupling parameter β, scattering matrix S₁₁, and axial electric field profile E_z. This paper provides the basis for an understanding of the cavity as a transfer structure     

Broad-band simultaneous measurement of complex permittivity andpermeability using a coaxial discontinuity

A technique for simultaneously measuring the real and imaginary parts of both the permittivity and the permeability of a given material is discussed. A gap in a coaxial line is filled with the material under test. Complex permittivity and permeability are computed from the S-parameter (S₁₁ and S₂₁) measurement made on the gap, taking into account higher-order modes excited at the discontinuity. Measured ϵ_r and μ_r data for several materials are presented from 45 MHz up to 18 GHz. This technique shows good agreement between calculated and generally accepted values     

Experimental analysis of temperature dependence of oscillationwavelength in quantum-well FP semiconductor lasers

We experimentally evaluated the temperature dependence of the oscillation wavelength in 1.3-μm GaInAsP-InP strained multiple-quantum-well (MQW) semiconductor lasers compared to bulk lasers. The temperature dependence of the oscillation wavelength can be characterized by two newly introduced coefficients α₁ and α₂ which are the gain peak wavelength shift coefficients under the constant current condition and under the constant temperature condition, respectively. These two coefficients of various MQW structure lasers are the same as those of bulk lasers. This result means that the oscillation wavelength shift coefficient dλ/dT is only a function of the characteristic temperature T₀. The higher T₀ induces the large temperature dependence of the oscillation wavelength, When the characteristic temperature T₀ is equal to the characteristic temperature T_ltr of the transparency current I_tr, the oscillation wavelength shift coefficient dλ/dT takes the maximum value which is determined by the thermally induced bandgap narrowing effect dλ _g/dT. One possibility to solve the paradox between a high characteristic temperature T₀ and the small temperature dependence of the oscillation wavelength is the introduction of the temperature-independent leakage current